of Alkalies and Earths, . ^^-^ 



they made ufe of for this compofition, I took, twenty grammes 

 of the nitrate of aUimine, and expofed it to a ftrong heat in a 

 phitina crucible. After three ditTerent and (Ironsr evapora- 

 tions to drynefs, I obtained an earth perfectly white, and 

 infoluble in water. When treated with nitric acid, it was 

 entirely dilfolved. This nitric liquor, which was very clear, 

 was mixed with oxalate of ammonia ; but tliis re-ageut pro- 

 duced no change. The addition of ammonia, fo as to faturate 

 the acid, was tried, but in vain; it was only by an excefs 

 that a precipitate was obtained, but which, being folublc iir 

 potafli, was found to be almiiine; confequently I did not find 

 an atom of lime. It is true, that to prepare my nitrate of 

 alumine I employed an earth perfeAly pure, extraftcd froiu- 

 a natural itone at the time of my experiments on tlvc affinity 

 of earths. The acid employed was alfo very pure. 



Tile nitrate of magneiia, notwithllanding all my care, did 

 not give a more fatisfatlory rel'ult : the lime found by Des- 

 ormes was, no doubt, accidental. 



Kip. XVIil. This cxperirnent, which calls to mind the 

 J4th, 15th, and i6th, on account of the fame pha^nomenon 

 by which they are connected, is that which increafed the 

 opinion of the above authors on the recompofition of fimple 

 earths. Having inltantaneoufly made fulphurct of potafh, 

 and added oxalic acid, they obtained, as they announce, -a 

 fenfible difengagcment of ammonia inftead of fulphuratcd 

 hydrogen, and tlie refiduum was magnefia. 



After making two trials in a porcelain mortar without 

 difcovering ammonia, but a produ6l extremely fetid, which 

 1 fufpeCled might conceal the alkali 1 fought for, to aduFe 

 mvfelf of it I made the following experiments : 



irt, I mixed 30 grammes of puje potaih with 15 grammes 

 of fublimnted fulphur, and the mixture exa£lly made was put 

 into a tuluilated retort with two decilitres of water. 'l"o the 

 beak of the retort 1 adapted a bent tube, wliich was imTncrfcd 

 in a folution of fuli)hate of iron at its maximum oi" oxidation. 

 By the dlfpofition of my experiment it is feen that I muft 

 have perceived the fnialleft portion of ammonia; for it is 

 known, that if the fulphuraled hydrogen docs not precipitate 

 the fulphate of iron green, an atom of this gas combined 

 with anmionia will immediately maJiifcft itfelf. JNly appa- 

 raluB being thus arrange<l, 1 poured into the retort lix gram- 

 mes of pure and cryltatlizcd oxalic acid. A Hrou^ difen- 

 gagcment of fulphuratcd livdrogen was immediately pro- 

 duced ; the Ha(k containing the fulphate of iron was agi- 

 tatwl a long time by thii gafcous fluid j but when the opcra- 



VoL. Xi. Z tion 



