History.

Earlier efforts.

Much of the history of computer language design during the 1960s can be traced to the ALGOL 60 language. ALGOL was developed during the 1950s with the explicit goal to be able to clearly describe algorithms. It included a number of features for structured programming that remain common in languages to this day.  Shortly after its introduction, in 1962 Wirth began working on his dissertation with Helmut Weber on the Euler programming language. Euler was based on ALGOL's syntax and many concepts but was not a derivative. Its primary goal was to add dynamic lists and types, allowing it to be used in roles similar to Lisp. The language was published in 1965.  By this time, a number of problems in ALGOL had been identified, notably the lack of a standardized string system. The group tasked with maintaining the language had begun the ALGOL X process to identify improvements, calling for submissions. Wirth and Tony Hoare submitted a conservative set of modifications to add strings and clean up some of the syntax. These were considered too minor to be worth using as the new standard ALGOL, so Wirth wrote a compiler for the language, which became known as ALGOL W.  The ALGOL X efforts would go on to choose a much more complex language, ALGOL 68. The complexity of this language led to considerable difficulty producing high-performance compilers, and it was not widely used in the industry. This left an opening for newer languages.

Pascal.

Pascal was influenced by the ALGOL W efforts, with the explicit goals of producing a language that would be efficient both in the compiler and at run-time, allow for the development of well-structured programs, and to be useful for teaching students structured programming. A generation of students used Pascal as an introductory language in undergraduate courses.  One of the early successes for the language was the introduction of UCSD Pascal, a version that ran on a custom operating system that could be ported to different platforms. A key platform was the Apple II, where it saw widespread use. This led to the use of Pascal becoming the primary high-level language used for development in the Apple Lisa, and later, the Macintosh. Parts of the original Macintosh operating system were hand-translated into Motorola 68000 assembly language from the Pascal sources.  The typesetting system TeX by Donald E. Knuth was written in WEB, the original literate programming system, based on DEC PDP-10 Pascal. Successful commercial applications like Adobe Photoshop were written in Macintosh Programmer's Workshop Pascal, while applications like Total Commander, Skype and Macromedia Captivate were written in Delphi (Object Pascal). Apollo Computer used Pascal as the systems programming language for its operating systems beginning in 1980.  Variants of Pascal have also been used for everything from research projects to PC games and embedded systems. Newer Pascal compilers exist which are widely used.

Object Pascal.

During work on the Lisa, Larry Tesler began corresponding with Wirth on the idea of adding object oriented extensions to the language. This led initially to Clascal, introduced in 1983. As the Lisa program faded and was replaced by the Mac, a further version known as Object Pascal was created. This was introduced on the Macintosh in 1985 as part of the MacApp application framework, and became Apple's primary development language into the early 1990s.  The Object Pascal extensions were added to Turbo Pascal with the release of version 5.5 in 1989. Over the years, Object Pascal became the basis of the Delphi system for Microsoft Windows, which is still used for developing Windows applications, and can cross-compile code to other systems. Free Pascal is an open source, cross-platform alternative.

Implementations.

Early Pascal compilers.

The first Pascal compiler was designed in Zürich for the CDC 6000 series mainframe computer family. Niklaus Wirth reports that a first attempt to implement it in Fortran in 1969 was unsuccessful due to Fortran's inadequacy to express complex data structures. The second attempt was implemented in a C-like language (Scallop by Max Engeli) and then translated by hand (by R. Schild) to Pascal itself for boot-strapping. It was operational by mid-1970. Many Pascal compilers since have been similarly self-hosting, that is, the compiler is itself written in Pascal, and the compiler is usually capable of recompiling itself when new features are added to the language, or when the compiler is to be ported to a new environment. The GNU Pascal compiler is one notable exception, being written in C.  The first successful port of the CDC Pascal compiler to another mainframe was completed by Welsh and Quinn at the Queen's University of Belfast (QUB) in 1972. The target was the ICL 1900 series. This compiler, in turn, was the parent of the Pascal compiler for the Information Computer Systems (ICS) Multum minicomputer. The Multum port was developed – with a view to using Pascal as a systems programming language – by Findlay, Cupples, Cavouras and Davis, working at the Department of Computing Science in Glasgow University. It is thought that Multum Pascal, which was completed in the summer of 1973, may have been the first 16-bit implementation.  A completely new compiler was completed by Welsh et al. at QUB in 1977. It offered a source-language diagnostic feature (incorporating profiling, tracing and type-aware formatted postmortem dumps) that was implemented by Findlay and Watt at Glasgow University. This implementation was ported in 1980 to the ICL 2900 series by a team based at Southampton University and Glasgow University. The Standard Pascal Model Implementation was also based on this compiler, having been adapted, by Welsh and Hay at Manchester University in 1984, to check rigorously for conformity to the BSI 6192/ISO 7185 Standard and to generate code for a portable abstract machine.  The first Pascal compiler written in North America was constructed at the University of Illinois under Donald B. Gillies for the PDP-11 and generated native machine code.

The Pascal-P system.

To propagate the language rapidly, a compiler "porting kit" was created in Zürich that included a compiler that generated so called p-code for a "virtual" stack machine, i.e., code that lends itself to reasonably efficient interpretation, along with an interpreter for that code – the "Pascal-P" system. The P-system compilers were named Pascal-P1, Pascal-P2, Pascal-P3, and Pascal-P4. Pascal-P1 was the first version, and Pascal-P4 was the last to come from Zürich. The version termed Pascal-P1 was coined after the fact for the many different sources for Pascal-P that existed. The compiler was redesigned to enhance portability, and issued as Pascal-P2. This code was later enhanced to become Pascal-P3, with an intermediate code backward compatible with Pascal-P2, and Pascal-P4, which was not backward compatible.  The Pascal-P4 compiler–interpreter can still be run and compiled on systems compatible with original Pascal. However, it only accepts a subset of the Pascal language.  Pascal-P5, created outside the Zürich group, accepts the full Pascal language and includes ISO 7185 compatibility.  UCSD Pascal branched off Pascal-P2, where Kenneth Bowles used it to create the interpretive UCSD p-System. It was one of three operating systems available at the launch of the original IBM Personal Computer. UCSD Pascal used an intermediate code based on byte values, and thus was one of the earliest "byte code compilers". Pascal-P1 through Pascal-P4 was not, but rather based on the CDC 6600 60-bit word length.  A compiler based on the Pascal-P4 compiler, which created native binaries, was released for the IBM System/370 mainframe computer by the Australian Atomic Energy Commission; it was named the "AAEC Pascal Compiler" after the abbreviation of the name of the commission.

Object Pascal and Turbo Pascal.

Apple Computer created its own Lisa Pascal for the Lisa Workshop in 1982, and ported the compiler to the Apple Macintosh and MPW in 1985. In 1985 Larry Tesler, in consultation with Niklaus Wirth, defined Object Pascal and these extensions were incorporated in both the Lisa Pascal and Mac Pascal compilers.  In the 1980s, Anders Hejlsberg wrote the Blue Label Pascal compiler for the Nascom-2. A reimplementation of this compiler for the IBM PC was marketed under the names Compas Pascal and PolyPascal before it was acquired by Borland and renamed "Turbo Pascal".  Turbo Pascal became hugely popular, thanks to an aggressive pricing strategy, having one of the first full-screen IDEs, and very fast turnaround time (just seconds to compile, link, and run). It was written and highly optimized entirely in assembly language, making it smaller and faster than much of the competition.  In 1986, Anders ported Turbo Pascal to the Macintosh and incorporated Apple's Object Pascal extensions into Turbo Pascal. These extensions were then added back into the PC version of Turbo Pascal for version 5.5. At the same time Microsoft also implemented the Object Pascal compiler. Turbo Pascal 5.5 had a large influence on the Pascal community, which began concentrating mainly on the IBM PC in the late 1980s. Many PC hobbyists in search of a structured replacement for BASIC used this product. It also began to be adopted by professional developers. Around the same time a number of concepts were imported from C to let Pascal programmers use the C-based API of Microsoft Windows directly. These extensions included null-terminated strings, pointer arithmetic, function pointers, an address-of operator and unsafe typecasts.  Turbo Pascal, and other derivatives with units or module concepts are modular languages. However, it does not provide a nested module concept or qualified import and export of specific symbols.

Other variants.

Super Pascal is a variant that added non-numeric labels, a return statement and expressions as names of types.  TMT Pascal was the first Borland-compatible compiler for 32-bit DOS protected mode, OS/2 and Win32 operating systems. The TMT Pascal language was the first one to allow function and operator overloading.  The universities of Wisconsin-Madison, Zürich, Karlsruhe and Wuppertal developed the "Pascal-SC" and "Pascal-XSC" ("Extensions for Scientific Computation") compilers, aimed at programming numerical computations. Development for Pascal-SC started in 1978 supporting ISO 7185 Pascal level 0, but level 2 support was added at a later stage. Pascal-SC originally targeted the Z80 processor, but was later rewritten for DOS (x86) and 68000. Pascal-XSC has at various times been ported to Unix (Linux, SunOS, HP-UX, AIX) and Microsoft/IBM (DOS with EMX, OS/2, Windows) operating systems. It operates by generating intermediate C source code which is then compiled to a native executable. Some of the Pascal-SC language extensions have been adopted by GNU Pascal.  Pascal Sol was designed around 1983 by a French team to implement a Unix-like system named Sol. It was standard Pascal level-1 (with parameterized array bounds) but the definition allowed alternative keywords and predefined identifiers in French and the language included a few extensions to ease system programming (e.g. an equivalent to lseek). The Sol team later on moved to the ChorusOS project to design a distributed operating system.  IP Pascal was an implementation of the Pascal programming language using Micropolis DOS, but was moved rapidly to CP/M-80 running on the Z80. It was moved to the 80386 machine types in 1994, and exists today as Windows/XP and Linux implementations. In 2008, the system was brought up to a new level and the resulting language termed "Pascaline" (after Pascal's calculator). It includes objects, namespace controls, dynamic arrays, along with many other extensions, and generally features the same functionality and type protection as C#. It is the only such implementation that is also compatible with the original Pascal implementation, which is standardized as ISO 7185.

