On the Action of a Spiral Conductor, &c. 331 
five or six hundred feet of wire be substituted, an increase of action 
will be manifest. The length of the coil must be in some ratio to 
the projectile force of the electricity, and also the quantity to the 
thickness of the conductor, in order to produce a maximum result. 
Thus, when a small battery is used with a large conducior, it must 
be charged with strong acid. 
The action of the spiral conductor depends on the inductive prin- 
ciple of an electric current discovered by Mr. Faraday, and is con- 
sequently intimately connected with the whole subject of Magneto- 
Electricity. 
If a magnet be fitted up in the ordinary manner, with a spool of 
wire covered with silk around the keeper, the intensity of the shock 
will be astonishingly increased, if the current generated in the spool 
be transmitted through a coil of several hundred feet of fine wire sur- 
rounding the legs of the magnet. It is necessary, however, to pro- 
duce this effect, that the wire on the spool, and that around the mag- 
net, should at first form a continuous closed circuit, and that this be 
interrupted at the same instant that the keeper is detached, so that 
the induced current may pass entirely through the body. 
The intense shock may also be given by generating a current with 
one magnet, and accelerated by passing it around a second magnet. 
Professor Emmet, of the University of Virginia, more than two 
years since, made the interesting discovery that the magneto-electric 
current is much increased in intensity by passing it through a portion 
of the generating magnet. This interesting fact, which he has appli- 
ed with much success, to improve the magneto-electric machine, may 
undoubtedly be referred to the same cause as the action of the spi- 
ral, and I have succeeded in modifying the application of it in seve- 
ral ways. 
These magnetic experiments were made on the first or second day 
of May last, while on a visit to Philadelphia, with the large magnet 
belonging to the museum, and kindly loaned me by Mr. Peal for the 
purpose. They were made with the assistance of my friend Mr. 
Lukins, but as I have not had an opportunity of verifying them, I 
cannot at present give a more detailed account. I have also made 
some preparations for applying the same principle to increase the ac- 
tion of a thermo-electric current. 
“a 4 hell alae! 
