AND OBSERVATIONS ON THE TORPEDO. 
265 
not intervened ; the shock was felt by the hands holding the wires ; needles 
in the spirals were magnetised, and the multiplier was moved. 
When a cotton thread, soaked in salt water, or in a strong solution of salt, 
was interposed beyond the contact-wires, both the power of affecting the mul- 
tiplier, and of giving polarity to the needle in the spiral, was arrested ; and 
this was uniformly the result in a considerable number of experiments made 
with three different fishes, of which two were very active, and with perfect 
conductors, free of this interruption, produced both effects readily. But the 
power of giving a shock was not equally arrested ; for on removing the mul- 
tiplier and spirals, and holding with the wet fingers the wires attached to the 
moist cotton thread, the shock was several times distinctly felt on stimulating 
the fish. The space of cotton thread between the wires was about one tenth 
of an inch, and to secure its perfect humidity or wetness, it was inclosed in a 
glass tube, with corks at each end, through which the wires passed. 
When the apparatus already described in noticing the chemical effects of 
the torpedo, was substituted for the wet cotton thread, the tubes being filled 
with a strong solution of salt, the multiplier was affected, and gas was given 
off at each of the points of the gold wires, and when steel needles were used, 
a fine current of gas rose from the point connected with the under contact- 
wire, and not a particle from the other point. In these experiments, there 
were interposed, at the same time, the chemical apparatus, one on each side, 
the spiral, one also on each side, and the multiplier intermediate, and there 
were necessarily many junctions of wires. I scarcely need add, that in an 
experiment made expressly to ascertain it, the shock of the fish was felt be- 
yond the saline solution ; for it had been previously proved, by the experi- 
ments of Mr. Walsh, that salt water, even in a long circuit of imperfect con- 
ductors, has the power of transmitting it. 
2. Observations on the Electrical Organs of the Torpedo, and on some parts 
of its structure connected with them. 
The peculiar columnar appearance of the electrical organs of the torpedo, 
their great proportional size, the vast proportion of nerve with which they are 
supplied, the manner in which the columns are sheathed in tendinous fibres, 
