[ 2Z6 ]

grains formed a kind of close plates, and the mass provedvery compact. In some, the texture was close and eventhroughout, without any distinguishable grains, fibres, orplates. Of some of these variations, the probable causeswill appear in the following section : others depended per-haps upon the nature of the glass employed.

Notwithstanding these, and other lesser differences, thegeneral appearances, and the gradation of the visiblechange proportionably to the degree of baking, are sostrongly marked, that, from the texture of the porcelainon breaking, we can always judge with certainty of itsquality, or of the degree to which it has been baked.Reaumur has also taken notice of something of this kind,finding the porcelain sometimes turn out granulated in-stead of fibrous : but his experiments do not seem to havebeen carried far enough to discover the foundation of thisdifference ; to discover, that the different kinds of textureregularly succeed one another from the continued actionof one cause, that they are all at the command of theworkman, and that they are accompanied with remark-able differences in the intrinsic qualities of the porcelain.

S E C T. II.

Experiments of the quality of the fubfance into which GreenGlass is converted by baking.

T H E porcelain into which glass is converted by bak-ing, whatever its superficial colour be, is, in its inter-nal substance, always white ; and its whiteness is frequentlynot inferiour to that of the internal part of China ware. Itssurface is unhappily the part which is least beautiful. Allthe thick pieces were quite opake : several thin ones hada degree of transparency, resembling that of China ware.In this respect considerable differences appeared : a very

thin