The Baltimore County union. [volume] (Towsontown, Md.) 1865-1909, 1907-12-07
Correspondence Baltimore County Union.
SCIENTIFIC MISCELLANY.

Eye Injury From Light-Radium-C olored
Rubies-A Color Phenomenon-The
A Mushroom School, impliied First
Aid-The Malaria Fish Manganese
Manure.
Two kinds Of partial blindness due to light
are recognized by DR.. A. Birch Hirschfeld-
one caused by luminous rays and the other by
ultraviolet rays Looking at the sun with the
naked eye Injuries the center of the retina,
often permanently, and this is due to luminous
rays, other rays being nearly all sifted from
sunlight by the atmosphere. The night blind
ness of fatigued and illnourished persons re-
suits from slow recovery Of the retinal nerves
after exposure to strong light The electric
arc, electric spark, magnesium light and mer-
curry vapor lamp emit a large proportion of
ultraviolet rays, and these produce such effects
as snow blindness, electric light blindness. light
ming blindness. and erythropsia or seeing red
The snow blindness usually occurs in high alti-
tudes where sunlight is rich in ultraviolet rays.
Smoke colored glasses give the best protection
against luminous rays, but thickness of the
glass is more important than color a shield
from the ultraviolet rays. The eyes of the
weak, nervous and .ill-nourished especially need
guarding from intense light.
sss
Exposure to radlum for q month in Prof.
Bordas' experiments. seems to have changed
light red corundum to ruby red. violet to sap
phire blue and blue to emerald green, while white
became topaz yellow. An expert pronounced
the changed specimens genuine precious stones,
the ruby Of large value, and the ruby and sap
phire appear to differ in no respect from the
natural gems.
Photography, or change of color in light and
restoration to original color in darkness has been
found by Marckwaldt in q very few substances.
OF possible value in photography, the discovery
70 especially interesting as representing posi-
BILE direct conversion of light waves into chemi-
cal energy.
Electrical engineers foresee at least one more
stage In the evolution of Atlantic liners.
The steam turbine is most efficient at high speed,
while the propeller slips without doing full
work when driven beyond comparatively slow
rate, and gearing down is impracticable with
the great horse power Of large vessels. With
turbines like those Of the Lusitania, made large
for a rate of only $50 revolutions per minute
much steam reaches the condensers without
giving up its full energy. A suggestion that is
being worked out already is the use of turbines
to drive electric generators, which would propel
the vessel through electric motors, and it is
turbines would more than balance the loss in
Transforming mechanical energy into electricity
and back again. The Encouragement of ma
chinery would leave more room for cargo. 1t
Is predicted that the coming fast passenger ship
may be given a speed of thirty knots by six
turbo- generators of 20 900 horse power each, one
to be used only in case of break down, with
four propellers each having six motors Of 5000
horsepower, one to be kept in reserve for in
slant use In emergency. The motors could be
reversed almost instantaneously, while the
navigation officer would control the vessel direct
from the bridge instead of through signals to
the engineers.
A material for which not much use has yet
been found is the wax of Myrica cordifolia, q
shrub originally planted in Cape Colony to bind
drift sands. The Cape berry. as the fruit is
known, is about as large as pea, and three
bushels produce ten to fourteen pounds of wax,
which is now valued In London at $275 per ton.
The wax seems to be adapted for making soap,
and possibly for candles
srA
A novel institution of Tarare, France, is q
theological laboratory, where expert judg
ment is pronounced upon mushrooms. The
fungi are abundant In the locality, and the ex-
aminers have found that excellent edible quail
ties are possessed by an astonishing number Of
varieties that had been avoided as dangerous.
ss
Oxygen has become the almost universal
remedy in cases of poisoning by gases such as
coal gas, acetylene, foul air from sewers, after
damp of mines, etc.-but its application is some
times q difficult matter for the inexperienced
by-stander. new apparatus by DR.. Brat, made
in Westphalia, is designed to clear the lungs
and act more or less automatically in giving
artificial respiration. The portable form con-
sists of fair-sized oxygen cylinder, chest
containing small air-pump, levers and other
parts and the usual face mask for the patient
When able to do 30. the patient breathes the
oxygen without help. In necessary, the attend
ant gives a rhythmlcal motion to the pump
valve, and the liberated oxygen actuates the
pump. withdrawing air from the lungs. Respira-
tion is thus restarted or supported.
az
The "blue eye." o-called on account of the
brilliant blue of its iris, is a small fish. IL to
inches long. living in shallow Australian waters,
but the creature has been made very big in
Importance by the discovery of Count Burger
Moerner, Swedish consul, that it subsists on
mosquito larvae. After some difficulty, enough
of the fishes have been captured and sent to
Naples to test their possible influence in alter
ing the condition of the malarious swamps and
marshes of Italy. To science the fish is known
as Psendomugil signifier, and it belongs to the
family of Athorinide, represented in different
parts of the world by IA principal kinds and 65
subvarieties, which will be eagerly Investigated
If the italian experiments succeed.
IS
In the efforts of the Belgian State Agricultural
Institution to improve farm plants manganese
salts have given such surprising and remarkable
results as a manure for potatoes that this crop
seems to have been made very profitable. The
effect of manganese on beets, however, proved