Chemistry and Physics. 5' 



SCIENTIFIC INTELLIGENCE. 



L Chemistry KSiD Physics. 



1. Thermo-chemical investigatlom. — Under this title J, Tno.\ 

 SKX in Copenhagen, has published a series of valuable reseaiclK? 

 the principal results of which, in the author's own lantriiaue, are a 

 follows: -- ■ 



(].) As a general law it appears that for all acids 



a. When a molecule of sodic hydrate iu aqueous solution act 

 upon an acid the evolution of heat is very nearly proportional t. 

 the quantity of acid until this amounts to 1, ^, \ or j of a molt 

 cule, according as the acid is one-, two-, three , or tour-liasit>. 



h. But when the quantity of acid exceeds tliat wliicli is iieco 

 sary to form the normal salt, a diftereiice between tlie acids i 

 exhibited, so that according to the constitution of the acid tli 

 heat* produced by its excess is either zero, jx.sitive or negative. 



(2.) a. When a molecule of an acid iu aqueous solufuni act 

 upon sodic hydrate the evolution of heat iu a majority of cases i 

 ■ ' ... - ^^ g^^^ ^^^.j ^j^. 



c hydra 

 , two-, three-, or four-basic. The deviations from this 



approximately proportional to the quant 



molecules of sodic hydrate according a 



phich at first signt appears 

 upon closer consideration to correspond completely 



law find an explanation in what is stated under heads 1- 



b. But if the quantity of soda is increased above this, no ma- 

 terial change occurs in the heat-toning. 



(3.) If the magnitude of the molecule is determined in some 

 other manner, the basicity of the acid, if indeed it has such, may 

 be certainly found by this method of investigation. 



(4.) From this it distinctly appears that suTphyii-ic acid is mono- 

 basic and that its formula must be considered H . SH ; since the 

 second atom of hydrogen cannot in an aqueous solution be re- 

 placed by sodium, this result which at first sight appears 

 -^ • - - ' rupletely 



3 hand it 



perfectly explains the behavior of the acid, and on the other pre- 

 sents a material support to the theory of hydroxyl, as the great 

 analogy between sulphur and oxygen renders it extremely prob- 

 able that the formula of water must then be H.OH, and that 

 water is to be regarded as a mono-basic acid. It follows also that 

 the so-called neutral metallic sulphides, e. g., NagS, do not exist 

 in an aqueous solution, any more than the corresponding oxides 

 (Na2e),and that the so-called sulphydrates, Na. SH, Ba. 2SH, 

 and Mg. 2SH, are to be regarded as normal salts of the acid 

 soluble in water. 



(5.) Since the mono-basic acids contain only one atom of hydro- 

 gen replaceable by sodium, the second molecule of sodic hydrate 

 must be without action upon the sodium salt, which is fully verified 

 by experiment. Since further the mono-basic acids form no acid 

 salts, an excess of acid must be without action upon the sodium 

 * In the original " Warmetonung," heat-toning. 



