J. P. Cooke, Jr., on Cryophyllite. 225 
Analysis of Rockport Lepidomelane. 
i 2. 3. 4. 5. 6. rf 8. Mean. Oxygen. 
Silica, 39:50 39:49 —— 39-79 39-438 —— —— ~— 39: 
Fluorid of silicon, 062 —~ —— —- — —— ~—— 062 0-19=21:28 
Alumi 16°72 16.41 16°90 16°87 —— —— —— 16°73 78] 
—— 063 058 059 — 18 
Sesquiox. of manganese — — 
Neh —— —— 1221 1201 11°98 12°07 3-62 
—— — 1757 17-47 17-41 1748 3°88 
— — 064 059 —— 
M 
Potae 10°68 10°63 —— —— —— 10°66 1°38] 
Lithia, 060 057 —— - — 0:59 0°32 
Rubt ee 
u pee egg ten Pe piel eet sche ene ee ae pele: 
Water” — — 155 140 152 152 154 150 138=19-20 
100°42 
Oxygen ratio, 19°20 : 21°31, 
a : 
already stated, the material used in the fourth analysis was a 
portion of a perfect crystal completely isolated in a mass of feld- 
Spar, and the results of this analysis agree almost precisely with 
those obtained in No.5 by an entirely different process and with 
wholly different material. Here then are the same unsatisfactory 
Phe: which have been obtained again and again in the analyses 
or t i 
wo 
isomorphous salts crystallize together from the same solution, 
j re mixtures of the two in definite 
= 
o 
° 
oo 
8 
= 
fo) 
Rec} 
pm 
2 
same results followed in the one case as in the o er, and that 
* See Rammelsberg’s important paper on this subject, Pogg- Ann, x¢i, 321. 
