Amador ledger., 1910-07-29

hOOIn LOT improvement III l1lBub- n
New Airship Alloy-Portable Wire.
less-Paint for Monuments-The
Miners Fire Curtain Cheap Metal
for Bearings-Jamaica Meal-All
Roads in One.
The magnetic detector of Rossi sig
nails the arrival of Hertzian waves by
changing the twisting oscillation of a
fine iron wire stretched in a magnetic
field. Two bar magnets are in line
parallel to the wire, with like poles
pointing in opposite directions. The
wire carries small mirror at it's
center, and is surrounded by a wire
coil traversed by an alternating cur
Nent having frequency equal to that
of the torsional oscillation of the
stretched wire around it's axis. The
mirror oscillates with the wire.
Placed in circuit with the antenna, the
degree of oscillation of the stretched
wire is diminished whenever it is
traversed by the high frequency cur
rents produced in the antenra by the
arrival of Hertzan waves, and the
signals so received can be recorded
photographically by ray of light
from the mirror. This receiver, unlike
others. can be made to respond only to
special waves. 1t can be adjusted for
various frequencies, and is affected
only by trains of waves of very
small range of frequency.
Light without heat" was found
twenty years ago in in large Cuban
irefy. In the "Photinus Pyralis," a
smaller firefy common in Washington,
Drs. II. E. Ives and w. w. Cobblentz
have now made more complete in
vestigation, and have found the lumi-
nous efficiency to be SO. 5 per cent, as
compared with 0.4 per cent for the
carbon glow lamp, 1.9 for the lungs
tenlamp and less than per cent for
the mercury arc, the most efficient
artificial illuminant The freely light,
being green, is not adapated to human
use. 1t is possible that white light
may be built up by combining the
emissions of several substances like
the firefly material, and then the
efficiency might reach As per cent.
Ruebel bronze, new German alloy
of magnesium, zinc, copper and alumi-
mum, has considerable strength and the
specific gravity Of water. Used as the
metal of Zeppelin airship, the weight
would be lessened nearly tons.
The military wireless telegraph of
Major Beddington, of the British
army, is very portable, and can be put
into operation on the field within Is
minutes. In lake test near Keswick
messages were sent and received over
distance of 1614 miles, although a
hill 1900 feet high was interposed be-
tween the stations, the probable
effective range being estimated not
less than 40 miles. An ordinary two
horse e-power motorcycle engine is
used to drive dynamo to produce the
electric discharges, and the impulses
are sent through 100 yards of double
copper wires suspended between two
24foot poles. A copper wire gauge
mat on the ground gives earth connec-
&c iItr iO1
on horseback, the mat-weighing 200
pounds the heaviest load, while
the motor and dynamo weigh only ITO
pounds, and the poles are attached to
a pack saddle in 6-foot sections.
The stone-preserving compound of
R. M. Caffall is a mixture of paraffin
with creosote dissolved in turpentine,
and is designed primarily to protect
against atmospheric action, while the
paraffin prevents organic growth.
This is the material with which was
checked the decay of the pink granite
Egyptian obelisk that was set up in
New York in 1881. On it's new site
the obelisk began to weather rapidly
and IN 1885, when the protective coat
ing was applied, 790 pounds of loose
chips were removed. The heating of
the surface necessary in applying the
mixture-the melting point of which
is 41O deg, F-dld not have the in
furious effect feared. The heat caused
the substance to be absorbed to the
depth of half an inch, and 6734 pounds
were applied to the 200 sqaure yards
Of shaft and plinth. In the 25 years
since then, the stone has SHOWN no
decay.
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