212 
ME. N. STOEY-MASKELYNE ON THE 
The examination and the analysis of this meteorite had therefore to be performed 
on very minute quantities ; in fact on a few grains of debris that had become detached 
from the brittle little stone. 
The conspicuous ingredient in this meteorite is a pale yellow-green, or primrose- 
coloured mineral, with a tint similar to that of a very pale peridot or chrysolite, occur- 
ring in crystalline grains cemented together, in a state of very slight aggregation, by a 
white opaque silicate, which in a microscopic section has a flocculent appearance. 
The granules of green minerals present in the microscope the appearance of tolerably 
symmetrical crystals, and are seen of every size, from that of a small pin’s head to that 
of a microscopic dust. 
In separating this green mineral from the fragile mass, I have never succeeded in 
obtaining a crystal of it entire. 
The mineral is enstatite ; if, at least, we are to include under this name every iso- 
morphous mixture of iron and magnesium silicates with the formula M Si 0 3 and crystal- 
lised in the prismatic system, but without the distinguishing features either of hyper- 
sthene or of diaclasite. 
Two of the grains selected from the picked green mineral for measurement gave the 
following results, — 
Maneganm enstatite. 
10 0, 110 = about 46° 
I 0 0, 1 0 1 = 49° 4' 
1 1 0, 1 1 0 = about 88° 
I I 0, 1 0 1 = 58° 39' 
Breitenbach enstatite. 
45 52 
48 49 
88 16 
58 24 
The comparison of these measurements with those obtained from the enstatite of the 
Breitenbach siderolite given in the second column will suffice for the identification of 
the two minerals as enstatite. 
The analysis of the Manegaum mineral was performed by the method of distillation 
already described. 0-2658 grm. was taken. 
Silicic acid . . . 
Magnesia 
Iron monoxide . . 
Lime 
= 0-14805 
= 0-0606 
= 0-0546 
= 0-0035 
per cent. Oxygen ratios. 
55-699 = 29-706 
22-799 = 9-1191 
20-541 = 4-564 V14-059 
1-316 = 0-376J 
0-26675 100-355 
If we allow for the probable presence of a little augite, corresponding proportionately to 
the lime found in the analysis, this Manegaum mineral will have the formula of an ensta- 
tite richer in iron than even that of the Breitenbach siderolite, the formula for which 
is (fMg-yFe) Si 0 3 . The formula (fMglrFe) Si 0 3 requires a percentage compo- 
sition of Si0 2 =54'2; Mg 0=24; Fe 0=21-7, which would accord very closely with 
