California Gold Region. 157 
mont’s new map), and in many other places, are represented 
as peculiarly rich. 
There was one specimen of gold, mingled with quartz, 
found near Stanislaus last autumn, which I had resolved to 
procure, if possible, for the cabinet of Yale. It was irregu- 
lar in form, about 4 inches in diameter, and weighed 53 
pounds avoirdupois. The metal was interspersed in irregular 
masses through the stone, and, as near as I could judge with- 
out special investigation, was equivalent to about 2 pounds 
troy, perhaps a little more. Other specimens, much larger, 
are said to have been found, and one of 20 pounds weight 
pure, near the Stanislaus ; but these I have not seen.—( Ame- 
rican Journal of Science and Arts, vol. vili., No. 24, 2d Series, 
p. 415.) 
On the Identity of Sillimanite, Fibrolite, and Bucholzite, with 
Kyanite. 
Sillimanite was originally described by Bowen,* from an analysis 
made in Yale College Laboratory, in 1825, which, shewed it to be a 
silicate of alumina with a proportion of silica too high to allow it to 
come within the formula of Kyanite. It was subsequently analysed 
by Dr Thomas Muir, in the laboratory of Dr Thomson, who found 
in it a large quantity of zirconia, an observation which all subsequent 
researches have failed to confirm. Since that time, it has been ana- 
lysed by various chemists, viz., by Connel, Norton, Staff, Hayes, 
and Thomson. The most recent of these analyses which has been 
published, is that by Thomson, who reports it to contain 45-65 per 
cent. of silica. We have, then, the following discordant results in 
the amount of silica found in Sillimanite by different chemists, in 
the order of their publication :— 
Bowen. Muir. Connel. Norton. Staff. Hayes. Thomson. 
Per cent. 42°67 38:67 36°75 - 37:40 37:36 42°60 46°65 
The cause of this disagreement will undoubtedly be found in the 
difficulty of effecting a complete decomposition of anhydrous silicates 
of almunia, which contain a high per-centage of alumina. This de- 
composition can be completely effected only by the aid of caustic 
potash, applied to the mixture of carbonates and the mineral during 
the fusion, as first recommended by Berzelius, or by fluo-hydrie acid. 
* Journal Acad. Nat. Sci. Phil., iii. p. 375. 
