100 W. A. Norton on Comets. 
V2 
+ Or & 
V2 
Whenee, ; =>-> (15) 
This equation gives the ratio of g to k, for any assumed value 
of V, and the ratio of & to the force of gravity of the sum’ 
made known by the velocity imparted by & to the cometic mat 
ter flowing away in the tail of a comet. The calculation may 
also be made for any supposed value of V, in case the sun’st® 
pulsion is inoperative. ou 
As we do not know to what extent a projectile force is in 
ration, we cannot be positive that the smallest masses 
ties we have determined are not too large. In fact, by hypo 
thetically increasing the initial velocity, and diminishing 
‘ repulsive force of the nucleus, we may reduce the mass aD dea- 
sity to any extent. We may even sup that the nuclei 
- neither sensibly repels nor attracts the matter projected from ty 4 
and conceive the whole effect to result from the pee 0 
The velocity of projection, on this supposition would be giv® 
by the equation, 
(16) 
ed. 
tler.— 
ve the 
