Scheerer on Isomorphism. 69 
8. Stellite. (The same.) 
25:00: 4-17: ‘en 9(R)? Si+R? Si’. 
It j is here assumed that this mineral contains, not as Thomson 
- asserts, 3-524 protoxyd of iron, but a eens quantity of & 
peroxyd. The mineral, it must be remarked, is snow-white, and 
the alumina which amounts only to 5-301 would not, of itself, be 
sufficient. The formula of stellite would also answer for Thom- 
son’s vermiculite, whose oxygen ratio = 25:50:3-40: 13-26, if 
indeed, as Thomson says, the whole of the iron is contained in 
the form of a protoxyd. Calculating a small portion thereof to 
exist in the state of peroxyd would afford an oxie ratio still 
closer to that of steliite. ‘The two minerals, however, in spite 
of similar formula, applicable perhaps to both, are essentially dif- 
i ferent from each other. For, whereas, in’stellite (R) =30-96 Ca, 
5-58 Mg, 6108 Ef, in vermiculite (R) =16-12 Fe, (or upon the 
aforesaid supposition somewhat less,) 16-964 Mg, 10-276 H. 
9. Weissite. ('Trolle Wachtmeister.) 
31-01 :: 10°17: rai: css see 
31-00 : 10:33 : 5-17 _ (R)? Sit +2 Al Si. 
Remark.—This is where aspasiolite belongs, whose formula, 
as has been already stated, is (R)? Si?-+3R Si. 
10. Rhodalite. (Thomson. ) . 
29:04: 7:38: paete 3(R) Sith Si. = 
$e-% 
29:00 : 7:25 : 7:25 
(R) consists almost entirely of water, inasmuch as it is =1°1 Ca, A. 
0-6 Mg and 22-0 Ht. According to Thomson, this mineral oceurs | ‘e 
in aggregated rectangular prisms. 
11. Neurolite. (The same.) site 
37°92 : 8:23 : 2-77 chee g te ail es 
: 38-00 : 7-60 : 2-53 i (R) Si’ All 87", ‘ 
formula of the Iviken mica. In that, (tk) = = 4661 Mg, 3-528 K, 
1292, and 1:197Ca. In neurolite, (R) = =3- 25Ca, 1:50 Mg, 
4:30 . 
i B. Amorphous.* 
ro 1. Pitchstone. (Du Menil. ) 
» 37°92 3 6-65 : 3-08 
i __ 38-00 ; 5-43 ; 3: 62 ‘ ; 
. Or at least apprestly 4 so. some of these yey canal Saend of an ag- 
cry 
gregation of microscopic 
aR) Si? +RSi*. 
