The New York herald., 1879-09-04

methods of arranging mines for the defenee OF
hirbor together with the lead OF cables.
Lieutenant W. w. Gilpatrck showed the objects
OF circuit closers, circuit breakers and circuit
shunis. and how they differed from each other.
using the blackboard to illustrate the dicuit SUD-
ject
Lieutenant Belden again called to the front
and ordered to describe fhe electric shut.
ter used for signalling the approach OF vessels ana
Tor announcing faults in cables leading to mines.
for hripg mines and also for announcing
which nine had been fired This machine is in
circuit with instrument which shuts all neighbor-
ing torpedoes out OF the circuit, 80 that they may
not be hred by the explosion OF the one in contact
with the vessel.
Lieutenant Harber described the English shutter
apparatus. It's construction. use, &c. 1t was CON
clusively proved that IL very much inferior t. 7
the one IN at the station.
Lieutenant Handy explained various clecro-con.
tact and electro-chemical torpedoes aud wires the
most Interesting OF which was that which the Rus
SLAMS used in the late war with Turkey.
lieutenant Meade was called upon to tell the Board
how 10 make an improvsed torpedo with the mate
rial usually found oil shipboard in of emer.
Gency together with the material for firing the
Lieutenant Shaw described and illustrated ON thu
blackboard the method OF determining tho position
of vessel by observation with reference to any
given torpedo, and tho method of firing Mt tbs
proper time lie then showed what Siemien' q de.
tector could do. This machine transfers the oh.
seryations OF two persons at points distant from
each other to the same plane and to table which
also contains plat of the torpedo field The OBJ
ut the plane table can fire any torpedo when
vessel may be over it by electricity
SIGNALLING WITH ELECTRIC LIGHTS.
Lieutenant Commander A. IL. Wright described
tho apparatus producing elcctrlc llpht aud lts
use ns applied to defensive warfare, Farmers hand
lamp, to be used III = launch or for signalling pur
poses. by flashing the light held in the hand upon
tho clouds 1t night signals may be made by the
Myers code and read at great distance when inter-
vening objects prevent the use of ordi.
nary torchlight or hreba This lamp was
shown to be specially intended for in picket
launches, where the larger lights would be too
heavy and would require too much power. A larger
light by Professor Farmer. he said had system Of
shutters to flash signals by night from ship. This
lamp had been used with great success. The
machinery to it is very light and portable and
the lamp can easily be held in one hand.
CLEARING A HARDOR.
The officer WAS called upon to show how an
enemy harbor coud be cleared OF tOrpedoes, chaina
aud other distractions, and from diagram he
showed in very clear and interesting manner the
method OF counterminlng against an enemy's tor-
pcdoes. He demonstrated q mode OF counterniinlng
by sending steam launch, entirely controlled
by electricity. like the Success, referred to in
today's HERALD. This boat could carry the
counIermncs slung her rail. drop them by
electricity at will, and they might then be simuia
neously exploded from the point where the boat
controlled thus rendering channel safe for vessels,
providing the countcrmines had been so placed that
the circ of destructive effect intersected when all
mines, whether ground or buoyant. would probably
be Exploded.
At this point the examination adjourned until
tomorrow. The Board Gill complete the work carly
in, thc 1ay