The Baltimore County union. [volume] (Towsontown, Md.) 1865-1909, 1900-08-11
Correspondence Baltimore County linton.
SCIENTIFIC MIS- CELLANY.

Correspondence Baltimore County linton.
SCIENTIFIC MIS- CELLANY.
The Lowest Dry Land-Skin Eruption
from Observation-Disclosures Not a Glass
Eater-Britain'sN New Gold Mine-Earth-
quake Sounds-Self- Stopped Trains-A
New Propeller Blade-The New System
in Typhoid-Cloth Ventilating Pipes.
One of the most remarkable holows in the
earth is the Lukchun depression discovered a
considerable time ago in Central Asia. Results
or meteorological observations In the place Tor
Nv nSvs dS frO hs baraec comnsr
sons it appears that the lowest spot in the region
must be about 400 feet below sea level. The
meteorological conditions are OF unusual in
terest. The barometer has a greater yearly
range than in any other spot known, the monthly
averages for January being LIZ inches greater
than those for July, and the highest July tenn
perature Q1s0 F) is one of the highest in Asia.
The dryness of the air equals that of the Sahara.
A curious case Of netatle-rash due to eye strain
has been recorded by DR.. G. A. Oliver,
Pennsylvania physician. The patient was an
forty-irst year had suffered from an unaccoun-
table eruption, which disappeared when she was
lifted with pair Of lenses for constant use TO
q return of the eye trouble, with the eruption,
led her to seek new glasses. This time there
the skin disturbance vanished. Further expert
ments proved a true relationship between the
general VaSOmOCOr ana the reIractlVe anu NUS
cular anomalies.
-
The wei known powerful action Of fiourine
upon glass is shown by M. Moissan to depend
upon the presence of hydrofuoric acid and
moisture as impurities. Perfectly clean, dry
glass is unattached after weeks of contact with
pure hOurine, but the merest trace OF organic
matter on the glass leads to the formation of
hydrohuoric acid, and corrosion.
The Eaeou.ia ylusOids;s. in il which Prof. Dybow-
sky has found 20 per cent. of gutta percha, is
abundant in some of the British colonies, but
has been hitherto regarded as worthless plant.
The sounds of earthquakes have received
little attention. From late paper by DR.. @.
Dawson, 1t appears that they approach the
lower limit of audibiity, and they are frequently
distinct to some observers while others equally
alert hear nothing. In earthquakes among
Englishmen sound is usually perceived before
and after the shock. In Japan even violent
earthquakes are frequently unnoticed by the
ear while sound is seldom heard after the shock
the conclusion being that the Japanese have
inferior perception for deep sounds. The
different auditors. A deep rumbling, like that
of heavy wagon passing, is generally heard:
but at the epicenter of the earthquake loud
away become rougher and more grinding, and at
a great distance may be subdued into low and
monOtonous roll like distant thunder. Earth
sounds without shocks, appearing to be earth
quakes too weak to be felt, are sometimes heard
Earthquakes are supposed by DR.. Dawson to be
caused by the slipping of rocks along faults
and the scund-vibrations are traced chiefly to
the margins of the slides.
In the Laffas system of automatically stop
ping railway trains, to prevent accidents,
block In the middle of the track is set by the
signal man. This block has curved surface,
which. when the signal is standing at danger, is
so raised that rod with little wheel makes
contact and actuates the valve of the air brake
placed either on the engine or one of the cars.
In a recent English test train of an engine and
nine cars with total weight of 100 tons, was
run on a slight downward incline. On touching
hIrN0lr n 6rafO 0rrafln fV.or
stopped In 46 yards, at 30 miles in 200 yards, and
at 30 miles in 2lO yards.
A new treatment of arc light carbons. patented
by ]. 4. Robinson, is claimed to increase the
durability, improve the light and lessen the con-
soaked two to four days in solution of caustic
soda or potash containing powdered talcous
asbestos.
A spray of heavy. oil added to the fuel Of blast
furnaces has been found in France to facilitate
reduction of ore and increase the yield
The shape of propeller blades is a shipbuilding
detail that seems to be not yet fully worked out.
should give better grip of the water, F. S.
Snowdon and W. j. Orr have fitted two battens
on each blade, and in a small craft tested in New
zealand waters the effect of the change has been
to give an increase of over ten per cent in speed
The same propeller was used while the load and
the same as before the addition of the battens.
Two channels are formed by the battens, which
are roughly L-shaped, and the water is thus pre-
vented from slipping off in the usual easy way.
Suitable setting of the battens tends to throw
the water in toward the CENTRE giving the pro-
peller more solid water to act upon.
A*s
Anti-typhoid inoculations made by Prof A. E.
Wright among British troops in India seem to
have given very promising results. The total
number of men under observation was II ,295, of
whom 1856 had been inoculated and 8460 had not,
and the inoculated were mostly newly arrived
young men, especially liable to typhoid fever,
while the uninOculated were mainly more sea-
soned and less susceptible individuals. Yet the
percentage of the uninoculated attacked by
~ was Oe5 The deaths were less affected, hay
ATs aa.ss..s~s1
Air pipes of strong sailcloth impregnated
with rubber, are made by Dusseldorf firm for
use in mines. They are air and water-tight and
possess numerous advantages over pipes of wood
or zinc, being cheaper and lighter, easily put up
and made fast, and readily removed out of dam
ger from blasts and replaced. Steel rings are
inserted at intervals to keep the piping from
kinking around sharp curves.
50
The divining rod, as a means OF finding under
ground water, is being made subject of scien-
tiflc investigation by French commission, who
seek information from everybody having it.
The results are expected to prove more interes-
ting than important.
"a
Dust from French blast furnaces contains 4.6
per cent. of potash and 20.5 of lime. and proves
an excellent fertilizer for some soils.
Niagara Falls Excursions.