The Sun.
London, England, 1861-04-29 00:00:00

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Al very valuable paper under this title has hetes
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by Professor Wheatstone and Mr. Able on behalf
of the War Department.
One of the mast prominent effects ef electricity
is well known to be the production of fire. Thus
buildings are fired by lightning flashes, and too often
charged magazines. Very natural was it, then, to •
ascertain whether this
be tun— . ,anie -account in the'
engineering, both civil and military. Thus, to
effect the dislodgment of masses agency
ofro
ckpracticeby could
gun-
powder explosions, charges of gunpowder for cen-
turies past have been buried within the mass and
ignited ; but long before any electrical resources
were sought for this purpose the ignition had been
accomplished by a slowly burning train. Subse-
quent to the discovery of electricity this agent has
been pressed into service, and by the aid of very
rough electrical expedients engineers have long
been able to ignite one gunpowder charge at a time.
but the desideratum remained of igniting many
gunpowder charges simultaneously. Such was the
problem to which Professor Wheatstone and Mr.
Abel recently turned their attention, and in which
they have been successful.
Here it must be premised that electricity may be
obtained from many sources, and, according to the
source obtained so does its property vary. It may
be obtained from the friction of glass, for example,
as in the common electrical tnacnine ; and, were it
not for the difficulties and uncertainties attendant
upon the working of this arrangement, perhaps it
might have best answered the purpose intended of
it. When, however, the point is borne in mind that
an electrical machine will barely act, or not act at
all, in a damp atmosphere,of course theprecautions
are many that would have to betaken for employ-
ment of such electricity out of doors. With all its
disadvantages, however, frictional electricity has
done some good engineering
service. In 1831 Mr.
Moses Shaw, of New York, ignited by this electri-
city fuses containing a mixture of gunpowder and
fulminate of silver. thereby dislodging large masses
of rock ; but he states that lie was unable to ope-
rate during the greater part of the year because of
bad . weather. More favourable results Were ob-
tained by Professor Warretitrap, of Brunawiek, and
• Gatzmann, of Freiburg, in 1812 and 1843. Employ-
ing fuses which contained a mixture of sulphide of
antimony and chlorate of potash, and special con-
trivances for insuring a more perfect insulation,
they succeeded in exploding from 8 to 10 mines
simultaneously, through 78.5 metres. Notwith-
standing their precautions, the evil effects of
humidity compelled them to discontinue the expe-
riments. Still more successful results were ob-
tained, in 1845, by Mr. Charles Winter. By means
of a fuse, containing a • preparation of phosphcrus,
he inflamed powder through the telegraphic line
between Vienna and Hotzendorff—a distance of
4,906 metres. In point of fact the results were
s-
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machine electricity as the agent for effecting mili-
tary explosions. They employ a portable electrical
machine—tho electricity being excited by two glass
plates, one foot in diameter and four lines of thick-
ness, in conjunction with a Leyden jar, having an
external coating of 276 square inches. These seve-
ral parts are enclosed in a case, the interior of which
is kept dry and heated by means of a small portable
stove, so arranged that the products of combustion
do not enter the case. The conductors are copper
wire covered with gutta percha. Thus guarded,
and in very scientific hands, the efficiency of the
Austrian apparatus is perfect. On several occa-
sions no less than 50 mines have been simultaneously
exploded by it. Thirty-six discharges have even
been simultaneously exploded by it under water in.
the Danube, the charges having remained sub-
merged 20 hours previous to the operation.
Nevertheless, machine electricity was deemed to
be attended with such great drawbacks by military
engineers in the British service, that a substitute
was sought, and, to a certain extent, found, in the
ordinary voltaic battery. This apparatus, how-
ever, left much to be desired ; hence the recent in-
vestigations of Professor Wheatstone and Mr. Abel.
They first tried the hydro-electric machine of Sir
William Armstrong—the sort of apparatus that was
for many years exhibited at the Polytechnic Insti-
tution. Notwithstanding the stupendous effects
produced by this apparatus in the lecture-room, it
did not answer well in the field. They next tried
electricity from a galvanic battery, intensified by
transmission through a Kulitnkorff's coil, borrow-
ing the idea from the Spanish colonel, Verdu ; but
even this arrangement did not quite answer the
expectations the experimenters had been led to
form of it. Finally. their investigations led
them to a trial 'of electricity developed from
magnets; and this, all things considered, was found
to be the most. satisfactory of the whole series, so
that in future we suppose this form of electricity
will be employed in the British military service.
Having decided on the best source and character of
the electricity, the operators had next to determine
what was the best sort of fuse. The fuse employed
by Colonel Verdu, and introduced by him into the
Spanish engineering service, is the discovery of an
Englishman, Mr. Statham, and is commonly desig-
nated here and elsewhere as the Statham fuse."
' It may be said to consist of a broken circuit, inter-
vening between the ends of two copper wires enve-
loped in gutta percha, the intervening space being
filled with sulphate of copper. It is very delicate'',
but Messrs. Wheatstone and Abel required a fuse of
still greater delicacy, and in the end discovered it.
The Abel fuse may be shortly stated to be a Statham
fuse,wherein subphosphide of copper takes the place
of sulphide of copper, and apparently leaves nothing
to be desired. It is pretty certain in its action,
easily prepared, and age does not seem to affect R
I all valuable requisitions in a military point of
vie w.