Propirt'ies and Hahltudet of the tiew Earth contained in the Beryl. 361 



5. The nitrate of alumine, mixed with tartrite of potafh, immediately formed a depoff- 

 tion m flocks, and the fuper-natant liquor became clear and colourlefs. — 6. The fait of the 

 earth of beryl, with the fame re-agent, did not produce any fign of precipitation after feve- 

 rnl days. 



7. The- nitrate of alumine, mixed with a folution of the phofphate of foda, afforded a 

 gelatinous femi-tranfparent precipitate, which fubfided very flowly. — 8. The fait of the 

 earth of beryl alfo formed a precipitate with the fame re-agent ; but it was lefs gelatinous,, 

 a«d lefs tranfparent, and it alfo fell down more fpeedily. 



9. The nitrate of alumine, mixed with very pure Pruihate of potafli, inftantly afforded a 

 very abundant whitifli precipitate, which becama green at the end of a few hours. — 10. 

 The fait of the earth of beryl, with the fame re-agent, afforded no precipitate, even after 

 feveral days. ■ 



II. Th.e nitrate of alumine, mixed with a faturated folution of potafli, afforded a gelati- 

 nous magma, which was femi-tranfparent, and foon becajne filled with numerous bubbles 

 of gas, which raifed it to the upper part of the fluid. — 12. The fait of the earth of beryl, 

 mixed with the fame re-agent, afforded a precipitate in flocks, which was not filled with- 

 bubbles like the foregoing, and which fell to the bottom of the liquid. 



13. The nitrate of alumine, mixed with a fokition of cauflic potafli, at firfl afforded a 

 gelatinous depofition, which was afterwards taken up by the excefs of alkali. — 14. The fait 

 of the earth of beryl, treated with the fame re-agent, was affetled in the fame manner, ex- 

 cepting only that a larger quantity of alkali was required for the fecond folution. 



15. The nitrate of alumine, mixed with a folution of carbonate of ammoniac, formed a 

 precipitate which was not rediffolved by an excefs of alkali. — 16. The fait of the earth of 

 beryl, mixed with the fame re-agent, afforded a precipitate which was entirely re-diffolve'd 

 by an excefs of alkali. 



We fee by moft of thefe experiments, that the earth of beryl effentially differs from alu- 

 mine, which however it refembles much more than any other earth, and with which it may 

 even be eafily confounded in certain refpe£ls. 



But the experiment which induced me to fix my opinion irrevocably with refpecl to this- 

 earth, was that which fliewed the comparative degree of attraclion of the two earths for the 

 fame acid. 



To acquire this knowledge, I diffolved in the nitric acid twelve parts of very pure alu- 

 mine, and evaporated to drynefs, in order to expel the furplus of acid which was in the 

 fluid. The refidue being diflblved in water, I added to the folution ten parts of the earth 

 of beryl, recently precipitated from its folvent, well wafhed, and (till moift. 



I added no more than ten parts of the earth of beryl, to precipitate the twelve parts of 

 alumine, th(jugh I had afcertained, by other experiments, that a fomewhat greater quantity 

 ef the earth of beryl than of alumine was neceffary to faturate the fame quantity of acid ; 

 but I chofe rather that a fmall quantity of alumine fhould remain in folution, than that 

 any portion of the earth of beryl fliould mix with the precipitate. When therefore the 

 mixture had thus been made, I boiled the fluid for a quarter of an hour, then filtered it, and 

 retained on the filter the earthy precipitate. After wafliing this, I combined it with the ful- 

 pauric acid, and evaporated to drynefs, in order to expel the excefs of acid j after which, 



rerdiffohinS- 



