The Baltimore County union. [volume] (Towsontown, Md.) 1865-1909, 1902-03-15
Correspondence Baltimore County Union.
SCIENTIFIC MISCELLANY.

SCIENTIFIC MlSCELLAN 4.
Electric Waves-Makine Cloud Records
Weighing Thought and Exercise
Volcanoes as Factory Sites-New Plan
etary Meaeurements-Afric SPIDER
Snk-Sulphurous Acid Fire Prevention
Ink Of the Cesars.
Some interesting experiments with electric
waves-such waves as Marconi has sent across
the ocean-illustrated recent Royal Institu-
ton lecture by Prof. Fleming. The apparatus
was contained in two boxes. each open at one
end-one box holding radiator. with battery
producing sparks between two brass balls, while
In the other was receiver, with nickel filings
connected with an electric bell. With the
mouths of the boxes exactly opposite, the pas
sage of sparks between the two balls set up q
corresponding current in the other box, ringing
the bell. When sheet-iron. tinfoil, carbon, a
bottle of water or piece of moist tobacco was
interposed, the bell did not ring. but wood, a
dozen sheets of window glass, leather, brown
paper or dry tobacco caused no interruption.
The waves-traveling with the velocity of light
were stopped by all electric conductors,
while non-conductors were transparent to them.
-.
Cloud photography is one of the branches of
science in which important facts are learned
through long and careful observation. One of
the most energetic workers in this field is NJ.
Teisserence de Bort, whose observatory near
Paris includes two stations threequarters of a
mile apart on the same level, these stations be-
ing connected by telephone. A point of the
cloud having been fixed upon, two photographs
are taken simultaneously. A scale shows the
inclination of the camera and another the d.
rection Of the cloud, and from the inclination
angles of the two cameras and the known base
line the clouds height is calculated. Two more
pictures show its travel in given time.
-
After an elaborate investigation, covering ten
years of time, Prof. Wilson has calculated the
suns temperature to be 6,20Oo Cent. ul,1920
Fahr.)
The flow of blood to the head in concentrated
thought was shown several years ago by Prof.
A. Mosso, of Turin, by means of balance for
tho body. The more sensitive apparatus, or
"muscle-bed.r of DIR. w. G.. Anderson, of the
Yale Gymnasium, in a couch balanced on knife
edges. and capable of adjustment by rolling
from one side to the other as necessary. This
apparatus shows that the mental effort of
written test shifts the centre of gravity of a
student upward from sixteenth of an inch to
turned in the opposite direction by exercising
the lower extremities after study, and mere
thinking of leg gymnastics by a perfectly
poised man has sufficed to send enough blood
downward to cause the feet to sink. Muscle
weighing has proven that uninteresting exer-
else has small value. When it is carried out in
a listless or mechanical way. the extra flow of
blood to the parts is small, but this is much in
creased by conscious and interested manner,
and by pleasure in the effort.
-
The temperature of the earth is estimated to
be at least 5OOO0F. at depth of SO miles, and in
many places comparatively high temperatures
are found very near the surface. The utiliza-
ton of this heat is one of the great problems
now in the minds of engineers. With the direct
and economical conversion of heat into cleo
tricity on large scale, which is looked for in
the near future, the earth's hotspots should be-
come important manufacturing centres.
a.
The diameter of Jupiter, according to Prof.
T. J. J. Sees new determination is So, 203 miles !;
that of Mars, 4,l55 miles, and that of Mercury,
2657 miles. The following are found to be the
densities of the planets, water being / Mer-
cury3; Venus, 514; Earth, $50; Moon. 1884
Mars, 4; Jupiter, 1.35; Saturn, 06S; Uranus, 1853;
Neptune, 2.29.
peculiar fever, occurring in irregular attacks
of few days. for several months, has been re-
ported by DR.. ]. E. Dutton in European in
South Africa. A parasite from the blood re-
sembles that of the 'tsetse fly disease of cat
tie.
Gold and silver silk are interesting pre-
ducts that we may expect from South Africa.
The t1bers are spun by two remarkable spiders
of Rhodesia, and an experimenter has found
that the creatures may be reared in captivity
and that the silk can be utilized. The webs are
stretched on bushes and trees, often in vast
network. Both fflaments have brilliant metal
lie luster and very fine and strong, the fine
ness of the golden silk being about that of the
silkworm's thread, but the strength being much
greater. A thread of steel of the same size, in
fact, has only two-thirds the strength of this
spiders thread. The golden-silk spider at least.
the larger of the two kinds, exists in vast num-
bers on the veldt where it feeds on the common
fly.
Spontaneous combustion continues to en-
danger coal-carrying vessels in spite of all at
tempts that have been made to prevent it.
Successful protection is claimed at least by Mr..
Thomas Clayton, of London, whose plan con-
ssts in injecting sulphur dioxide gas into the
hold after loading. and then battening down the
matches. Explosion and combustion are thus
made impossible. In recent test of this in
vention torches were extinguished in cham
Der containing six per cent. of sulphur dioxide,
and red-hot iron bar failed to ignite naptha-
soaked straw and was quenched in bucket of
naptha as in water.
-.
Lampblack seems to have formed the basis of
ancient ink. The contents of two bronze cylin-
ders from Roman ruins in France have been
found by M. Leidie to consist of lampblack, con-
tanning traces of copper, tin, iron and chalk, and
this was undoubtedly ink. 1t must have been
much like the Indian ink of to-day.
~
The rotation of waterspout at the surface of
the sea has been estimated by Prof Bigelow as
354 miles per hour, or nearly six miles minute.
miscellaneous.