xlii Annual Report of the Council. 



In Marcellin Berthelot the world has lost perhaps one 

 of the most versatile, certainly one of the most strenuous of her 

 men of genius. 



Born in Paris in 1827 Berthelot began his professional 

 career as laboratory assistant to Professor Ballard at the College 

 de France. His first paper, published in 1850, was on the 

 liquefaction of carbonic acid gas, but he soon turned to organic 

 chemistry and described the action of heat on alcohol and on 

 acetic acid. A chair of organic chemistry being created for him 

 at the College, he worked first on oil of turpentine and then on 

 glycerine and its compounds. His first organic syntheses were 

 those of animal fats (1854), ethyl alcohol from ethylene (1855), 

 formic acid from carbonic oxide (1855), and of methyl alcohol 

 (1857). Then followed the important synthesis of acetylene 

 direct from carbon and hydrogen (1862), and by heating 

 acetylene he prepared benzene (1866)* In the same year he 

 synthesised marsh gas. Berthelot was the first to show that at a 

 high temperature several molecules of a hydrocarbon may unite 

 to form a new molecule — sometimes with the elimination of 

 hydrogen : in this way he prepared diphenyl from benzene and 

 anthracene from toluene. 



In 1861 Berthelot published, with Pean de Saint Gilles, the 

 first of his researches on affinity. He showed that the rate of 

 formation of an ester depended upon the molecular quantities 

 of the alcohol and acid present, thus affording an experimental 

 proof of the law of mass action enunciated by Berthollet. As a 

 ccrollary to this work, Berthelot naturally attacked the con- 

 clusions of Bunsen concerning the step-like nature of explosions 

 in gases and of the incomplete combustion of carbonic oxide 

 and hydrogen. Berthelot's own work on explosions culminated 

 in 1 88 1 in his discovery of the explosion- wave (l'onde explosive) 

 in gases, and his theory of its propagation through explosive 

 mixtures. This work was followed by a long investigation, 

 in conjunction with Vieille, on the pressures produced in 

 gaseous explosions from which the temperatures and specific 

 heats of the products of combustion were deduced. 



