Evening star., 1914-09-27

accomplished either mechanically OF
chemically. In shape and size thesS
contact mines vary. but are usually
either cylindrical or spherical in shape,s
the latter type predominating, as itsf
globular case offers the least resistanccf
Of any OF the mine types to the currenc
OF rivers or bays. and can also stand al
greater amount Of external pressure thar
any other. The cases OF these mines arC
constructed OF mild steel
Controalable mines. socailed IN contvnl
distinction to the contact mine derivd
their names from the fact that they ard
detonated usually by An electric cur1
rent from wires leading to a switchboard
ashore. This type Is itself divided into
two classes. fixed mines and obserya atom
mines The fixed mine is tho sinples
form 1t is planted and then exploded
from tho switchboard The observatioq
mine. on the other hand. when struck
by vessel passing above II does not
explode. but sends a signal to the
switchboard room ashore. The operates
there may then explode the mine bH
current II he SO desires.
The difference between the buoyan6
type and the ground mine is appareneS
The buoyant mine rests Just beneath th%'
surface. and is fired either by contact
or by current. The ground mine is an
chored deep in the water. usually at 70
depth OF thirty-five or forty feet. It II
exploded either by current or by n
smaller sphere which floats near the sur
face and which contains q circuit cioser
In the construction Of a submarins %
mine. no matter what the character mas
be. the charges used are generally gun
cotton; and In some .ms Instances as dynamiss
IL seldom explodes in sympathy with
other mines. thus permitting the ex-.
plosion OF individual controllable mines
In field and the holding OF others ~
reserve Guncotton. too. Is safe tdl
handle and store. and may even be used
in its wet state.
One Of the most usual types Of harocr
mine 10 the contact chemical mine. This
mine generally consists Of a sphere fllled
with guncotton or dynamite From the
surface of the mine a number of leaden
piungers project When one OF these
plungera is struck. II breaks tube oc
picric or sulphuric acid imbedded in
powdered sugar and chlorate OF potash
and the detonation results.
Inventors in Germany. .Austria-Huneary
and italy have been especially active In
the last few years In putting together
these engines OF destruction. and recently
a good many patents have been issued
upon them in the United States.
Foremost among the European in
ventors of the submarine bomb rs
Giovanni Emanuele Ella Of Rome. who
within the last few months has re-
ceiyed two patents on submarine bomhs-
One Of Elias patents provides
mechanism by which a ship. striking
his mine near the bow causes the mine
to oscillate and work itself backward. so
that when the explosion occurs the de-
stroyfng engine is nearer amtdsh'ps and
at a more vital point of attack than the
bow.
The second Ella patent issued this year
calls for two mines connected by
fioating cable and rugged with sea
anchors, 30 that when the bow of ves-
sci engages the floating cable. both the
mines are dragged inward along the
vessels SIDES. while another cable at
tached to the sea anchors operates
mechanism to explode the bombs.
third patent issued by the patent
ventor. The feature of this engine con-
sists Of a glass cap placed at the apex
of the bomb. Contact with ship
breaks this cap. permit ing the entrance
of sea water, the weight OF which re-
This bomb is also equipped with
decorating cap, causes the explosion
This bomb is alsa equipped with q
device by which barrier may be In
terposed between the firing hammer and
the cap, rendering it safe during tbs
operation of planting.