170 W. A. Norion—Coggia’s Comet. 
cometic particles may differ greatly in size or mass. This 
coma. But both of these suppositions seem to be irreconcilable 
with certain facts of observation. 
Explanation of General and Special Phenomena.—It should be 
repulsion, whatever may be its origin, is exerted normally, or 
approximately so, to the surface of the body, and that the radial 
impulses of this force take effect unequally on different gaseous 
bly on solid cometic particles differing in size or mass. A mag- 
netic condition of the nucleus, sufficiently decided to determine 
e 
field, is however an essential feature of the theory. 
The precise character of the phenomena should depend, to 
s of rotation of the 
m this position there will be two efficient causes of special 
phenomena to be considered : (1) the point of maximum evap- 
