The inventor of Mayer's reagent and one of the founders of thermodynamics, Julius von Mayer was the first to enunciate what phrase, known as the first law of thermodynamics?
Mayer's reagent Mayer's reagent is an alkaloidal precipitating reagent used for the detection of alkaloids in natural products. Mayer’s reagent is freshly prepared by dissolving a mixture of mercuric chloride (1.36 g) and of potassium iodide (5.00 g) in water (100.0 ml). Most alkaloids are precipitated from neutral or slightly acidic solution by Mayer’s reagent (potassiomercuric iodide solution) to give a cream coloured precipitate. This test was invented by the German Chemist, Julius Robert Von Mayer (1814–1878).
Entropy in thermodynamics and information theory There are close parallels between the mathematical expressions for the thermodynamic entropy, usually denoted by "S", of a physical system in the statistical thermodynamics established by Ludwig Boltzmann and J. Willard Gibbs in the 1870s, and the information-theoretic entropy, usually expressed as "H", of Claude Shannon and Ralph Hartley developed in the 1940s. Shannon, although not initially aware of this similarity, commented on it upon publicizing information theory in "A Mathematical Theory of Communication".