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clastic vapour istues with vehemence through the smallorifice, and the fire is animated in the lame manneras by air impelled by bellows; whence this instrumenthas been called the æolian bellows and philosophers bel-lows. From this effect of the æolipile on an open fire, it hasbeen imagined that it would perform the fame office whenits neck was inserted, like the nose of a common bellows,into the cavity beneath the grate of a furnace, and accord-ingly some practical writers have given figures of it asemployed in this use. But on trial, I have constantlyfound it, when thus applied, instead of exciting, to ex-tinguish the fire ; and the event was the same, in all othercafes, where the vapour did not pass through a portion ofthe atmosphere before its admission to the burning fuel.From this observation it may be presumed, that it is notthe included matter, or any particular element in it, thatanimates fire, but the common air of the atmospherewhich the watery vapour imbibes or propels before it.This mention is here made of the æolipile, to preventethers from being put to the expence and disappointmentof such an apparatus as gave rife to these observations.

A CLOSE-bottomed pot, such as that used for the fore-going blast furnace, but without a grate, makes a furnacefor the fusion of metals, the revival of metallic calces, andthe smelting or assaying, of ores, trans, carbones as it iscalled,, or in contact with the burning fuel, as practised-in the large works. The furnace being intensely heated,and almost filled with fuel, some of the subject-matter issprinkled upon the coals, chiefly about the middle, andtowards the side opposite to the bellows, but with carethat it no where touch the fide : more charcoal is thrownover it ; the fire, according to the nature of the subject,is either kept up strong, or abated a little, by Lessening

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