PRECIPITATION OF A SOLUTION OF SULPHATE OF LIME. Q^J 



it ceased to give signs of acidity; which rendered the pro- 

 cess complicated, and deprived it of precision. 



1 had equally hoped, that carbonate of potash thrown into 

 acetic acid would have given me the ratio of acidity by the 

 quantity of carbonic acid evolved : but 1 found, that trials 

 of this kind differed more from each other than the following. 



I exposed potash to a strong red heal, yet I was lar from That adopted, 

 supposing it to be totally deprived of water. For more r'a- 

 cility of proceeding, and to reduce any errour to a tenth 

 part, I dissolved one part of this potash in nine parts of dis- 

 tilled water. Into a given quantity of the liquids resulting 

 fVom the distillation of the acetates I poured some of this so- 

 lution; and when the tinged papers indicated, that the point 

 of saturation was at hand, by letting it fall drop by drop from 

 a very slender tube I attained a degree of accuracy more than 

 sufficient, to answer the other parts of these researches. 

 (To be concluded in our next. J 



XTV. 



On the Precipitation of a Solution of Sulphate of Lime by 

 Sulphuric Acid. ByT. Le Gay Brewertojj, Fellow of 

 the Royal Physical Society, Edinburgh. 

 To Mr. NICHOLSON. 



N a paper on the acids produced by treating ginger root 

 with nitric acid, which you honoured with a place in your 

 Journal*, was this note, 



| " The fact of sulphuric acid causing the deposition °f sulphate of 

 *f sulphate of lime from a state of solution, to me is not a lime precipi- 

 *f little surprising, however it may perhaps be well known p^uru/acid" 

 " to those more versed in chemical experiments and in no 

 " manner puzzling." 



That sulphate of lime may be rendered more soluble by . . 

 an excess of acid, is a well established fact; but that a still purity of the 

 greater excels of acid should cause the deposition of the acw *> 

 6ulphate already dissolved, seems an operation ot so anoma- 

 lous a nature, that it cannot be received as true without 

 the greatest scepticism. Impressed with this idea, I at- 

 tempted to discover the source whence the deception had 

 originated, and found it to be in the sulphuric acid. 



The 

 *Vol.2XV,p. 177. 



