The Baltimore County union. [volume] (Towsontown, Md.) 1865-1909, 1902-06-07
Correspondence Baltimore County Union.
SCIENTIFIC MIS- CELLANY.

Correspondence Baltimore County Union.
SCIENTIFIC MIS- CELLANY.
Blue Light as a Germ Killer-Electric
MISUNDERSTANDING Barium-Co-op-
Grafton in Evolution--Wings With
Horns Living Lamps-Cloth Battery
Plates-One City's Soot-Glowing Pic
tures-An Engineering Problem.
Pure blue light is the new consumption cure
with which G. Kaiser is experimenting IN Ger
many. The rays from an arc lamp concentrated
through a lens containing methylene blue de-
stroyed tubercle bacilli in about 30 minutes,
and, as the printing of a Photographic POSITIVE
proved the passage Of the rays through the hu-
man body, it was shown to be possible to reach
the bacill in the lungs and to kill them all with
blue light. In two advanced cases of the dis
ease, great improvement resulted in six days.
-
The high-frequency electric currents of DAT
sonval are applied by two German dentists in
stead of ordinary anaesthetics. Application of
the current to the part is made through mold
ing, which is covered inside with metallic pow
der and a layer of tinfoil, with an additional
layer of asbestos to absorb heat. Out of Is cases
of extraction of teeth with one root. 10 opera
lions were completely painless. The patientre-
mains in waking condition, and the usual risks
and annoyances are avoided.
-.
Pure barium. as lately obtained by NJ. Guntz
in the electric furnace, is silver-white when
freshly cut. almost as soft as lead, fuses alta low
red heat, and volatilzes rapidly at bright red.
1t oxidizes rapidly in the air, often taking fire.
s~a
Darwin laid great stress the survival of
the fttest'' in the struggle of living forms for
place on earth. Prince Kropotkin, in a new
work, shows that mutual aid" a kind OF CO
operation in nature has been, like competition,
leading factor in evolution.
~
Eucalyptus and other trees of the Australian
deserts store up water. which the natives pro-
cure by cutting up the roots and standing the
pieces. on end.
Birds with vestiges of claws on the wings are
well known though not common. Mentioning
some of them, NJ. v. Delosiere states that the
Archaeopteryx, the Oldest of fossil birds, had at
the end of its wings well-formed fingers, each
with strong claw. The "hand'' terminating
the wings of modern birds usually has three
fingers without claws. But there are still wings
with horns or spurs. If these cannot be called
claws, and the wing of the ostrich the largest Of
birds. is armed with double horn. The Chionis
of southern lands, the Spiny Hoplopters of
Africa, and the Jacana of South America are
other birds having spurs or spines on the wings.
Most formidably armed of all birds is the Kami-
chi or Horned Screamer, large and strong
voiced blackbird. of Brazil and neighboring for
est regions, this creature having near the top Of
each wing two sharp horns, one about two inches
or four inches in length. The beak and claws of
this bird are very powerful.
-
Luminous bacteria, interesting as a source Of
cold light occur chiefly entirely in seawater.
Mr.. j. E. Barnard who has been studying them,
reports that about 25 species have been isolated,
but some of these may be identical or very close
ly related. The organisms, which grow at vary
ing temperatures between freezing point and
blood heat, can be cultivated on peptone beef
broth gelatine to which chlorides of sodium
magnesium and potassium have been added.
The cultures may be made to glow for days at
time when supplied with oxygen, and culture
seven weeks old could still be made to give light
-.
Very light plates for electric primary cells are
made by A. De Castro, of Berlin, by depositing
metal on textile fabrics by electrolysis. Sail
cloth, for instance, may be impregnated with
reduced copper for the negative elements, and
with reduced zinc for the positive elements.
80
Though Vesuvius has been for centuries dis
charging steam charged with hydrochloric acid,
extensive injury to vegetation in the surround
ing region seems to have been unknown until
last year.
A perpetual cloud of SCOT, gradually settling
down, is known to overhang every large manu-
featuring city. To determine the amount of
this wasteful dirt deposit in Manchester, Eng,
Mr.. W. Irwin weighed the solid matter obtained
from a sample of snow that had been lying on
the ground ten days and has found an equiva-
lent of 1917 pounds per acre, or three tons per
square mile. AS the sample represented the
condition over at least, 100 square miles, the
chimneys of Manchester are convicted of throw
ing out not less than 300 tons of SCOT in ten days.
Analysis showed 1876 per cent of carbon, SO of
heavy oil and grease, and AS of ash, from which
it appears that each days 80 tons of SCOT given
adhesiveness by about two tons of oily matter.
80
Luminous photographs are made by means of
calcium sulphide, or luminous paint, according
tn German authority. A sheet of transparent
celluloid is coated with an emulsion of nine
parts of geatine, one of potassium bichromate,
five of calcium sulphide, and 100 of water. AS
precaution against washing off the image, the
printing is done fromra positive through the
celluloid film, development being by hot water.
Backed with black velvet or paper, the print
appears as an ordinary positive by daylight but
after free exposure to light is self luminous in
the dark.
&*s
A mysterious loss of water is often noticed in
boilers under steam but not in use. The valves
appear to be tight no escaping steam is seen. but
in a few;hours it is necessary to introduce more
water. What becomes of the lost steam is
problem that could be thoroughly investigated
with profit. In one case, it is stated, the loss
was partly accounted for when windows over
the boiler were opened, the cold air making visi
bic leaksof steam from every valve.
sts
Human serum, contrary to expectation, has
proven effective in counteracting effects of the
tsetse fly bite in lower animals, and feebly active