Chemistry and Physics. 71 
one of them at Bonanza City, probably two or three miles 
distant, where the same evidence of decomposition is found, 
and in the rocks at this place I found also the turquois in 
forms not to be distinguished from those of the old mine. Mr. 
Hyde has shown me lately in New York a large number of the 
Cerillos turquois polished, one of huge size; and among them 
a few of good color and worthy of consideration as gems, some 
of them an inch in length and quite thick, but they are not of 
faultless beauty. 
SCIEN TIF IC INTELEAGLACE. 
I. CHEMISTRY AND PHYSICS. 
n Free Fluorine in Fluor Spar.—The cause of the peculiar 
odor possess by the dark violet fluor spar of Wélsendorf has 
been much discussed. Schafhiutl ascribed it to the presence of 
Pe hypochlorite, Schrotter to ozone, Pepa to antozone, 
and Wyrouboff to a hydrocarbon. Loxrw, noticing the similarity 
of the odor on freshly ee surfaces to eee of chlorine, con- 
cluded that it was due to the presence of fluorine formed by the 
dissociation of some foreign Rivne present in minute quantity. 
The ozone theory was given up by Schrétter when he found that 
the odor was not destroyed by a heat of 310°. Moreover, he 
Levee an alteration in this odor when the mineral was ground 
portions at a time, the filtrate and wash-waters from the earlier 
being used with the later quantities. The last filtrate was 
mixed with sodium carbonate, evaporated, the residue treated 
in a platinum capsule with sulphuric acid, and PES bi en 
a watch glass, kept at 40° to 50° for a a long ti 
ining the glass it was found to be very ceuikershly Seen 
Since fluor spar is not entirel ee in water, the experiment 
was repeated, using the inodorou ral. The result was so 
exceedingly feeble as to dispose entirely of this objection to the 
ormer result. Since these dark radiated varieties of fluorite 
contain cerium, the author thinks a ceric fluoride is the source of 
Br “On Arsenobenzene.—Azo-benzene C,H,.N=NC,H,, has Jong 
been known, and phosphobenzene C,H H,P—Pc Ase ‘has recently 
been discovered. The cortehponten. pees of arsenic, arseno - 
