Characters of the Fisher Meteorite. — Winchell, 175 
common orientation, and the lamella? themselves extinguish 
in unison and frequently parallel to their elongation. Occa- 
sionally a granule, not exactly in line with the series consti- 
tuting one of the lamellae, but rather between two lamelhe, 
extinguishes at a different angle. The lamellae in the olivine 
chondri are nearly straight and parallel. Between them is 
sometimes an isotropic substance which is probably glass, but 
sometimes this substance affords an aggregate polarization. 
In those olivine chondri in which the lamellae are cut parallel 
to 001, that is, perpendicular to the mean axis of elasticity, 
the distinct cleavages run directly transverse to the elongation 
of the lamellae as viewed. Hence the lamella? are of the nature 
of plates parallel to 100. Sometimes the lamelhe contain no 
interlamellar glass, but the alternate lamelhe are differently 
oriented, there being two directions, with an angle of about 
2-1 degrees between them. Sometimes parts of different chon- 
drites are closely adjacent, each having its independent 
orientation. In this condition the appearance somewhat 
resembles the radiating lamelhe of the chondrules of enstatite, 
and in some of the enstatite chondrules olivine constitutes a 
portion of the interlamellar mineral. 
There are apparently two isotropic substances in this 
meteorite, one being glass (at least glassy) and the other 
having a cleavage. The latter is clear as ^lass in ordinary 
light, and has refraction approaching that of olivine, as 
shown by the shagreen which is produced <m lowering the 
condenser. It may be niaskelynite, which is a mineral dis- 
covered by Tschermak in 1872, isotropic but having nearly 
the composition of labradorite. Below is ;i pencil sketch of 
the aspect. of the cleavable grain in common light with the 
condenser lowered. This indeed is the only grain of the 
isotropic substance which I have been able to find 
^=j showing a distinct cleavage. The non-cleavable 
|t( substance, appearing like glass, is rather widely dis- 
tributed, but there is no certainty that they are the 
same, although the glassy substance seems occasionally to 
transmit a little light between crossed nicols. The cleavable 
mineral has occasionally a trace of a second cleavage as repr- 
esented. 
