ee ee 
Chemistry and Physics. — 417 
ed; and the necessity of 
; y of the parallelogram, when hung ed 
set itself axial, is also mani Si sy a 
S may be expected, when the parallelogram is made very long in 
comparison to its width, the long diameter of our hypothetical egg, is 
overpowered by the united action of a aumber of short ones, and the 
oblong stands axial. 
aa percha and ivory, to imitate almost all the experiments which we 
ve made with both classes of crystals. 
negative or positive, as asserted by Professor Pliicker. 
eroid will be of a 
: Faraday* to the optical axis, 
inverts the right course of proceeding ; the attraction or repulsion of 
this axis being a secondary result, depending first of all upon the mag- 
a EI ea aS een 
# Phil. Mag., Jan., 1849, p. 75. 
Szconp Szries, Vol. IX, No. 27.—May, 1850. 