Language constructs.

Pascal, in its original form, is a purely procedural language and includes the traditional array of ALGOL-like control structures with reserved words such as if, then, else, while, for, and case ranging on a single statement or a begin-end statements block. Pascal also has data structuring constructs not included in the original ALGOL 60 types, like records, variants, pointers, enumerations, and sets and procedure/pointers. Such constructs were in part inherited or inspired from Simula 67, ALGOL 68, Niklaus Wirth's own ALGOL W and suggestions by C. A. R. Hoare.  Pascal programs start with the program keyword with a list of external file descriptors as parameters<ref name="iso/iec 7185:1990 6.10">Pascal ISO 7185:1990 6.10</ref> (not required in Turbo Pascal etc.); then follows the main block bracketed by the begin and end keywords. Semicolons separate statements, and the full stop (i.e., a period) ends the whole program (or "unit"). Letter case is ignored in Pascal source.  Here is an example of the source code in use for a very simple "Hello, World!" program: program HelloWorld(output); begin end.

Data types.

A type in Pascal, and in several other popular programming languages, defines a variable in such a way that it defines a range of values which the variable is capable of storing, and it also defines a set of operations that are permissible to be performed on variables of that type. The predefined types are:  The range of values allowed for each (except boolean) is implementation defined. Functions are provided for some data conversions. For conversion of codice_1 to codice_2, the following functions are available: codice_3 (which rounds to integer using banker's rounding) and codice_4 (rounds towards zero).  The programmer has the freedom to define other commonly used data types (e.g. byte, string, etc.) in terms of the predefined types using Pascal's type declaration facility, for example type

Subrange types.

Subranges of any ordinal data type (any simple type except real) can also be made: var

Set types.

In contrast with other programming languages from its time, Pascal supports a set type: var A set is a fundamental concept for modern mathematics, and they may be used in many algorithms. Such a feature is useful and may be faster than an equivalent construct in a language that does not support sets. For example, for many Pascal compilers: if i in [5..10] then... executes faster than: if (i > 4) and (i < 11) then... Sets of non-contiguous values can be particularly useful, in terms of both performance and readability: if i in [0..3, 7, 9, 12..15] then... For these examples, which involve sets over small domains, the improved performance is usually achieved by the compiler representing set variables as bit vectors. The set operators can then be implemented efficiently as bitwise machine code operations.

Type declarations.

Types can be defined from other types using type declarations: type  Further, complex types can be constructed from simple types: type

File type.

As shown in the example above, Pascal files are sequences of components. Every file has a buffer variable which is denoted by "f^". The procedures "get" (for reading) and "put" (for writing) move the buffer variable to the next element. Read is introduced such that "read(f, x)" is the same as "x := f^; get(f);". Write is introduced such that "write(f, x)" is the same as "f^ := x; put(f);" The type text is predefined as file of char. While the buffer variable could be used for inspecting the next character to be used (check for a digit before reading an integer), this leads to serious problems with interactive programs in early implementations, but was solved later with the "lazy I/O" concept.  In Jensen & Wirth Pascal, strings are represented as packed arrays of chars; they therefore have fixed length and are usually space-padded.

Pointer types.

Pascal supports the use of pointers: type var Here the variable "NodePtr" is a pointer to the data type "Node", a record. Pointers can be used before they are declared. This is a forward declaration, an exception to the rule that things must be declared before they are used.  To create a new record and assign the value "10" and character "A" to the fields "a" and "b" in the record, and to initialise the pointer "c" to the null pointer ("NIL" in Pascal), the statements would be: New(NodePtr); NodePtr^.a := 10; NodePtr^.b := 'A'; NodePtr^.c := NIL;  This could also be done using the with statement, as follows: New(NodePtr); with NodePtr^ do begin end;  Inside of the scope of the "with" statement, a and b refer to the subfields of the record pointer "NodePtr" and not to the record Node or the pointer type pNode.  Linked lists, stacks and queues can be created by including a pointer type field (c) in the record.  Unlike many languages that feature pointers, Pascal only allows pointers to reference dynamically created variables that are anonymous, and does not allow them to reference standard static or local variables. Pointers also must have an associated type, and a pointer to one type is not compatible with a pointer to another type (e.g. a pointer to a char is not compatible with a pointer to an integer). This helps eliminate the type security issues inherent with other pointer implementations, particularly those used for PL/I or C. It also removes some risks caused by dangling pointers, but the ability to dynamically deallocate referenced space by using the "dispose" function (which has the same effect as the "free" library function found in C) means that the risk of dangling pointers has not been entirely eliminated as it has in languages such as Java and C#, which provide automatic garbage collection (but which do not entirely eliminate the related problem of memory leaks).  Some of these restrictions can be lifted in newer dialects.

Control structures.

Pascal is a structured programming language, meaning that the flow of control is structured into standard statements, usually without 'goto' commands. while a <> b do WriteLn('Waiting');  repeat until a = 10;  case i of end;

Procedures and functions.

Pascal structures programs into procedures and functions. program Printing;  var i : integer;  procedure Print(j : integer); begin end;  end.  Procedures and functions can be nested to any depth, and the 'program' construct is the logical outermost block.  By default, parameters are passed by value. If 'var' precedes a parameter's name, it is passed by reference.  Each procedure or function can have its own declarations of goto labels, constants, types, variables, and other procedures and functions, which must all be in that order. This ordering requirement was originally intended to allow efficient single-pass compilation. However, in some dialects (such as Embarcadero Delphi) the strict ordering requirement of declaration sections has been relaxed.

Semicolons as statement separators.

Pascal adopted many language syntax features from the ALGOL language, including the use of a semicolon as a statement separator. This is in contrast to other languages, such as PL/I, C etc. which use the semicolon as a statement terminator. No semicolon is needed before the end keyword of a record type declaration, a block, or a "case" statement; before the until keyword of a repeat statement; and before the else keyword of an "if" statement.  The presence of an extra semicolon was not permitted in early versions of Pascal. However, the addition of ALGOL-like empty statements in the 1973 "Revised Report" and later changes to the language in ISO 7185:1983 now allow for optional semicolons in most of these cases. A semicolon is still not permitted immediately before the "else" keyword in an "if" statement, because the else follows a single statement, not a statement sequence. In the case of nested ifs, a semicolon cannot be used to avoid the dangling else problem (where the inner if does not have an else, but the outer if does) by putatively terminating the nested if with a semicolon – this instead terminates both if clauses. Instead, an explicit codice_5 block must be used.

Resources.

Compilers and interpreters.

Several Pascal compilers and interpreters are available for general use:

Standards.

ISO/IEC 7185:1990 Pascal.

In 1983, the language was standardized, in the international standard IEC/ISO 7185, and several local country specific standards, including the American ANSI/IEEE770X3.97-1983, and ISO 7185:1983. These two standards differed only in that the ISO standard included a "level 1" extension for conformant arrays (an array where the boundaries of the array are not known until run time), where ANSI did not allow for this extension to the original (Wirth version) language. In 1989, ISO 7185 was revised (ISO 7185:1990) to correct various errors and ambiguities found in the original document.  The ISO 7185 was stated to be a clarification of Wirth's 1974 language as detailed by the User Manual and Report [Jensen and Wirth], but was also notable for adding "Conformant Array Parameters" as a level 1 to the standard, level 0 being Pascal without conformant arrays. This addition was made at the request of C. A. R. Hoare, and with the approval of Niklaus Wirth. The precipitating cause was that Hoare wanted to create a Pascal version of the (NAG) Numerical Algorithms Library, which had originally been written in FORTRAN, and found that it was not possible to do so without an extension that would allow array parameters of varying size. Similar considerations motivated the inclusion in ISO 7185 of the facility to specify the parameter types of procedural and functional parameters.  Niklaus Wirth himself referred to the 1974 language as "the Standard", for example, to differentiate it from the machine specific features of the CDC 6000 compiler. This language was documented in "The Pascal Report", the second part of the "Pascal users manual and report".  On the large machines (mainframes and minicomputers) Pascal originated on, the standards were generally followed. On the IBM PC, they were not. On IBM PCs, the Borland standards Turbo Pascal and Delphi have the greatest number of users. Thus, it is typically important to understand whether a particular implementation corresponds to the original Pascal language, or a Borland dialect of it.  The IBM PC versions of the language began to differ with the advent of UCSD Pascal, an interpreted implementation that featured several extensions to the language, along with several omissions and changes. Many UCSD language features survive today, including in Borland's dialect.

ISO/IEC 10206:1990 Extended Pascal.

In 1990, an extended Pascal standard was created as ISO/IEC 10206, which is identical in technical content<ref name="ISO/ANSI identical"></ref> to IEEE/ANSI 770X3.160-1989 As of 2019, Support of Extended Pascal in FreePascal Compiler is planned.

Variations.

Niklaus Wirth's Zürich version of Pascal was issued outside ETH in two basic forms, the CDC 6000 compiler source, and a porting kit called Pascal-P system. The Pascal-P compiler left out several features of the full language that were not required to bootstrap the compiler. For example, procedures and functions used as parameters, undiscriminated variant records, packing, dispose, interprocedural gotos and other features of the full compiler were omitted.  UCSD Pascal, under Professor Kenneth Bowles, was based on the Pascal-P2 kit, and consequently shared several of the Pascal-P language restrictions. UCSD Pascal was later adopted as Apple Pascal, and continued through several versions there. Although UCSD Pascal actually expanded the subset Pascal in the Pascal-P kit by adding back standard Pascal constructs, it was still not a complete standard installation of Pascal.  In the early 1990s, Alan Burns and Geoff Davies developed Pascal-FC, an extension to Pl/0 (from the Niklaus' book 'Algorithms+Data Structures=Programs'). Several constructs were added to use Pascal-FC as a teaching tool for Concurrent Programming (such as semaphores, monitors, channels, remote-invocation and resources). To be able to demonstrate concurrency, the compiler output (a kind of P-code) could then be executed on a virtual machine. This virtual machine not only simulated a normal – fair – environment, but could also simulate extreme conditions (unfair mode).

