a New Class of Salts. 353 



purple blue shade. It cannot then be dried in the water-bath, 

 where it quickly decomposes and becomes green. 



The following analysis wa6 made on two portions which 

 were dried in the air-pump, until they ceased to lose weight 

 and had all their properties unchanged. They were oxidized 

 by nitrate of ammonia ; the residue was dissolved in nitric 

 acid. The iron was precipitated as peroxide, the sulphur 

 estimated as sulphate of barytes, and the soda as a sulphate. 



I. 14-210grs. gave 3-4.20 Fe^ O^, 5-710 BaO, SO^ and 9-38 

 NaO, SO^. 



II. 8-99 grs. gave 3*88 BaO, SO^, and 6-62 NaO, S0^ the 

 iron being accidentally lost. 



The combustion was made by chromate of lead, peroxide 

 of lead being used to arrest the sulphurous acid. 



I. 6-20 grs. gave 3-855 grs. CO^ and 0-440 gr. HO. 

 II. 10-565 grs. gave 68 10 grs. CO^ and 0-675 gr. HO. 



100-00 10000 100-00 



In such a variable compound as this, close results can 

 scarcely be looked for in two analyses. As an approximation, 

 however, it will be seen that the iron is to the sodium as 5:8, 

 and to the sulphur as 5 : 3. 



The blue unchanged compound gives with protosulphate 

 of iron a beautiful precipitate of the same purple blue colour 

 as itself, but this is decomposed by washing. With salts of 

 lead it gives a brownish-yellow precipitate, with salts of copper 

 a brown precipitate, both these being obviously products of 

 decomposition. 



28. The purple blue compound dissolved in water speedily 

 becomes red, and when in this state, a salt of lead throws 

 down a pinkish red precipitate. This red solution however 

 soon decomposes, a brownish precipitate falling, and the yel- 



* It should be stated that in many analyses of this compound in its par- 

 tially decomposed state, the most discordant results were obtained. The 

 two analyses here adduced were made on the only specimens which appear 

 to be unchanged; in all the other cases the compound had become green 

 and therefore was decomposed, as it no longer dissolved in water with its 

 characteristic purple tint. 



