748 
ELECTRICAL ANIMALS. 
a certain action of the electric fluid ; but as not the least spark of fire, 
or noise, could ever be perceived, this too seemed insufficient. Subse- 
quently, however, Mr. Walsh, with indefatigable pains, not only explain- 
ed this surprising phenomenon on the known principles of electricity, 
but gave a demonstration of his being in the right, by constructing an 
artificial torpedo, by which a shock resembling that of the natural 
one can be given. The electric organs of the torpedo consist of two 
sets of very small cylinders lying under the skin, one of which is 
electrified positively, and the other negatively, seemingly at the plea- 
sure of the fish. When a communication is made between a set of 
cylinders positively electrified, and those which are negatively so, a 
discharge and shock ensue, like what happens in the case of the Ley- 
den phial. 
The only difficulty now is, to account for the total absence of a 
spark, which in the case of the torpedo never exists even in the 
smallest degree, and the impossibility of conducting the shock through 
the smallest interval of air. But this also is explained in a satisfac- 
tory manner by Mr. Walsh, and shewn to be nothing else than what every 
day takes place in our electrical experiments. 
It is well known, that a small charge of electricity, if put into a 
little phial, will occasion a bright spark and loud noise when dis- 
charged ; but if the same charge is put into a phial much larger, the 
spark and noise will be less in proportion : neither will the spark 
break through near such a space of air in the latter case as in the 
former, though the shock would in both cases be the same to a per- 
son who received it through his body. If, instead of a large phial, 
W'e suppose the charge to be diffused all over a large battery, the 
shock would still be the same, and yet the spark and noise attending 
it would be almost imperceptible. The case is the same with the tor- 
pedo; each of the electric organs is a battery composed of innumerable 
small cylinders, which discharging themselves all at once, produce a 
formidable shock : but by reason of the smallness of the charge of 
^ach, the spark is imperceptible. 
The truth of this was exemplified by Mt. Walsh’s artificial torpedo, 
which though it would give a very considerable shock through a con- 
ductor totally uninterrupted, yet on the least breach therein, even for 
the breadth of a hair, no shock was felt. In every other respect the 
electricity of the torpedo agrees with that exhibited by the common 
electrical machines. An insulated person cannot receive a shock by 
touching one of the organs of the fish; but a violent stroke is given 
to the person, whether insulated or not, who lays one hand on the 
positive and the other on the negative organ. The fish, as is reason- 
able to imagine, seems to have this electric property in its own power ; 
and appears sensible of it, for when giving the shock, it is accompa- 
nied by a kind of winking of the eyes. 
The ancients considered the shocks given by the torpedo as capa- 
ble of curing disorders ; and a modern philosopher will scarcely 
hesitate to believe their assertions, now that electricity has been found 
to be a remedy for many diseases. 
The third fish, which is known to have the power of giving the 
shock, is found in the rivers of Africa, but we have a very imperfect 
