of Alkalies and Earths, 347 



ture wss evaporated to drynefs ; and towards the end of the 

 evaporation care was taken to add a gramme of nitric acid to 

 diflblve the oxalate of lime which might be produced. The 

 evaporation was repeated four ix.wts, fucceflivelv, adding wa- 

 ter at each operation, and a gramme of nitric acid. The 

 refiduum was then taken up by a new <5uantJty of diftilled 

 water, which completely dilTolved the whole of the matter. 

 As there were fome atoms dilfeminated throughout the li- 

 quor, it was filtered, but it was not poflible to appreciate thd 

 refiduum, as the liquor was very clear. The nitric acid was 

 faturated with ammonia, to precipitate the oxalate of lime; 

 but in vain was an excels added, for tlie liquor ftill remained 

 clear. 



The fame experiment performed cold did not exhibit more 

 fuccefshd refults, though the mixture remained fifteen days 

 in contact, as reconmiended by the authors above mentioned. 



Ex'P V. The fifth experiment, which feems to have con- 

 firmed C. Guyton and Deformes in the opinion they had 

 formed of the converfion of potafli into lime, is that which 

 they performed with hyper-oxygenated muriate of potatli and 

 the phofphoric acid. ^\fter treating a mixture of 20 grammes 

 of this fah with 10 grammes of acid till reduced to glafs, 

 they dillolved it in water; and, having faturated the excefs of 

 acid by ammonia, filtered the liquor, expofed it to evapora- 

 tion, and made it again pafs to the ftate of glafs. By fix dif- 

 ferent evaporations, they obtained two or three grammes of 

 phofphate of lime, as they believed. 



irt, The hyper-oxygenated muriate of potafli, decompofcd 

 by the phofphoric acid, obferving the proportions above an- 

 nounced, produces, by evaporation to drynefs, a vitriform mat- 

 ter, a part of which remains infoluble in the water under the 

 form of a granulated white powder brilliant like I'alt. 



2d, The li<|uor feparated from the infoluble part being 

 again calcined, ftill leaves a certain quantity of infoluble 

 powder fimilar to the former; a third calcination produces 

 the fame etfecT: ; and fo in fucceffion, till the matter is ahnoft 

 entirely converted into this infoluble powder. 



3d, If the calcination is performed in a ftrong heat, and 

 continued a long time, the quantity of the infoluble powder 

 is more confiderable, and fewer calcinations are required to 

 convert the matter into this powder. 



It is feen by the three preceding paragraphs, that we ob- 

 tained a great deal ot this fait; it is indeed not difficult to 

 procure it. We fiiall now defcribe the experiments to which 

 we fubjected it, and which evidently proves that this fait is 

 toot pholphale of lime. 



4th, 



