20 
BRITISH ASSOCIATION.- 1835. 
An Inquiry into the Possibility and Advantage of the Application of 
Magnetism as a Moving Power, with Remarks on the Nature of 
Magnetism. By the Rev. James William M’Gauley. 
To consider with advantage the possibility of applying magnetism 
as a moving power, we must examine its nature and peculiar pro¬ 
perties, because otherwise we cannot pronounce with accuracy on the 
quantity at our command, or the probable cheapness of its produc¬ 
tion. In this inquiry the author does not contemplate such a power 
as that attained in magnetic rotations and similar mechanism ; it could 
never be advantageous; for the force of the magnet is not directly 
applied, or is applied at such a distance as to be almost annihilated. 
The quantity of magnetism we may produce seems to have no 
limit, since we can combine any number of powerful magnets. 
The ceconomy of magnetism. A very small electrical power, which 
may be produced if necessary by the agency of sea-water, will 
abundantly suffice. 
The obstacles likely to prevent the application of magnetism as 
a moving power. Of these the principal seems to consist in the 
disturbing influence which magnets of any power exercise over 
each other. This prevents the necessary reversion of the poles. 
Experiment 1st. The author tried to reverse the poles of one 
electro-magnet in contact with another: the sudden rush of elec¬ 
tricity evidently caused a magnetic needle near the magnet to be af¬ 
fected, but there was no separation or repulsion of the magnets, nor 
any permanent change of polarity.—Experiment 2nd. The similar 
poles of two electro-magnets of very different power were brought 
together : they attracted each other ; the poles of the smaller magnet 
were reversed by the larger, and a counter-current was formed 
through its battery, and indicated by a galvanometer placed in the 
circuit.—Experiment 3rd. Only one of-the magnets was excited, 
then its poles reversed; the other, acting as a keeper, was thrown 
off, and attracted with great violence.—Experiment 4th. Between 
two semicircular magnets A and B, a bar of soft 
iron, C, was suspended, and their poles reversed in 
such a manner alternately as to throw off the bar from 
one magnet and cause it to be attracted by the other. 
—Experiment 5th. A bar of magnetized steel xvas 
placed between the magnets; but the effect was not so powerful, 
since the iron bar became by induction a stronger magnet than the 
steel, and hence the mutual actions of the iron bar and the magnets 
was more powerful. 
The very limited space within which magnetic action is confined 
presents a very considerable obstacle. The power is inversely as 
the square of the distance ; at the eighth of an inch the power even 
of a large magnet is comparatively trifling. The stroke of one eighth 
of an inch, directly applied to machinery, would be nothing: we must 
increase the stroke, and at the same time diminish the power as little 
