FORMED OF AZOTE, SULPHUR, AND OXYGEN. 475 



are dissolved in pure water. The nitrosulphate of ammonia contains 

 one atom of water ; its formula is : H^ Az'^ S Az% 0\ + HO. 



Nitrosulphate of Potash. 

 This salt is white, very soluble in water, insoluble in alcohol, with- 

 out smell, of a slightly bitter taste, without action upon the test papers ; 

 it crystallizes in irregular hexagonal prisms, similar to those of nitrate 

 of potash. Exposed to a heat of from 110° to 115°, it is not de- 

 composed, nor does it lose any weight ; at a little higher temperature, 

 nearly 130°, it is destroyed ; but instead of being converted into sul- 

 phate and protoxide of azote, like the nitrosulphate of ammonia, it 

 gives rise to a disengagement of deutoxide of azote, and to a residue of 

 sulphite of potash. The weakest acids disengage from it a gas, which 

 has been found to possess the properties and the composition of prot- 

 oxide of azote. 



Platina sponge, oxide of silver, the sulphates of copper and manga- 

 nese, chloruret of barium, and acetate of lead, decompose it and 

 produce the neutral sulphate of potash and protoxide of azote : these 

 actions are always manifested with greater slowness than vdth the 

 nitrosulphate of anmionia. I have already said in general terms that 

 the stability of the nitrosulphate of potash was greater than that of the 

 corresponding ammoniacal compound ; it is even sufficient to enable us 

 to employ boiling water as a means of purifying this salt: in this treat- 

 ment only a small quantity is decomposed ; and by washing with very 

 cold water the ciystals which are deposited in the solution, we easily 

 separate them from the sulphate of potash with which they are im- 

 pregnated. 



This salt is anhydrous, and is formed of one atom of potash and one 

 atom of nitrosulphuric acid. Its formula is : Ka"^ Az- SO*. By ana- 

 lysis it has been found to contain 20 parts of protoxide of azote, and 80 

 of sulphate of potash. 



The nitrosulphate of soda is much more soluble ; in other respects 

 it appears to me to possess the general properties assigned to the last 

 salt ; and as its preparation is difficult, I have not made it the object of 

 particular study. 



It only remains for me, in concluding this Memoir, to consider two 

 principal points of view in which it seems to me possible to regard the 

 constitution of the nitrosulphates : whether they are formed by a pecu- 

 liar acid, composed of two atoms of azote, one atom of sulphur, and 

 four atoms of oxygen ; or sulphates combined with protoxide of azote, 

 acting in an analogous manner to the water of crystallization. The 

 first hypothesis seems to me preferable, and the following are the rea- 

 sons on which it is based : 



1. The nitrosulphates are not precipitated by baryta-water; and, 

 if the protoxide of azote entered into these salts in the way the water 

 Vol. I._Paut III. 2 k 



