W. A. Norton—- Coggia’s Comet. 175 
shown in the diagram. The jets proceed from n’ ve’r’, and 
_were projected from the lower latitudes of the right hemis- 
phere, or between e¢ and r (Fig. 8). Jets issuing from the corre- 
sponding are e r, of the other hemisphere, would form a similar 
set of curves to the right of ce’ #. Other sets of parabolic 
jets are projected from latitudes above 35°, or from the ares r z 
and r, « (Fig. 8); but these will have sensibly the same outer 
boundary as those from e7’ ander, unless the initial velocity 
or the solar repulsion is different. It is to be observed that ce 
is so small a fraction of ce’ (Fig. 8) and ce’ so small a fraction 
of ¢ V (Fig. 4) that we may without material error regard v as 
coincident with n’, and 7’ as coincident with e’. 
° ‘g 
oa’ 100 nie 
he 
1B0 
5, 
The hypothesis made in the construction of Fig. 4, that the 
solar repulsion is constant for all values of a, or in other wo 
magnetic needle on the earth’s surface, and varies, we may su 
pose, with the latitude according toa similar law. Let it be 
denoted by £. 