Borland-like Pascal compilers.

Borland's Turbo Pascal, written by Anders Hejlsberg, was written in assembly language independent of UCSD or the Zürich compilers. However, it adopted much of the same subset and extensions as the UCSD compiler. This is probably because the UCSD system was the most common Pascal system suitable for developing applications on the resource-limited microprocessor systems available at that time.  The shrink-wrapped Turbo Pascal version 3 and later incarnations, including Borland's Object Pascal and Delphi and non-Borland near-compatibles became popular with programmers including shareware authors, and so the SWAG library of Pascal code features a large amount of code written with such versions as Delphi in mind.  Software products (compilers, and IDE/Rapid Application Development (RAD) in this category:

Reception.

Pascal generated a wide variety of responses in the computing community, both critical and complimentary.

Early criticism.

While very popular in the 1980s and early 1990s, implementations of Pascal that closely followed Wirth's initial definition of the language were widely criticized as being unsuitable for use outside teaching. Brian Kernighan, who popularized the C language, outlined his most notable criticisms of Pascal as early as 1981 in his article "Why Pascal is Not My Favorite Programming Language". The most serious problem described by him was that array sizes and string lengths were part of the type, so it was not possible to write a function that would accept variable-length arrays or even strings as parameters. This made it unfeasible to write, for example, a sorting library. Kernighan also criticized the unpredictable order of evaluation of boolean expressions, poor library support, and lack of static variables, and raised a number of smaller issues. Also, he stated that the language did not provide any simple constructs to "escape" (knowingly and forcibly ignore) restrictions and limitations. More general complaints from other sources noted that the scope of declarations was not clearly defined in the original language definition, which sometimes had serious consequences when using forward declarations to define pointer types, or when record declarations led to mutual recursion, or when an identifier may or may not have been used in an enumeration list. Another difficulty was that, like ALGOL 60, the language did not allow procedures or functions passed as parameters to predefine the expected type of their parameters.  Most of Kernighan's criticisms were directly addressed in the article "The Pascal Programming Language" by Bill Catambay, specifically, under "Myth 6: Pascal Is Not For Serious Programmers".  Despite initial criticisms, Pascal continued to evolve, and most of Kernighan's points do not apply to versions of the language which were enhanced to be suitable for commercial product development, such as Borland's Turbo Pascal. As Kernighan predicted in his article, most of the extensions to fix these issues were incompatible from compiler to compiler. Since the early 1990s, however, most of the varieties seem condensed into two categories: ISO and Borland-like.  Extended Pascal addresses many of these early criticisms. It supports variable-length strings, variable initialization, separate compilation, short-circuit boolean operators, and default (codice_6) clauses for case statements.

Pascal is an imperative and procedural programming language, designed by Niklaus Wirth as a small, efficient language intended to encourage good programming practices using structured programming and data structuring. It is named in honour of the French mathematician, philosopher and physicist Blaise Pascal.

Pascal est un langage de programmation impératif qui, conçu pour l'enseignement, se caractérise par une syntaxe claire, rigoureuse et facilitant la structuration des programmes.


Education path.

Students in Quebec who intend to pursue post-secondary education must attend a college (i.e., CEGEP) before enrolling in a Quebec university. Students who follow a general studies program in Quebec complete six years of primary school (grades 1 through 6), followed by five years of secondary school (called "grades 7 through 11" or "secondary 1 to secondary 5" in English and "1 secondaire au 5 secondaire" in French). Quebec students complete one grade fewer in total than other North American students before beginning post-secondary studies, completing high school at grade 11 instead of grade 12. CEGEP programs are typically two years in length with the exception of certain technical programs that are three years in length; the latter programs are generally for those wishing to enter a technical profession. Following successful completion of CEGEP, most in-province undergraduate programs are three years in length for Quebec students; hence, the total number of years of study for Quebec students from primary school through a bachelor's degree is the same as for other students in North America. For example, a Quebec student who has completed a CEGEP diploma would begin a 3-year Quebec-based university program in Year 1 whereas an out-of-province student who has completed grade 12 would instead begin the same Quebec-based university program in Year 0. Contrarily, students who possess a CEGEP diploma may also generally attend out-of-province universities in which case diplomas are treated by universities in the same manner as the 2-year college diplomas (associate degree) or are awarded with one year of advanced standing. Some advanced courses at the CEGEP level may be assessed as equivalent to introductory courses at university.  For students intending on completing their post-secondary studies outside of Quebec, there are three options. First, several Quebec-based secondary schools have a specialized curriculum for students who wish to enter directly into out-of-province post-secondary programs. In these instances, students may take one year of courses at high schools that offer this option in order to fulfill the grade 12 requirements of the institution to which they are applying. Second, students may complete one year of CEGEP courses prior to transferring to an out-of-province university so as to begin in the first year of an out-of-province post-secondary degree. For example, students wishing to attend an Ontario university may complete one year of CEGEP and apply as a regular applicant who has completed grade 12 in Ontario. Third, students who have completed two years of CEGEP may apply for admission with one year of advanced standing to post-secondary institutions outside of Quebec.

Programs.

Most, but not all colleges offer two types of programs: pre-university and technical. The pre-university programs take two years to complete, whereas the technical programs take three. These programs share a core curriculum, consisting of French, English, Humanities, Physical Education and complementary courses (elective courses unrelated to the program of study).

Pre-university program.

A pre-university program is two years long. It covers both the subject matter that roughly corresponds to the additional year of high school common elsewhere in Canada and the courses corresponding to those taken in first-year university in preparation for a chosen field in university (Sciences, Humanities, Commerce or Arts). Upon the completion of studies, the provincial government issues a Diploma of College Studies (DCS), or DEC ().  Students are then prepared to complete certain undergraduate programs at a Quebec university in 3 years, as opposed to 4 years outside Quebec. Students with a DEC who choose to attend university in another province in Canada or outside the country are eligible to either skip the first year and enter university as a second year student, or gain advanced standing or extra credit for their first year. The amount of extra credit accepted is at the discretion of each university. In practice, most universities do accept Quebec college credits, but only up to one year, given the difference in structure of education systems between Quebec and the rest of the provinces.

Technical program.

Quebec colleges also offer three-year technical programs for students who wish to pursue a skilled trade. Unlike the pre-university programs, these are not preparation for university, although this does not prevent a student from attending a university afterwards. The technical programs also lead to a DEC. Examples of such technical programs are Industrial Electronics, Architectural Technology, Nursing, Building Engineering Technology, Computer Science, and Theatre. Though those programs can also lead to the university, they are geared towards immediate employment after completion.  Adult continuing education programs are also offered at colleges. Many of those programs lead to a college certificate (Attestation of College Studies (ACS), : "Attestation d'études collégiales"—"AEC"), which is similar to a DEC but does not include the core curriculum. This certificate is delivered by a college's continuing education department, while a diploma is issued by the Ministry of Education, Recreation, and Sport of Quebec (later renamed The Ministry of Education and Higher Education, in French).  In addition, the majority of the province's thirty-one "Technology Transfer Centres" have been established by CEGEPs. At these centres, applied research is carried out in a specific field in cooperation with industrial partners.

Language.

Students can attend either a French-language or English-language cégep.

CEGEP ( or ; ; also CÉGEP, Cegep or Cégep ) is a publicly funded post-secondary education pre‐university, collegiate technical college exclusive to the province of Quebec's education system. A loanword from French, it originates from the French acronym for, sometimes known in English as a "General and Vocational College", it is now considered a word in itself.

Un cégep (acronymie de collège d’enseignement général et professionnel) est un établissement d’études supérieures public, "sui generis" et unique au Québec, qui, dans le système d'éducation québécois, suit les études secondaires et précède l'Université. On y dispense un enseignement dit "collégial" suivant deux parcours ; les formations préuniversitaires et les formations techniques. Les formations préuniversitaires, d’une durée de quatre sessions (2 ans), servent de préparation pour les études universitaires. Les programmes techniques, qui durent généralement six sessions (3 ans), mènent à la pratique d'un métier technique (soins infirmiers, éducation spécialisée, technique policière, etc.). Les cégeps offrent également de la formation continue. Les études collégiales aboutissent à l'obtention d'un diplôme d’études collégiales (DEC) ou d'une attestation d’études collégiales (AEC).


Etymology.

The word "lymph" is derived from the name of the ancient Roman deity of fresh water, Lympha.

Structure.

Lymph has a composition similar but not identical to that of blood plasma. Lymph that leaves a lymph node is richer in lymphocytes than blood plasma is. The lymph formed in the human digestive system called chyle is rich in triglycerides (fat), and looks milky white because of its lipid content.

Development.

Blood supplies nutrients and important metabolites to the cells of a tissue and collects back the waste products they produce, which requires exchange of respective constituents between the blood and tissue cells. This exchange is not direct, but instead occurs through an intermediary called interstitial fluid, which occupies the spaces between cells. As the blood and the surrounding cells continually add and remove substances from the interstitial fluid, its composition continually changes. Water and solutes can pass between the interstitial fluid and blood via diffusion across gaps in capillary walls called intercellular clefts; thus, the blood and interstitial fluid are in dynamic equilibrium with each other.  Interstitial fluid forms at the arterial (coming from the heart) end of capillaries because of the higher pressure of blood compared to veins, and most of it returns to its venous ends and venules; the rest (up to 10%) enters the lymph capillaries as lymph. Thus, lymph when formed is a watery clear liquid with the same composition as the interstitial fluid. However, as it flows through the lymph nodes it comes in contact with blood, and tends to accumulate more cells (particularly, lymphocytes) and proteins.

Function.

Components.

Lymph returns proteins and excess interstitial fluid to the bloodstream. Lymph may pick up bacteria and bring them to lymph nodes, where they are destroyed. Metastatic cancer cells can also be transported via lymph. Lymph also transports fats from the digestive system (beginning in the lacteals) to the blood via chylomicrons.

