Hi, A. Newton— Origin of Comets, 167 
8. Besides these we must suppose that there is a large num- 
ber of cometic masses which will strike the plane outside of 
the circle. If there is any law of distribution of the initial 
directions and velocities of the masses at A, that law will be 
exhibited in the distribution of the points of impact with the 
plane. ‘Thus if like the principal members of the solar system 
the masses leave A with a velocity belonging to a circular 
orbit, nearly at right angles to AS, and nearly in the plane of 
the solar system, then the points of impact in the target plane 
will be near each other at a distance from S equal to AS; for the 
masses will describe circles, approximately. Again, if the masses 
pass through A on their way from the stellar spaces and so have 
motions that bear no relations to the motions of the solar system, 
then the distribution of the points of impact on the target plane 
ought if numerous enough to be uniform about the point 
; ght to be 
large compared to the area of the circle above described. The 
€ orbits corresponding to the points of impact in the two 
Sectors next beyond (one on each side) will have inclinations 
between 10° and 20°; and so on, up to 180°. Hence, the 
