Chap. XVII.] 
GONDITE SERIES : COMPOSITION. 
349 
be composed almost entirely of quartz and garnet with a small quantity 
of apatite and rutile. The analysis was made by Messrs. J. and H. S. 
Pattinson of Newcastle, the weight of the piece of rock ground up for 
this purpose being 42 23 grammes. The result of the analysis is shown 
below : — 
Analysis of typical gondite from Wagora, Chhindwdra distnct. 
G.=:3-42. No. 16-984. 
MnO 
Fe203 
FeO 
AI2O3 
CaO 
MgO 
KoO 
Na20 
Si02{combined) 
Si02{free) 
P2O5 
CuO 
Ti02 
CI . 
Combined water 
Moisture at 100°C. 
13-37 
7-47 
0- 13 
12-36 
2-60 
1- 90 
0-03 
0-19 
20-60 
39-85 
0-68 
0-02 
0-46 
Trace. 
0-20 
0-10 
99-96 
Manganese 
Iron 
Silica (total) 
Phosphorus 
10-36 
5-33 
60-45 
0-30 
The process adopted in calculating this analysis into terms of the 
mineral composition of the rock is to first take out the titania (Ti02) 
as rutile, and next to take the lime (CaO) necessary for the formation of 
apatite with the phosphoric oxide (P2O5), the required amount of chlor- 
ine or fluorine being assumed to be present. The free silica is all assumed 
to be in the form of quartz, as there was no evidence of the presence of 
any other form of free silica such as chalcedony. There are then two 
methods that may be adopted in dealing with the remainder of the 
constituents. In either case the cupric oxide (CuO), combined water, 
and moisture, are not considered, but are regarded as impurities. 
The alternatives are either to regard the potash and soda as impurities, 
or to suppose that they are present as felspar. Taking the first alter- 
native (I) and thus regarding the combined silica as all present in the 
garnet, this silica is used as the basis of calculation, More than suffi- 
cient alumina (AI2O3) is present for the formation of spessartite, so that 
