Decompofttion cf the Add of Borax. , 293 



in twenty-four hours. I changed the phial, towards the cbfe of the operation, for an- 

 other, that the former might be gently heated^, and the fluid, by that means, be poured 

 back, with the greater fafety, upon the warm fait, through the tube of the retort. In 

 this manner, during an uninterrupted lire of fourteen days, the acid was fourteen timet 

 diftilled, and returned upon the fait. On the third day, yellow fpots appeared. On the 

 fourth, fome particles of oil or fat were difcovered, fwimming on the furface of the fluid 

 in the phial ; which particles, after cooling and emptying the phial, adhered to its fides, fo 

 as to obfcure its tranfparency. More or lefs of thefe oily particles were difcovered in every 

 fucceffive operation ; and the oily xnatter, adhering to the infide of the glafs, increafed con- 

 fiderably. 



Exper. LT. When the fluid was diftilled, the receiver was changed, and the fire increafed. 

 A confiderable quantity of fublimate was obtained, pretty white in colour, as was likewife the 

 furface of the mafs of fait at the bottom of the retort ; but lower down, it was almoft of a light 

 afti-grey. After the fublimate ceafed to arife, I diminilhed the fire. 



Exper. LII. Upon the mafs of the former experiment, I poured the fluid obtained by 

 Exper. XLIX. and continued a gentle digeftion. I very foon perceived fomething rifing 

 towards the furface, and fwimming upon it : after fome hours, it appeared to be a thick wrin- 

 kled (kin, like fat, or a (kin of mould, increafmg in fize, until it covered the whole furface. 

 White fpots of fublimate appeared upon it, but it did not fink. It afliimed gradually a fine 

 lemon colour ; and fome yellow matter, though not in large quantity, afcended the fides of 

 the retort. The fluid having been gently diftilled, and the receiver changed, I placed the 

 retort in an open fire ; on which more fublimate foon appeared ; but, not long after, it all 

 vaniftied, and the retort loft its tranfparency. The mafs contained in it began to rife, firft 

 gently, and then violently, jefpecially in the centre, in large frothy bubbles. The diftillation 

 was finiflied, after obtaining one dram of fluid, and when the frothy bubbling had ceafed^ 

 The retort being broken, that part where the bubbling had been ftrongeft was found to be 

 black ; the upper furface being covered with a thin greyifh matter, under which a folid, 

 compad, and almoft vitrified fubftance appeared. Upon this I poured water, and diflblved 

 it in the ufual manner ; filtered it, let it evaporate, and treated it as defcribed above, Exftr. 

 XXII.— XXX. 



Exper. LIII. I obtained a white fait, a, and fome coal, b (which deflagrated brilkly with 

 nitre), in nearly the fame proportions as throughout the feries of experiments defcribed from 

 Exper. XXII. to XXXIII. which I will not repeat, on a.ccount of the little variety obferved 

 in them ; one of them, however, deferves to be diftinguiflled from the reft. 



Exper, LIV. I put fix grains of the coal, b (of Exper. LIII.), in three drartis of common 

 muriatic acid, and digefted them for two days, till the acid had gradually evaporated. I then 

 added one dram of the fame acid, with one fcruple of nitric acid, and, when they had eva o- 

 rated, boiled the refiduum full half an hour in diftilled water. By this procefs I obtained a 

 red folution ; and having laturated it with mild alkali, a fort of ikin rofe to the furface, with 



V«i. IlI.^OcTOBER 1799. ^^S fome 



