[ l 59 1 
to me fufficiently accurate, and for this 
reafon : the before-mentioned quantity of 
five or fix degrees do£s not call forth ,muf- 
cular irritability in all the circumfhmces 
tinder which metals are employed with 
fuccefs; and befides, this rneafure cannot 
ferve as a common rneafure for all anima.ls„ 
Some time ago, I made feveral experi- 
tnents with artificial electricity, and was 
at a lofs how to determine by this way, the 
direction of the animal electricity. 
I then learnt that the quantity of elec¬ 
trical fluid capable of occafioning flrong 
contractions in frogs, when applied im¬ 
mediately to the nerves, loft all its power 
on making it pafs over a metal conductor 
of great length, or through water, by 
forming myfelf a part of the chain. Never- 
thelefs, the experiment fucceeds in thefe 
animals with a conductor of 200 feet, 
(Paris rneafure) and even of ftill greater 
length. It is the fame thing, provided 
the 
