198 
ME. N. STOEY-MASKELYNE ON THE 
ditions under which the ingredients of that rock came into their present form were very 
unlike those met with on the surface of our globe. Water and free oxygen must alike 
have been absent, or only present in inappreciable quantities ; indeed the existence of 
the metallic iron in the state of minute division in which it so frequently occurs in mete- 
orites would lead to a similar conclusion. But the evidence afforded by the aerolite of 
Busti seems, further, to point to a reducing agent having been present during the forma- 
tion of its constituent minerals; while the crystalline structure of Oldhamite, and of 
the Osbornite next to be described, must certainly have been the result of fusion at an 
enormous temperature. 
The detection of hydrogen by Professor Graham in meteoric iron tends to confirm the 
probability ot the presence of a reducing agent among the conditions under which these 
meteoric minerals were formed. 
V. Osbornite. 
The golden-yellow microscopic octahedra that have been mentioned in the descrip- 
tion of Oldhamite were furnished by the analysis of that mineral to the amount of only 
(M)028 grm., the first analysis having yielded 0-0013, and the second 0-0015 grm. Yet 
even this minute weight, forming less than 0-3 per cent, of that of the Oldhamite, was 
divided between upwards of 150 crystals. These crystals were nevertheless capable of 
being measured by the goniometer. 
This microscopic mineral I wish to name Osbornite in honour of Mr. Osborne, and in 
order to commemorate the important service that gentleman rendered to science in pre- 
serving and transmitting to London in its entirety the stone which his zeal saved at the 
time of its fall, and in recording all he could collect about the circumstances associated 
with that fall. 
That the octahedra of Osbornite are “regular” octahedra will be apparent from the 
following results of their measurement. A supplementary lens applied to the object- 
glass of the telescope of the goniometer enables the observer to determine that position 
of the face of a crystal in which the illumination from a narrow slit in a distant window 
is at its maximum. In this way the angles between faces can be measured when the 
faces themselves are too small, or are too dull, or too much striated for use as reflectors 
of the image of the slit. 
This approximate method of measuring the angles of so minute a crystal, when used 
with some crystals of Osbornite, gave for: 
111 
111a mean 
of fifteen 
measurements on two crystals 
70° 
27'' 
Eegular 
octahedron. 
70° 3P 
111 
111 
nine 
measurements on ditto ditto 
109° 
3P 
109° 
28' 
111 
111 
six 
measurements on ditto ditto 
69° 
58' 
111 
111 
six 
measurements on a third crystal 
70° 
37' 
The analysis of this mineral presented a very difficult problem, the total amount 
