1 6 8 Mr. c a vex dish on the Torpedo, 
Let the quantity in the plate be to that in the row as x ta i ; 
it is plain, that the electricity in the row will be clirni- 
niflied each time it is communicated to the plate, in the 
proportion of i to i + x, and confequently after being com- 
municated 1 1£ times will be reduced in the proportion 
i 
of i to i+x 4 ; therefore, \+x 4 =2 ; and i +x—2 
Whence the value of x may eafily be found by logarithms. 
But the readied: way of computing it, and which is exaCt 
enough for the purpofe, is this : multiply the number of 
times which you communicated the eleCtricity of the row 
to the plate, by 1,444; an d from the produCt fubtraCt 
\ 
the fraction the remainder is equal to - , or the num- 
ber of times by which the eleCtricity in the row exceeds 
that 111 the plate. 
The way by which I eftimated the ftrength of the 
charge given to the battery, was taking a certain num- 
ber of jars, and electrifying them till the balls of the 
electrometer feparated to a given diftance, and then 
communicating their eleCtricity to the battery. This 
method proved very convenient; for by uling always 
the fame jars, I was fure to give always the fame charge 
with great exaCtnefs; and by varying the number and 
fize of the jars, I could vary the charge at plealure, 
and belides could eftimate pretty nearly the proportion 
of the different charges to each other. It was alfo the 
only convenient method which occurred to me; for I 
could not have done it conveniently by charging the 
whole battery till an electrometer fufpended from it fe- 
parated 
