64 Existence of Compound Radicals in Amphide Salts. 



" The general adoption of the binary theory of salts has de- 

 prived of much of its interest and importance a question, which 

 some years since was very ingeniously discussed, viz. — whether, 

 in the formation of double salts, the salts which unite had the 

 same relation to each other that acid and base were then thought 

 to have. Thus it was supposed that the electro-negative quali- 

 ties of sulphuric acid being less controlled by oxide of copper 

 than by potash, the alkaline sulphate acted as a base to the sul- 

 phate of copper, when these two salts combined to form the dou- 

 ble sulphate of potash and copper, and so on in other instances; 

 but in addition to the circumstance that all we have said as to 

 the constitution of the salts militates against this view, we have 

 the positive evidence that, first, these double salts are formed not 

 by combination merely, but by replacement of the constitutional 

 water of the sulphates of the copper or magnesian class, which 

 water nobody would contend to act in them as a base ; and sec- 

 ond, that when a solution of such a double salt is decomposed by 

 the battery, the two salts are not separated as if they were acid 

 and base, but are decomposed independently in the proportions 

 of an equivalent of each, making together the sum of the chemi- 

 cal energy of the current. 



" A similar idea was advocated by Bonsdorff regarding the dou- 

 ble chlorides, iodides, &c. He proposed to consider the chlorides 

 of gold, platina, mercury, &c. as chlorine acids, and those of po- 

 tassium, &c. as chlorine bases, and so with the iodides. This 

 view, however, although at first very extensively adopted, has 

 given way to the gradual growth of knowledge. There is no 

 analogy between a dry oxygen acid and a chloride ; but the chlo- 

 rides are in perfect analogy with the neutral salts. Thus CuCl 

 does not resemble SO 3 , but Cu.SO 4 and CuCl + KCl is analogous 

 not to S0 3 .KO, but to the double salt Cu.SO 4 -f K.SO 4 . Bons- 

 dorff's idea was exactly counter to the direction of truth ; he sought 

 to bring all salts under the one head, by extending to all the con- 

 stitution of oxygen acids and oxygen bases, whilst the progress 

 of science has led us to the opposite generalization of reducing all 

 salts to the simple haloid type." 



Respecting the Isomeric Acids of Phosphorus. 



A very important modification has been made with respect to 

 the three isomeric states of phosphoric acid. They are inferred 



