fonts chemical Experiments on Tabalheer. 381 
and very flowly. When the folution was effe&ed, the faline 
pearl remained perfectly clear and colourlefs. 
(B) With phofphoric ammoniac (made by faturating the acid 
obtained by the Cow combuftion of phofphorus with cauftic 
volatile alkalij the Tabalheer very readily melted on the char- 
coal at the blow-pipe, with effervefeen.ee, into a white frothy 
bead. 
(C) Fufed, by the fame means, on a plate of platlna, with 
the vitriols of tartar and foda, it appeared entirely to refill 
their adtion ; the little particles employed continuing to revolve 
in the fluid globules without fuftaining any feiifible diminution 
of fize, and the faline beads on cooling affumed their ufual 
opacity. 
(D) A bit of Tabalheer was laid on a plate of filver, and a 
little litharge was put over it, and then melted with the blow- 
pipe. It immediately adted on the Tabalheer, and covered it 
with a white glaffy glazing. By the addition of more litharge 
the mafs was brought to a round bead, though with confidera- 
ble difficulty. This bead bore melting on the charcoal, with- 
out any reduction of the lead, but could not be obtained 
tranfparent. 
(E) The eafe with which this fubllance had melted with 
vegetable alhes, led to the trial of it with pure calcareous 
earth. A fragment of Tabalheer, fixed to the end of a bit of 
glafs, was rubbed over with fome powdered whiting. As foon 
as expofed to the flame of the blow-pipe, it melted with confi- 
derable effervelcence ; but could not, even on the charcoal, and 
with the addition of more whiting, be brought to a tranfparent 
flate, or reduced into a round bead. 
Equal weights of Tabalheer and pure calcareous fpar, both 
reduced to fine powder, were irregularly mixed, and expofed 
in 
