182 Sir W. Snow Harris’s Researches in Statical Electricy. 
the proportion of 1:2°5; that is to say, the globe should have 
taken 12°5 measures. 
This result may be also examined by the process (Exp. 18). 
29. A similar result ensues in the charges of circular plates, 
either as compared with each other, or with spheres of the same 
area, as we have just seen. The area of a plate and sphere being 
taken as equal, each surface to each surface, the relative charges 
will beas VP; that is, as 1: /2, the circumference of a sphere 
being to that of a plate of twice the diameter as 1 : 2. 
With respect to hollow cylinders and closed surfaces of other 
forms, their charges may be determined by comparing them with 
the charges of the plates into which they may be supposed to be 
expanded. Thus if a square plate, whose side is 10 inches, be 
turned up into a hollow cylinder, the charge of the cylinder will 
be to the charge of the square plate as 1: 1°4, as in the case of 
a sphere and circular plate of twice the diameter, in which the 
total surfaces are the same. 
The quantity of electricity which can be accumulated on a simple 
insulated conductor of rectangular figure, appears to vary with 
the surface and perimeter conjointly. If the surface be constant, 
it varies with “P; if the perimeter be the same or nearly so, 
or does not differ in any very great degree, then the charge will 
either be as “S, or come very near it. 
Exp. 20. Take a square plate whose side is 10 inches, giving 
a unit of surface of 100 square inches, and a perimeter of 40 
inches, and transform this square into a rectangular plate 37°3 
inches in length by 2°7 inches in width, which exposes the same 
surface of 100 inches under a perimeter of 80 inches; then the 
relative charges of these two surfaces, as before tested (25), will 
be as 1: 2. 
Exp. 21. Take a rectangular plate of about 40 inches in 
length by 5 inches in width, and suppose it divided longitudi- 
nally into two parts; we have then in each rectangle one-half 
the area under nearly the same perimeter. In this case the 
quantity of electricity which can be accumulated upon the half 
surface will be to the quantity upon the whole surface also as 
1:2, that is, it will be as “S. A double surface will not 
take up twice the quantity of electricity, except it be placed under 
twice the perimeter. If we take a plate 34°14 inches long by 
5°86 inches wide, which gives twice the surface and twice the 
perimeter of a square whose side is 10 inches, then if we charge 
the square with 5 measures and the rectangle with 10 measures, 
the reactive forces, as in Exp. 17 (27), will be the same. 
30. These phenomena are not only of great interest, but they 
have an important signification in any theoretical explanation of 
