AND OBSERVATIONS ON THE TORPEDO. 
261 
covered with water. One wire was applied to the under surface of the elec- 
trical organ, and the other to its upper surface, and contacts were made at 
intervals during about five minutes, when the fish seemed much exhausted by 
its exertions. On taking the needle out, and bringing it near some fine iron 
filings, it proved magnetic, and powerfully attracted them. This experiment 
I have repeated several times, with fishes of different sizes, some larger and 
others smaller, and with the same result, when the fish has been active and the 
contacts similarly made. 
The next trial which I made of the electricity of the torpedo, was on the 
multiplier. The precaution was taken to insulate the instrument well, by 
smearing with sealing-wax the feet of the stand supporting the coil. The 
same wires for contact were used in this as in the former experiment, and the 
junctions were carefully made. Applying one wire to the under surface, and 
the other to the upper surface, with every fish which I tried I succeeded in 
obtaining decisive results ; the needle by active fishes was generally thrown 
into violent motion, and even by the feeblest was distinctly affected. I have 
met with no instance of a fish which had the power of magnetising a needle 
in the spiral wire, failing to move the needle in the multiplier ; but I have met 
with more than one example of a fish whose electricity was equal to the latter 
effect, and not to the former. 
The experiments which I have instituted, with a view to ascertain if the 
electricity of the torpedo has any igniting power, or power of passing through 
air and producing light, have been attended with less satisfactory results. 
Very active fishes were tried on circles of perfect conductors, interrupted only 
by a space just visible with the aid of a powerful magnifier. The terminal 
wires, coated with sealing-wax, excepting at their extremities, were introduced 
through a perforated glass stopple into a small glass globe, which was held in 
the hand of an assistant. The contacts were made in the dark ; but not the 
faintest spark could be perceived, nor could any ignition be perceived when 
the extreme points were connected by silver wire not exceeding one thousandth 
of an inch in diameter. 
When a torpedo was put into a metallic vessel, insulated by a glass stand, 
and contacts were made on its back, with the insulated wire resting on the 
edge of the vessel, or at a distance from it, luminous appearances were fre- 
2 M 
MDCCCXXXII. 
