The Baltimore County union, the Towson news., 1909-10-02
so1ENTrFIo mIsCELLANY.

SCIENTIFIC MISCELLANY.
The Electric Barometer-Solid Fuel for
Automobles-Steel Strengthened by
Magnetism-Nature's Planting-Coast
Surveys Still Incompetent Pedestrian
Motor-Porosity of Solids-S o n d 8
Heard by Touch.
Correspondence of The Union News)
In the novel barometer of P. B. Goldschmidt,
as described to the Royal Medical Society of
Brussels, the readings are taken from galva-
nometer, giving much greater sensitveness and
accuracy than the ordinary instrument. A
minute V-shaped carbon filament is sealed in
the vacuum at the top of the ordinary barome-
ter and by platinum wires is connected in circuit
with sensitive galvanometera and few battery
cells giving constant current. The rise of the
mercury in the tube submerges the ilament to
a degree that is promptly indicated by the galva-
nometer. The apparatus records changes of
less than 004 of an inch, and the galvanometer
scale is so graduated as to give the barometric
pressures without calculation. The sensitive
ness has led to the discovery that the atmos-
pheric pressure is changing from second to sec
ond, indicating that great air pillows are con-
stanty passing over us.
-
Naphthalene as automobile fuel has given very
satisfactory results in the tests of Chardon and
Sion with 45 horse power motor-truck hauling
tons of useful load. Gasoline was used for the
first IL minutes, when the naphthalene-crystal-
lized, in pieces the size of a chestnut-became
melted and was then introduced into the car
bureter at temperature Of l76' F.. together
with air heated by the escaping gases. About
20 pounds Of naphathalene were used per hour
later experiments showing the running cost to
be one-third to two thirds cent per ton mile.
-
That magnetism effects the strength of iron
and steel seems to have been proven by W. j.
Crawford at the Technical Institute of Belfast,
ireland. He used bars of mild steel and wrought
iron inches long by 35 to 1 inch in diameter.
part of them being kept at magnetic saturation
in a solenoid, and in the testing machine the
elongation of the magnetized pieces was de-
creased Q to Is per cent while the average break
ing load seemed to be increased.
-
On April 26, 1883, the island of Krakatoa, in the
Strait of Sunda, between Java and Sumatra,
was the scene of a volcanic eruption, and half Of
the island was blown away in the greatest ex-
plosion known to man. The surface was changed
from a beautiful tropical forest to a waste of
volcanic ash and pumice, destitute of all life.
The island is IL miles from the nearest land and
% from the nearest point of Sumatra, the most
probable source of seeds, but in the quarter of
century that has elapsed nature has restored
luxuriant vegetation, including trees 80 feet
tall The return of the plants has been mat
ter of such Importance and interest to botanists
that its story is given in a new book by Prof. A.
Ernst. Wind-blown spores seem to have begun
the work, and in 1886 the surface had become
largely covered with blue-green algae, which
were preparing a soil in which few ferns and
grasses had already taken root, while Towering
plants from sea- borne seeds had begun to appear
on the shore. In 1897 the species had increased
to So seed-plants and II higher cryptogams, por-
tions of the ground being covered with green.
Since then the progress has been marvellous,
and the south side Of the island is mostly a mass
of green with fruit and seeds OF land-plants on
the beach, a forest of cocoanut palms, screw
pines and figs farther inland, and jungle OF
grasses, reeds and vines beyond the forest. 1t
is estimated that 80 to ~ per cent. of the seed
plants have been brought by sea-currents, 10 to
10 by birds, and 16 to 80 by winds.
IS
Even now the shores of the ocean are imper-
fectly known, and as many as 1858 rocks and
shoals dangerous to navigation were discovered
in 1908 charting of the seas and coasts of the
globe as reported by the photographer of the
British Admiralty OF these 10 were made known
by vessels striking on them, 29 were found by
British surveying ships, and $50 were reported
by Colonial and Foreign Governments. Pre-
viously reported dangers were investigated, and
26 were dropped from the charts.
$s%
Paint for indicating heated bearings in ma
chimes is made by Tollner from equal parts OF
iodide of mercury and iodide of copper with
enough distilled water to form good paste.
The paint turns black at 14O0 Far, returning to
red on cooling.
A novel kind of roller skate devised by tutor
in the University of Upsala, Sweden, is called
the tachypod, and has two large wheels, giving
it the appearance of miniature bicycle. The
skates are used with the ordinary motion of
walking. When the foot is pressed down the
weight depresses the joint connecting pair of
arms, thus forcing the wheels apart, and un-
winding a wire cable from reel on the rear
axle. The reel at other times running loose,
engages pawl as it is unwound, thus turning
the wheel. A spring winds up the cable as the
pressure is released and the two wheels are
brought together, and the shifting of the weight
from one side to the other alternately causes
one rear wheel or the other to be continually
acting as driver, the weight of the body being
the source of energy. The walker wearing the
apparatus is pushed along at fair and uniform
velocity. speed equal to that of good bicyclist
having been attained.
~
The densest form of matter is now understood
to be neither continuous nor homogeneous, but
full of holes. In a late Royal Institution lect-
ure, Sir James Thomson showed how hydrogen
can be passed into vacuum tube through an
incandescent platinum window; and the passage
of sodium through glass in a similar manner is
utilized in the manufacture of high-vacuum
tubes as a means of absorbing the traces of
oxygen that cannot be pumped out. An Italian
physicist has passed hydrogen through iron even
when cold.
The impulses of an alternating electric cur
rent have been heard by Joseph Rieder at
Sterlitz, Germany, without converting them
into mechanical movement in telephone. The
inner coating of a Leyden jar is connected to
one pole of an induction coil, the opposite pole
being grasped by the hand, when pressing the
outer metallic coating of the jar to the ear
causes the ear-drum to vibrate and thus pro-
duce audible sound. This simple experiment
suggests possible method of making some deaf
persons hear. The action on the ear is very
different from that of the telephone and de-
pressing effect shows need of caution in repeat
ing the experiment.