The record-union., 1897-01-11

mersed engines of death have for a
long time been operated by electric de-
vices worked from either shore of a
passage or port approach
In addition, mines have been sunk
that would be discharged beneath ships
by their contact with half submerged
floats and devices, stretched wires and
cables, and the like But the chief
means has been the discharge OF the
mines by electric currents turned ON
from shore ends when lookouts sta
toned in observatories ON either side
determined that the approaching ship
was over the mine or torpedo. Range
finders in these two obServatorieS, sit
uated on opposite shores and connected
by telephone or telegraphic apparatus,
enabled the officers in charge to explode
the mine at the proper time. Obviously,
however, this has been q very costly
system, requiring two observatories,
two sets of operators and connecting
telegraphic wires.
In addition such methods are neces-
sarily restricted to observation of one
| vessel at time, and are open to the
| objection that the lime of communica-
ton between the two range finders may
be broken or get out Of order.
Now comes science and by yet an
other step in advance removes all these
objections and makes the approaching
ship itself signal to the shore operator
of the mine the exact instant when the
mine, or ONE of a series Of mines or
planted torpedoes, should be fired to
work the greatest destruction. Just how
this new device is to be defended
against by approaching fleets is the
next most important question.
The apparatus for making the mass
of floating iron the certain agency of
its own destruction operates upon the
principle that the apparent electrical
resistance of a coil Of wire having an
iron core is modified by the presence
within the path Of the open magnetic
circuit of the coil of great masses Of
iron or steel. If such a coil therefore
Is placed near a mine and an albernat-
ing current is kept passing through 1T, a
very simple device will indicate when
the strength Of the current is affected
by the approach Of mass of metal by
| the increase or decrease of the self in
ductton Of the coil.
| It is easy to understand that this de-
vice may be SO constructed as to indi-
cate upon q dial the almost exact dis
taDce at which the disturbing mass is.
| the speed OF its approach and the ap-
proximate volume of the mass, and
therefore just when the mine should be
exploded to do most effective work
| 1t lis obvious that such a device can
be so adjusted that 1T may be placed at
a considerable distance outside of the
channels of navigation, so that no
finders of amy approach fleet can dis
cover it. 1t will not be affected by fog
or by heavy weather as are the observ-
aItory systems, and will Indicate the
approach Of an iron ship and just what
her position is In relation to cross sec
ton OF the channel or harbor opening
when she cannot be seen from either
| shore.
Indeed, the new invention goes still
further, for 1t can be SO adjusted and
related TO automatic machinery as it
self to act upon the switch that closes
the fuse circuBt and explodes the mine.
More than this, by some slight modifi-
cation, the inventor points out how it
can be made applicable to self-pro-
pelling type of torpedo, so as to explode
it at an effective distance, thus obviat-
ing the necessity Of actual contact with
the ironclad's bottom or side, and rem
dering unnecessary the unreliable
clockwork sometimes employed, on time
calculation for the explosion of the
torpedo.