HYDROGEN AND PHOSPHORUS. 417 



phuric acid with a base, which consists of an atom of oxide of 

 copper and an atom of water, and represents it thus : 



Sulphate of copper . . Cu O, H O + S O 3 ; 

 to which he assimilates the 



Sulphate of ammonium . Ad H, H O + S O 3 . 



The hypothesis of the equivalency of two atoms of the mag- 

 nesian and one of the potash class, has received new support 

 from Dr. Kane's researches ; but it is still (in my opinion) 

 too doubtful to form a safe basis for any theoretical super- 

 structure. At the same time, this hypothesis has enabled 

 Dr. Kane to develope many new and interesting relations 

 among the ammoniacal compounds, and may, perhaps, pre- 

 sent a closer and more distinct view of the intimate con- 

 stitution of these bodies, than the ammonium theory exhibits. 

 At present, however, our theories of the constitution of com- 

 pounds are too uncertain to be regarded otherwise than as 

 artificial aids to facilitate our conception of the manner in 

 which the formation of these bodies occurs, and of the trans- 

 formations which they undergo ; and a theory of constitution 

 is, therefore, adopted more for its convenience than its truth. 

 This state of things leads to the retention of the ammonium 

 theory, which has introduced a degree of simplicity into our 

 views of that particular class of ammoniacal compounds to 

 which it is applicable, that could not easily be exceeded. But 

 its adoption must not be allowed to preclude the considera- 

 tion of other theories, such as that of Dr. Kane, which facilitate 

 investigations in the meantime, and may prove to be truer to 

 nature in the end. 



SECTION IV. 



HYDROGEN AND PHOSPHORUS. 



Solid hydruret of phosphorus. Magnus forms a phosphuret 

 of potassium, by fusing phosphorus and potassium under naph- 

 tha. When this compound is thrown into water, a compound 

 of phosphorus and hydrogen precipitates in the form of a yellow 

 powder. It contains less hydrogen than the following com- 

 pound. 



E E 



