MINERAL CONSTITUENTS OF METEORITES. 
O /? f- 
ob i 
analyses of the mottled 
variety of silicate furnished the results given below 
I. 
Oxygen. 
II. Oxygen. 
Silicic acid .... 
52-831 
28-176 
52-725 28-12 
Iron protoxide . 
21-863 
4-859 
22-992 5-109 
Calcium oxide . 
0-502 
0-143 
Magnesium oxide . 
24-266 
9-706 
24-085 9-63 
Chromite .... 
0-643 
100-105 
99-802 
These numbers correspond with the formula (Mg* Fei)Si 0 3 , which is identical with 
the bronzite of the Manegaum meteorite*. 
In fact the olivine found by Baadielsberg does not exist in the sample of the meteorite 
analyzed at the British Museum. This is probably due to the portions of the meteorite 
examined in his laboratory and mine being from different parts of the mass. 
To check these determinations, a portion of the mottled variety was submitted to the 
action of acid in the cold, and subsequent treatment with alkali to remove the liberated 
silicic acid. The results now given show this action to have been confined to that of a 
solvent. 
I. By treatment with a mixture of one part of strong hydrogen chloride and two of 
water for sixty-six hours in the cold, and subsequently with soda, there were removed 
the following percentages of 
Silicic acid 
. . 1-507 
Oxygen. 
0-804 
Iron protoxide . 
. . 0-974 
0-216 
Magnesium oxide 
. . 1-058 
0-423 
3-539 
II. A corresponding treatment of another portion with 
a mixture of one part of strong 
hydrogen sulphate and two of water, for 
240 hours, gave 
the numbers : — 
Silicic acid . . 
. 3-900 
Oxygen. 
2-bs 
Iron oxide . 
. 1-799 
0-399 
Magnesium oxide . 
. 1-S77 
0-75 
7-576 
The slight excess of iron found in both cases was doubtless the result of a little un- 
separated meteoric iron. It certainly would not justify my assigning any appreciable 
portion of the silica to the constitution of an olivinous ingredient of the meteorite. 
In recording the results detailed in the analyses here given, I have to express my ob- 
ligations to Dr. Walter Flight, Assistant in my Department at the British Museum, 
for his skilful and zealous cooperation. 
* Philosophical Transactions, 1870, p. 1S9. 
3 E 
MDCCCLXXI. 
