The Sun.
London, England, 1857-12-26 00:00:00

THE MILITIA.

The West Norfolk Militia left Norwich on Wed-
nesday afternoon for the North of England. The
regiment, which is upwards of 600 strong, is divi-
ded into three parties, Lieutenant-Colonel Cus-
tance proceeding with three companies to Chester;
Major Bedingfeld, with three ether companies, to
Liverpool ; and Capt. Narsham, with two com-
panies, to Stockport. The head-quarters will be at
Chester, and the depot of the regiment will remain
at Norwich.
The Dutchman and Adonis steayterso which ar-
rived at Portsmouth on Thursday morning for the
embarkation of the Ist Surrey Militia (who ar-
rived by rail from Richmond, (Surrey), will con-
vey that regiment to Waterford on Tuesday next.

ELECTRO-MAGNETISM AS A MOTIVE
POWER.

In a recent article on the subject of Mr. Bagg's
process for applying steam to quicken the move-
ments of the electric telegraph we alluded to the

researches which weregoing forward into the value
of electro-magnetism as a motive power. We have
space now to refer to this important subject at a
length more in accordance with its merits, and to
notice the gradual steps making towards a disco-
very, the' immense value and utility of which, in
spite of the progress already made by steam, will
when attained equal in importance our first know-

ledge of that great power. It is almost superfluous
to enumerate the many important ad vantages which
an electro-motive power has over seam. There is
perfect safel from all danger from tire or explo-
sion. There is no expenditure of materials when
the engine is not in action, and its power can be
applied at a moment's notice. It is always ready
for action without previous consumption of ma-
terials in getting up steam, and'in marine en-
gines there would be no waste in freightage
al for carrying coal. These are the most important
of the advantages it offers, but many others will
occur t, any who reflect for a moment on the pecu-
liar nature of the two forces employed. With such
high rewards in view plans to convert the power of
electro-magnetism into a motive force have always
been among the most cherished schemes of electri-
cians. The Russian and American Governments
have spent large sums in endeavouring to solve this
problem ; France still holds out a great reward to
those who can produce an electro-motive engine
which shall only consume 19 ounces of zinc per
horse power per hour, and in that empire the idea
that these moderate conditions will be fully attained
is firmly believe]. In this country no official en-
couragement his ever been offered to such attempts
and 1 itterly the notion has been much frowned upon
by scientific men, who on all such questions are ge-
nerally the most conservative and impractieahl.e
portion of the public. The grounds upon which their
opposition has lately been based are—first, the
undoubted failure of the various attempts
hitherto made ; secondly,
a comparison of cost
between the working of the best kind of electro-
motive engine and a steam eneine and, lastly, , a
hasty, but most erroneous to6pinion of Liebig s,
which utterly condemned the idea of an electro-
motive engine altogether, though on
grounds which
men of equal eminence in science, though less in
fashion, have not hesitated to declare as " perfectly.
absurd." It is needless to refer to the attempts of
the scientific men who have sought to utilise the
power obtainable from electro-magnetism. All the
principal electricians have dabbled
in it more or
less from Oersted downwards, and every fresh at-
tempt hasled to fresh improvements! id discoveries.
The first important invention of the kind was exhi-
bited by a Mr. Davenport, in America, in 1837, and
was followed in 1838 by another eleetro-megnettc
engine, by a Capt. Taylor. In the same year Jacobi
produced a vessel upon the Neva worked by electro-
magnets. It was 28 feet long
7
broad, and, with
14 persons on board, was worked against the stream
at the rate of four miles an hour. In 1842 Mr.
Davidson built an engine adapted for use on a rail-
way, and tried it on the Ediuburgh and Glasgow
line. This engine with
magnets and battery
weighed five tons, but in consequence of the very
faulty arrangement of the magnets there was a
great loss of power. The utmost speed attained by
it was only four miles per hour, and the attempt
was therefore condemned as a total and irredeem-
able failure, people quite forgetting in their eager-
ness to blame that the first steam locomotive tried
in England on a level plain wade only five miles
an hour, and that ten years later Stephen-on had
so little improved the machinery that with eight
carriages and 30 tons' weight he scarcely attained
lour miles an hour on a dead level. This inven-
tion of Davidson'e, therefore, was given up, and
attention was soon afterwards occupied by the
engine of Professor Page, in America, which was
one of the best of them all, and which was iu turn
followed be the improvements of Hjorth and of the
Messrs. Harrison. The latter gentlemen, indeed,
claim to hear° fulfilled all conditions, and rather
more than all which it was even hoped or expected
electricity would be able to fulfil ; but, as they
have not to our knowledge entered into details, it
is impossible to say how far their assertions can be
borne out. Nevertheless, with all these attemps,
and with others by Dal Negro, M‘Gailley, and
Wheatstone, not one of the electromagnetic engines
could be regarded as a great success in the path of
discovery towards the new power. In fact, all the
plans when tried practically were found to be at
variance either with the laws of electricity or of
mechanics, and the two main
points for solution in
the employment of electricity—its application and its
economy—werebothinoreor le.is overlooked. Nearly
all these machines, then (except those of Page and
Hjorth), were made either with oscillating or rotary
direct action engines ; in the former the electric
current was always cut off long before the mag-
netic force had reachedits maximum,
and in the
latter the magnets successively brought into action
were necessarily placed at such different distances
that it was impossible to produce an equal motion
by means of them. In the rotary engines, also, a
given it was of course found that in a system of mag-
nets constructed to produce power, when
set in revolution, an immense reduction of their
original force immediately took place, so that their
combined action in practice fell infinitely
short of
:heir estimated force. And not only did each
magnet sustain an actual diminution of power,
amountieg to at least one half, but the power
thus lost was converted into a current of electricity,
acting in opposition to the primary current by
which the magnetism was induced. This loss of
force was great, and appeared unavoidable until
she improvements of Page and Hjorth ; bu
tho machines of those gentlemen lost so
much
' even
power, and were worked at such a cost, that all