On the Decomposition of certain Sulphomethylates. 41 



Experiment. CaS0'' + 2aq. 



Ca 23-150 23-256 



SO-* .... 55-724 55-814 



HO .... 21-000 20-930 



99-874 100-000 



The crystals were not altered by an exposure of two hours to 

 a temperature of 100° C. ; heated a few degrees above this point 

 they lose water, becoming milk-white. 



The white amorphous powder filling the lower part of the 

 bottle was sulphate of baryta, but occurring here and there in it 

 were botryoidal masses of granular sulphate of lime. An ana- 

 lysis of this sulphate gave numbers approaching somewhat closely 

 to the formula 2CaS0* + aq; a sulphate of lime having this 

 formula has been observed occurring as a grayish crystalline 

 deposit from a boiler working under a pressure of tv/o atmo- 

 spheres*. 



The crystalline crust from which rose the prismatic crystals 

 already described, was also sulphate of lime, of the formula 

 CaS04 + 2aq. 



The yellow fluid previously mentioned was thoroughly ex- 

 amined. Its reaction was strongly acid : on the addition of pure 

 precipitated carbonate of baryta, an escape of carbonic acid took 

 place and a heavy powder was precipitated, this was separated 

 by filtration and proved to be sulphate of baryta. The filtrate, 

 now perfectly neutral, was introduced into a retort and distilled ; 

 water having a slightly aromatic odour collected in the receiver; 

 the residue in the retort solidified on cooling to a mass of colour- 

 less crystals. From this substance, recrystallized by means of 

 alcohol, dissolved in the smallest possible quantity of water, and 

 separated again by spontaneous evaporation of the water, the 

 following analytical result was obtained, the crystals having been 

 dried between folds of bibulous paper: — -415 grm. of salt gave 

 -2445 grm. of suljihate of baryta, corresponding to 58'91 per 

 cent, of Ea SO'^ ; theory, as C^ W Ba 2S0''4-2aq, requires 59-02. 

 A second analysis, for which a portion of the salt dried at 100° C. 

 was employed, gave me the following numbers: — -5605 grm. of 

 salt furnished -3637 grm. of sulphate of baryta, corresponding to 

 61.-88 per cent, of BaSC; theory,asC2H315a2SO'', requu-cs 64-9. 



The saturated solution of this salt is not altered by prolonged 

 ebullition, and the crystals may be heated above 100° C. without 

 becoming acid or otherwise decomposing. 



The final products of the spontaneous decomposition occurring 



* Johnstoq, Pliil. Ma^. vol. xiii. p. 325. 



