n6 TEE POPULAR SCIENCE MONTHLY. 



Synthesis ") 1860 ; and " Lecons sur les methodes g&n&rales de synthese 

 en chimie organique " (" Lessons on the General Methods of Synthesis 

 in Organic Chemistry "), a course of lectures in the College de France, 

 1864. 



M. Berthelot has also pursued elaborate researches in specific heat, 

 and in tbe relations between the heat developed in composition and 

 decomposition, and the force of affinity. On the subject of the rela- 

 tions of specific heat with the composition of bodies he said, in 1873, 

 in a discussion in tbe French Academy with M. Dumas : " Tbe study 

 of tbe specific heats established by tbe most recent researches tends 

 to prove that there is a positive characteristic which, it seems to me, 

 distinguishes tbe elements of modern chemistry from its compounds, 

 and sbows tbat no known compound body ought to be considered as 

 of the same order as an actually simple one. The importance of such 

 a characteristic can not be doubted, and it becomes greater on account 

 of the mechanical meaning which modern theories attach to specific 

 heat. . . . Nevertheless, exaggerated conclusions must not be drawn 

 from such an opposition between the mechanical and physical charac- 

 teristics of our simple and compound bodies. If our elements have 

 not as yet been decomposed, and appear not to be decomposable by 

 tbe forces which are at present at the command of the chemist, noth- 

 ing compels us to assert that they are not decomposable in another 

 way than our compounds are ; as, for instance, as Mr. Loekyer asserts, 

 by means of the forces acting in cosmical space. Nor does anything 

 prevent that such a discovery as that of voltaic electricity would 

 enable tbe chemists of tbe future to overpass tbe limits which are 

 imposed upon us. The possible fundamental identity of tbe matter 

 constituting our elements, and the possibility of transmuting into one 

 another the so-called elements, can, moreover, be admitted into the 

 category of more or less plausible hypotheses without it necessarily 

 resulting that there is a single really existing matter of which our 

 actual elements represent unequal states of condensation. In fact, 

 nothing compels us to conceive the existence of a final decomposition 

 which shall tend necessarily to reduce our elements either to more 

 simple bodies, from the addition of which they arise, or to multiples 

 of a single elementary ponderable xmit." 



M. Berthelot's views of the relations between chemical affinity and 

 the intensity of chemical action were presented in his " Essai de m6ca- 

 nique chimique fondee sur la thermo-chimie " (" Essay on Chemical Dy- 

 namics based on Thermo-Chemistry "), 1880, of which Mr. M. M. Patti- 

 son Muir said, in " Nature," that its publication " marks an important 

 point in tbe advance of modern chemistry." Among the more recent 

 investigations which M. Berthelot has pursued in the light of his 

 thermo-cbemical theories are those into the properties of explosives 

 and the laws of the propagation of explosions. 



