Punctuation the marks hierarchically, in terms of weight". Cecil Hartley's poem identifies their relative values: <poem style=margin:4em;> The stop point out, with truth, the time of pause A sentence doth require at ev'ry clause. At ev'ry comma, stop while "one" you count; At semicolon, "two" is the amount; A colon doth require the time of "three"; The period "four", as learned men agree. </poem> The use of punctuation was not standardised until after the invention of printing. According to the 1885 edition of "The American Printer", the importance of punctuation was noted in various sayings by children such as: <poem style=margin:4em;>
Colon (punctuation) Colon (punctuation) The colon ( : ) is a punctuation mark consisting of two equally sized dots centered on the same vertical line. A colon precedes an explanation or an enumeration, or list. A colon is also used with ratios, titles and subtitles of books, city and publisher in bibliographies, Biblical citations between chapter and verse, and for salutations business letters and other formal letter writing, and often to separate hours and minutes. The most common use of the colon is to inform the reader that what follows the colon proves, explains, defines, describes, or lists elements of what preceded