The Baltimore County union. [volume] (Towsontown, Md.) 1865-1909, 1907-03-09
Correspondence Baltimore County Uss0n.
SCIENTIFIC MISCELLANY.


SCIENTIFIC MISCELLANY.
The Sky's Light-A Source of the Ola.
mond-A New Disinfe ctant-Wi
EIectricity-A New Industry-Sounos
of the Working Muscles-Metais TX
ploded by HAmmef1ng-In the Land OF
White Coal-A Door Key Alarm.
The brightness of the sky on clear, moonless
night is one of the mysteries astronomers are
trying to explain. The stars appear to shine
from a slightly luminous background. and in
recent paper, Mr.. G. ]. Burns, a British astron-
omer, considers that the total light may be
roughly taken as equal to that OF lOOO first
magnitude stars. while the light OF all stars
visible at one time has been estimated as equal
to that of 70 flrst-magnitude stars. A common
theory is that the light Of the sky is due to
telescope stars. If this were the sole cause
however, the luminosity should diminish near
the horizon, but instead of this an increase In
brightness has been actually found to be per-
ceptible. This and a variability in the bright
ness observed at different times might be ex-
planned by assuming that the sky's luminosity
Is partly due to a stratum Of luminous particles
at o moderate distance from the earth.
s~s
The origin of the diamond has been long In
dispute. When the stones of South Africa were
traced from the river graveis to the "blue
Rround'-an aggIomerate filing the pipes of
old volcanoes 1T was supposed that the real
matrix had been discovered, but 1t has since
appeared that the diamonds were picked up
from an older rock broken through by the
volcanic eruptions. The Government geologist
Of New South Wales, E. f. Pittman, has now
described small diamond from dolerite dyke.
AL %Hnao
was actually formed in this igneous rock as it
solidifed from molten state.
80
Soap to which from one to FIVE per cent. OF
naphtha acids have boon addodfs recommended
in Germany by A. P. Lidow as ready destroyer
of virulent disease germs.
sss
The use of windmills for generating electric
current has given favorable results in the tests
for the Danish Government made at Askow by
Prof. LaCour. The four-wing wheel proves to
be the best form. With such wheel having Is
square yards of surface, he obtained two horse
power from wind of 20 feet per second. and ten
horse power from wind of 80 feet per second.
As reserve power when there is no wind, a small
petrol motor has been more satisfactory and
less expensive than a storage battery. The
AslEow plant cost "a, 100 including land and the
annual expense of operation is $165. 1t feeds
$50 incandescent lamps. with some arc lamps
aud motors. smaller outfit, costing about
$1,000, is recommended Tor farm purposes, and
number of these windmill electric plants are
already running in Denmark.
-
The collecting laboratory of Prof
Batelli. at the mineral springs of San Ginluano,
near Pisa, is an experiment whose outcome will
be awaited with interest. The radioactive water
is continuously pumped into a vacuum receipt
acle about 30 feet above the spring. and this
separates the gas-consisting of carbonic anhy-
bride and nitrogen carrying practically all of
the radfnm emanation-and conducts it to a
gasometer. while the water escapes through
discharge pipe The gas is then liquefed by
compression in brass retainer. AS it is drawn
OF by a stopcock, most of the anhydride is left
behind, and the rest is removed by caustic soda
solution; the gas then remaining being filtered
through pumice soaked in sulphuric acid to
abstract the water, and finally cooled in bath
of liquid air. This liquefes the radium emana-
ton, when the nitrogen is passed off through
tube.
The roaring heard when the hand covers the
ear has been traced by physiological expert
menter to the muscles of the palm and arm
when at work. The sound was absent when the
ear was closed by book. and the roaring became
louder as the tension of the muscles was in
creased.
Quite violent explosions, with sparks and
flashes of light, have been noticed by Herr
Doermer on hammering calcium on an anvil,
and the presence of rust on the iron seemed to
increase the explosibility. One suggestion is
fhof o1aOrbad bvdr mir @ha
phenomenon. DR.. Ohmann has made extensive
observations which indicate that the explosion
is due to a vaporization of the metal near the
edge, where the pressure is greatest, and a COM
bination of the vapor with atmospheric oxygen.
In pure oxygen the flashes were much more
Sbrill1aut. Similar results were obtained with
other metals, sodium and potassium yielding
colored flames. lithium emitting brilliant flashes
with a report and sparks. and powdered alumni
mum and magnesium giving sparks without ex-
plosion.
The hydraulic power now used in Switzerland
for running electric plants is estimated at more
than 225000 horse power of which 40 per cent. is
employed for electric lighting, 10 per cent. for
traction 20 per cent. for electrolytic work, and
"a per cent. for motors. Even with this work
done by water, the imports of foreign coal
amount to nearly $1,000 600 annually. Continued
increase in electric plants is thus assured. and
projected one in the Bernese Oberland promises
10000 horse power, while others are expected to
follow to supply the 10000 horse power needed
by the railroads. hydro-electric plant on the
Rhine near Numpf is to have 23O foot head of
water, with canal 10 miles long to lead the
water from the dam to the turbine station.
~
~.
of small box containing dry battery with an
electric bell on top. The apparatus is fastened
on the door above the key, and contacts are so
arranged that any attempt to turn the key or
open the door rings the bell. If desired, the
hnIl can be nlaced at distance. as In the usual