The Baltimore County union. [volume] (Towsontown, Md.) 1865-1909, 1908-10-03
Correspondence Baltimore County Union.
SCIENTIFIC MISCELLANY.

COfTe8DOUOefCe OutCtDOTc COtfttH OHtOUs
SCIENTIFIC MISCELLANY.
How the Lakes Breathe--A Meteorlc
Shower Forecast-Jupiters Captured
Moons-The Body In Electric Circuit
Seconds by Phonograph-A Sensitive
Moisture Indicator-Source of Our
Ozone-Oxygen for Runners.
Lack of respiration by inland lakes explains to
Prof. e. A. Birge many of the failures in stock
ing with trout and other fish. The lake absorbs
air for animal and plant life and exhales nitro
gen, carbonic acid and sometimes other gases
but it takes its only full inspiration in autumn,
with less complete one in spring, does not
breathe at all in winter, and during Summer has
but very shallow respiration. When cooled to
uniform temperature near freezing. the wind
turns it over and over, saturating it with one
per cent. by volume of oxygen-twice what the
water can hold at summer heat. This store may
suffice, life being most inactive in winter, but
there is sometimes shortage of oxygen ere the
ice is gone. Another turning is given by winds
in spring. 1T simperfect, however, for the fast
warming surface soon stops circulation of water
below. aud the oxygen supply is lessened during
the warm period of activity aud greastest need.
Thus it is that the bottom-except in some very
deep lakes, where the stock of dissolved oxygen
is large-accumIates carbonic acid and products
of decay to such an extent as to limit the fish
life that can be supported.
-
As the earth crosses the orbits of certain
comets, shooting stars appear, indicating that
streams of fragments are following in the wake
of the comets. Mr.. w. f. Denning. the British
astronomer, has lately suggested that meteors
radiating from the constellation Aquarius
during the first week in May are in the orbit of
the famous Halley's comet, the 75-year visitor
now being so eagerly awaited. and as these
meteors are visible nearly every year. the comet
dust must form an immense elIiptical ring reach
ing from near the sun to point beyond Nep-
tunes orbit. The stream being densest just be-
hind the comet. great shower may come near
the perihelion passage-probaby in May, 1910.
The great size of Jupiter. its mass being great
er than all other planets combined and 2lS times
that of the earth, gives it great possible infiu-
ence upon such wanderers from space as comets.
1t is supposed that most of the comets of short
period have been visitors from outer space that
approached near this great planet and we're so
powerfully attracted that they were unable
again to pass beyond the attraction of the sun
but were slowed down and confined to the solar
system In comparatively small elliptic orbits.
Prof. George Forbes now attributes an even
more remarkable capture to Jupiter by seeking
to identify the newly discovered eighth satellite
with the Lexelles comet of ITO. Good reasons
for the theory are shown, but Prof. Tarrida del
Marmol. himself believing that the satellite has
been recently acquired by Jupiter, finds evil
dence of a different source. He THINKS it was
once an asteroid. a late discovery is that the
asteroid ring between Mars and Jupiter spreads
out beyond the orbit of the latter, and it is easy
to suppose that one of the little bodies has come
so near as to be permanently entrapped. This
astronomer regards the sixth and seventh satel-
lites also as former asteroids-with others yet
undiscovered.
Experiments have shown that the human body
between the feet and the hands, has an average
electrical resistance of about 5000 ohms when
the hands and the shoe-soles are wet, and from
10000 10 10000 ohms when hands and feet are
practically dry. With the last resistance. 100
ampere current will pass through the body of
the hand completes a 1OO-volt circuit through
the earth. In the commonly-used alternating
circuit of 100 volts and so cycles per second
there may be difficulty in letting go of the wire
and such circuit of 500 volts is very dangerous,
especially If tTaversing vital organs.
A*s
The photograph is suggested by French pho
tographer as a means of timing when a clock
cannot be watched. He has fitted his machine
with cylinder counting from to 240 with in
tervals of one second between the numbers.
"a
The electric MICROSCOPE of ]. Poenchon. as de-
scribed to the Paris Academy of Sciences, is so
extremely sensitive that it indicates the varia-
tons in moist vapor emanated from different
parts of the hand, the back of the hand at half
an inch from the instrument causing the spot of
light indicator TO be DETECTED about two inches
on the scale, while the end of the finger gives
much stronger action. In circuit with battery
or dynamo of about 100 volts are placed sensi-
tive mirror galvanometer and a silvered glass
tube half an inch in diameter and four inches
long. The tube is coated beth inside and out
side. the silvering stopping half an inch from
one end but extending to the very edge at the
dry, no current passes between the two layers OF
silver, and the spot of light of the galvanometer
remains at zero, but as trace of vapor causes
moisture to condense on the glass, the current
crosses and the galvanometer promptly re-
spends.
The formation of ozone in the air has been
traced by Henriet and Bonyssey to ultra violet
solar rays at great attitudes. 1t increases when
amount, and is therefore supposed to be brought
from the upper air-where carbon dioxide is
lacking-by wind and rain Some ozone. how
ever, is formed even in lower strata by solar
radiation in clear weather. The maximum ozone
is present when the wind is west and southwest,
and the minimum with an east wind.
-.
Rapid breathing from running, followed by re-
covery or second breath" after a time, is ex-
planned by DR.. Leonard Hill as due to exhaustion
of oxygen from the blood more rapidly than it
is absorbed. By inhalng oxygen runner can
hold his breath much longer, and oxygen inhala-
ton is also a means of relieving the distress
from an exhausting run. This has suggested
that portable oxygen inhalers offer new field
for enterprise.
WILLIAM A. LEE.
TOWSON. Md.
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