1866.] Mining, Mineralogy, and Metallurgy. 429 
from the arseniates which had been analyzed by Bournon, Haiiy, and 
Beudant, in containing a notable quantity of oxide of iron. Amongst 
the analyses which have been made of Aphanese or Clinoclase as it 
was supposed, was one by Chenevix, which gave arsenic acid 33°5, 
oxide of copper 22°5, oxide of iron 27°5, water and sand 15:0. 
This was suspected to be an error until Mr. Adam analyzed a 
specimen for M. Pisani, and proved it to be a species different from 
the other arseniates of copper. His analysis was:— 
Arsenic Acid . ° ° ° e ° 32° 20 
Phosphoric Acid . ° . : a AP atL 
Oxide of Copper . : . . s yole70 
Oxide of Iron . ‘ A - ' wah 
Lime 5 : . ¢ c 2 « O34 
Water 3 é . : = 5 POR 
100°30 
To this mineral, which so nearly approaches the arseniate of 
copper analyzed by Chenevix, it is proposed to give the name of 
Chenevixite. It is found in little compact masses in the quartzose 
rocks of Cornwall. They are usually so interpenetrated with the 
gangue, that it has been impossible to separate the one completely 
from the other; thus the density which has been obtaimed 1s only 
approximate, namely, 3°93; its hardness beng 4°8. It is opaque, 
with a conchoidal fracture, and of a dull-green colour passing to 
yellow.* 
A peculiar example of a physical change in a diamond has 
recently been brought under the notice of the Académie des Sciences 
of Paris. M. Frémy exhibited at the meeting on the 7th of May a 
diamond weighing more than sixty grains, which at the ordinary 
temperature is lightly shaded yellow, but which, when submitted to 
the action of an elevated temperature, assumed a rose tint, which it 
preserved for several days, returning gradually to its normal yellow 
tint. This diamond being rose-coloured at one séance, will, if pre- 
served in the cabinet of the Institute until the next séance, again 
exhibit its original yellow colour. The ordinary price of a diamond 
of this weight would be about 60,000 frances ; with the rose-colour, 
if this was permanent, the value would be at least tripled. We 
believe this is the first example of a diamond of variable colour. 
Professor J. D. Whitneyt has been examining Clear Lake in 
California and its neighbourhood. This lake is sixty-five miles 
north-west of Suisun Bay, and is about twenty-five miles long. On 
the south-west side of a narrow arm of this lake is a small lake 
about two-and-a-half miles in circumference, known as the “ Borax 
Lake.” From the waters of this lake, evidently of volcanic origin, 
there can be extracted, without much trouble, a large quantity of 
* «Les Mondes,’ April 12, 1866. ‘Comptes Rendus,’ No. 12, p. 690. 
+ ‘ Geological Survey of California, by J. D. Whitney, State Geologist. 
