Professor Leslie on Electrical Theories. 
therefore^? is much less than 
G D 
DA’ 
and the deflexion of the 
curve extremely small, compared with the angular variation of 
A E, Hence the inclination which the tangent makes with A E 
will continually increase, and when A E comes into the position 
A B, the curve will cut the middle perpendicular O C obliquely, 
and it will still continue to recede from A B, until the sum of 
all the little impulses A e , which are now exerted to better ef- 
fect, is sufficient to counterbalance the force of its divergency. 
If the distance between the bodies is too great, the particle may 
never even reach B. Thus, in every case, the portion of the 
curve opposite to C will bend from A B, and when the curve is 
finite, the absciss will make a smaller angle with the origin than 
with its termination. The motion of the particle will indeed be 
retarded in its progress through the air, but this resistance will 
never affect its direction, and consequently the general form of 
the curve will remain the same ; only G H will be more con- 
siderable in regard to D G, and therefore the momentary de- 
flexions, or the elementary angles G D H, greater. Hence 
there are two cases in which the recession of the curve will be 
increased : If the particle passes through a rare atmosphere, and 
consequently suffers little obstruction, the attraction of B will 
have less influence in bending its course ; or if the particle is 
sent obliquely at first, it will require a greater amount of oppos- 
ing impulses to change its direction, and consequently will pro- 
ceed farther beyond the middle before it begins to return to- 
wards A B. 
Let us now suppose that A and B are two pointed bodies of 
some length (PI. I. Fig. 6.) If 11 A and S A be perpendicular to 
the surface at A, it is evident that they will limit the course of 
all the aerial particles that are repelled from that point. Those 
which are emitted near the direction A B will fall variously at 
B , but the particles that have a more oblique projection will 
proceed to K and M before they bend their course inwards. 
At such distances, the action of the point B will be considerable, 
if compared with that of the large surface B and Q, and there- 
fore the particles will tend indiscriminately to the nearest parts 
of that surface. But all the particles, whether they converge to 
B or spread over the surface L Q, were alike sent from the 
