38 I’. Scheerer on Polymerous Isomorphism. 
The oxygen ratio is 31-94 : 0-39 : 13-46 : 2°52, giving — 
ing to Scheerer’s theory of substitutions, 32: 20: 1430=9: 
the hornblende ratio. The same locality affords cas a 
foliated talc, and this ratio is common to both. 
3. Columnar Tale. 
Includes hydrous anthophyllite. 
4, Sparry Crystalline Tale. 
Si Mg Fe 
23. Fenestrelles, Piedmont, 61:96 -. 8102 147 4:92== 99- 37 G—2"19 
2°29 0: 15 81°55. 1:22 -4:88=— 
1 
25. Jndur'd Tale Gloggnits, Be 013 32:08 047 478= 99-93 G==3'18 
26, 012 32-41 0:39 470=10031 Rr. 
The oxygen ratio is "the same as for the first group 15: 6 : 2, 
and the hornblende ratio 9 : 4 is deducible in the same way. 
5. Massive Crystalline Talc. 
i Mg e H 
27. Steatite, Wunsiedel, 62-03 soy 31:44 1:88 —_ vn Rr. 
28. = = 61:98 trace 3117 1-48 481= 9 
29. sid pseudom. 62:07 0°39 31:13 169 peat 1 
80. x Ms 62°35 trace 31°32 1:24 4°78= 99-79 
$1. “ Parma, 62°18 +55e 30°46 2°53 497=10014 Rr. 
32. Agalmatolite, China, 61:48 aces 31:27 165 4:86—= 99°26 
33. 62°30 0-06 31:32 1°62 4:89=100°19 
The oxygen ratio of No. 27, is 32°21: 0-00: 12-99: 4- — BG : 
the others are nearly the same ) giving the ratio again 15: 
the hornblende ratio 9:4. The older analyses are also aed 
6. Amorphous Tale. 
Si Al Me Ga Te 
34. Meerschaum, ae: 20) & perm 0:06 
= 61:4 
H ’ 
28°43 9°83 0°67==100°16 
28°13 0° 60 O12 982 0-67=100°83 Rr. 
6. 6130 ... 2839 ... 008 974 05610007 
a. - « doubéful 58-20 ‘53 64 2°73= 99-83 Rr 
S178: 4 64 2 
Oll 2819 .,.. 009 957 1-74=100-16 
"ane the € and Ga combined as carbonate of lime, the 
oxygen ratio for No. 34 is 31:76: 11:14: 8-74; for No. 36, 
31°83 : 11:17: 866; for No. 37, 30:22: 10-54 : 8-57. Substi- | 
tuting 3H for 1Mg, the ‘first corresponds 2 fa ‘76: 14:05, which — 
equals (and so with the others) the : 
7. Hashes 
The two analyses of Crocidilite by Stromeyer, afford the mean 
oxygen ratio for the silica, protoxyds and water, 26-60 : 10-40 : 426, 
whence the formula 4k Si Re Si?+3H. But adding one-third of 
4-26 to 10-40, the ratio becomes 26°60: 11 ‘82, or 9:4, which is 
that of hornblende. A tremolite from Reichenstein afforded— 
Si Al a. Fe Ht 4 
39. 58:89 0°67 9337 9°57 379 360=99'89, Rr. 
oreo Pg ae ratio, 30°58 : Boek: 12-92: ras which es E 
comes by the aut pimps te 4 al nearly. We — 
pass by Scheerer’s review of some earlier anal 2 
