186 Systems of Chemical Notation. 
ratios as in the gaseous state, it is for one of the two following 
reasons, either the specific heats of the solid elements change 
unequally with the temperature, as I believe is the case, or two 
gaseous molecules are united in one solid molecule, as the atom- 
ists suppose. In either case, it seems to me that the specific 
heats of solids must be put aside in the determination of abso- 
lute equivalents.* : 
L insist the more on this point that the new equivalents, if 
we attribute to this word the extensive meanin that you 
rightly give to it, introduce an undeniable complication in 
chemical reactions. In your classical researches on the specific 
heats of saline solution you found yourself obliged to double 
the atomic weights of hydrochloric and of nitric acid and of 
their salts, with the object of expressing with greater clearness 
the analogies and parallelism of their properties. You wrote: 
: H°Ccr’; Na’Cl’; N?0°, H*0; N*0°, K’0, 
and in the same manner you were led to double acetic acid and 
the acetates : 
C*H’O*, H’O ; C*H*0*, K’0. 
The same necessity has been felt by all those who have had 
to express the equivalent ratios of acids, of water and of bases, 
* I cannot accept your opinion on the absolute value of the law of Weestyn in 
calculation of the specific heats of solid . You know very well 
that M. Kopp, who went to the bottom of this question in 1864, found himself 
obliged, in verifying this relation, to attribute to the solid elements in their com- 
bination specific heats varying from 6°4 (silver, chlorine, nitrogen), down to 4 
(oxygen), 2°3 (hydrogen), and 1-8 (carbon). 
