8ULPHATE OF BARYTA IN ACID SOLUTIONS. 



89 



TABLE No. 2. 



1 was much surprised to find, that even after standing twenty- 

 four hours, no precipitates were formed in jars Nos. 6, 7, 8, 9, 

 and 10, although the quantity of salt employed was capable 

 of giving rise to 4.46 of sulphate of baryta. 



These results are also interesting in another point of view, 

 viz., if we calculate the quantity of sulphate of baryta dis- 

 solved by lOOOgrs. of acid in jar No. 6, the quantity found 

 is 1 .593, or in other terms, there is .592 more salt dissolved 

 per 1000 grs. of acid, than in the jar No. 2 of No. 1 Table; 

 this difference of solubility can only be owing to the influence 

 exercised by a greater quantity of sulphate of potash and 

 nitrate of baryta being employed, since everything else was 

 equal. In pursuing the reading of this paper it will be seen 

 that the influence exerted by quantity on mass is clearly con- 

 firmed. Having remarked that in the jars, Nos. 1, 2, 3, 4, 

 and 5, of the above series, the precipitates diminished rapidly 

 in quantity, I collected them, and washed them until the liquor 

 gave no precipitate, either with sulphate of potash or nitrate 

 of baryta ; but these washings are very tedious, the nitrate of 

 baryta or the sulphate in excess adhering to the sulphate of 

 baryta with extraordinary tenacity ; and this difficulty, as I 

 frill show further on, increases still more when the recom- 



