DISTRIBUTION OF ELECTRICITY ON A PLANE AND SPHERE. 
437 
Table VI. 
Reaction 
before con- 
tact at 22° 
distance. 
Reactions after contact. 
Reaction at 14°. 
Reaction at 22°. 
Plate. 
Sphere. 
Plate. 
Sphere. 
o 
22 
o 
14- 
O 
14 + 
O 
7 
o 
8- 
A 
B 
C 
In column A we have the force communicated to the proof plate at first. In 
column B the force after the respective contacts of the sphere and plate, as shown 
by the mere deflection of the needle. Column C shows the reaction at the original 
distance of 22°. 
23. In order to obtain more readily a repetition of the original charge, I placed the 
insulated sphere immediately under the suspended plate of the electrometer described 
in my former paper *, and as represented for the cylindrical conductor in fig. 18. 
Having reproduced a given force, as indicated by this instrument, by repeatedly touch- 
ing the sphere with a small transfer conductor charged to a sufficient intensity from 
the knob of a charged jar, the sphere was removed, and submitted to experiment. 
By this process the original electrical reaction of 22° could be easily obtained. 
24. The result, therefore, arrived at by Coulombe’s method of experiment may be 
classed with those cases in which the repulsive force exercised by the balance is not 
proportionate to the quantity of electricity. Thus, if we suppose, by way of further 
illustration, that in certain experiments similar to those detailed by Coulombe, the 
respective quantities of electricity communicated to the tangent disc had been really 
in the ratio of 2:1, but so circumstanced as to have been at first equal to and sub- 
sequently half the quantity with which the disc of the needle was charged ; and sup- 
pose that the respective reactions had been taken at a distance of 24°, 18°, 12°, or 9°, 
with intensities corresponding to those given in columns B and d of Table IV., we 
might have then found the reactions in the ratio of 3 : 1, or nearly so ; or supposing 
the proof plate, after both contacts, to have become charged to a higher intensity than 
the disc or ball of the needle, the respective quantities on the repelling bodies being 
in the proportions of 1 : \ and \ : \ ; that is, supposing the proof plane to have re- 
ceived, before the contact with the plate, four times as much electricity as existed on 
the ball of the needle, and after the contact only twice as much, then if the reactions 
were taken at a distance admitting of a sensible inductive disturbance (15.), the re- 
pulsive forces might still be in the ratio of 3 : 1, or nearly so, although the respective 
quantities of electricity on the proof plate producing the repulsion in each case should 
be really as 2:1. This is shown in columns h and d of Table IV., in which the 
forces corresponding to the distances 12°, 18°, and 24°, are nearly as 3 : 1, whilst the 
* Philosophical Transactions for 1834, Part II. p, 215. 
