The Baltimore County union. [volume] (Towsontown, Md.) 1865-1909, 1900-11-24
Correspondence Baltimore County Union.
SCIENTIFIC MIS- CELLANY.

Correspondence Baltimore County Union.
SCIENTIFIC MIS- CELLANY.
Swimming Magnets-Fish Deception-A
French Want-The Problem of Flight
Economical Separation of Sea-Water
Gold-Uniform Time by Electric Waves
The New Brick-Making-A Remark
able Cement-A Tropical Potato.
Magnetic attraction and repulsion are illu-
trated in very interesting manner in new ex-
pertinent devised by Prof. s. p. Thompson.
circular coil of wire is placed with its axis hori
zontal in tank of water, and a number of
small bar magnets into glass tubes is so adjusted
that some just float while others just sink.
When current is passed through the wire, the
magnets are attracted and sucked into the coil,
and If the current is suddenly cut of and re-
versed as they are approaching, they are re-
PEELED and turn back. By careful manipulation
the tubes seem simply to dart at and through
the coil.
So great is the sensibility of the leech Clspsine
that the creature is disturbed by the touch of
needle point on the surface Of the water of its
containing vessel. There is reason to believe
that fishes also quickly detect disturbances in
the water, but DR.. r. w. Shufeldt thinks the pc
cuIiar constituencies to teasing of the snowy
kEptfteptetU5
explanation. On being much disturbed, this
fish appears to have fit, then floats belly up
wards, at the same time changing color. 1t is
suggested that this seeming death-struggle is
intended to keep Off predatory fishes, which
prefer to take their prey in health.
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Fish scales have been cleansed and dyed, and
considerably used for decorative purposes. In
France a novel demand has now sprung up for
the white mucus with which these scales are
fabricated. This mucous is supplied by the
bleak and other species, and it takes 10000
fishes to furnish single pound. Glass bulbs
lined with this material afford beautiful imita-
The oldest mining company in the world is
represented in the Swedish Department of
the Paris Exposition. This company began to
produce copper in the year 1925, and it has
records of its production for nearly three CEN
turtles.
Reviewing the progress made in air naviga-
ton, Mr.. Henry Wilde finds that the problem Of
fight remains about where Leonardo da Vinci
left it in 1900, after inventing the aerial screw
and parachute. Recent experiments have
strangely neglected the essential requirements,
which are-that a flying machine should have
the power under ordinary conditions to ascend
or descend at any place and any time; that it
should be able to move in any direction or re-
main stationary above the earth and that it
should contain some automatic principle of
safety to enable the aeronauts to reach the
earth without danger in the event of accident
to the mechanism. All means OF navigating the
air thus far devised are lacking in more
of these essentials. Unless some new property
of matter should be discovered. the only promis-
ing means of solving the problem seems to be
by applying power to the parachute, for when
the power of ascending is once given this,
travelling in a horizontal direction may be
brought about by inclining the parachute in the
direction of motion required, while safe de-
scent is assured by the sustaining surface.
Soaring aeroplanes fail conspcuously, partak
ing more of the character of projectiles than
of means of locomotion.
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The new gold-from-sea-water scheme of a
British inventor consists in the construction of
shallow reservoir on chalky coast. A ball
valve would open at high tide, allowing the
water to enter with such force as to scour the
bottom of the reservoir and stir up the sludge,
and the discharge would be gradual through an
outlet just above low-water mark. 1t is claimed
that the gold would adhere to the sludge, set
tleing with it in the reservoir. AS each ton of
sea-water is assumed to contain from two to
five grains of gold, it is easy to figure for
such reservoir a valuable accumulation of
precious metal, which would be obtained
periodically by fusion or dissoving the chalk
in acid.
A clock regulated by Hertzan waves was a
novelty shown at the late Royal Society con-
versazoine. 1t was suggested that all the clocks
of London-public and private-could be con-
trolled by wireless telegraphy. a coherer on
each clock receiving the electric waves and
causing the time to be set to that of the central
transmitting clock
"A model of the human heart. working In
life and pumping blood to and fro through arti-
fetal arteries is the work of a French physi-
clan.
Bricks of quartziferous sand mixed with
small proportion of lime can be made in many
places where clay is not available, and they
have the advantages of being proof against
water, frost and acids. A serious difficulty in
their manufacture has been the extremely va
riable quality caused by changes of the wealth
err By mixing the sand and lime in vacuum
with steam heat, and admitting steam to supply
the exact amount of moisture necessary, Will
helm Schwarz of Zurich, has overcome this diff
ficulty, thus perfecting an industry that Consul
B. H. Warner. Jr, predicts will prove of great
Importance in all countries The process en-
sures beginning of the combination of silicic
acid and lime before the mixture is pressed into
moulds and prevents all deleterious aeration of
the lime by the atmosphere. The apparatus
consists of steam-tigh mixing machine pro-
vided with revolving arms, with an air pump at
tached to exhaust the air and draw out exces-
civa rnoiat1re and n f1ha inside for admitting
the exact amount of steam required. Proper
management of three valves ensures a uniform
product.
Cement made from blast-furnace Stag is stated
to have remarkable tensile strength and resis-
lance to compression. In process for making
it described by Ritter Won Schwarz, the Stag is
ground into sand and mixed with limestone and
Stacked lime, and the mixture is reduced to fine
powder and made into bricks with water. After
drying in the air, these bricks are burnt into
clinker in a special furnace. the clinker being
then stored for six weeks before being finally
ground
The Oussunify, for which the botanical name
of Plectranthus Coppinni has been proposed, is
edible tuber of the Soudan to which NJ. Maxine
Cornu has just drawn attention. 1t resembles
the potato, with the advantage that it can be
grown in truly tropical climate.
AFs
Probably the greatest diurnal temperature
range on record is that reported by NJ. Itchy,
late traveller in Mongolia. The temperature at
Urga was 1929 at A. M, and at noon it had
risen to 1882
-.
The microbes of dental carries stated by
NJ. Choquet to number five species, and they
cause decay ON being experimentally introduced
into sleeps tooth.
MONEY TO LOAN.
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