jl^^' ^mt'ity ef the tnvo Sarlfs cwtaimi h the Btrjf. 



iiartronate liad Tcry perceptibly decreased. At the expiration of thai time I filtered ths 

 fluid, to feparate the undiffolved part : this laft, after wafliing and ignition, weighed 

 5 grammes, and had all the properties of alumine. 



Expeyime/it 3. — I expofed the ammoniacal folution to the aflion of heat in a capfule of 

 porcelain : as foon as the temperature was fufficiently elevated to drive off the carbonate of 

 ammoniac, a large quantity of a white, granulated, and very voluminous earth was depo- 

 Cted. I continued the evaporation until all the ammoniacal fait was diffipated. I then 

 threw the refidue upon a filter, and waflied it with much water. This refidue, after drying 

 by a gentle heat, was perfe£lly white, pulverulent, and foluble in acids, with a ftrong effer- 

 vefcence. It weighed 4.2 grammes, which by a red heat were reduced to 25 grammes ( 

 whence it follows, that thcfe 42 grammes contained 17 grammes of carbonic acid and 

 writer. 



Confequently, the three quintals of beryl having afforded 24 grammes of the new earth 



which was not difTolved by potafli, and the alumine which thefc three quintals afforded 



having alfo, as has been juft obferved, 25 grammes of the fame fubftance, it is evident that 



each quintal of beryl contains 16,33. One hundred parts of beryl are therefore cotni 



pofed of 



69 parts filex, 



16 earth of beryl, 



13 alumine, 



I oxide of iron, 



0,5 lime, 



99.5 



Experiment 4. — I have obferved in my firft Memoir, that alumine diflblved m the nitria 

 acid was precipitated by the earth of beryl. I was defirous of knowing whether the fame 

 phenomenon would likewife take place with alum. I therefore diflblved one hundred parts 

 of this fait in about fix hundred parts of hot water. The folution afforded cryftals of alum. 

 Into this folution I put a certain quantity of the earth of beryl, recently precipitated from a; 

 falotion by ammoniac, and well wafhed. The mixture was boiled for an hour. I foon per-, 

 ceived that the earth of beryl was taken up ; and in proportion as the excefs of acid in tlie 

 alum was faturated, there fell down a great quantity of earthy matter, in white flocks, in 

 a very divided flate. As foon as the decompofition appeared to me to be complete, I fil- 

 tered the liquor, and coUedbed the precipitated earth, which, when wafhed and difTolved 

 in the fulphuric acid, afforded, with a fufficient quantity of fulphate of pot-afh, cryftals of 

 alum perfedly oftahedral. 



The fluid from which the alumine had been feparated pofTefTed a very faccljarine taflc ; 

 and, when fubjeded to evaporation, it did not afford alum. Hence we find, that the earth 

 of beryl has a greater afBnity than alumine with refpefk to the fulphuric acid, as well as 

 the nitric. 



Experiment 5.— Being defirous of afcertaining ftill more efFe^ually the difference which 

 exifts between alumine and the earth of beryl, I diflblved ten parts of the former earth m 

 the fulphuric acid ; and after having add€d the neceffary quantity of fulphate of pot- 



afh, 



