52 Drushel and Linhart — Metallic Alkyl Sulphates. 



phate had settled. The clear liquid was decanted and concen- 

 trated on the steam hath in a large crystallizing dish to incip- 

 ient crystallization.* The solution was theu rapidly filtered, 

 by means of suction, through a hot water funnel to prevent 

 crystallization on the filter. The clear filtrate was quickly 

 transferred to a crystallizing dish, which was placed upon snow 

 or shaved ice. During the process of cooling the liquid was 

 kept agitated by rapid stirring, and when well cooled the finely 

 crystalline mass was transferred to a Buchner funnel and freed 

 from mother liquor by suction. Finally the salt was well dried 

 on a porous plate and between filter papers and put into glass 

 stoppered bottles. , 



The salt thus prepared corresponds to the formula : 

 Ba(C,H 6 S0 4 ) 5 .2H,0. 



BaS0 4 calculated 

 Salt analyzed BaS0 4 found from formula 



0-9080 s rm 0-4998s rm 0-5004s rm 



55-05$ 55-11$ 



Method of hydrolysis. — In order to duplicate, if possible, 

 the results of Kremann we worked under conditions described 

 by him, using, however, a temperature of 60° instead of 55° or 

 66° C. The hydrolyses were made in sealed test tubes of about 

 30 cmS capacity. Twenty cubic centimeters of water, or aqueous 

 hydrochloric' acid, and l'351 grm of Ba(C,H 6 S0 4 )„.2H 2 (corre- 

 sponding to 1-236^"" of Ba(C 2 Hj30 4 ) 2 , "the amount used by 

 Kremann) were introduced into each tube. As soon as ten 

 tubes were thus charged with the salt and water, or acid of a 

 given concentration, they were sealed, cooled, and shaken until 

 the salt was entirely dissolved. They were then submerged in 

 the thermostat and held in position by coil springs. At certain 

 intervals a tube was withdrawn and the hydrolysis checked by 

 cooling in ice-water. The contents of the tube were filtered 

 through an ignited and weighed perforated platinum crucible 

 fitted with an asbestos mat. After thoroughly washing the 

 precipitate with hot distilled water, the crucible was ignited, 

 cooled in a desiccator and weighed. 



The precipitate obtained as previously described was not 

 quite pure barium sulphate, for on heating the crucible to incip- 

 ient redness the material began to char, first around the edges, 

 then gradually toward the center until the whole mass assumed 

 a grayish appearance. This was not due to insufficient washing 

 of the precipitate, for the final wash water gave no indication 



* Contrary to Kremann's results, we found that this method of prepara- 

 tion is very satisfactory, and that the loss of salt due to hydrolysis during 

 evaporation is very small. 



