formerly supposed to be Zeolite , &c. 34a 
and exposed the retort to a charcoal fire. The neck of the 
retort was soon covered with moisture, which passed into the 
receiver ; and I observed a white crust gradually forming in 
the arch and neck of the retort. 
O11 examination of the fluid in the receiver, it was found to 
have the same empyreumatic smell that I had observed before. 
It resembles very much the smell which that fluid is found to 
have which is distilled from the white crust that surrounds 
flint as a nucleus. 
It changed litmus paper to a faint reddish hue. It produced 
no change on a solution of nitrat of silver, and scarcely a per- 
ceptible one, on that of nitrat of mercury. 
The crust formed in the neck of the retort consisted of thin, 
scales, which after the vessel had been dried, were disposed 
to separate from the glass in some places, but in others they 
firmly adhered unto it. They were opaque, like white ena- 
mel, and reflected the colours of the rainbow. A portion 
of this subtance exposed to the flame of the blow-pipe upon 
charcoal turned at first black, and then melted into a globule, 
that exhibited somewhat of a metallic splendor which soon 
grew dull. This substance is soluble in water ; on evapora- 
tion of it, it assumes, at the edges of the fluid, a saline appear- 
ance, which, as the moisture evaporates, becomes earthy, 
opake, and white. Some of the solution changed litmus paper 
to a faint red. Lime and strontian waters produce in it 
white clouds, which a drop of nitric acid removes. Muriats of 
lime and barytes produce no change in it. Nitrat and acetat 
of barytes disturb its transparency, the effect produced by the 
latter is more evident. Nitrat of silver produces no effect, but 
nitrats of mercury and lead cause copious precipitates, which 
