494 SCIENCE PROGRESS 



hydroxide or caustic soda, Na(OH). In point of fact it is so 

 only to a very slight extent. The conclusion is forced upon 

 us, therefore, that a small, but only a very small, proportion of 

 ammonium hydroxide is formed when ammonia dissolves in 

 water ; but as dissolution takes place so readily and to such 

 an extent, it is difficult to avoid the conclusion that combination 

 does take place, and it seems not improbable that a compound 

 such as is represented by the formula H 3 N = OH 2 is the main 

 product. Apparently, therefore, ammonia has much less influence 

 over hydrogen oxide than it has over hydrogen chloride. 



Applying a similar argument in the case of hydrogen 

 chloride and water, it may be supposed that chloride and oxide 

 interact in the following manner : 



H.,0 + HC1 = H 2 (V 



This product, being unstable and having no tendency to 

 crystallise under ordinary conditions, cannot be isolated. But 

 sulphur — which is own brother, as it were, to oxygen among 

 the elements — gives rise to compounds of this type, such as 

 trimethylsulphonium chloride, S(CH 3 ) 3 C1. There is, therefore, 

 every reason to believe that compounds of oxygen may exist 

 such as that postulated above. 



The question arises whether the reciprocal interchange is 

 not also effected, namely : 



HCl + HX> = HCl^ 



\)H 



For reasons which cannot well be discussed in this article, it 

 is more than probable that it is. And this conclusion also finds 

 support in the argument from analogy. Thus iodine, which is 

 so closely related to chlorine, is known to give rise to well- 

 defined compounds in which it exercises the functions of a triad, 

 such as — 



CLHs C d H 5 



I (Diphenyliodonium hydroxide) 

 (OH) 



which, it may be pointed out, is an altogether remarkable 

 compound, inasmuch as it has the properties of a caustic alkali, 



