AND OBSERVATIONS ON THE TORPEDO. 
275 
a shock appear very similar* ; its power of passing through air is infinitely 
less, as is also (if it possess it at all) its power of producing heat and light. 
There are other points of difference ; I allude chiefly to the results obtained 
in the experiments already described, in which the metallic communication 
was interrupted by a strong solution of salt. In this instance the full power of 
the fish appeared to pass ; water was decomposed, a shock was received, 
needles were magnetised, and the multiplier was affected. When the same ex- 
periment was made on the electricity excited by the small voltaic combination 
of a single plate of copper and zinc, each less than an inch in length, and half 
an inch in breadth, immersed in an acid, neither water was decomposed nor 
was the multiplier affected. When it was made on the electricity of the elec- 
trical machine by means of a Leyden jar, all the effects were witnessed except- 
ing the motion of the multiplier, and the order of succession of poles in the 
needles magnetised in the spirals. 
How are these differences to be explained ? Do they admit of explanation 
similar to that advanced by Mr. Cavendish in his theory of the torpedo ; or 
may we suppose, according to the analogy of the solar ray, that the electrical 
power, whether excited by the common machine, or by the voltaic battery, or 
by the torpedo, is not a simple power, but a combination of powers, which may 
occur variously associated, and produce all the varieties of electricity with 
which we are acquainted ? 
As regards the mode of production, or the cause of the electricity of the 
torpedo, it is unavoidably enveloped in great mystery. Like animal heat, and 
the light emitted by certain animals, and, I may add, like the secretions of 
animals generally, it appears to be a result of living action, and connected 
with a peculiar and unusually complicated organization. All the attempts I 
have made to obtain electrical excitement in the fish, after it has been deprived 
of life, have been in vain. 
The observations which I have detailed relating to its anatomical structure 
* There is this difference when two spirals are used, one connected with the inside of a Leyden jar, 
and the other with the outside, — a needle in each similarly placed acquires opposite polarities, the north 
pole in one being where the south pole is in the other ; whilst in the instance of the torpedo they 
accord, so that a line of needles passing from one side of the electrical organ to the other would ex- 
hibit a succession of similar poles. 
