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PROCEEDINGS OF THE ACADEMY OP 
tioa and measurements by Mitscherlich : Pogg. Ann., 58, 469, but at present 
not having the works to compare, I am unable to conclude whether or not it is 
another salt, homoeomorphous with the one just described. The similarity of 
form between compounds, in which there is a difference in the equivalents of 
water, is an interesting subject for investigation, and I shall endeavor to show 
at a future time, that the Trimetric sulphate of ammonia, generally considered 
anhydrous, may contain one or two equivalents of water, and yet preserve its 
homoeomorphism.] 
Lecontite was brought to this country, in January last, by Dr. John L. 
Le Conte, on his return from Honduras. He discovered it in the cave near Las 
Piedras, in the vicinity of Comayagua. It occurs in crystals imbedded in a 
black matrix, resembling bitumen in appearance, which Dr. Le Conte considers 
to be the decomposed excrement of bats, which infest this cave in great num- 
bers, and have, most likely, inhabited it for ages. The cave near the entrance 
was, at the time of his visit, being worked for nitre, which was obtained 
'•^ directly by lixiviating the earth taken from near the mouth of the cave. 
" The material containing the crystals merely furnished a tarry, black, semi- 
fluid mass, without nitre." On some of the crystals were observed minute 
hairs of the bats adhering, and I observed mor^, when removing the crystals 
from their matrix. In honor of Dr. Le Conte, for this interesting species 
which he has been the means of adding to mineralogy, I propose to call the 
mineral Lecontite. 
Sulphate of Ammonia and Soda. 
In looking over specimens of minerals recently presented to the Acade- 
my, my attention was attracted by a substance labelled " Ammonia," from 
the Chincha Islands of the Pacific Ocean; from its appearance it was suspected 
to be a sulphate of ammonia, and a qualitative examination confirmed my 
suspicion. It is in compact lumps, about the size of hickory nuts ; hardness 
from 2.5 to 3 : its color is a yellowish white, with a crystalline structure, 
taste pungent and bitter : opaque and permanent in the air. By a qualitative 
analysis, I found it to contain sulphuric acid, ammonia, soda and some or- 
ganic matter, and by my first trials iu a matrass I could not find water ; on repeat- 
ing them, I have found a small quantity. Whether the water is really a part of 
the mineral a quantitative analysis only can determine. I made an approxima- 
tive determination of the sulphuric acid from a small fragment, and found it 
to contain about 48 per cent. Heated on platinum foil it blackens and fuses, 
though not very readily, leaving a white bead, which is soluble in water, and 
tastes a little saline and bitter. This mineral was presented to the Academy, 
I believe, by Dr. Bridges. 
Siercoriie ? 
I am indebted to Dr. Bridges for a specimen of a mineral from the Chincha 
Guano Islands, accompanying the sulphate above described, which, from a 
qualitative analysis, I now suppose to be Stercorite, (microcosmic salt,) which 
has been discovered by T. J. Herapath, Esq., in the guano from the Island of 
Ichaboe, on the western coast of Africa ; it never has to my knowledge been 
found in the Pacific guano. I hope to get sufficient material to settle definitely 
whether it belongs to this species. The mineral which I have is columnar in 
structure, and has evidently been taken from a crevice in the guano. It is 
opaque ; yellowish white in color, very soft, taste somewhat sharp, saline and 
slightly ammoniacal, partially deliquescent in the air. 
B. B. or gently heated on platinum foil over a spirit lamp it intumesces and 
blackens, giving off ammonia and water ; afterwards it fuses to a clear bead, 
which is readily soluble in water and has a saline taste. By a qualitative ex- 
amination I found ammonia, soda, and an excess of phosphoric acid. 
The physical characters are quite different from those of the stercorite de- 
scribed by Mr. Herapath, but the chemical components and the reactions before 
the blow pipe are similar. 
[Aug. 
