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parcels of lamp-black, procured from different shops, Icould not find that it gave any tincture at all, either tospirit or to water.

Suspecting some mistake or sophistication, or that thelamp-black had been burnt or charred, as it sometimes isto sit it for some particular uses, I prepared myself somesoot from linseed oil, by hanging a large copper pan overthe flame of a lamp, to receive its smoke. In this me-thod the more curious artists prepare lamp-black for thenicer purposes, and from this collection of it from theflame of a lamp, the pigment probably received its name.The foot so prepared gave no tincture either to water orto spirit, any more than the common lamp-black of theshops. I tried different kinds of oily and resinous bodies,with the fame event: even the foots obtained from fishoil, and tallow, did not appear to differ from those of thevegetable oils and resins. They were all of a finer colourthan the lamp-black commonly fold.

Some foot was collected in like manner from fir andother woods, by burning small pieces of them slowlyunder a copper pan. All the soots were of a deeper blackcolour than thole obtained from the lame kinds ot woodin a common chimney, and very little if at all inferior tothose of the oils : they gave only a just discernible tinctureto water and spirit, while the soots of the chimney im-parted a strong deep one to both. she loot of mineralbitumens, in this close way of burning, appears to beof the fame qualities with those of woods, oils, and re-sins : in some parts of Germany, as I am informed by aworthy foreign correspondent, great quantities of goodlamp-black are prepared from a fort of pitcoal.

It appears therefore that the differences of foots do notdepend altogether on the qualities of the subjects, but ingreat measure on the manner in which the subject is

burnt,