612 TRANSACTIONS OF SECTION G. 
A conductor, carrying an electric current, if placed in a magnetic field, is found to 
experience a mechanical drag, which is neither an attraction nor a repulsion, but 
a lateral force tending to move it at right angles to the direction of flow of the 
current and at right angles to the direction of the lines of the magnetic field in 
which it is situated. Still this was a toy. Two years later came the announce- 
ment by Sturgeon of the invention of the soft-iron electromagnet, one of the most 
momentous of all inventions, since upon it practically the whole of the constructive 
part of electrical engineering is based. For the first time mankind was furnished 
with a magnet the attractive power of which could be increased absolutely 
indefinitely by the mere expenditure of sufficient capital upon the iron core and 
its surrounding copper coils, and the provision of a sufficiently powerful source of 
electric current to excite the magnetisation. Furthermore the magnet was under 
control, and could be made to attract or to cease to attract at will by merely 
switching the current on or off; and, lastly, this could be accomplished from a 
distance, even from great distances away. How slowly the importance of this 
discovery was recognised is now a matter for astonishment. To state that Sturgeon 
died in poverty twenty-six years later is sufficient to indicate his place among 
the unrequited pioneers of whom the world is not worthy. Six years elapsed, 
and then there came a flood of suggestions of electric motors in which was applied 
the principle of intermittent attraction by an electromagnet. Henry in 1831 
and Dal Negro in 1832 produced see-saw mechanisms so operated. Ritchie in 
1833 and Jacobi in 1834 devised rotatory motors. Ritchie pivoted a rapidly 
commutated electromagnet between the poles of a permanent magnet—a true type 
of the modern motor—while Jacobi caused two multipolar electromagnets, one 
fixed, one movable, to put a shaft into rotation and propel a boat. A perplexing 
diminution of the current of the battery whenever the motor was running caused 
Jacobi to investigate mathematically the theory of its action. In a masterly 
memoir he laid down a few years later the theory of electric motive power. But 
in the intervening period, in 1831, Faraday had made the cardinal discovery of 
the mechanical generation of electric currents by magneto-electric induction, the 
fundamental principle of the dynamo. Down to that date the only known way 
—save for the feeble currents of thermopiles—to generate electric currents had 
been the pile of Volta, or one of the forms of battery which had been evolved 
from it. Now, by Faraday’s discovery, the world had become possessed of a new 
source, And yet again, strange as it may seem, years elapsed before the world— 
that is, the world of engineers—discovered that an important discovery had been 
made. Not till some thirty years later were any magneto-electric machines made 
of a sufficient size to be of practical service even in telegraphy, and none were 
built of a sufficient power to furnish a single electric light until about the year 
1857. Inthe meantime in America other electric motors, to be driven by batteries, 
had been devised by Devonport and by Page; the latter’s machine had an iron 
plunger to be sucked by electromagnetic attraction into a hollow coil of copper 
wire, thereby driving a shaft and flywheel through the intermediate action of a 
connecting-rod and crank. Page’s was, in fact, an electric engine, with 2-foot 
stroke, single-acting, of between 3 and 4 horse-power. The battery occupied 
about 3 cubic feet and consumed, according to Page, 3 lb. of zine per horse-power 
per day. This must have been an under-estimate ; for if Daniell’s cells were used 
the minimum consumption for a motor of 100 per cent. efficiency is known to be 
about 2 lb. of zine per horse-power per hour, 
Electric Motive Power Impossible in 1857. 
Upon the state of development of electric motors fifty years ago information 
may be gleaned from an exceedingly interesting debate at the Institution of Civil 
Engineers upon a paper read April 21, 1857, ‘On Electromagnetism as a Motive 
Power,’ by Mr. Robert Hunt, F.R.S. In this paper the author states that, though 
long-enduring thought has been brought to bear upon the subject, and large 
sums of money have been expended on the construction vf machines, ‘ yet there 
does not appear to be any nearer approach to a satisfactory result than there was 
