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spongy : but those, in which a large coarse grain hadsucceeded to the sine one, could scarcely be made to sof-ten at all, whether exposed to the fire in crucibles, or incontact with the burning fuel. These unfusible pieces,though a continuance of the baking with a moderate heatwould have rendered them more and more porous andfriable, on being hastily urged with an intense fire becameremarkably more compact than they were before; someof them seemed superiour in solidity to any kind of wareI know of.

It may hence be presumed that the smooth texture ob-served in several pieces after the baking, so close andcompact that neither grains nor fibres can be distinguished,proceeds from their having undergone a greater degreeof fire than the others. Several of the pieces, which ac-quired this appearance in the baking, had in part begunto melt, and others had not : perhaps the former receivedtheir compactness from an augmentation of the heat, inthe earlier period of the cementation, and the latter inthe subsequent stages when their fusibility had beengreatly diminished •, and probably the semitransparencyof some of the compact pieces, and the perfect opacityof others, proceeded from the same cause. It is plainthat the resistance to fire, which Reaumur makes a ge-neral property of this kind of porcelain, belongs to itonly in certain states; and that the vessels, which hefound to bear the vehement heat of a forge, could not beof the fibrous porcelain he describes, but such as had beenbaked considerably beyond that period.

From the foregoing general results of a great number ofexperiments, a particular detail of which could add littleeither to the instruction or entertainment of the reader,it follows, that this porcelain, though little adapted forornamental purposes, on account of its want of beauty4 on