Dr. Kane on the Compounds of Ammonia. 121 



sition as compound bodies^ 'without reference to any other cir- 

 cumstance. In the first the proper theory of the salts of am- 

 monia is that of Berzelius, but for the second purpose it is ne- 

 cessary to adopt the ideas on which mine is founded. 



For in fact the question is, What is sal-ammoniac ? Its 

 most striking philosophical character is its equivalence to chlo- 

 ride of potassium. It has the same crystalline form. It enters 

 into combination subject to the same laws. They are two bo- 

 dies formed decidedly upon the same plan. But chloride of 

 potassium contains only two elements, while sal-ammoniac 

 contains three. There is one common to both. The residual 

 elements are equivalent, and Cl K and Cl N H 4 , as well as 

 K and N H 4 , are bodies which correspond to each other. 

 Ammonium when isolated, as it has, in the amalgam, all but 

 been, appears to possess the properties of an alkaline metal ; 

 it markedly resembles potassium. That is the Berzelian 

 theory, in which to the full I believe as well as Berzelius. 

 The equivalency of sal-ammoniac and chloride of potassium 

 is a fact, and the equivalency of the K in the one and of the 

 N H 4 in the other, is the natural inference from it. When 

 therefore the equivalency of the ammoniacal and potash salts 

 is under question, the ammonium theory is correctly used : it 

 is not ammonia, it is not amidide of hydrogen which replaces 

 potash, but it is to be called oxide of ammonium in compari- 

 son. 



But if we for a moment cease to consider the relation of the 

 ammoniacal and the potash compounds, and taking sal-ammo- 

 niac by itself, proceed to examine what light can be derived 

 from other sources towards illustrating its internal constitution, 

 the question presents itself, can we believe the ammonium to 

 be ready-formed in sal-ammoniac ? Can we consider the am- 

 monium, which in the amalgam gives up its hydrogen sponta- 

 neously, to retain it so strongly when in contact with iodine or 

 chlorine, and to enter into combination only as a single and 

 perfect group ? The answer to this question, in the framing 

 of which all the classes of ammonia compounds require to 

 be taken into account, led me to the development of my the- 

 ory. 



The combinations of ammonia with the anhydrous chlorides 

 of copper, zinc, and mercury, resemble in all essential charac- 

 ters sal-ammoniac, and moreover, like it, those which are vo- 

 latile or soluble without decomposition are found to belong to 

 the regular system of crystallization. They further combine 

 with the metallic chlorides of the magnesian class to form dou- 

 ble chlorides. Thus there are 