Circulation.

Tubular vessels transport lymph back to the blood, ultimately replacing the volume lost during the formation of the interstitial fluid. These channels are the lymphatic channels, or simply "lymphatics".  Unlike the cardiovascular system, the lymphatic system is not closed. In some amphibian and reptilian species, the lymphatic system has central pumps, called a lymph hearts which typically exist in pairs, but humans and other mammals do not have a central lymph pump. Lymph transport is slow and sporadic. Despite low pressure, lymph movement occurs due to peristalsis (propulsion of the lymph due to alternate contraction and relaxation of smooth muscle tissue), valves, and compression during contraction of adjacent skeletal muscle and arterial pulsation.  Lymph that enters the lymph vessels from the interstitial spaces usually does not flow backwards along the vessels because of the presence of valves. If excessive hydrostatic pressure develops within the lymph vessels, though, some fluid can leak back into the interstitial spaces and contribute to formation of edema.  The flow of lymph in the thoracic duct in an average resting person usually approximates 100ml per hour. Accompanied by another ~25ml per hour in other lymph vessels, the total lymph flow in the body is about 4 to 5 litres per day. This can be elevated several fold while exercising. It is estimated that without lymphatic flow, the average resting person would die within 24 hours.

Clinical significance.

Histopathological examination of the lymph system is used as a screening tool for immune system analysis in conjunction with pathological changes in other organ systems and clinical pathology to assess disease status. Although histological assessment of the lymph system does not directly measure immune function, it can be combined with identification of chemical biomarkers to determine underlying changes in the diseased immune system.

As a growth medium.

In 1907 the zoologist Ross Granville Harrison demonstrated the growth of frog nerve cell processes in a medium of clotted lymph. It is made up of lymph nodes and vessels.  In 1913, E. Steinhardt, C. Israeli, and R. A. Lambert grew vaccinia virus in fragments of tissue culture from guinea pig corneal grown in lymph.

Lymph (from Latin, "lympha" meaning "water") is the fluid that flows through the lymphatic system, a system composed of lymph vessels (channels) and intervening lymph nodes whose function, like the venous system, is to return fluid from the tissues to the central circulation. Interstitial fluid – the fluid which is between the cells in all body tissues – enters the lymph capillaries. This lymphatic fluid is then transported via progressively larger lymphatic vessels through lymph nodes, where substances are removed by tissue lymphocytes and circulating lymphocytes are added to the fluid, before emptying ultimately into the right or the left subclavian vein, where it mixes with central venous blood.

La lymphe est un liquide biologique blanchâtre, transporté par le système lymphatique. Sa composition est analogue à celle du plasma sanguin, dont elle n'est qu'un filtrat : elle contient des globules blancs, notamment des lymphocytes ; dépourvue de globules rouges, elle baigne les organes ; elle est plus pauvre en nutriments que le sang, plus riche en déchets.


Biography.

Family and education.

Born at Clamecy in Nièvre, he is the son of Michel Montebourg, born in 1933, a civil servant employed in the Ministry of Economy and Finances, and Leïla Ould Cadi, born in 1939 in Oran, a professor of Algerian descent, who was born to a family of "wālis" (governors) from Hachem, Northern Algeria. His fourth great-grand father, Ahmed Ould Cadi, "agha" (chieftain) of Frendah (Oran) was appointed Grand Cross of the Legion of Honour in 1867.  Arnaud Montebourg became an attorney following university. Together with the notable attorney Thierry Levy, he defended Christian Didier, charged in the 1993 slaying of René Bousquet. The former Vichy official had been indicted for war crimes and was soon to be tried. Didier was convicted in 1995 and received a 10-year sentence.

First involvements in politics.

Montebourg was first elected to the National Assembly during the 1997 legislative election. He was reelected in 2002 and 2007. Together with Bastien François, a professor of Political Science at Pantheon-Sorbonne University, Montebourg was the cofounder of the "Convention pour la VI-ème République" (C6R) in 2001. This convention called for significant constitutional changes, leading to the founding of a Sixth French Republic.  Montebourg was one of the founding members of the political movement known as the "Nouveau Parti Socialiste" (New Socialist Party). He left to create a new movement within the Socialist Party called "Rénover, Maintenant" (Renewal, Now). He was one of the leading opponents of President Jacques Chirac's immunity from prosecution, especially concerning the corruption scandals in the Paris region. Montebourg also supported reporter Denis Robert for his role in revealing the illegal system of double-accounts maintained by Clearstream, a clearing-house based in Luxembourg. He has also been engaged in a campaign against the rules governing taxation of foreign nationals and banking secrecy of Switzerland. Montebourg was appointed as spokesman for Ségolène Royal's presidential campaign following his endorsement of her candidacy during the Socialist Party primary election of November 2006. On 18 January 2007, Royal suspended Montebourg from her campaign for one month the day after he said on a Canal+ talk show, "Ségolène Royal has only one fault, her partner." He was referring to the contradictory statements on tax policy made by Royal's partner, François Hollande, who was at the time serving as First Secretary of the Socialist Party. Montebourg had offered his resignation, which Royal refused to accept.  In 2008, Monteboug became President of the General Council of Saône-et-Loire while retaining his mandate as a parliamentarian. In 2011, when Dominique Strauss-Kahn was released from jail and flew back to France, Montebourg urged him to apologise for embarrassing the Socialist Party.

Minister during the presidency of François Hollande.

Montebourg placed third in the Socialist Party's primary election for the 2012 presidential election, receiving about 17% of the votes. François Hollande was first and Martine Aubry was second. After Hollande was elected President of the French Republic, Montebourg was appointed as Minister of Industrial Renewal in the government of Prime Minister Jean-Marc Ayrault on 16 May 2012.  He made a controversial statement that nuclear energy is "an industry of the future" despite the 2011 Fukushima Daiichi nuclear disaster. Interior Minister Manuel Valls backed up Montebourg while the alliance of the Socialist Party with the Green Party might worsen if this statement confirms in practice a backtracking of the nuclear commitment of François Hollande and the Ayrault Cabinet. In November 2012, Arnaud Montebourg made further controversial statements about Lakshmi Mittal by declaring that "Mittal's lies since 2006 are overwhelming (...) he has never kept his word", urging him to leave the country: "We no longer want Mittal in France because they don't respect France". Further on the topic of nuclear energy, he canceled in February 2013 the proposed EPR at the Penly Nuclear Power Plant, citing the capacity for electricity production and massive investments in renewable energy along with his confidence in the EPR as a competitive project in foreign countries.  In 2014, contemporary with the proposed General Electric takeover of Alstom, Montebourg introduced a decree, nicknamed the "décret Alstom", quickly nicknamed "décret Montebourg" by the press, extending the French state's right of veto of foreign takeovers to assets in the fields of energy supply, water, transport, telecoms and public health. Montebourg was quoted as saying the decree protected France's strategic interests and represented the end of laissez-faire economic policy.  On 28 May 2014, Montebourg said that if the United Kingdom "were to vote to leave the EU, France will roll out the red carpet to British investors who will flee their country. They will all come to France because companies need Europe." He has often been critical of austerity measures pushed by Germany. On 24 August 2014, he told a meeting: "France is the euro zone's second-biggest economy, the world's fifth-greatest power, and it does not intend to align itself, ladies and gentlemen, with the excessive obsessions of Germany's conservatives."

Resignation from the Ministry of the Economy.

At the end of October 2014, Montebourg enrolled in the INSEAD graduate business school for a four-week course and sought a bursary for his studies. On 30 December 2014, he announced his retirement from politics. Between 16 and 26 February 2015, he was invited as a visiting professor of Economics at Princeton University. On 19 March 2015, he was appointed vice president of the supervisory board of the furniture chain, Habitat. On 26 March, the French-based consulting and business analyst company, Talan, announced that Montebourg had been given a place on its strategic policy committee.

Candidacy in the 2017 presidential election.

He announced on 21 August 2016 that he planned to stand again as a candidate for the Socialist Party's presidential nomination in the 2017 presidential election. He finished third with 17.8% of the vote.  Montebourg has since then stayed out of the public eye, sometimes appearing as a guest speaker at various events. He remains a well-liked figured on the left side of the political spectrum. He currently runs his own business, Bleu Blanc Ruche ("Blue White Hive"), a wordplay with the colours of the flag of France.

Personal life.

Montebourg lived with journalist Audrey Pulvar from 2010 to 2012 and fellow Minister Aurélie Filippetti from 2014 until 2017.  In February 2015, Montebourg saved several fellow diners as the New York City brasserie Balthazar from serious injury by single-handedly holding up a mirror which had fallen from the restaurant's ceiling until more people could intervene. Afterwards he was lauded as a hero.

List of offices held.

Government  Minister for Industrial Renewal: 2012–2014  Electoral mandates  Member of the National Assembly for Saône-et-Loire (6th constituency): 1997–2012  President of the General Council of Saône-et-Loire : 2008–2012  General Councillor of Saône-et-Loire for the canton of Montret: 2008–2015

Arnaud Montebourg (; born 30 October 1962) is a French politician and entrepreneur who served as Minister of Industrial Renewal from 16 May 2012 to 25 August 2014. Starting on 31 March 2014, as a member of the short-lived First Valls government, Montebourg held additional ministerial responsibilities whereby his overall brief encompassed the Economy, Industrial Renewal and Digital Affairs. He was succeeded by former investment banker Emmanuel Macron.

Arnaud Montebourg, né le à Clamecy (Nièvre), est un avocat, entrepreneur et homme politique français. Avocat de profession, il adhère au Parti socialiste en 1985. Il est député à l'Assemblée nationale, élu dans la sixième circonscription de Saône-et-Loire, de 1997 à 2012. Il est également président du conseil général de Saône-et-Loire de 2008 à 2012. À partir du congrès de Reims de 2008, il est secrétaire national du Parti socialiste chargé de la rénovation.


Geologic materials.

The majority of geological data comes from research on solid Earth materials. These typically fall into one of two categories: rock and unlithified material.

Rock.

