392 O. N. Rood’s Stauroscopic Observations, 
3. Through the centre of an elliptically shaped plate the cross 
was altered by revolution and arranged 4 
itself in the directions of the major and _ 
minor axes. The same is true for the 
spaces along the dotted lines. 65 ‘ 
The inclinations of the crosses to the % 
axes of the ellipse in different portions 
of the plate will at once be seen by the 
winased diagram, and also that the ar- 
rangement of the outer portions is essen- 
tially the same as in the circle, the main 
difference being in the occurrence of the 
pralenened spaces on either side of the 
Ocl 
40 
4. Through the centre of the square 
the cross remains tolerably unchanged by 
revolution; near the middle of its sides <0) (9) 
the cross is altered by revolution and 
arranges itself at right angles to the sides. 
In the angles it was inclined to the sides of the square at al- 
gles of from 30° to 50°. In a perfectly evenly cooled plate ib 
would probably arrange itself according to the diagonals. 
5. Through the centre of a rhombic- ‘ 
shaped plate the cross: arranged itself 
parallel to ha two sides of the aed, SB 
it remained always somewhat colored. Ge, 
— under ierculae polarized light. ane 
Through the spaces s,s, s,s, it arrange @ 
itself according to the diagonals. four 
6. Through the centre of a. rectangle, whose length was!) 
times its breadth, the cross arranges itself according to ea 
ameters: in the angles the crosses are inclined at certain ang 
to the diameters. ther 
er two pieces of this shape are laid one upon the age 
parallel or at right angles, and viewed through their com 
centre, the cross still arranges itself parallel and at right ang 
to their sides. k 
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