7i 
of the Acid of Borax . 
hours, with a gentle heat. Upon the fluid swam a white com- 
pact substance, and some small particles of the same kind lay 
at the bottom, which however rose, on the application of heat, 
and swam about with the rest. 
Exp. lviii. to lxiii. I poured the whole distillation back 
upon the salt, and, by means of a digesting heat, again drew 
off a fluid, which appeared covered with a thin fat skin. I then 
poured the fluid back, distilled it again, and thus repeated the 
process three times more. No phaenomenon particularly re- 
markable appeared, except that the thin fat skin grew more 
inconsiderable, and at last seemed almost to vanish. 
Exp . lxiv. The salt separated from the fluid, by the gentle 
distillation in Exp. lxiii. emitted now, by the force of additional 
heat, dark red vapours, as is usual in strong nitrous acid. 
When the distillation was at an end, the retort was exposed to 
an open fire ; but, during this operation, no black matter ap- 
peared ; nor was any coal separated from the mass, upon dissolv- 
ing it in distilled water.* 
Exp. lxv. I now tried the effect of a mixture of four drams 
of strong vitriolic acid and twelve drams of the muriatic acid, 
repeating the usual digestion and distillation six times. I will 
pass over other circumstances, and only mention, that after the 
sixth distillation of the fluid, a stronger heat, and at length an 
open fire, was applied; but hardly any fluid was produced, 
though the fire was so violent, that the whole mass appeared 
to be melted down into one uniform compact substance. 
Exp. lx vi. The vessels having cooled, the mass was of a 
* Here the nitrous acid seemed to destroy, and carry off, the inflammable matter, 
sooner than it could become coal ; as it had before occasioned the oily and fat sub- 
stance to vanish, in the beginning of this experiment. 
