A16 Scientific Intelligence. 
it must, however, be handled with clean fingers, and even thus very 
with a diamagnetic body ; hung vertically, however, it could be dis- 
submitted them to chemical analysis. n experienced mineralogist 
was unable to detect the slightest visible difference between these crys- 
tals; the analysis, however, showed t se whose optical axes were 
and this without in the slightest degree interfering with the optical prop- 
erties of the crystal. It is even likely that Nature, as in the case be- 
result remained specifically constant ; further, on being hung edgeways, 
the parallelogram stood strongly magnetic ; and when one pole was re- 
moved, the whole mass was attracted by the other. 
hence, then, this apparent diamagnetism of the gutta percha? The 
answer to this question will perhaps throw a light upon the complicated 
phenomena exhibited by crystals generally. The equatorial position of 
the gutta percha is manifestly due to the comparative facility with 
hich the magnetic force can act in the direction of the fibre. Let us 
