34^' On the Analyjts and Sjmthcjls 



give no proportions, I fliall make known thofe which I em- 

 ployed, and the refult I obtained. 



To get pure oxalnte of potafn, I faturated potafli purified 

 by alcohol with oxalic acid. I took i8 grammes of this fait, 

 evaporated almoft to drynefs, and, havino; mixed it with 9 

 grammes of fubiimated fulphur, moiftened the mixture with 

 half H decilitre of water. I then placed the cai)fule contain- 

 ing it on a fand-bath, and evaporated it at a gentle heat. The 

 refiduum taken up by diftilled water being fihered, there re- 

 mained on the filter a blackifli yellow reliduum, and the li- 

 quor had aflTumed a flight yellow colour. The refiduum was 

 treated with nitric acid; but notwithftanding the care em- 

 ployed in this operation, no oxalate of lime was found. The 

 acid liquor abfolutely contained none of it. The fulphur 

 which remained was burnt in a platina crucible, and left no 

 refiduum whatever. 



Hoping that this experiment would fucceed better with a 

 ftronger heat, the fame quantities of oxalate of potafh and 

 fulphur were employed, and the mixture was placed in a 

 platina crucible over a naked fire. Half an hour after, being 

 brought to a red heat, it was taken off, and the mafs obtained 

 was treated with diftilled water, which atfumed a dark >el- 

 low colour, and the real fmell of an hydrogenated fulpburet. 

 The liquor was filtered, but no lime was found in the refidu- 

 um. This refiduum, which weighed only two centigrammes, 

 was found to be charcoal, furnifhed in all probability by the 

 potafli emplin'cd, which had been purified with alcohol. I 

 aflured myfeU" that all the oxalate of potafli had been deconi- 

 pofcd, and that there had refulted from it a fulphate of 

 potafli. 



Exp. IV. They put oxalate of ammonia into ver}^ pure 

 oxygenated muriate of potafli, and caufcd it to evaporate at 

 feveral times, taking care to maintain an cxcefs of nitric 

 acid to diflblve the oxalate of lime which was formed. In 

 this manner a very large quantity was obtained. 



This fourth experiment, which appears to be that which 

 has hitherto given to the above authors the mofl: lime, by the 

 decompofition of the hyper-oxygenated muriate of potafli, 

 was made vi'ith great care, but always without fucccfs. As 

 thefe authors do not fpeak of the quantities employed, I fliall 

 give an account of my experiment. 



I took 16 grammes of h)per-ox3-genated muriate of 

 potafli, pure and cryftallized, and 8 grammes of oxalate of 

 ammonia, alfo pure and cryftallized, and put them into a 

 porcelain capfnle, with two decilitres and a half of diftilled 

 water. The capfule being placed on a fand-bath, the mix- 

 ture 



