﻿82 M. Dumas 5 s Remarks on Affinity. 



But having, for my own part, been led to pay homage to the 

 power and accuracy of his chemical knowledge, it seemed to me 

 that at the moment in which they have been brought to the atten- 

 tion of scientific men by our illustrious dean, when he communi- 

 cated to the Academy his very interesting philosophical studies, 

 I might anticipate by a few weeks a publication in which they 

 play an important part. 



Newton, it is known, had made numerous chemical experiments 

 which have been lost. The conclusions which he had drawn 

 from them have been summed up by himself. They served as 

 basis for the chemical doctrine of Bergmann and for that of 

 Buffon, who, by a premature use of Newton's principles, have not 

 a little contributed to prevent chemists from according to them 

 the respect they merit. Thus the name of Newton has disap- 

 peared from treatises on chemistry; and I think, with M. Chevreul 

 as well as M. Trouessart, that it ought to be restored, as he 

 was the first to comprehend the nature of affinity. 



Lavoisier, contemporary with Buffon, but more reserved with 

 regard to a subject with whose difficulties he was better ac- 

 quainted, never expressed himself definitely on the subject of 

 affinity. He even considered this branch of science too high 

 for the reach of the chemists of his time; and he recommended 

 them, before busying themselves with it, to settle on a solid basis 

 the elements of chemistry, in the same manner, says he, that we 

 fix with certainty the principles of elementary geometry before 

 approaching the difficulties of the higher geometry. 



Lavoisier, therefore, postponing the investigation of the force 

 which produces chemical phenomena, had concentrated his atten- 

 tion on the part which ponderable matter plays. He had doubt- 

 less considered the heat disengaged or absorbed in the reactions 

 of bodies a fundamental phenomenon, the measurement of which 

 was as necessary for their explanation as the determination of the 

 weights of the substances employed and of the substances ob- 

 tained ; but we do not see that he regarded this heat as an ex- 

 pression of the chemical force. 



Ponderable matter, heat, molecular attraction are the three 

 terms to which Lavoisier had recourse, and with which he con- 

 tented himself for the explanation of chemical phenomena. He 

 measured most exactly and delicately matter and heat in their 

 displacements. He left attraction on one side as a notion inac- 

 cessible to experiment, and as only giving rise in his time to use- 

 less hypotheses. 



Lavoisier, then, had assumed chemical attraction, affinity, but 

 had not endeavoured to explain it. In that respect he agreed 

 with Newton. This great man, almost a century before, enun- 

 ciated in the following terms the result of his labours and his 



