The times., 1899-05-12
THE RECENT TESTS
OF AIR TELEGRAPHY
General Greely's Experiments
and the Result.
Wireless Communication Establish
ed With Fort Myer.
Messages Transmitted With Some
Degree of Success-The Use of
RcHectors Discussed.

General Greedy made public yesterday
the result Of recent experiments with
wireless telegraphy by the Signal Corps,
U. S. A., as follows:
Since the announcement of the tests in
space telegraphy by Senior Marconi two
years ago the subject has been under con-
sideration by the Signal Corps of the Army
and experiments have recently been be-
gun with the object of thoroughly testing
the value Of this means of communication
for military and other governmental pur-
poses.
Special apparatus has been designed
and constructed for these tests, which have
already shown sufficient promise to war;
rant further and systematic trials. In
view of the great public interest and in
order to facilitate experiments by ether
scientists in the United States, it is deemed
proper to put forth this statement OF oper-
ations to the present time.
THUS far in the experiments the ef-
hciency of several forms of transmitters
for the generation of the Hertzian waves
have been used. and much promise has
been realized from the use of a large al
ternating current coil in oil as a gen
orator instead of the ordinary Rhumkorff
coil, employed by Marconi. This coil is
energized by a three quarter horse power
rotary transformer, furnishing 125 volts
alternating potential. and this arrange
ment makes very powerful and efficient
source of Hertzian radiation.
THE former receiver used has been sub
stantially the Branksy 'coherer discov-
cred in 1891, and the signals transmitted
are recorded upon receiving tape. The
transmitter has been mounted upon the
west elevation of the State, War, and Navy
building, utilizing the present wooden flag
| pole for the vertical wire of the trans
i mi tor THA
| the old Naval Observatory grounds about
three-quarters of mile distant, and later
| moved to the Signal Corps station at Fort
| Myer, Va.
| During the experiments constant CON-
| munication by heliograph and flag between
the transmitting and receiving stations
has been kept up by the trained men of the
regular signal corps. and this has greatly
| facilitated the work. Signals, letters, and
words have been transmitted and received
between these stations, but the great deli
cacy and constant adjustment required in
the present receiver have made the trans
mission of regular messages as yet unre-
| liable and uncertain. The presence of
| large buildings and masses of iron and
metal necessarily present in cities make
| such places undesirable for carrying on
experiments of this character. The dis
| tance over which signals may be trans
| mitted by given apparatus is gauged by
| the height of the vertical wire used at
| either end, and this has naturally sug-
gested the use of small gas balloons such
as have already been used for signal and
| other purposes by the signal corps. A
supply of these balloons has already been
obtained and will be used for this purpose
in the near future.
That there is a field of usefulness for
| space telegraphy is undoubted, but that it
VIII supplant, to a material extent, the
use OF wire for ordinary commercial teleg-
raphy is not believed. Its value for con-
nection between lighthouses and lightships
and the shores at points where cables can
not now be permanently maintained, will
be great. For signaling between ships at
sea and to replace ordinary flag methods
in use between naval vessels, It should
prove invaluable. since no kind of weather,
neither fog, darkness, or storm avail TO
! affect its use
The use of metal reflectors to augment
and direct the radiation to particular
| points has already met with partial sue
cess, and should be thoroughly investigat-
ed. At present the radiation proceeds from
the transmittor in all directions. and the
same message can be received at any point
within the proper radius at which re-
ceiver is placed. A satisfactory directing
reflector, and receiver of the proper
electrical capacity, or, In other words,
tuned to the vibrations of the particular
transmitter, would make a great advance
in space telegraphy. and do much toward
the extension of its field OF practical use
| fulness.
While secrecy OF transmission is among
the probabilities. the present stage of ex-
pertinent does not justify its positive per-
| diction"