258 Chemical formulas of the Silicates. 
silicates and Bisilicates containing aluminum contain also one 
or more basic metals in the protoxyd state. 
_ The formulas of the mineral species here included. are as fol- 
lows, if the oxygen be not divided—the only method according 
to which they have been written in recent works on chemistry.* 
A. a 
Ratio. 
Chondrodite, 4:3 R,1(0, F):.|8is Mg, (0, F)ss|5is 
Tourmaline, 4:3 (gs, R,@R,dR2)e(O, hig (Rs, R, BAL 6B2)s](O, F)is)Sis 
Andalusite, 3:2 BR:0, Si BAls|O,|Si 
Sillimanite, 3:2 «“ BAls]Os|Si 
Kyanite, 3:2 “ BAI, |Os|Si 
Gehlenite, 3:2 (R, BR)2]O.4Si (4R+48R)s]0s Si 
Sphene, 3:2 (R, 7R)s] 065i (40a-+37Ti)s| 00181 
Tscheffkinite, 3:2 “« (ER+87Ti)s] 0s] Si 
Grothite+ 3:2 (R, BR, YR)sJOs|Si  (¥Ca-++46Fe-+47Ti)s] Os]Si 
es : GSR+PR+ Tio OS 
_— er BR|(0, F)s|Si pAle|(G0-+4F IS 
Staurolitet 2:1 (12, R, BR),JO,]Si (3(as, R)+$GR)s10 615i 
Schorlomite, 2:1 {R, BR, 7R),JO,|Si (4-R+38R+/ 4 7K) O15i 
oi B. Hydrous, 
atio, 
Pyrosclerite, 4:3 — (#,,R,BR)s[O:s[Sistnaq (fa,+2R+}3R)+]O.4|Sist2098 
Pennine, “ (R, BR)s]O:.JSistnaq  — (#R+4SR)s] 0.) Sis4agl 
Ripidolite, «“ “ (ERHBR).10.,|SirH4oal 
Cookeite, £ (Ha, Be, BR)s]Ors|Sis+naq (psHetzy(ti, K)o+} QB Al) 
JO, ]Sis+8aq 
The principles of the new syst m to suggest for the rational formula one 
of ‘the two following methods; which oes the iets lL leave for ae » oer 
I, (R, BR R)O{O,ISi (R, BR)O.1O,18i (R, 8R)0s10, 18% 
IL (R, BR)O.]0.]Si0 _(B, BR)0s0,|8i0 (R, BR)O» | 02] 810s 
; Pier von Kobell's ii sin: oe ratte Silt ot th ded; be ae 
e prog be excl 
4:3 asin Pennin , if half the water be made basic. As int case of the s! 
| nother name- 
- Being the jiraterystallized chlorite name; and iti oe 
