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those existing in the case of our earth, we are boundto recognize at least the possibility that water once
cinder oozes from below. The outflow from this chasm soon becomeslocalized so as to form a single crater, or a small chain of craters;these gradually develop into cones by the accumulation of out-flowing lava, so that when the whole mass has solidified it iscovered more or less thickly with a number of such hillocks.These, however, are much smaller than in the former case, reachingto only one or two inches in height, with a proportionate base. Itis evident that the dimensions of these miniature volcanoes aredetermined mainly by the depth of the molten matter from whichthey are formed. In the case of the bogies, they are exaggeratedby the overpowering resistance of the solid iron bottom and sides,which force all the exudation in the one direction of least resistance,viz., towards the centre of the thin upper crust ;’and thus a singlecrater and a single cone of the large relative dimensions abovedescribed are commonly formed. The magnitude and perfection ofthese miniature volcanoes vary considerably with the quality ofthe pig iron and the treatment it has received, and the differenceappears to depend upon the evolution of gases, such as carbonicoxide, volatile chlorides, fluorides, &c. I mention the fluorides parti-cularly, having been recently engaged in making some experimentson Mr. Henderson’s process for refining pig iron by exposing it whenfused to the action of a mixture of fluoride of calcium and oxides ofiron, jalumina, manganese, &c. The cinder separated from thisiron displayed the phenomena above described very remarkably,and jets of yellowish flame were thrown up from the craters whilethe lava was flowing. The flame was succeeded by dense whitevapours as the temperature of the cinder lowered, and a deposit ofsnow-like flocculent crystals was left upon and around the mouthor crater of each cone. The miniature representation of conicaleruptions was thus rendered still more striking, even to the whitedeposit of the haloid salts which Palmieri has described as remain-ing after the recent eruption of Vesuvius .
“ The gases thus evolved have not yet been analyticallyexamined, and the details of the powerful reactions displayed mthis process still demand further study, but there can be no doubt