NECKOLOGICAL NOTICE OF M. DULONG. 
65 
object the new determinations of the proportions of water 
and the density of some elastic fluids; finally, that in con- 
junction with M. Thenard, relative to the property which 
certain metals possess to facilitate the union of certain gases, 
which had for its aim the verifications of the excellent expe- 
riments of Dcebereiner upon the inflammation of hydrogen 
by platinum sponge, will always deserve the esteem and re- 
membrance of chemists. 
The students of physical science have, perhaps, even more 
obligations to him, for the excellent researches which he un- 
dertook, along with M. Petit, upon the laws of the dilatation 
of solids, liquids, and elastic fluids, and upon the exact mea- 
sure of temperature; as well as for those upon the specific 
heat of bodies, which have rendered it certain that the atoms 
of simple bodies have always an equal specific heat, what- 
soever may be their chemical nature, and which have deter- 
mined that this equality is so exact, that by determining the 
specific heat of one body, we may from thence determine, 
numerically, the specific heats of all other simple bodies, as 
well as their chemical combinations, by means of their atomic 
weight. An ingenious and fruitful idea, which has caused 
great progress in the study of the atomic theory. 
Finally, that excellent work which he undertook, together 
with M. Arago, in 1S29, upon the relation between the tem- 
perature and pressure of vapor in boilers, will always remain 
as a model of precision and exactness in science. 
A man endowed with such great sagacity, and such solid 
attainments, could not long remain unknown to the learned 
of Europe. 
In 1815, when thirty years of age, he was the competitor 
of M. Girard for the vacancy in the section of general physic, 
caused by the death of M. Leveque, but was foiled in the contest! 
In 1S23, when Fourier was named perpetual secretary, in the 
place of M. Delambre, M. Dulong was nominated his suc- 
cessor, and has since preserved in the Academy that influence 
which unpretending knowledge and a benevolent character 
always gives. Successively, professor in the snliool of Alfort, 
VOL. V. NO. I. 9 