The majority of research in geology is associated with the study of rock, as rock provides the primary record of the majority of the geologic history of the Earth. There are three major types of rock: igneous, sedimentary, and metamorphic. The rock cycle illustrates the relationships among them (see diagram).  When a rock solidifies or crystallizes from melt (magma or lava), it is an igneous rock. This rock can be weathered and eroded, then redeposited and lithified into a sedimentary rock. It can then be turned into a metamorphic rock by heat and pressure that change its mineral content, resulting in a characteristic fabric. All three types may melt again, and when this happens, new magma is formed, from which an igneous rock may once more solidify.

Tests.

To study all three types of rock, geologists evaluate the minerals of which they are composed. Each mineral has distinct physical properties, and there are many tests to determine each of them. The specimens can be tested for:

Unlithified material.

Geologists also study unlithified materials (referred to as "drift"), which typically come from more recent deposits. These materials are superficial deposits that lie above the bedrock. This study is often known as Quaternary geology, after the Quaternary period of geologic history.

Magma and lava.

However, unlithified material does not only include sediments. Magmas and lavas are the original unlithified source of all igneous rocks. The active flow of molten rock is closely studied in volcanology, and igneous petrology aims to determine the history of igneous rocks from their final crystallization to their original molten source.

Whole-Earth structure.

Plate tectonics.

In the 1960s, it was discovered that the Earth's lithosphere, which includes the crust and rigid uppermost portion of the upper mantle, is separated into tectonic plates that move across the plastically deforming, solid, upper mantle, which is called the asthenosphere. This theory is supported by several types of observations, including seafloor spreading and the global distribution of mountain terrain and seismicity.  There is an intimate coupling between the movement of the plates on the surface and the convection of the mantle (that is, the heat transfer caused by bulk movement of molecules within fluids). Thus, oceanic plates and the adjoining mantle convection currents always move in the

Earth structure.

Advances in seismology, computer modeling, and mineralogy and crystallography at high temperatures and pressures give insights into the internal composition and structure of the Earth.  Seismologists can use the arrival times of seismic waves in reverse to image the interior of the Earth. Early advances in this field showed the existence of a liquid outer core (where shear waves were not able to propagate) and a dense solid inner core. These advances led to the development of a layered model of the Earth, with a crust and lithosphere on top, the mantle below (separated within

Geologic time.

The geologic time scale encompasses the history of the Earth. It is bracketed at the earliest by the dates of the first Solar System material at 4.567 Ga (or 4.567 billion

Dating methods.

Relative dating.

Methods for relative dating were developed when geology first emerged as a natural science. Geologists still use the following principles today as a means to provide information about geologic history and the timing of geologic events.  The principle of uniformitarianism states that the geologic processes observed in operation that modify the Earth's crust at present have worked in much the same way over geologic time. A fundamental principle of geology advanced by the 18th century Scottish physician and geologist James Hutton is that "the present is the key to the past."

Absolute dating.

Geologists also use methods to determine the absolute age of rock samples and geological events. These dates are useful on their own and may also be used in conjunction with relative dating methods or to calibrate relative methods.  At the beginning of the 20th century, advancement in geological science was facilitated by the ability to obtain accurate absolute dates to geologic events using radioactive isotopes and other methods. This changed the understanding of geologic time. Previously, geologists could only use fossils and stratigraphic correlation to date sections of rock relative to one another. With isotopic dates, it became possible to assign absolute ages to rock units, and these absolute dates could be applied to fossil sequences in which there was datable material, converting the old relative ages into new absolute ages.  For

Geological development of an area.

The geology of an area changes through time as rock units are deposited and inserted, and deformational processes change their shapes and locations.  Rock units are first emplaced either by deposition onto the surface or intrusion into the overlying rock. Deposition can occur when sediments settle onto the surface of the Earth and later lithify into sedimentary rock, or when as volcanic material such as volcanic ash or lava flows blanket the surface. Igneous intrusions such as batholiths, laccoliths, dikes, and sills, push upwards into the overlying rock, and crystallize as they intrude.  After the initial sequence of rocks has been deposited, the rock units can be deformed and/or metamorphosed. Deformation typically occurs as a result of horizontal shortening, horizontal extension, or side-to-side (strike-slip) motion. These structural regimes broadly relate to convergent boundaries, divergent boundaries, and transform boundaries, respectively, between tectonic plates.  When rock units are placed under horizontal compression, they shorten and become thicker. Because rock units, other than muds, do not significantly change in volume, this is accomplished in two primary ways: through faulting and folding. In the shallow crust, where brittle deformation can occur, thrust faults form, which causes deeper rock to move on top of shallower rock. Because deeper rock is often older, as noted by the principle of superposition, this can result in older rocks moving on top of younger ones. Movement along faults can result in folding, either because the faults are not planar or because rock layers are dragged along, forming drag folds as slip occurs along the fault. Deeper in the Earth, rocks behave plastically and fold instead of faulting. These folds can either be those where the material in the center of the fold buckles upwards, creating "antiforms", or where it buckles downwards, creating "synforms". If the tops of the rock units within the folds remain pointing upwards, they are called anticlines and synclines, respectively. If some of the units in the fold are facing downward, the structure is called an overturned anticline or syncline, and if all of the rock units are overturned or the correct up-direction is unknown, they are simply called by the most general terms, antiforms and synforms. Even higher pressures and temperatures during horizontal shortening can cause both folding and

Methods of geology.

Geologists use a number of field, laboratory, and numerical modeling methods to decipher Earth history and to understand the processes that occur on and inside the Earth. In typical geological investigations, geologists use primary information related to petrology (the study of rocks), stratigraphy (the study of sedimentary layers), and structural geology (the study of positions of rock units and their deformation). In many cases, geologists also study modern soils, rivers, landscapes, and glaciers; investigate past and current life and biogeochemical pathways, and use geophysical methods to investigate the subsurface. Sub-specialities of geology may distinguish endogenous and exogenous geology.

Field methods.

Geological field work varies depending on

Petrology.

In addition to identifying rocks in the field (lithology), petrologists identify rock samples in the laboratory. Two of the primary methods for identifying rocks in the laboratory are through optical microscopy and by using an electron microprobe. In an optical mineralogy analysis, petrologists analyze thin sections of rock samples using a petrographic microscope, where the minerals can be identified through their different properties in plane-polarized and cross-polarized light, including their birefringence, pleochroism, twinning, and interference properties

Structural geology.

Structural geologists use microscopic analysis of oriented thin sections of geologic samples to observe the fabric within the rocks, which gives information about strain within the crystalline structure of the rocks. They also plot and combine measurements of geological structures to better understand the orientations of faults and folds to reconstruct the history of rock deformation in the area. In addition, they perform analog and numerical experiments of rock deformation in large and small settings.  The analysis of structures is often accomplished by plotting the orientations of various features onto stereonets. A stereonet is a stereographic projection of a sphere onto a plane, in which planes

Stratigraphy.

In the laboratory, stratigraphers analyze samples of stratigraphic sections that can be returned from the field, such as those from drill cores. Stratigraphers also analyze data from geophysical surveys that show the locations of stratigraphic units in the subsurface. Geophysical data and well logs can be combined to produce a better view of the subsurface, and stratigraphers often use computer programs to do this in three dimensions. Stratigraphers can then use these data to

Planetary geology.

With the advent of space exploration in the twentieth century, geologists have begun to look at other planetary bodies in the same ways that have been developed to study the Earth. This new field of study is called planetary geology (sometimes known as astrogeology) and relies on known geologic principles to study other bodies of the solar system.  Although the Greek-language-origin prefix "geo" refers to Earth, "geology" is often used in conjunction with

Applied geology.

Economic geology.

Economic geology is a branch of geology that deals with aspects of economic minerals that humankind uses to fulfill various needs. Economic minerals are those extracted profitably for various practical uses. Economic geologists help locate and manage the Earth's natural resources, such as petroleum and coal, as well as mineral resources, which include metals such as iron, copper, and uranium.

Mining geology.

Mining geology consists of the extractions of mineral resources from the Earth. Some resources of economic interests include gemstones, metals

Petroleum geology.

Petroleum geologists study the locations of the subsurface of the Earth that can contain extractable hydrocarbons, especially petroleum and natural gas. Because many of these reservoirs are found in sedimentary basins, they study the formation of these basins, as well as their sedimentary and tectonic evolution and the present-day positions of the rock units.

Engineering geology.

Engineering geology is the application of the geologic principles to engineering practice for the purpose of assuring that the geologic factors affecting the location, design, construction, operation, and maintenance of engineering works are properly addressed. In the

Hydrology and environmental issues.

Geology and geologic principles can be applied to various environmental problems such as stream restoration, the restoration of brownfields, and the understanding of the interaction between natural habitat and the geologic environment. Groundwater hydrology, or hydrogeology, is used to locate groundwater, which can often provide a ready supply of

Natural hazards.

Geologists and geophysicists study natural hazards in order to enact safe building codes and warning systems that are used

History.

