Ss 
ype ah Pe oe eg ea all ns a eo Pines ae Fae 
Se ae sie =i é x 
= S'on that these two minerals are isomeric, 
Mineralogy and Greology. 417 
0:82, cobalt, a trace, arsenic. 45°34, sulphur 14-:00=100; leading to 
the formula Ni?(As, $)%.. It crystallizes in the tesseral system, and 
has the specific gravity 6-08. Heated in an open tube it affords arsen- 
gus acid, metallic arsenic, and sulpburet of arsenic. . It fuses easily be- 
fore the blowpipe, disengaging arsenical fumes. Nitric acid dissolves it, 
with a deposition of the sulphur. 
19. Margarodite—This name has been given by Schafhautl, to the 
schistose talc of Zillerthal, a mineral allied to mica, and consisting of 
silica 47-05, alumina 34:90, peroxyd of iron 1-50, magnesia 1-95, pot- 
ash 7-96, soda 4:07, water 1:45—98:88. — 
20. Mowenite and Hurmotome ; (L’Institut, No. 644.)—MM. Da- 
Mour and Desctoizeavx, suggest the propriety of uniting the mowenite 
of Thomson, with harmotome, both on crystallographic grounds and 
chemical composition. Mowenite afforded on analysis, silica 47-60, 
alumina 16-39, baryta 20-86, oxyd of iron 0°65, potash 0-81, soda 0-74, 
water 14°16—101-21. a. 
21. Brochantite and Krisuvigite ; (Poggend., Ann. Ixii, 138 ; Berz. 
Jahresb., XXV, 1845, 395.)—M. Ramme.ssere obtains for the formula 
of Brochantite CuS+3Culz, which is also that of the so-called Kris- 
Uvigite: 
22. Perowskite ; (Poggend. Ann., lxii, 596; Berz. Jahresb., xxv, 1845, 
370.)—Perowskite has been analyzed in the laboratory of H. Rose, and 
25. Arragonite and Calc Spar ; (L’Institut, No. 654, July 15, 1846, 
. 
set 
p. 240.)—_MM. Silberman and P. A. Favre have arrived at the conclu- 
and that the dimorphism of 
of lime is due to this principle. The arragonite is shown to 
’ the isomeric compounds. 
| Secoxp Srrizs, Vol. HI, No. 6.—Nov., 1846. 
