ANALYSIS. 255 



(2.) The fluid and the edulcorating water were evaporated Defcription and 



to drynefs, and rediflblved in diailled water. Here again, to ^".^'^^'^ «/ * 

 ■' ' „ , . mineral from 



my furprife, a reparation took place of a white earth, more Cornwall. 



abundant than is uiual in cafes where ammonia is employed as 



a precipitant. 



(3.) This earth and the precipitate were edulcorated with 



diftilled water, until it ceafed to afFeft a folution of nitrite 



of mercury. Collefted, dried, and ignited, for one hour 



it weighed zvhiljlji ill warm 32 •^%. 



F. 



(1.) This earth was placed in a crucible of platina, and 

 repeatedly moiftened with fulphuric acid, which was abftrafled 

 from it in the fand bath; diftilled water afFeded the folution 

 pf the whole, except a white powder which weighed, after 

 ignition, 2/^ grains. It was proved to be filica. 



(2.) This folution was now mixed with fome acelat of 

 potafh and gradually evaporated; large and regular cryftals 

 of alum were from time to time formed. A fmall portion 

 of filica which weighed after ignition -j^ of grain was de- 

 pofiled; fome fulphate of lime alfo made its appearance, 

 which walhed with diluted alcohol and dried in a low heat 

 = -f? of a grain. 



(3.) A portion of the fluid remained which neither the addi- 

 tion of potafli nor the lapfe of many weeks could induce to 

 cryftallize. Sufpefting that it might contain glucine, I preci- 

 pitated the contents by carbonate of ammonia, added to excefs, 

 and ftiook the mixture repeatedly and ftrongly. The precipi- 

 tated earth was colleded and the fluid boiled, but it was found 

 to contain nothing but a minute portion of alumina. 



(4.) The edulcorated earth was rediflblvedin fulphuric acid, 

 except -|- of a grain of ignited filica. 



The folution was mixed with a little potafli, and gradually 

 evaporated. Sulphate of lime was feparated at feveral times 

 and after long intervals, which fufficiently waflied and dried in 

 a low heat = ^^ .Some filica alfo feparated, but too minute in 

 quantity to be afcertained by weight. The remaining fluid at 

 length cryftallized into regulaWy formed alum. 



(5-) The whole, therefore of the 32 ^V (E- 3.) confifted 

 of alumina except 2|. of filica, and the lime contained in j| of 

 fulphate of lime, which may be eftimated about -^ of a grain ; 

 the alumina, therefore, = 29; the alumina in B. and D; = j% 

 Vol. XIII.— March, 1806. T the 



