1 62 Analj/sis of Scientific Books. 



sition, the specific gravity will be that of defiant gas and that 

 of muriatic acid gas added together*." 



On his salts, we shall waste few words. Atomical conceits 

 perpetually vitiate his descriptions of them. Thus in treating 

 of the carbonate of ammonia of the shops, he says, " When 

 in its perfect state, this subspecies is composed of 1 atom 

 carbonic acid, and 1 atom of ammonia, or by weight of 

 Carbonic acid,. 2.75 56.41 100 

 Ammonia, 2.125 43.59 77.27 



But the longer it is kept, the greater is the proportion of car- 

 bonic acid, and the smaller the proportion of ammonia, which 

 it contains, because the alkali gradually makes its escape into 

 the atmosphere. I have obtained it from shops in London com- 

 posed as follows : 



Carbonic acid, 55.70 100 

 Ammonia, 21.16 46.98 



Water, 18.13t" 



How is the water introduced into his " perfect" salt ; for it is 

 not deliquescent ? In truth, the Doctor knows very well, that 

 this is not the constitution of the solid subcarbonate of the 

 shops. The commercial salt is never " composed of 1 atom car- 

 bonic acid and 1 atom of ammonia." It consists of 3 atoms car- 

 bonic acid + 2 atoms ammonia + 2 atoms water ; which form 

 the pungent smelling compound. By exposure to air, this 

 becomes a scentless salt, consisting of 2 atoms carbonic acid 

 + 1 atom ammonia + 2 atoms water ; so that it loses an atom 

 of carbonic acid and an atom of ammonia =: one atom of M. Gay- 

 Lussac's carbonate, in the transition J. On sulphate of ammonia 

 we observe one of his quotations to be corruptly given. On 

 turning to his reference (Amials of Philosophy , X. 294), we 

 find the sulphate deduced by experiment as consisting of 

 Sulphuric acid, 61.00 1 atom is 60.60 

 Ammonia, 25.96 1 25.76 



, Water, 13.04 1 13.64 



The Doctor chooses to make it, acid 60, base 40 in 100 parts. 

 His own </teo?'e<ica^ composition " is acid 70.17 + base 29.83 

 IT 100." We do not profess to know what Dr. Thomson means 

 by theory; whether it be an explanation you»c?ed in _/ac<s, and 

 adequate to account for the phenomena ; or an explanation un- 

 connected with facts, and inconsistetit with the phenomena. 



The salts, generally speaking, remain with all the errors and 

 imperfections of the old edition. We shall give one example, 

 among many, of the vitiation of this part of cheniistry, by 

 atomical conceits. " According to Proust, the acetate of cop- 

 per is composed of, 



* System, H, 359. t Ibid., II, 413. 



♦ Annals of Fhilosophy, X. 206 i aud this JoMrna/, VII. 294. 



