280 Experiments on Ailanite. 
at the low specific gravity noted by Mr. Allan, which wag 
3°480, broke down one of the specimens which had been 
sent him, in order to procure the substance in the purest 
state possible, and the result of four experiments was as 
follows: 4°061, 3°797, 3°654, 3°119.——In a subsequent 
experiment of Mr. Allan’s, he found it 3°665. From these 
it appears that the substance is not in a pure state.’ Its 
colour is so entirely the same with the mica, with which it 
is accompanicd, that it is only by mechanical attrition that 
they can be separated. es 
Colour, brownish-black. 
External lustre, dull; internal, shining and resinous, 
slightly inclining to metallic. — wiv iis 
Fracture, smal] conchoidal. 
Fragments, indeterminate, sharp-edged. 
Opake. 
Semi-hard in a high degree. Does not scratch quartz 
nor feldspar, but scratches hornblende and crown-glass. 
Brittle. ay we : 
Easily frangible. 
Powder, dark greenish-gray. ae 
Before the blow-pipe it froths, and melts imperfectly inte 
a brown scoria. j 
Gelatinizes in nitric acid. In a strong red heat it loses 
3°98 per cent. of its weight. ; 
Il. Experiments to ascertain its Composition. 
My first experiments were made, on the supposition that 
the mineral was a variety of gadolinite, and were pretty 
much in the style of those previously made on that sub- 
stance by Ekeberg, Klaproth, and Vauquelin. — 
1. 100 grains of the mineval, previously reduced to a 
fine powder in an agate mortar, were digested repeatedly 
on a sand-bath in muriatic acid, till the liquid ceased to 
have any action on.it. The undissolved residue was silica, 
mixed with some fragments of mica. Wher heated to 
redness, it weighed 33°4 grains. 
- 2, The muriatic acid solution was evaporated almost to 
dryness, to get rid of the excess of acid, dissolved in 4 
large quantity of water, mixed with a considerable excess 
of carbonate of ammonia, and boiled for a few minutes. 
By this treatment, the whole contents of the mineral were 
precipitated in the state of a yellowish powder, which was 
Separated by the filter, and boiled, while still moist, in pot- 
ash-ley. A small portion of it only was dissolved. The 
potash-ley was separated from the undissolved portion by 
; the 
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