The Baltimore County union. [volume] (Towsontown, Md.) 1865-1909, 1905-03-11
Correspondence Baltimore County linton.
SCIENTIFIC MISCELLANY.

Correspondence Baltimore County Union.
SCIENTIFIC MISCELLANY.
Electric Discharge Prints-Insect Elec-
trocution-Oxygen Preservation Of Milk
The Suns Radition-The Air of Paris
Pull on Various Roads-A Tree-Need-
Ing Land-Weight Of Solid Gases-Aus-
tralia's Buried Lakes.
Under the discharge of high-tension electric
current, glass plate remains apparently I'M
changed, but on breathing upon it characteristic
ngures appear. These figures. however, disap-
pear when the glass is cleaned. The magic prints
are made permanent by Hans Axmann, Ger
man physicist, by using an induction apparatus
giving sparks of about 20 inches, and connecting
one pole with the edge of the glass plate and the
other pole with soft metal electrode of suit
able shape held upon the glass by slight pres
sure. The experimenter has kept for ten years
plates on which. in spite of all cleaning, the dis
charge figures stand out clear and distinct when
ever the breath condenses upon the glass.
~
novel apparatus for destroying insects and
larvae upon the ground has been presented to
the Odessa Technical Society by N. Lokuze-
jenvski. A horse or motor wagon carries small
dynamo, which is geared to the axle, and is con-
nected with an induction coil with wehnelt
interrupter. The negative pole of the coil is
connected with the iron framework to the earth,
while the positive pole at high tension charges
series of metallic brooms behind and under the
wagon. These brooms, movable vertically emit
large shower of sparks, and any insects within
range are killed.
Oxygenated water at twelve volumes is pro-
nounced by N. A. Renard the best preservative
of milk. Added directly after milking In the
proportion of two or three per cent, it decom-
poses into six or eight hours into water and oxy-
gen, leaving no foreign substance as do borax or
salicylic acid and effecting no change like boil
ing or freezing. The antispectic action persists
long enough to prevent alteration.
-.
Diminution of glaciers within a half century
has been noted in Spitzbergen Iceland. Central
Asia, the Rockies. and Alaska
s's
Long experiment resulted quarter of CEN
tury ago in the evolution of Stefans fourth
power law" which suggests that the energy
emitted from a fully radiating surfaces sur
face that is black when colds proportional to
the fourth power of the temperature, reckoned
from the absolute zero 273o below freezing point
on the Centigrade scale. This law states Prof.
]. H. Poynting has served as the starting point
Of new and most fertile researches, both theo-
retical and practical. Among the results is the
calculation that the suns temperature is $1,000;
and that small black sphere-one square cent?
meter in cross section-would be heated by solar
radiation to 1900 at 3X million miles, 327O at %
million miles, 2l00 at the distance of Mercury,
$50 at the distance Of Venus, 27o at the distance
of the Earth 300 below zero at the distance of
Mars, and 2100 below zero at the distance of
Neptune. The Earth's average temperature
agrees closely with the calculation. On reduc-
ing the size Of the object receiving the radia-
: ton, the receiving surface is increased while
gravitation remains the same. and if the Earth
were broken into spheres about 100000 of an
inch in diameter, the particles would be neither
attracted nor repealed by the sun. Made still
smaller, they would be repealed, like the matter
of comets tails.
The proportion of carbonic acid gas is no lon
ger accepted as a guage of the atmospheric
wholesomeness. The air of Paris is regularly
analysed, and the analyst states that there are
30 liters of carbonic acid per 100 cubic meters of
air in the sewers "a to 102 lters in the stations
of the underground railway, III to 1S9 in the
carriages of this railway 20 liters in the Senate
$50 in the board schools, and 81 to 221 in the
Palace of Justice.
"a
by Max Schieman to be to IS pounds per ton,
on tramways rs to 80 pounds, on good stone
pavement from A to So pounds. on bad stone
pavement from &c to rs pounds, on good macadam
from A to 81 pounds, on bad macadam from n to
100 pounds, and sand roads from 100 to go
pounds.
"a
Iceland seems to be hardly as destitute of trees
as some suppose, an old idea being that it
possesses but single tree. An investigation
by Prof. @. v. Prytz, of Copenhagen, shows that
the island really contains woods having various
trees of considerable size, and that the climate
is not unfavorable to tree growth, as there is
evidence that it was once much more heavily
wooded than now. Reckless destruction of the
forests is the cause assigned for the decline.
Prof. Prytz believes reafforestation to be FEAST
BILE, with care in the selection of trees and places
OF planting. and suggests planting around en-
closed meadows and on mountain sides. An at
tempt has been made already to grow Denmark
frs and pines at Hallormstaden. Birches spring
up naturally, and where they are protected by
deep SHOWS in winter it is believed sheep will
not trouble them, as these animals seem to eat
birches only when grass is not to be had.
-.
The density of several frozen gases has been
measured by Sir James Dewar at temperature
DeIWeen 10 anu IL OenIlgraue degrees ABOVE aD-
soute zero. He finds that the specific gravity
of solid oxygen is 1,425 solid nitrogen, 1O26 and
solid hydrogen, 0.076. A curious fact is that If
the elements oxygen and hydrogen occupied in
water the space they do in the solid state, given
weight of water would have volume nearly
twice as great as it actually does have.
So
Several rivers of Australians interior sink into
the earth and are lost. A recent discovery in the
district of Eucla shows that they form subter-
ranean lakes 25 or 80 feet below the surface, and
these lakes, if they prove to contain sufficient
potable water, are expected to lead to the de-
velopment of new territories in the arid region
in which they occur.
The new anaesthesia of Geneva dentists is OBJ
tanned by exposing the patient to blue light of
16-candIe power for three minutes. Conscious
ness is retained, but all sense of pain is lost