24 
BRITISH ASSOCIATION.- 1835. 
with 7-i- yards of wire, and the same battery was used with each 
magnet. 
No. 1. The wire was coiled only on the ends, and crossed 
straight from one pole to the other .. 1 o 
2. Wire coiled on the ends, but connected by a spiral 
round the magnet... 11 0 
3. Wire divided, and each half placed as a helix on 
one end of the magnet .. 6 0 
4. Wire coiled equally over the whole magnet. 7 0 
5. W T ire divided into 4 equal parts, each coiled on one 
fourth of the magnet. 5 0 
6 yards of wire were coiled on a magnet 7-f inches 
long, -4 square . 7 0 
14- yard of wire were coiled on a magnet 7-f inches 
long, q- square . 3 0 
Hence the power of the magnet increases far more rapidly than pro¬ 
portionately with its size. 
Remarks on the Nature of Magnetism. The author in this part 
of his paper discusses the prevalent theories of magnetism, and 
compares them with a variety of experiments corresponding to the 
analysis which he presents of the subject. It would be nearly 
impracticable to do justice to Mr. M’Gauley’s views on the nature 
of magnetism in the compass of an abstract. The following brief 
notice will serve to convey some idea of his mode of reasoning. 
Magnetism does not arise from the circulation of electrical cur¬ 
rents, but from the electrical excitation of the mass or the particles 
in the magnet: not from currents, because it can begin to exist 
without them, can continue to exist without them, and because cur¬ 
rents can be generated in conducting substances of sufficient quan¬ 
tity, velocity and intensity, without the development of magnetism. 
Magnetism is mere electrical excitation, provided that by mere elec¬ 
trical excitation we can cause its existence, and its various pheno¬ 
mena are such as we should expect from mere electrical excitement; 
and provided not electrical currents but electricity at rest be always 
coexistent with it. Such, the author contends, are the facts, and he 
proceeds to prove his position by appropriate experiments. 
He then offers explanations in agreement with these view’s of se¬ 
veral leading phenomena, as terrestrial induction, the mutual at¬ 
traction of conjunctive wires, the position of the poles, of a perma¬ 
nent magnet, and of an electro-magnet, the retention of magnetism 
in steel, the destruction of magnetism by heat, the development of 
it by percussion, &c. He finally observes: 
If magnetism be merely electrical excitation it is probable that, 
cheap as their production is at present, a more oeconomical mode of 
forming powerful magnets may yet be discovered. Though it may 
be said that magnetism is not now’ for the first time applied to ma¬ 
chinery, the author believes it will be acknowledged that the attempt 
to apply magnetism to machinery, as an advantageous and a powerful 
