_FEB., 1906. THE SHELBURNE METEORITE. I5 
continued treatment with strong nitric acid the nickel-iron was en- 
tirely dissolved out and the troilite was left free. It was found 
to be chiefly in the form of small elongated and flattened nodules and 
plates, showing a tendency to faceting at some points, but with no 
determinable planes. One of these nodules hada length of 3 mm. 
The separation between these nodules and the nickel-iron seemed 
complete, there being no intimate intergrowth of the two sub- 
stances. The troilite was of dark bronze-yellow color, non-magnetic 
and easily fusible to B. B. a magnetic globule. 
The microscopic characters of the meteorite have been quite 
fully described by Borgstrém, and the features which he points 
out are essentially duplicated in the sections .before the writer. 
The-chondritic structure of the meteorite is very marked, and the 
chondri exhibit a variety of structures. Especially well represented 
are those made up of parallel lamellae of chrysolite and glass. 
These lamellz run in different directions in different chondri. In 
“ 

Fig, 2. Diagrammatic representation of arrangement of chrysolite lamelle in 
chondri of Shelburne meteorite. 
some they are all parallel and, together with the border of the chon- 
drus, extinguish simultaneously. In others they may be found run- 
ning in two or more directions, in which case those lamelle which 
are parallel extinguish simultaneously, but extinctions are different 
for the different groups. In the accompanying diagrams, Fig. 2, 
are represented some of the arrangements of lamelle observed. 
The first diagram shows a simple single arrangement, the second 
two sets of lamella meeting at angles of 135°, and the third prac- 
tically two sets of lamellae meeting at angles of 90°, although 
on one side the lamella are somewhat bent. Extinction in all these 
forms is parallel to the long axis of the lamella. The width 
of the lamelle in the chondri of this character is remarkably 
uniform, .and is about .or mm. The diameter of the 
chondri themselves is from 1 to 1.5 mm. When the individual 
lamellz are studied with a high magnifying power their apparent 
continuity in the direction of length resolves itself into two 
