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Observations oti

SECTION XIII.

Of the Vitriolic Acid.

H E most remarkable observation that

JL I have made relating to the vitriolicacid will be found under the article of ni-trous vapour with which I impregnated it,and which precipitates all the vitriolic acid,in the form of crystals, and leaves thewater in the possession of the nitrous acid.My other observations are neither nume-rous, nor important.

It is well known that there is an earthymatter in the common oil of vitriol. Butthis I find is not essential to it: for almostthe whole of it is deposited in the first distil-lation, and when I distilled this acid a ie-cond time there was little or none of it left.On this account, oil of vitriol that is con-centrated by merely boiling the water outof it is not quite transparent, the earthymatter being dispersed in it, but that whichhas been diltilled twice may be as highly

con-