AMIDOSULPHOXIC ACID. 239 



The silver salt. — Before passing to the results of our own examin- 

 ation of the important silver salt, we give Berglund's excellent account 

 of it. ' It crystallises best of all the salts ; it is also the least soluble, 

 requiring about 15 parts of water at the ordinary temperature (19°). 

 It forms bundles of striated prisms, looking much like those of the 

 sodium salt, and almost as hard and brittle as glass. It blackens only 

 extremely slowly ; its solution is quite neutral. It is best prepared 

 from barium amidosulphonate and a solution in boiling water of its 

 equivalent of silver sulphate.' (Then follows its analysis, showing it 

 to be anhydrous). With the acid itself fit disposal, the above mode of 

 preparing the salt will never be adopted. The hardness and brittleness 

 of the crystals are no more noticeable than in crystals of silver nitrate 

 or of amidosulphonic acid ; Berglund was impressed by these 

 properties, probably, because most amidosulphonates form delicate 

 fibrous crystals. 



Silver amidosulphonate cannot be prepared from the potassium 

 salt and silver nitrate. The most concentrated solutions of these salts, 

 mixed in molecular proportions, yield no crystals, even in contact with 

 one of silver amidosulphonate itself. Thus, we may prepare a 

 solution equivalent to that of the salt in twice its weight of water, al- 

 though the salt is not soluble in less than fifteen parts. Such a solution, 

 with a crystal of the silver salt in it, dried up in the desiccator, gave 

 three kinds of crystals ; some were silver amidosulphonate in com- 

 bination, apparently, with nitrate ; others were potassium nitrate ; 

 and the rest in opaque prisms, were silver potassium amidosulphonate 

 nitrate. The unreadiness here displayed by the potassium, to give 

 place to silver, is more strikingly manifested in the behaviour of the 

 silver salt towards alkalis. 



Potassium hydroxide added to a solution of the silver salt, not 

 too dilute, gives a bright yellow-ochre precipitate, in tough, granular 



