19th century in science Carnot captured some of the ideas of thermodynamics in his discussion of the efficiency of an idealized engine. Sadi Carnot's work provided a basis for the formulation of the first law of thermodynamics—a restatement of the law of conservation of energy—which was stated around 1850 by William Thomson, later known as Lord Kelvin, and Rudolf Clausius. Lord Kelvin, who had extended the concept of absolute zero from gases to all substances in 1848, drew upon the engineering theory of Lazare Carnot, Sadi Carnot, and Émile Clapeyron–as well as the experimentation of James Prescott Joule on the interchangeability of mechanical, chemical,
Diseases and epidemics of the 19th century 1905, with the last outbreak affecting New Orleans. Diseases and epidemics of the 19th century Diseases and epidemics of the 19th century reached epidemic proportions in the case of one emerging infectious disease: cholera. Other important diseases at that time in Europe and other regions included smallpox, typhus and yellow fewer. Epidemics of the 19th century were faced without the medical advances that made 20th-century epidemics much more rare and less lethal. Micro-organisms (viruses and bacteria) had been discovered in the 18th century, but it was not until the late 19th century that the experiments of Lazzaro Spallanzani and Louis