ihc lariarcnx A/iJ from a-uJe Tartar. ^J 



feparable part of their colour, and until they become infipict. 

 This tartrite of lime is then deoompored by eight pounds of 

 fulphuric acid diluted with as much water; and the acid fe- 

 parated, is again diluted with 50 or 60 pounds of that liquid* 

 It is necefTary that the acid ihould contain a flight excefs of 

 fulphuric acid. The liquor is then feparated from the ful- 

 phat of lime; and after it has been mixed with from four to 

 fix pounds of charcoal duft, it is evaporated to the point of 

 cr)'ftallifation by being kepi in a continual ftate of ebullition. 

 When the liquor has cooled, you feparate from it a fmali 

 remnant of the fulphat of lime which has been depofited, 

 and you fubjecl it to infenfible evaporation to make it crvf- 

 tallife. 



M. Lowitz mentions a mode of afcertaining the jail: pro- 

 portion of the free fulphuric acid which the liquor ought to 

 contain in order to prevent a portion of the tartrite of lime 

 from remaining diifolvcd in the ftate of acidulous tartrite, 

 which caufes the tartarous acid, inftcad of cryftallifing, to 

 confolidate itfelf into a falinc mafs, without form, and pul- 

 verulent. This method confifts in diluting in an ounce of 

 water half a dram (gros) of the acid folution, and adding 

 from 10 to 15 drops of the liquid acetite of lead. On drop- 

 ping nitric acid into this mixture, if the liquid immedi- 

 ately becomes tranfparent, and remains fo for feveral hours, 

 it is a proof that there is too little acid: if the liquid does 

 not immediately become" clear, there is too much : in the 

 laft place, if, after having become clear, it again grows turbid 

 at the end of a few minutes, the juft point has been attained. 

 This trial ought to be made at the time when the liquor has 

 reached the point of faturation to be expofed to cryftalhfe. 



This operation will furnifli eight pounds of tartarous acid 

 in very beautiful cryftals, and exceedingly white. To free it 

 from any of the fulphuric acid which may be adhering to it, 

 nothing will be ncccfliiry but to throw over it a little cold 

 water. 



We would advife thofe who wifli to follow this proccfs, to 

 dilute the fulphuric acid with at leaft four times its weight of 

 water, in order to prevent the de-hydrogcnating adlion of 

 that acid on ihc tartarous acid; not to dilute the acid wdi 



the 



