The Baltimore County union. [volume] (Towsontown, Md.) 1865-1909, 1908-01-11
Correspondents Baltimore County Union.
SCIENTIFIC MISCELLANY.

Correspondence B0Aina0re County Union.
SCIENTIFIC MISCELLANY.
Light Of Men and otners-spectacula
Metallurgy-Welle at an Angela
Room Without Noise-Some Life Of an
Acre-Sun-Heat Being Worked Out-A
Vanishing Screen-The Workshop
Lamp.
The eyes of man and the higher animals have
important differences. Prof. Heine, at the Ger
man Naturalists Congress, pointed out that the
human eye is normally at rest for an infinite
distance, accommodation being accomplished
by angular muscles in the socket that make the
ball more convex. In apes and all mammaia
and birds. as well as in some amphibia the me.
chanism is the same. Birds have an advantage,
as their striped muscular system enables them
to make rapid changes, keeping fast-moving
images In focus. Reptiles and fishes give quick
adjustment of drawing back the lens instead of
deforming it. The bigger the animal the poorer
its accommodation. Among very inferior in
vertebrates are found very high eye mechanism
and some mollusks have eye adjustment COM
parable to that of highly developed birds. In
some Representation, sight, smell, etc.,-man is
surpassed by other animals.
asA
On recently fusing little tantalum powder.
Siemens and Halske placed TINA kind of Crooks
tube instead ofan electric furnace. On the anode
the metal powder received the bombardment Of
particles from the cathode, and was quickly
fused. A magnet detected the tiny stream of
bundles. and made it act upon any desired part
first Of the mass of metal exposed at the adobe.
sys
OF 235 bore-holes in the WitWatersrand area,
l5 go below 10000 feet. Most of these are in
bedded strata. with dip. and are not vertical.
J. Kitchln. a London engineer, reports that %
boreholes have an average inclination of 440 feet
at depth of 1000 feet. and an extreme of 2870 in
bore-hole 1900 feet deep.
s's
For many experiments now It Is necessary to
exclude all outside sound. What is endorsed by
Prof. s. /. Franz as the one absolutely noiseless
room is room about feet square and high on
the top floor of the physiological laboratory of
the University of Utrecht. Its walls are about
IL inches thick. From the inside these are
made up of successive layers of horse-hair felt,
porous stone dead air. wood-partition, ground
composition and plastered surface. The cell
ing. though somewhat simpler made, has similar
layers. The boards of the floor were sawed and
the joints filed with lead to stop vibration, a
layer of lead was then covered over all to the
thickness of more than an inch and over thisfn
turn 1s used a carpet nearly half an inch in
thickness. and sometimes second carpet. A
small window opens into little connected room
with roof-Window, the two windows supplying
both sunlight and ventilation. The door is double
the outer part accurately fitted with felt, and
the inner part composed of three layers with an
air space. In the noiseless room sensations vary,
sometimes including variety of body sounds,
sometimes feeling of pressure. The shell held
to the ear no longer seems to give forth sound,
the tones for which the shell is resonant being
absent.
The great abundance of life in the ground is
again shown by A. 3. Hickmott, gardener of
Reading, Eng. To improve his garden he made
30 depressions in the ground, an inch or two
deep, pressing cabbage or lettuce leaf into
each, and covering them with pieces of board,
moisten1ng In dry weather. In one day he
caught 376 slugs, and from July to the middle of
November total of 4,l7O. Hensen, a German
naturalist, placed the earth-worms of an acre
5000 but If this garden has 90 square yards it
must have supplied slugs at the rate of 1,15O,OOO
to the acre.
The suns temperature has been lately esti-
mated at 6S73o, 5000 and 54OOO c. Millochau,
French astronomer. has compared the thermal
and optical results with those of an electric fur
1880 - AAAO"A tCtu pcEdbuEes
-
The aerial graphoscope of Eric Stuart Bruce.
Secretary of the London Aeronautical Society,
has the curious feature of showing lantern pic
lures In bold relief without the aid of the long
familiar white screen. The picture is projected
upon lath of wood, painted dark gray, between
nve and six feet long and about two inches wide
which is revolved steadily and more or less rap
IDLY Tue method gives improved effects with
spectroscopic and other pictures. 1t will be es
pecially an apparatus of the investigators
laboratory, and it will give particularly very
delicate means of measuring the exact duration
OF persistence of vision on the individual retfna
s"s
InaC the mercury vapor lamp Is to take lead
Ing place in lighting workshops is the conclusion
reached by K. Norden, a German. because the
light has proven less fatiguing to the eye than
any other illuminant. He pronounces the Aron
mercury-vapor lamp the most satisfactory, as it
has self-lighting attachment. The lamps are
In the form of vertical tubes-one-half water to
one meter long, and these can be distributed to
give any desired effects.
-
Shooting bombs at clouds has proven an inef-
fective method of preventing hail in Belgium.
With his pear shaped balloons, Adhema de la
Hault claims to be able to get closer to the
source of the hail, and to dispense the cloud by
firing explosives in its midst. The first trials
have been reported to be very successful. The
same balloon carries meteorological instruments
and thus furnishes useful weather records.
-.
In novel finishing machine for wooden and
worsted cloth, the material is drawn under
pneumatic pressure over rolls covered with
nnely ground glass. The millions of fine glass
particles produce an effect that cannot be given
In any other way, and the result is uniforms
smooth, polished surface with very thick map.
The process is capable of very accurate regu-
lation.