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vero multum distant ab experimentis doctorum Deloroche 
atque Berard, ad qu nostra propius accedunt ratione flui- 
dorum elasticorum elementariorum, experimenta D. Apjohn 
yatione aerum compositorum.” The opinion, however, here 
expressed cannot, Dr. A. conceived, be considered as well 
sustained by the numbers adduced by Suerman. Thus, to 
give buta single example, the specific heat of hydrogen com- 
pared to that of an equal volume of air, as deduced by 
Suerman, was 1.3979, and as deduced, according to Suerman, 
by Dr. Apjohn. was 1,8948. Here is a material difference, 
quite beyond the probable errors of experiment, in expla- 
nation of which Dr.’ Apjohn stated, that 1,8948, and the 
other numbers attributed to him by Suerman, were, in 
point of fact, not those which flowed from his experiments ; 
and at the same time admitted, that when they were so con- 
sidered by Suerman, he, Dr. A. himself, was in some degree 
to blame. He had published his first results as the specific 
heats of equal weights, when they were in reality the specific 
heats of equal volumes ; but in arriving at them it was neces- 
sary to be subjected to a particular correction, which, howe- 
ver, materially different in its influence upon them, according 
as it is applied to the case of equal volumes or of equal 
weights. Of these facts Suerman was not aware, and was 
thus prevented from perceiving that the very close corres- 
pondence which he recognized between the two series of 
results amounted to an almost perfect identity. 
This identity, however, Dr. A. stated to be true of them 
when viewed relatively but not absolutely. The direct de- 
terminations by Suerman of the specific heat of air and of 
the different gases, were, Dr. A. alleged, in every instance 
greater than those at which he had arrived. This he attri- 
buted to three causes: Ist. To Suerman’s estimating the 
ealoric of elasticity of vapour higher than Dr. Apjohn had 
done. 2nd. To his employing the formula of Gay-Lussac, 
which differed from that which Dr, Apjohn had employed in 