The study of the physical material of the Earth dates back at least to ancient Greece when Theophrastus (372–287 BCE) wrote the work "Peri Lithon" ("On Stones"). During the Roman period, Pliny the Elder wrote in detail of the many minerals and metals then in practical use – even correctly noting the origin of amber.  Some modern scholars, such as Fielding H. Garrison, are of the opinion that the origin of the science of geology can be traced to Persia after the Muslim conquests had come to an end. Abu al-Rayhan al-Biruni (973–1048 CE) was one of the earliest Persian geologists, whose works included the earliest writings on the geology of India, hypothesizing that the Indian subcontinent was once a sea. Drawing from Greek and Indian scientific literature that were not destroyed by the Muslim conquests, the Persian scholar Ibn Sina (Avicenna, 981–1037) proposed detailed explanations for the formation of mountains, the origin of earthquakes, and other topics central to modern geology, which provided an essential foundation for the later development of the science. In China, the polymath Shen Kuo (1031–1095) formulated a hypothesis for the process of land formation: based on his observation of fossil animal shells in a geological stratum in a mountain hundreds of miles from the ocean, he inferred that the land was formed by erosion of the mountains and by deposition of silt.  Nicolas Steno (1638–1686) is credited with the law of superposition, the principle of original horizontality, and the principle of lateral continuity: three defining principles of stratigraphy.  The word "geology" was first used by Ulisse Aldrovandi in 1603, then by Jean-André Deluc in 1778 and introduced as a fixed term by Horace-Bénédict de Saussure in 1779. The word is derived from the Greek γῆ, "gê", meaning "earth" and λόγος, "logos", meaning "speech". But according to another source, the word "geology" comes from a Norwegian, Mikkel Pedersøn Escholt (1600–1699), who was a priest and scholar. Escholt first used the definition in his book titled, "Geologia Norvegica" (1657).  William Smith (1769–1839) drew some of the first geological maps and began the process of ordering rock strata (layers) by examining the fossils contained in them.  James Hutton (1726-1797) is often viewed as the first modern geologist. In 1785 he presented a paper entitled "Theory of the Earth" to the Royal Society of Edinburgh. In his paper, he explained his theory that the Earth must be much older than had previously been supposed to allow enough time for mountains to be eroded and for sediments to form new rocks at the bottom of the sea, which in turn were raised up to become dry land. Hutton published a two-volume version of his ideas in 1795 (Vol. 1, Vol. 2).  Followers of Hutton were known as "Plutonists" because they believed that some rocks were formed by "vulcanism", which is the deposition of lava from volcanoes, as opposed to the "Neptunists", led by Abraham Werner, who believed that all rocks had settled out of a large ocean whose level gradually dropped over time.  The first geological map of the U.S. was produced in 1809 by William Maclure. In 1807, Maclure commenced the self-imposed task of making a geological survey of the United States. Almost every state in the Union was traversed and mapped by him, the Allegheny Mountains being crossed and recrossed some 50 times. The results of his unaided labours were submitted to the American Philosophical Society in a memoir entitled "Observations on the Geology of the United States explanatory of a Geological Map", and published in the "Society's Transactions", together with the nation's first geological map. This antedates William Smith's geological map of England by six years, although it was constructed using a different classification of rocks.  Sir Charles Lyell (1797-1875) first published his famous book, "Principles of Geology", in 1830. This book, which influenced the thought of Charles Darwin, successfully promoted the doctrine of uniformitarianism. This theory states that slow geological processes have occurred throughout the Earth's history and are still occurring today. In contrast, catastrophism is the theory that Earth's features formed in single, catastrophic events and remained unchanged thereafter. Though Hutton believed in uniformitarianism, the idea was not widely accepted at the time.  Much of 19th-century geology revolved around the question of the Earth's exact age. Estimates varied from a few hundred thousand to billions of years. By the early 20th century, radiometric dating allowed the Earth's age to be estimated at two billion years. The awareness of this vast amount of time opened the door to new theories about the processes that shaped the planet.  Some of the most significant advances in 20th-century geology have been the development of the theory of plate tectonics in the 1960s and the refinement of estimates of the planet's age. Plate tectonics theory arose from two separate geological observations: seafloor spreading and continental drift. The theory revolutionized the Earth sciences. Today the Earth is known to be approximately 4.5 billion years old.

Geology (from the Ancient Greek γῆ, "gē" ("earth") and -λoγία, "-logia", ("study of", "discourse")) is an earth science concerned with the solid Earth, the rocks of which it is composed, and the processes by which they change over time. Geology can also include the study of the solid features of any terrestrial planet or natural satellite such as Mars or the Moon. Modern geology significantly overlaps all other earth sciences, including hydrology and the atmospheric sciences, and so is treated as one major aspect of integrated earth system science and planetary science.

La géologie (du grec ancien "gê", la Terre, et "logos", le discours) est la science dont le principal objet d'étude est la Terre, et plus particulièrement la lithosphère. Discipline majeure des sciences de la Terre, elle se base en premier lieu sur l'observation, puis établit des hypothèses permettant d'expliquer l'agencement des roches et des structures les affectant afin d'en reconstituer l'histoire et les processus en jeu. Le terme « géologie » désigne également l'ensemble des caractéristiques géologiques d'une région, et s'étend à l'étude des astres.


Childhood.

Thomas Lanier Williams III was born in Columbus, Mississippi of English, Welsh, and Huguenot ancestry, the second child of Edwina Dakin (August 9, 1884 – June 1, 1980) and Cornelius Coffin "C. C." Williams (August 21, 1879 – March 27, 1957). His father was a traveling shoe salesman who became an alcoholic and was frequently away from home. His mother, Edwina, was the daughter of Rose O. Dakin, a music teacher, and the Reverend Walter Dakin, an Episcopal priest from Illinois who was assigned to a parish in Clarksdale, Mississippi, shortly after Williams' birth. Williams lived in his parsonage with his family for much of his early childhood and was close to his grandparents.  He had two siblings, older sister Rose Isabel Williams (1909–1996) and younger brother Walter Dakin Williams. (1919–2008).  As a young child Williams nearly died from a case of diphtheria that left him weak and virtually confined to his house during a period of recuperation that lasted a year. At least in part as a result of his illness, he was less robust as a child than his father wished. Cornelius Williams, a descendant of hearty East Tennessee pioneer stock, had a violent temper and was a man prone to use his fists. He regarded what he thought was his son's effeminacy with disdain. Edwina, locked in an unhappy marriage, focused her attention almost entirely on her frail young son. Many critics and historians note that Williams drew from his own dysfunctional family in much of his writing.  When Williams was eight years old, his father was promoted to a job at the home office of the International Shoe Company in St. Louis, Missouri. His mother's continual search for what she considered to be an appropriate address, as well as his father's heavy drinking and loudly turbulent behavior, caused them to move numerous times around St. Louis. Williams attended Soldan High School, a setting he referred to in his play "The Glass Menagerie". Later he studied at University City High School. At age 16, Williams won third prize for an essay published in "Smart Set", titled "Can a Good Wife Be a Good Sport?" A year later, his short story "The Vengeance of Nitocris" was published (as by "Thomas Lanier Williams") in the August 1928 issue of the magazine "Weird Tales". These early publications did not lead to any significant recognition or appreciation of Williams' talent, and he would struggle for more than a decade afterwards to establish his writing career. Later in 1928, Williams first visited Europe with his maternal grandfather Dakin.

Education.

From 1929 to 1931, Williams attended the University of Missouri in Columbia where he enrolled in journalism classes. He was bored by his classes and distracted by unrequited love for a girl. Soon he began entering his poetry, essays, stories, and plays in writing contests, hoping to earn extra income. His first submitted play was "Beauty Is the Word" (1930), followed by "Hot Milk at Three in the Morning" (1932). As recognition for "Beauty," a play about rebellion against religious upbringing, he became the first freshman to receive honorable mention in a writing competition.  At University of Missouri, Williams joined the Alpha Tau Omega fraternity, but he did not fit in well with his fraternity brothers. After he failed a military training course in his junior year, his father pulled him out of school and put him to work at the International Shoe Company factory. Although Williams hated the monotony, the job forced him out of the gentility of his upbringing. His dislike of his new 9-to-5 routine drove Williams to write prodigiously. He set a goal of writing one story a week. Williams often worked on weekends and late into the night. His mother recalled his intensity:  Tom would go to his room with black coffee and cigarettes and I would hear the typewriter clicking away at night in the silent house. Some mornings when I walked in to wake him for work, I would find him sprawled fully dressed across the bed, too tired to remove his clothes.  Overworked, unhappy, and lacking further success with his writing, by his 24th birthday Williams had suffered a nervous breakdown and left his job. He drew from memories of this period, and a particular factory co-worker, to create the character Stanley Kowalski in "A Streetcar Named Desire". By the mid-1930s his mother separated from his father due to his worsening alcoholism and abusive temper. They never divorced.  In 1936, Williams enrolled at Washington University in St. Louis where he wrote the play "Me, Vashya" (1937). In the autumn of 1937, he transferred to the University of Iowa, where he graduated with a B.A. in English in August 1938. He later studied at the Dramatic Workshop of The New School in New York City. Speaking of his early days as a playwright and an early collaborative play called "Cairo, Shanghai, Bombay!", Williams wrote, "The laughter... enchanted me. Then and there the theatre and I found each other for better and for worse. I know it's the only thing that saved my life." Around 1939, he adopted "Tennessee Williams" as his professional name.

Literary influences.

Williams' writings reference some of the poets and writers he most admired in his early years: Hart Crane, Arthur Rimbaud, Anton Chekhov (from the age of ten), William Shakespeare, Clarence Darrow, D.H. Lawrence, Katherine Mansfield, August Strindberg, William Faulkner, Thomas Wolfe, Emily Dickinson, William Inge, James Joyce, and Ernest Hemingway.

Career.

