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larger admixture ossaline rnatter: they begin to melt nearlyas soon as the fire is raised high enough to change them ;and how carefully soever the process is managed, a partof the inside commonly runs out, and the sand they aresurrounded with bakes into a hard crust upon the surface.The lower portion of one of these vials having been ce-mented with a mixture of sand and gypsum, a part of itappeared changed throughout into a pretty hard porcelain,a part into a substance resembling the mixture baked to-gether, and a part seemed scarcely changed at all: therewere many large cavities, and the glass, which had runout from them, coated a part of the mixture with a greenglazing. In some other trials the change was more equal,but I have never obtained from these vials a porcelain souniform, or so hard, as from the common bottles.

Glass tubes, of a pale green colour, were affected nearlyin the same manner as the Hungary water vials : theyseemed to be somewhat less disposed to melt, and the sanddid not so strongly adhere to them : from whence it maybe presumed, that this kind of glass has a larger propor-tion of saline matter than the common bottles, but less thanthe Hungary vials.

The common pale green glass retorts and receivers didnot answer well. A piece cut off from the bottom of aretort, and several circular segments of receivers, wereplaced within one another in a large pot, with some boneash between and surrounding them, and cemented in awind-furnace for several hours. They ail became brown-ish, rough and shrivelled on the surface, in some parts blis-tered, and in some extremely thin as if part of the glasshad melted off. They were semitransparent, nearly inthe same degree as the finer sorts of stone ware. Theyeasily broke, and appeared internally white, not fibrous orgranulated, but of a smooth glassy surface.

Kk

Common