[ 28 ] EXPERIMENT XL. 85. If an ore before its calcination has a fibrous, ftriated texture, it is probably an antmonial one; it therefore may be put into a pot with a fmall hole at its bottom, fixed into another pot or crucible, without touching its bottom, and then let it into a forge; when it will yield with eale in the lower pot crude antimony. EXPERIMENT XLI. 86. If a ftrongly-calcined ore be infufed with acid of vitriol, and the folution after evaporation and cryftallization will yield white or rofe, coloured cryftals, it is zinc or calamine. EXPERIMENT XLIT By. If an ore before calcination be very onder- ous, has a. dark-red or black and redVibur, and a ftriated fibrous texture, it is probably a mercurial ore; and it may be eafily afcertained by the following method: Take a clear earthen fmall pot, fit into its mouth, as exadtly as pofiible, a flat piece of iron, pierced with a quantity of fmall holes; pour fbme water into the pot, about two inches high ; then take the ore, put it on the iron plate; take another pot, exa&ly fitting within the mouth of the former, lute all the holes, efpecially round the joining of the two pots, carefully. Bury the firft or lower-maft pot in aihes, or foil, and cover it round with ftones; then make a good fire round the uppermoft pot, till it becomes red- hot; keep it thus for about half an hour; after which operation, the quicksilver muft needs be in the lower veflel, covered with water. A SERIES