30 Professor Leslie on Electrical Theories. 
ings, and AH, GY denote their opposite electricities ; the in- 
tensity of A will gradually diminish to the centre D, which is 
neutral, and again gradually increase with opposite electricity 
to G. Hence, during the transmission of the electricity from 
A to D, an equal quantity is also communicated from G to D ; 
and therefore, the discharge will be performed in the same 
time that the electricity would be conducted from one of the 
coatings A and dissipated at the middle point D. 
If the flexures of the conducting substance are not sudden, 
the time of communication will depend on its length, and not on 
the distance between the extremities ; for the gradation of inten- 
sity is uniform in the successive portions AB, BC, CD, &c., and 
these may be regarded as indefinitely small chords inscribed in 
a curve, to which they are therefore equal. 
Let AC (Plate I. Fig. 10.) be a compound conductor, of 
which the part BC is either narrower than the other AB, or of 
a slower conducting quality. Let the intensity of the electri- 
city of A and of B be AE and BF ; produce EF to meet the 
extension of AC in D and join FC ; make the minute part A a 
equal to B h. Since the same quantity of electricity must be 
transmitted through every part of the conductor, the differences 
E& and Fi between the proximate intensities at A and B, are 
inversely as the conducting powers of the two portions AB and 
BC. But EA or FA : Fi : : BC : BD ; and the rate of commu- 
nication will evidently be the same in the uniform conductor 
AD as in the compound one AC. This method of investigation 
might be extended to more intricate cases, were it judged ne- 
cessary *. 
To bring the various circumstances into a single point of view . 
* In the case of a chain and other interrupted conductors , the celerity of com- 
munication will depend chiefly on the surface of contact. Thus , the shock sent 
through a chain , stretched by a considerable weight, is sharper than through a chain 
only spread loose. If a dissected frog , having its thighs and its spine sheathed with 
tinfoil , be laid on a table , and several persons grasping each others ?noistened hands , 
while two of them , holding merely a brass chain , form a circuit ; this very sensible 
electrometer will , after the first tremor , continue quiescent , but on giving the chain a 
sudden tug , the subject will be thrown into violent convulsion , which is renewed at 
every twitch. By applying strong pressure to enlarge the quantity of contact , the 
general effects may be greatly augmented in recent and very curious experiments of 
electro-magnetism . 
2 
