> 
\ * 
#@ 
t 
ud ¥. 7” 
Scheerer on Isomorphism. 71 
(R) = = 6:00 Ca, 68K, 55H. Huronite and aca ap- 
pear to have the same formula therefore, namely, that of aspasio- 
lite. But in the latter, (R) = 6-97 to 8-04 Mg, Ca, a hehe 2°30 
to 2:39 Fe (a part thereof perhaps as Fe), Mn a 
6S8H, 
a , from Plombieres. 
22°86 : 10: 08 : TOO pe eee eae 
23:00 : 11-50: tex (R)* Si+ Al Si, 
1-0 loss. (R) =25-0H, 2:0Mg. ‘The bole from pact 
which has been analyzed by Rammelsberg, appears to have the 
same formula. Its oxygen ratio is = 23°86 : 10-35 : 8-76, pg 
by it it is to be noticed that a loss of 2°17 per cent. was obtained. 
' (R) in this bole = 25:86 H, 3-90 Ca, 
9. Nontronite, from Villefranche. _ (Dufrénoy.) 
O13; 1119:7732 Aes ws 
22-00: 11:00 : 733 § (Ry? SitRSi. 
Essentially this is the formula of the preceding mineral. — (R) 
= 23-0 HB, 2:37 Mg. Chloro Toph ye also (which see); and ottre- 
. lite (see likewise), have this form 
10. Kaolin. (Forchhammer.) . a 
Its formula, Al* Sit +6H, may be also thus expressed : 
(R)? Si+3Al Si. i 
11. Nontronite; from Andreasberg. (Biewend.)  » 
2100:1200:6005 , 2¢k)*8i+4FeSi, 
formula of the Pargas mica, in which however, (R) = 10 27 Me, 
0°75 Uo 4 5 Ca, 8-45 K, 3-35 Ef, whereas (R) in nontronite con 
er alone, (21- 56 per cont: ) The nontronite of Autur 
shows, Retna to Berthier’s analysis, a ae 3 ie re hs 
= from Andreasberg, that is to say, 21: sei, 558, 
wr 
