‘ 
Dr. Genth's Contributions to Mineralogy. 421 
6. Coracite (LeConte) is Pitchblende. 
Dr. John L, LeConte kindly presented me with a specimen of 
the mineral from about 90 miles above Sault St. Marie on the 
north side of Lake Superior, which he had described as Coracite 
‘(Am. Journ. Sci. iii, 173 
Its great resemblance to pitchblende favored the opinion that 
it was really nothing else. Mr. Whitney (Bost. Soc. Nat. Hist., 
1849, 36), suggested that the Uranium might be in the form of 
U20s and not of UO, U:Os, but stated, that it yields a green 
solution with chlorhydric acid. : 
T endeavored to extract the carbonate of lime, which is me- 
chanically mixed with it, by very dilute acetic acid, but I soon 
observed that the coracite was also acted upon and that the 
liquid became green; I therefore washed it completely, dried over 
sulphuric acid and used the partly extracted substance, which 
was slightly acted upon by the acetic acid, for analysis. 
Before giving the results, I will state that the protoxyd of ura- 
nium was determined by dissolving the mineral in a mixture of 
chlorhydric acid and chloraurate of sodium and by calculation 
from the quantity of reduced gold. The separations were made 
as usual with exception of that of uranium from iron. By qual- 
itative experiments I ascertained that this separation could be 
made more easily and accurately by the precipitation of the 
Sesquioxyds of iron and uranium by ammonia from a boiling 
solution and re-solution of the sesquioxyd of uranium by 
tion with dilute acetic.acid. 
I obtained the following results: 
Sesquioxyd of uranium, - 46°21 contains en oxygen. 
Protoxyd of uranium. - - 1647 
Sesquioxyd of iron, 8°51 P. & 
Alumina, - - . 4 nf 
Lime, - Phos ea 
d of lead, ‘39 : 
an acid, - rk : 
Carbonic acid and water, 
99°28 
of lead, and though it is interesting that it is so readily solu . 
m chlorhydric a) rat 
from pitchblende. : : 
2s | 7. Epistilbite. 
Mr. GC. A. Kurlbaum, Jr., has examined in my le 
epistilbite from Beem with the following results: 