As Williams was struggling to gain production and an audience for his work in the late 1930s, he worked at a string of menial jobs that included a stint as caretaker on a chicken ranch in Laguna Beach, California. In 1939, with the help of his agent Audrey Wood, Williams was awarded a $1,000 grant from the Rockefeller Foundation in recognition of his play "Battle of Angels." It was produced in Boston in 1940 and was poorly received.  Using some of the Rockefeller funds, Williams moved to New Orleans in 1939 to write for the Works Progress Administration (WPA), a federally funded program begun by President Franklin D. Roosevelt created to put people to work. Williams lived for a time in New Orleans' French Quarter, including 722 Toulouse Street, the setting of his 1977 play "Vieux Carré". The building is now part of The Historic New Orleans Collection. The Rockefeller grant brought him to the attention of the Hollywood film industry and Williams received a six-month contract as a writer from the Metro-Goldwyn-Mayer film studio, earning $250 weekly.  During the winter of 1944–45, his memory play "The Glass Menagerie" developed from his 1943 short story "Portrait of a Girl in Glass", was produced in Chicago and garnered good reviews. It moved to New York where it became an instant hit and enjoyed a long Broadway run. Elia Kazan (who directed many of Williams' greatest successes) said of Williams: "Everything in his life is in his plays, and everything in his plays is in his life." "The Glass Menagerie" won the award for the best play of the season, the New York Drama Critics' Circle Award.  The huge success of his next play, "A Streetcar Named Desire," secured his reputation as a great playwright in 1947. During the late 1940s and 1950s, Williams began to travel widely with his partner Frank Merlo (1922 – September 21, 1963), often spending summers in Europe. He moved often to stimulate his writing, living in New York, New Orleans, Key West, Rome, Barcelona, and London. Williams wrote, "Only some radical change can divert the downward course of my spirit, some startling new place or people to arrest the drift, the drag."  Between 1948 and 1959 Williams had seven of his plays produced on Broadway: "Summer and Smoke" (1948), "The Rose Tattoo" (1951), "Camino Real" (1953), "Cat on a Hot Tin Roof" (1955), "Orpheus Descending" (1957), "Garden District" (1958), and "Sweet Bird of Youth" (1959). By 1959, he had earned two Pulitzer Prizes, three New York Drama Critics' Circle Awards, three Donaldson Awards, and a Tony Award.  Williams' work reached wide audiences in the early 1950s when "The Glass Menagerie" and "A Streetcar Named Desire" were adapted as motion pictures. Later plays also adapted for the screen included "Cat on a Hot Tin Roof", "The Rose Tattoo", "Orpheus Descending", "The Night of the Iguana", "Sweet Bird of Youth", and "Summer and Smoke."  After the extraordinary successes of the 1940s and 1950s, he had more personal turmoil and theatrical failures in the 1960s and 1970s. Although he continued to write every day, the quality of his work suffered from his increasing alcohol and drug consumption, as well as occasional poor choices of collaborators. In 1963, his partner Frank Merlo died.  Consumed by depression over the loss, and in and out of treatment facilities while under the control of his mother and brother Dakin, Williams spiraled downward. His plays "Kingdom of Earth" (1967), "In the Bar of a Tokyo Hotel" (1969), "Small Craft Warnings" (1973), "The Two Character Play" (also called "Out Cry", 1973), "The Red Devil Battery Sign" (1976), "Vieux Carré" (1978), "Clothes for a Summer Hotel" (1980), and others were all box office failures. Negative press notices wore down his spirit. His last play, "A House Not Meant to Stand," was produced in Chicago in 1982. Despite largely positive reviews, it ran for only 40 performances.  Critics and audiences alike failed to appreciate Williams' new style and the approach to theater he developed during the 1970s.  In 1974, Williams received the St. Louis Literary Award from the Saint Louis University Library Associates. In 1979, four years before his death, he was inducted into the American Theater Hall of Fame.

Personal life.

Throughout his life Williams remained close to his sister, Rose, who was diagnosed with schizophrenia as a young woman. In 1943, as her behavior became increasingly disturbing, she was subjected to a lobotomy, requiring her to be institutionalized for the rest of her life. As soon as he was financially able, Williams moved Rose to a private institution just north of New York City, where he often visited her. He gave her a percentage interest in several of his most successful plays, the royalties from which were applied toward her care. The devastating effects of Rose's treatment may have contributed to Williams' alcoholism and his dependence on various combinations of amphetamines and barbiturates.  After some early attempts at relationships with women, by the late 1930s Williams began exploring his homosexuality. In New York City, he joined a gay social circle that included fellow writer and close friend Donald Windham (1920–2010) and Windham's then-boyfriend Fred Melton. In the summer of 1940, Williams initiated a relationship with Kip Kiernan (1918–1944), a young Canadian dancer he met in Provincetown, Massachusetts. When Kiernan left him to marry a woman, Williams was distraught. Kiernan's death four years later at age 26 was another heavy blow.  On a 1945 visit to Taos, New Mexico, Williams met Pancho Rodríguez y González, a hotel clerk of Mexican heritage. Rodríguez was, by all accounts, a loving and loyal companion. But he was also prone to jealous rages and excessive drinking, and their relationship was tempestuous. In February 1946 Rodríguez left New Mexico to join Williams in his New Orleans apartment. They lived and traveled together until late 1947, when Williams ended the relationship. Rodríguez and Williams remained friends, however, and were in contact as late as the 1970s.  Williams spent the spring and summer of 1948 in Rome in the company of an Italian teenager, called "Rafaello" in Williams' "Memoirs". He provided financial assistance to the younger man for several years afterward. Williams drew from this for his first novel, "The Roman Spring of Mrs. Stone". When he returned to New York that spring, Williams met and fell in love with Frank Merlo (1922–1963). An occasional actor of Sicilian ancestry, he had served in the U.S. Navy in World War II. This was the enduring romantic relationship of Williams' life, and it lasted 14 years until infidelities and drug abuse on both sides ended it. Merlo, who had become Williams' personal secretary, took on most of the details of their domestic life. He provided a period of happiness and stability, acting as a balance to the playwright's frequent bouts with depression. Williams feared that, like his sister Rose, he would fall into insanity. His years with Merlo, in an apartment in Manhattan and a modest house in Key West, Florida were Williams' happiest and most productive. Shortly after their breakup, Merlo was diagnosed with inoperable lung cancer. Williams returned to him and cared for him until his death on September 20, 1963.  In the years following Merlo's death, Williams descended into a period of nearly catatonic depression and increasing drug use; this resulted in several hospitalizations and commitments to mental health facilities. He submitted to injections by Dr. Max Jacobson – known popularly as Dr. Feelgood – who used increasing amounts of amphetamines to overcome his depression. Jacobson combined these with prescriptions for the sedative Seconal to relieve his insomnia. During this time, influenced by his mother, a Roman Catholic convert, Williams joined the Catholic Church (though he later claimed that he never took his conversion seriously). He was never truly able to recoup his earlier success, or to entirely overcome his dependence on prescription drugs.  Edwina Dakin died in 1980 at the age of 95. Her health had begun failing during the early 1970s and she lived in a care facility from 1975 onward. Williams rarely saw his mother in her later years and retained a strong animosity toward her; friends described his reaction to her death as "mixed".  As Williams grew older, he felt increasingly alone; he feared old age and losing his sexual appeal to younger gay men. In the 1970s, when he was in his 60s, Williams had a lengthy relationship with Robert Carroll, a Vietnam veteran and aspiring writer in his 20s. Williams had deep affection for Carroll and respect for what he saw as the younger man's talents. Along with Williams' sister Rose, Carroll was one of the two people who received a bequest in Williams' will. Williams described Carroll's behavior as a combination of "sweetness" and "beastliness". Because Carroll had a drug problem (as did Williams), friends such as Maria St. Just saw the relationship as "destructive". Williams wrote that Carroll played on his "acute loneliness" as an aging gay man. When the two men broke up in 1979, Williams called Carroll a "twerp", but they remained friends until Williams died four years later.

Death.

On February 25, 1983, Williams was found dead at age 71 in his suite at the Hotel Elysée in New York. Chief Medical Examiner of New York City Elliot M. Gross reported that Williams had choked to death from inhaling the plastic cap of a bottle of the type used on bottles of nasal spray or eye solution. It was later reported that Williams was using the plastic cap to ingest barbiturates.  He wrote in his will in 1972:  But his brother Dakin Williams arranged for him to be buried at Calvary Cemetery in St. Louis, Missouri, where his mother is buried.  Williams left his literary rights to in Sewanee, Tennessee, an Episcopal school, in honor of his maternal grandfather, Walter Dakin, an alumnus of the university. The funds support a creative writing program. When Rose died in 1996 after many years in a mental institution, she bequeathed $7 million from her part of the Williams estate to The University of the South.

Posthumous recognition.

From February 1 to July 21, 2011, to commemorate the 100th anniversary of his birth, the Harry Ransom Center at the University of Texas at Austin, the home of Williams' archive, exhibited 250 of his personal items. The exhibit, titled "Becoming Tennessee Williams," included a collection of Williams manuscripts, correspondence, photographs and artwork. The Ransom Center holds the earliest and largest collections of Williams' papers, including all of his earliest manuscripts, the papers of his mother Edwina Williams, and those of his long-time agent Audrey Wood.  In late 2009, Williams was inducted into the Poets' Corner at the Cathedral of Saint John the Divine in New York. Performers and artists who took part in his induction included Vanessa Redgrave, playwright John Guare, Eli Wallach, Sylvia Miles, Gregory Mosher, and Ben Griessmeyer.  The Tennessee Williams Theatre in Key West, Florida, is named for him. The Tennessee Williams Key West Exhibit on Truman Avenue houses rare Williams memorabilia, photographs, and pictures including his famous typewriter.  At the time of his death, Williams had been working on a final play "In Masks Outrageous and Austere", which attempted to reconcile certain forces and facts of his own life. This was a continuing theme in his work. As of September 2007, author Gore Vidal was completing the play, and Peter Bogdanovich was slated to direct its Broadway debut. The play received its world premiere in New York City in April 2012, directed by David Schweizer and starring Shirley Knight as Babe.  The rectory of St. Paul's Episcopal Church in Columbus, Mississippi, where Williams's grandfather Dakin was rector at the time of Williams's birth, was moved to another location in 1993 for preservation. It was newly renovated in 2010 for use by the City of Columbus as the Tennessee Williams Welcome Center.  Williams's literary legacy is represented by the literary agency headed by Georges Borchardt.  In 1985, French author-composer Michel Berger wrote a song dedicated to Tennessee Williams, "Quelque chose de Tennessee" (Something of Tennessee), for Johnny Hallyday. It became one of the singer's more famous songs.  Since 1986, the Tennessee Williams New Orleans Literary Festival has been held annually in New Orleans, Louisiana, in commemoration of the playwright. The festival takes place at the end of March to coincide with Williams's birthday.  "The Tennessee Williams Songbook" is a one woman show written and directed by David Kaplan, a Williams scholar and curator of Provincetown's Tennessee Williams Festival, and starring Tony Award nominated actress Alison Fraser. The show features songs taken from plays of Williams' canon, woven together with text to create a new narrative. The show premiered at the Tennessee Williams/New Orleans Literary Festival. The show was recorded on CD and distributed by Ghostlight Records.  In 2014 Williams was one of the inaugural honorees in the Rainbow Honor Walk, a walk of fame in San Francisco’s Castro neighborhood noting LGBTQ people who have "made significant contributions in their fields."  In 2015, The Tennessee Williams Theatre Company of New Orleans was founded by Co-Artistic Directors Nick Shackleford and Augustin J Correro. The New Orleans based non-profit theatre company is the first year-round professional theatre company that focuses exclusively on the works of Williams.  Since 2016, St. Louis, Missouri has held an annual Tennessee Williams' Festival, featuring a main production and related events such as literary discussions and new plays inspired by his work. In 2018 the festival produced "A Streetcar Named Desire".  The U.S. Postal Service honored Williams on a stamp in 1994 as part of its literary arts series.  Williams is honored with a star on the St. Louis Walk of Fame. He is also inducted into the Clarksdale Walk of Fame.  On October 17, 2019, the Mississippi Writers Trail installed a historical marker commemorating William's literary contributions during his namesake festival produced by the City of Clarksdale, Mississippi.

