112 On the Generation of Statical Electricity. 
at which the point first shows signs of being acted upon, draw a 
cone of rays tangent to the exciting electrical atmosphere, having 
the point at the vertex; this cone of influence being formed of 
neutralizing rays, the intensity of their action, by the laws of 
induction, depends on the distance of the point from the exciting 
body. As the point approaches this body the elements of the 
cone, remaining tangent, diverge until having reached a certain 
degree of divergency depending on the intensity of the electrical 
action, they cease to separate; and if the point continue to ap- 
proach the excited body, the cone will be intersected by this 
body. These intersections decrease in extent until the point 
touches the body, when its influence, except for the correspond- 
ing point in contact, ceases. For electricity of low tension, the 
point being that of a common sized needle, the limiting angle 
of the elements of the cone appears to be about 166°, which, if 
the point be at one fourth of an inch distant from a plane exci- 
ting surface, will intersect such surface in a circle, whose diam- 
eter is about four inches. The electricity within the circumfer- 
ence of this circle will be entirely neutralized. It appears there- 
fore that the points of the prime conductor to collect electricity 
of low tension, should be needles, and placed not farther apart 
than four inches. The electricity on the glass surface on leaving 
the rubber, being of high tension, soon commences to be acted 
upon by the points of the conductor ; its tension rapidly dimin- 
ishes as it approaches the points, and when opposite, entirely 
ceases. ‘The prime conductor however being insulated, and hav- 
ing acquired a certain degree of tension itself, refuses to accu- 
mulate any more electricity of the same or lower tension; the 
parts of the glass opposite to the points being thus in an excited 
condition, electricity of higher tension arrives nearer and nearet 
‘to the points at each revolution; its inductive action causes the 
elements of the cones of influence again to diverge, enlarging the 
areas of the intersections. The prime conductor and glass having 
arrived at the same electrical state, those points which find them- 
selves in the most favorable positions, will receive the electricity 
having the highest tensiom, and the remaining points, in place of 
receiving; will give off electricity to those portions of the glass 
which may, from any defect, have less tension. It hence appears, 
that needle points should not be nearer to each other than four 
inches, to collect electricity of the lowest tension: as this how- 
