The record-union., 1898-12-06
THE REALM OF SCIENCE.
COMPRESSED AIR EFFECTS
CHINA's TIMBER SUPPLY.
The Earth's Rotation - Great
/ Steamship-Mica Mines
| in India

The effect of compressed air on the
health of men who are compelled 20
work in caissons or tunnels where the
air is supplied at considerable pressure,
was the subject of a paper recently
presented to the International Congress
of Internal Navigation, by three Aus
TRAN physicians, and as a result Of
their Investigations, a series of recon-
mendations were arrived at which, if
followed, would reduce to a minimum
the number of accidents and cases of
illness. The age of the laborer should
be between twenty and fifty years, and
he should previously undergo a rigid
physical examination to test his heart.
lungs and vascular system. The high
est pressure at which it is safe for men
to work was found to be five atmos-
pheres, corresponding to a head Of ITO
feet of water The chief precaution to
be followed is TO take sufficient time
when entering and leaving the COM
pressed-air chamber. Stress is laid
on the Importance of providing a .suffi-
cient amount of fresh air, which should
be renewed at the rate of 130 feet per
head per hour. In case the men work
at pressure greater than 11a atmos-
pheres, they should be hoESed in bar
racks near the work, and a pressure
chamber provided in which there would
be bed, telephone, and other conve-
niences for men suffering from the ef
fecG of the pressure.
The forests of Oregon are furnishing
the timber which is being used in The
construction Of the railroad now being
busit by the Russians across the Chin
ese territory of Manchuria. The lum
ber is shipped across the Pacific to
Viadiovstok. where it is transported by
rail to a. tributary Of the Amur River,
and by water routes to the line CT the
road. While there is abundant timber
in Eastern Siberia, yet it will not be
available until the railway has been
extended considerable distance furth-
er, and even then it is believed that the
water freights on the Pacific would be
less than the cost of land transporta-
ton. At any rate, the development of
China and Siberia seems to afford a new
and important market for the lumber
man of the Northwest.
The 800 mica mines situated in the
locality Of Hazaribagh, Gaya and Mon
gLyr. in India, furnish more than one
half the amount of this substance that
is used by the world. It is known as
Behar mica, and the available supply
is said to be practically inexhaustible.
In the neighborhood of 2,000,0 900 pounds
were mined last year. of which the
greater part was exported from Cal
cutta chiefly to Great Britain and
America. The use of mica in electri-
cal industries is constantly increas-
ing, and wherever mine is discovered
its paying properties are being most
carefully investigated
Owing to the rotation of the earth,
rivers flowing in a northerly and! south
erly direction manifest a tendency 10
crowd to the right, with the effect that
the right bank of such a river is apt TO
wear away slightly faster than the
left, while the channels also are apt to
be deeper towards that side. loco
motive moving north and south would
experience the same tendency, and the
amount of excess pressure on the right
rail has been computed by a German
scientist With a locomotive weighing
$4,000 pounds, and running at a speed
of forty-five miles per hour it was
found that there was an excess side
pressure to the right of 100 pounds.
This, however, is balanced by the fric-
tion of the engine on the rails. as there
is there a resistance of $4,000 pounds
to any side movement. Practical rail-
way men. however, do not find any
greater difference in the wear of ore
rail over the other from this cause,
while on a single-track road. the traf-
fic being in both directions, it could not
be detected in any case.
One of the advantages now claimed
for acetylene gas is that the products
of it's combustion are not at all in
furious to plant or animal life, as is
the case with. coal gas. A test was
recently made with acetylene in a
greenhouse, and absolutely no effect
was produced, whereas the coal gas
worked distinct and readily seen in
jury to the growing plants. On this
account, the new gas is recommended
to photographers for their darkrooms,
which generally do not have the best
of ventilation
The largest steamship in the world
will be the Oceanic, now building for
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