the wealuft Natural or Artificial Electricity, xxi 
duCtors is in proportion to their {urface, and not to their quan- 
tity of matter. 
35. This conclufion is true, but does not comprehend the 
whole theory, lince even the extenfion contributes to increafe 
the capacity ; fo that of two conductors, which have equal but 
diffimilar furfaces, that which is the more extended in length 
has the greater capacity*. In (hort, it appears from ail the 
experiments hitherto made, that the capacity of conductors is 
in proportion not to the furfaces in general, but to the furfaces 
which are free, or uninjiuenced by an homologous atrnojphere. 
36. But that which comes nearer to our cafe is, that the 
capacity of a conductor, which has neither its form nor 1 in face 
altered, is increafed when,, inftead of remaining quite infu- 
lated, the conductor is prefented to another conductor not infu- 
lated ; and this increafe is more confpicuous, according as the 
furfaces of thofe conductors are larger and come neaier to each 
other. 
When an i'nfulated conductor is oppofed or prefented to ano- 
ther conductor w'hatever, I call it a conjugate conductor, ^ 
37. The circumftance mentioned in the preceding paragraph, 
which augments prodigioufly the natural capacity of con- 
ductors, is that which I find to have been hitherto principally 
overlooked, far from any advantages having been deduced from 
It ; but let us begin with thofe experiments which fhew this 
increafed capacity in the fimpleft manner. 1 take, for example, the 
metal plate of an eleCtrophorus, and holding it by its infulating 
handle in the air, eleCtrify it fo high that the index of an 
electrometer annexed to it might be elevated to 6o°, then lower- 
ing this metal plate by degrees towards a table or other con- 
ducting plain furface, I obferve that the index of the electrometer 
falls g radually from 6o° to 50°, 40°, 30°, &c. Notwitbftanding 
this appearance, the quantity of eleCtricity in the plate re- 
mains the fame, except the faid plate be brought fo near the 
table as to occafion a tranfmiffion of the eleCtricity from the 
** See my DifTertation on th< 
the Opufccli Scelti for the year 17 
year. 
the Capacity of Conductors, publiflied at Milan in 
^78; and alfo in rozisr’s Journal for the enfuing 
D 2 
former 