Works.

Characters in his plays are often seen as representations of his family members. Laura Wingfield in "The Glass Menagerie" is thought to be modeled on his sister Rose. Some biographers believed that the character of Blanche DuBois in "A Streetcar Named Desire" also is based on her.  Amanda Wingfield in "The Glass Menagerie" generally was taken to represent Williams' mother Edwina. Characters such as Tom Wingfield in "The Glass Menagerie" and Sebastian in "Suddenly, Last Summer" were understood to represent Williams himself. In addition, he used a lobotomy as a motif in "Suddenly, Last Summer".  The Pulitzer Prize for Drama was awarded to "A Streetcar Named Desire" in 1948 and to "Cat on a Hot Tin Roof" in 1955. These two plays later were adapted as highly successful films by noted directors Elia Kazan ("Streetcar"), with whom Williams developed a very close artistic relationship, and Richard Brooks ("Cat"). Both plays included references to elements of Williams's life such as homosexuality, mental instability, and alcoholism.  Although "The Flowering Peach" by Clifford Odets was the preferred choice of the Pulitzer Prize jury in 1955, and "Cat on a Hot Tin Roof" was at first considered the weakest of the five shortlisted nominees, Joseph Pulitzer Jr., chairman of the Board, had seen "Cat on a Hot Tin Roof" and thought it worthy of the drama prize. The Board went along with him after considerable discussion.  Williams wrote "The Parade, or Approaching the End of a Summer" when he was 29, and worked on it sporadically throughout his life. A semi-autobiographical depiction of his 1940 romance with Kip Kiernan in Provincetown, Massachusetts, it was produced for the first time on October 1, 2006, in Provincetown by the Shakespeare on the Cape production company. This was part of the First Annual Provincetown Tennessee Williams Festival. "Something Cloudy, Something Clear" (1981) is also based on his memories of Provincetown in the 1940s.  His last play went through many drafts as he was trying to reconcile what would be the end of his life. There are many versions of it, but it is referred to as "In Masks Outrageous and Austere".

Plays.

Apprentice plays  Major plays

One-act plays.

Williams wrote over 70 one-act plays during his lifetime. The one-acts explored many of the same themes that dominated his longer works. Williams' major collections are published by New Directions in New York City.

Thomas Lanier Williams III (March 26, 1911 – February 25, 1983), known by his pen name Tennessee Williams, was an American playwright. Along with contemporaries Eugene O'Neill and Arthur Miller, he is considered among the three foremost playwrights of 20th-century American drama.

Thomas Lanier Williams III, dit Tennessee Williams, né le à Columbus dans le Mississippi aux États-Unis et mort le à New York, est un dramaturge et écrivain américain dont de nombreuses œuvres furent portées au cinéma. Aux côtés d'Eugène O'Neill et Arthur Miller, il est considéré comme l'un des dramaturges les plus importants du aux États-Unis.


Life.

Stapledon was born in Seacombe, Wallasey, on the Wirral Peninsula in Cheshire, the only son of William Clibbett Stapledon and Emmeline Miller. The first six years of his life were spent with his parents at Port Said, Egypt. He was educated at Abbotsholme School and Balliol College, Oxford, where he acquired a BA degree in Modern History (Second Class) in 1909, promoted to an MA degree in 1913. After a brief stint as a teacher at Manchester Grammar School he worked in shipping offices in Liverpool and Port Said from 1910 to 1912. From 1912 to 1915 Stapledon worked with the Liverpool branch of the Workers' Educational Association.  During the First World War he served as a conscientious objector. Stapledon became an ambulance driver with the Friends' Ambulance Unit in France and Belgium from July 1915 to January 1919; he was awarded the Croix de Guerre for bravery. His wartime experiences influenced his pacifist beliefs and advocation of a World Government. On 16 July 1919 he married Agnes Zena Miller (1894–1984), an Australian cousin. They had first met in 1903, and later maintained a correspondence throughout the war. They had a daughter, Mary Sydney Stapledon (1920–2008), and a son, John David Stapledon (1923–2014). In 1920 they moved to West Kirby.  Stapledon was awarded a PhD degree in philosophy from the University of Liverpool in 1925 and used his doctoral thesis as the basis for his first published prose book, "A Modern Theory of Ethics" (1929). However, he soon turned to fiction in the hope of presenting his ideas to a wider public. The relative success of "Last and First Men" (1930) prompted him to become a full-time writer. He wrote a sequel, "Last Men in London", and followed it up with many more books of both fiction and philosophy.  For the duration of the Second World War Stapledon abandoned his pacifism and supported the war effort. In 1940 the Stapledon family built and moved into a new house on Simon's Field, in Caldy, in Wirral. During the war Stapledon become a public advocate of J.B. Priestley and Richard Acland's left-wing Common Wealth Party, as well as the British internationalist group Federal Union.  After 1945 Stapledon travelled widely on lecture tours, visiting the Netherlands, Sweden and France, and in 1948 he spoke at the World Congress of Intellectuals for Peace in Wrocław, Poland. He attended the Conference for World Peace held in New York City in 1949, the only Briton to be granted a visa to do so. In 1950 he became involved with the anti-apartheid movement. After a week of lectures in Paris, he cancelled a projected trip to Yugoslavia and returned to his home in Caldy, where he died very suddenly of a heart attack.  Stapledon was cremated at Landican Crematorium. His widow and their children scattered his ashes on the sandy cliffs overlooking the Dee Estuary, a favourite spot of his that features in more than one of his books. Stapledon Wood, on the south-east side of Caldy Hill, is named after him.

Works.

Stapledon's fiction often presents the strivings of some intelligence that is beaten down by an indifferent universe and its inhabitants who, through no fault of their own, fail to comprehend its lofty yearnings. It is filled with protagonists who are tormented by the conflict between their "higher" and "lower" impulses.  Stapledon's writings directly influenced Arthur C. Clarke, Brian Aldiss, Stanisław Lem, Bertrand Russell, John Gloag, Naomi Mitchison, C. S. Lewis, Vernor Vinge, John Maynard Smith and indirectly influenced many others, contributing many ideas to the world of science fiction. The "supermind" composed of many individual consciousnesses forms a recurring theme in his work. "Star Maker" contains the first known description of what are now called Dyson spheres. Freeman Dyson credits the novel with giving him the idea, even stating in an interview that "Stapledon sphere" would be a more appropriate name. "Last and First Men" features early descriptions of genetic engineering and terraforming. "Sirius" describes a dog whose intelligence is increased to the level of a human being's.  Some commentators have called Stapledon a Marxist, although Stapledon distanced himself from the label. Stapledon's work also refers to then-contemporary intellectual fashions (e.g. the belief in extrasensory perception).  "Last and First Men", a "future history" of 18 successive species of humanity, and "Star Maker", an outline history of the Universe, were highly acclaimed by figures as diverse as Jorge Luis Borges, J. B. Priestley, Bertrand Russell, Algernon Blackwood, Hugh Walpole, Arnold Bennett, Virginia Woolf (Stapledon maintained a correspondence with Woolf) and Winston Churchill. In contrast, Stapledon's philosophy repelled C. S. Lewis, whose "Cosmic Trilogy" was written partly in response to what Lewis saw as amorality, although Lewis admired Stapledon's inventiveness and described him as "a corking good writer". In fact Stapledon was an agnostic who was hostile to religious institutions, but not to religious yearnings, a fact that set him at odds with H. G. Wells in their correspondence.  Together with his philosophy lectureship at the University of Liverpool, which now houses the Olaf Stapledon archive, Stapledon lectured in English literature, industrial history and psychology. He wrote many non-fiction books on political and ethical subjects, in which he advocated the growth of "spiritual values", which he defined as those values expressive of a yearning for greater awareness of the self in a larger context ("personality-in-community"). Stapledon himself named his spiritual values as intelligence, love and creative action. His philosophy was strongly influenced by Spinoza.

Film rights.

Film producer and director George Pal bought the rights to "Odd John" and in 1966 "Castle of Frankenstein" magazine reported that David McCallum would play the title role.  In 2017 a multimedia work adaption of "Last and First Men" by Oscar-nominated Icelandic composer Jóhann Jóhannsson was released, featuring narration from Tilda Swinton and a live score performed by the BBC Philharmonic.  In 2019 a short film adaption of Stapledon's story "A Modern Magician" was written by, produced by and starred Justin McDonald and Kate Hodgson. The film, which was directed by Mark Heller, also featured the voice of Brian Cox and marked the first ever live action adaptation of any of Stapledon's literary works.

William Olaf Stapledon (10 May 1886 – 6 September 1950) – known as Olaf Stapledon – was a British philosopher and author of science fiction. In 2014, he was inducted into the Science Fiction and Fantasy Hall of Fame.

William Olaf Stapledon, né le près de Liverpool et décédé le dans le Merseyside, est un philosophe anglais et un auteur de romans de science-fiction visionnaire ayant esquissé nombre des thèmes classiques explorés par la science-fiction du.