J. M. Blake on Gay-Lussite from Nevada Territory. 221 
near the shore were not dense enough to deposit these crystals; 
and that if we could reach the island we might find them there, 
where, from the absence of fresh water springs, the saline solu- 
tion of the lake would be more dense. This conjecture was 
fully verified. Mr. Semple, my secretary, succeeded in reaching 
the island in a very insecure boat, where he found the shores 
completely incrusted with beautiful clusters of these crystals, 
whose acute edges cut the naked feet. We secured an abundant 
supply of this rare and interesting mineral which, I believe, had 
not before been recognized in the United States. No other crys- 
tallized mineral was discovered. 
e Gay-Lussite obviously has its origin from the reaction of 
the salts of soda and lime with which the waters are abundantly 
charged, and being very slightly soluble is readily deposited in 
these situations where the density of the water is maintained or 
increased by solar evaporation.’ Hence it does not occur along 
the shores where the marginal springs of fresh water dilute the 
solution. The flow of these springs does not in summer fully 
replace the solar evaporation, as is evident from the water-line 
retiring slightly from its winter level. 
_ This interesting lake has no outlet. It has plainly been a 
point of volcanic activity in modern geologic times, its eruptions 
being confined to mud, ashes, pumice and lapilli. It is one of a 
considerable number of similar phenomena with whic reat 
Basin is dotted, and of which Mono lake, on the western margin 
of the Desert, is the most remarkable. The bottom of the an- 
with dead fresh-water modern shells, chiefly univalves. 
‘Seieennilaeeeni 
ArT. XXXIV.—On crystals of Gay-Lussite, from Nevada Terri- 
tory; by Joun M. BLAKE. 
THE crystals of Gay-Lussite here described were obtained by 
Prof. B. Silliman in 1864, at Little Salt Lake, near Ragtown, 
Churchill Co., Nevada. The crystals differ strikingly from 
thosé measured and described by Phillips (Phil. Mag. April, 
1827) in the proportional development of the planes as is shown 
by comparison with the figures given by Phillips, and by Des- 
cloizeaux (Ann. Ch. Phys., 8d series, vol. vii, p. 489). 
* Gay-Lussite has been made artificially by J. Fritzsche, by mixing eight parts 
by measure of a saturated solution of carbonate of soda with one of a solution of _ 
chlorid of calcium of 1-130—1-150 specific gravity.—J. f. pr. Ch., xciii, 339. 
Am. Jour. 8c1.—Szconp Sxrizs, Vou. XLII, No. 125.—Sept., 1866. 
29 
