Amador ledger., 1906-12-28

MISCELLANY
Reported weekly for the Ledger.

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An Indicator for Steel Tempering.
An Engineering Departure. Unsafe
Signals. Early Geological Gardens.
Light for the Diver.-An Improv-
ed File. "A Scientific Aquarium. =
Wired Glass. Count of the Stars.
The idea that the critical tempera-
ture for tempering steel is the
temperature at which the metal loses
its magnetic properties has suggested
to William Taylor, a British metal
lurgist, curious indicator for guild
ing tempering work. Proving his
theory by experiments with an cleo
tIical balance, he made for factory
work an instrument consisting of a
permanent horseshoe magnet having
extended soft-lron poles. one pole
being arranged to rock back under
normal conditions. A piece of cold
steel holds both soft. iron poles, but
when the sample is heated until its
magnetic prt perties are lost. the rock
ing pole is released, and its flying
back gives the signal for quenching
the steel. The device has proven of
great value in avoiding overheating,
with the resulting brittleness, crack
ing and warping.
Building engineering structures on
solid foundation of water is the
rather startling plan by which w. Il.
Murray, a California engineer, ex-
poets to confer great benefit upon the
world. The floating structures would
have large weighted base, with a
broad projecting tiange, and would be
immersed in the sea until the lower
portion would rest in the stable
waters below the disturbed surface.
with this form of construction it is
believed that the action of waves
would be slight. 1t is claimed that
this form of building should have a
wide range of usefulness, and it is
specially adapted for breakwaters,
lighthouses, forts and bridges.
When bell signals are sent under
water to vessel, Lord RayIeigh has
found that the microphone receiver
will indicate whether the sound is
from the right or the left, but that it
cannot be determined with certainty
whether the signal is from a point
ahead or one behind.
An attempt to trace the origin of
geological gardens and natural history
museums has been made by j. Won
Pleyel, German. He concludes that
originated partly in the
worship of sacred animals and partly
in the ambition of rulers to collect
specimens of rare, valuable and
savage creatures. The simplest form
of geological gardens was known to
the Chinese, Indians, Greeks, Romans
and pre-Spanish Mexicans in very
ancient times, a Chinese menagerIe
dating from 1l50 b. G. being the
Oldest on record. The den of lions
kept by Darius, of which we are told
in the Book of Daniel, is an ilIustra-
tion of the primitive menageries, and
the sacred white horses of Greece
and Rome and the so-caIIed white
elephants of Burma and Siam repre-
sent another type. The menagerie
founded in 1927 in Regents Park,
London, seems to have suggested the
establishment in Paris that is regard
ed as the earliest modern geological
garden.
Cropping in darkness or dim light,
the diver has been able hitherto to
make only the simplest makeshift
repairs, but with the Yale submarine
lamp and recently invented pneu-
matte tools it is possible for him to
do almost any repairing and cleaning
of vessels without docking. The lamp
comprises watertight metallic cas-
ing enclosing special regulator. A
double glass chamber beneath the
casing is protected by rigid metal
guard, and holds the carbons. A
storage battery or small generator
supplies electric current through a
suitable cable. The submerged lamp,
weighing but few pounds, may be
easily carried about, and brilliantly
lights space equal to a large room.
A novel file made by London tirm
has semicircular teeth, which have
the convex disc toward the point of
the file, and are cut very deep. The
file is adapted for hard and soft
metals, wood and MAI BILE, and is
claimed to do three times the work
of the ordinary file, while keeping its
edge longer, being self clearing and
cutting without slipping.
A new aquarium at Brussels is to be
made an institution of scientific I'M
portance, and, in place of the usual
few tanks of more or less unhealthy
looking fishes, it is expected even
tually to display the complete river,
Ia1r