168 Dr. Genth’s Contributions to Mineralogy. 
The sesquioxyd of iron was redissolved in hydrochloric acid 
and precipitated by ammonia; it weighed 1: : 
the soluble acetates, to which chlorid of ammonium 
had been added, the lime was precipitated as oxalate, which 
yielded 0-0106 grs. carbonate of lime. 
The filtrate was evaporated to dryness and the magnesia sepa- 
rated from the alkalies by oxyd of mercury ; the magnesia was 
redissolved and precipitated with all the requisite precautions as 
phosphate of magnesia and ammonia, which gave 0-0670 grs. 
pyrophosphate of magnesia. 
e mixed chlorids of sodium and potassium weighed 00185 
grs. and the platinum 0:0033 grs. 
IV. 1:3668 grs. dissolved and the silica separated as in III, 
gave 0°3187 grs. silicic acid. From the filtrate, oxydized by 
nitric acid, both sesquioxyd of iron and alumina were precipitated 
y ammonia, and the alumina separated from sesquioxyd of iron 
as above; it weighed 0:2138 grs. The sesquioxyd of iron re- 
dissolved and precipitated by ammonia was 0-7148 grs. The 
filtrate from the sesquioxyd of iron was added to the liquid con- 
taining lime and magnesia, and after being concentrated by evap- 
oration was precipitated by oxalate of ammonia. The oxalate 
gave 0:0100 grs. carbonate of lime. 
Mand V. I, IV and V. 
SiO, 23°10 23°32 23°21 contains oxygen == 12°05 
Fes Os 13:90 13°88 13°89 es Sa 4°16 11°45 
Als Os 15°58 15°64 15°59 "2 4-29 
FeO 34:58 34°58 34:58 e 7-68 
oe ene 
g 116 137 1-26 ig 0-49 
CaO 0°29 0-43 0°36 i. 0:10 _ 
NaO 0-41 0-41 O41 a O11 
K 0-08 0-08 @ 0-01 
HO 10°84 10°85 10°59 “ 9.42 
99°89 100-06 
The ratio of oxygen of RO: R203: Si03: HO is, 
8:39: 11-45 : 12-05 : 9-42 or very near 
1: 26: 2a 
PIR At eal 2 ae oy Pe 
