J. W. Mallet on the Nerwich Phosphate. 33 
Arr. IV.—On the Phosphate of Iron and Manganese from 
Norwich, Mass ; by Dr. J. W. Mauer. 
T'nis mineral, first observed by Dr. E. Hitchcock, Jr., and Mr. 
Hartwell, and since described by Professor Dana and analyzed 
by Mr. Craw,* possesses much interest from the distinctness of 
its crystals (which yet in their angles present unaccountable irreg- 
ularity), since it belongs to a class of minerals which are in gene- 
ral found massive, or but imperfectly crystallized. The following 
are the results of a chemical examination of some pure specimens, 
for which I am indebted to Mr. C. Hitchcock. They do not add 
much to our knowledge of the mineral, but serve to confirm es- 
sentially the former determinations by Mr. Craw. 
The crystals are opaque and of a dark brownish black color, 
and give a beautiful violet streak. Sp. gr. = 3364, higher there- 
fore than that of the specimen analyzed by Mr. Craw, which he 
gives as 2:876. Hardness about 5. Before the blowpipe the 
rend gaa of phosphoric acid, iron, and manganese, are easily ob- 
tained. 
A portion of the mineral was pulverized, weighed, and kept 
for some time at the temperature 100°C. ‘he loss of weight 
was scarcely appreciable. This portion was then exposed toa 
bright red heat, and on cooling was found to have assumed a 
light brownish yellow color, and to have lost 633 p.c. In an- 
other experiment the loss was 5°97 p.c. To ascertain the amount 
of water contained in the mineral, a portion, dried as before at 
100° C., was heated in a glass tube in a stream of dried air, and 
the water expelled was absorbed by chlorid of calcium and weigh- 
ed. It amounted to 1-92 p.c. In another experiment the pul- 
Verized mineral was heated in dry hydrogen, and lost 2°18 p.c. 
of water beyond that formed by the reduction of the peroxyds of 
iron and manganese to protoxyds. ores , 
‘The phosphoric acid and peroxyds were determined. by fusion 
with carbdnate of soda, and the lime, magnesia, and lithia, were 
estimated in a separate portion. ‘The results of analysis were— 
i %. 3. 4, 
Phosphoric acid, - - 43:12 4335 4265 —— 
Peroxyd of iron, - ~- 29:90 2923 2937 ——— 
Sesquioxyd of manganese, 23-02 21°98 2276 —— 
Lime, % r% 2 ; geen sa ae - 
Magnesia, : - + > . 
litte: . 2 19 
* Amer. Jour. of Science, [2] xi, 99, 100. 
Srconp Szams, Vol. XVIII, No. 52.—July, 1854. 
