412 A Chemical Analyjii of Three Species of Whinjlone, And Two of LaxHi. 



folution was then evaporated to drynefs. A faline mafs remained, confifting, in part, of 

 fulphate of ammonia ; to feparate whicli the whole was expofed to heat in a fmall crucible, 

 and when it ceafed "to emit fumes, the heat was increafed to rednefs. A fixed white fait 

 was left, which weighed 25 grains. 



This fait I re-diflblved in water, added fome carbonate of ammonia, and heated the 

 mixture till it boiled. A fmall quantity of an earthy precipitate was again thrown down, 

 which being feparated by filtration, the folution was evaporated to drynefs, and the fait 

 which remained heated red hot a fecond time. By thefe fucceffive operations, all the earthy 

 matter, at firft diflblved, was fepnrated. The fait now weighed 23 grains, and had all the 

 properties of fulphate of foda. Thefe properties were the following : 



1. It was not volatile in a moderate red heat. 



2. After being thus dried, it diflblved readily .in about fix times its weight of water, at 

 the temperature of 60 of Fahrenheit. 



3. This folution gave, by evaporation, cryftals exaftly the fame in form as artificial ful- 

 phate of foda ; and thefe cryftals .efflorefced in dry air. 



4. A part of the folution of this fait being boiled with carbonate of foda, gave no preci- 

 pitate ; a proof that it contained no earthy matter. 



5- Some of the folution being mixed with a very ftrong folution of acid of tartar, re- 

 mained unafi"e£led ; the fait therefore contained no pot-,a(h. 



6. Some of the fait being diflblved in water, was decompofed by nitrate of barytes ; and 

 the fulphate of barytes produced was feparated by filtration. The nitric acid, thus united 

 to the alkaline bafis, formed a faline compound, which, in the next place, was mixed and 

 deflagrated with charcoal. By wafhing the coaly refiduum, and evaporating the water, I 

 obtained pure carbonate of foda, which efilorefced readily in the air. 



There can be no fufpicion of the retort which was ufed furnifliing any part of the alkali ; 

 for I weighed it previoufly in a balance of great accuracy ; and after the operation was 

 finiflied, found its weight cxa£lly the fame as at firft, and the luftre of the glafs altogether 

 unimpaired. 



The whin which I next fubmitted to examination, for the purpofe of feparating the 

 foda, was taken from a quarry near the Water of Leith*. I ufed a confiderable quantity 

 800 grains; which were diftilled twice with fulphuric acid, and then treated in every re- 

 fpe£l cxadlly as the preceding. The fulphate of foda obtained, amounted to 43 grains. 



I afterwards fubjefted fome other whinftones to the fame kind of procefles, and in each 

 fpecies found foda. The nitric and muriatic acids alfo diflblve a certain quantity of the 

 alkali contained in thefe fubftances ; but their adlion is weaker than that of the fulphuric 

 acid. 



• This fpecies is theiirft mentioned in Sir James Hall's paper. When powdered, it effervefced flightly 

 with acids. I did not analyze it ; but, in the courfe of the procefs foi- detefling foda, one of the earthy 

 precipitates proved, upon examinatien, to be magnefia. It is the only whin in which I have found this 

 earth. 



4 By 



