The Baltimore County union. [volume] (Towsontown, Md.) 1865-1909, 1909-02-20
O0rrepondencs Baltimore County Union.
SCIENTIFIC MISCELLANY.

Correspondence Baltimore County Union.
SCIENTIFIC MISCELLANY.
The Rejecting Magic Lantern-Halleys
Comet to Decide Prize Contest-Com
plexity of Lightning Flashes-Arts of
the American Indian-Fly Days-Tele.
phone Signals of Fisnes-A Novel Elec-
trio Lamp-Rubber Tester-A Sunken
Rock Spire in a Deep Bay.
The Fifax refiectoroscope. an English appara-
tus. is claimed to be the best solution so far Of
the problem of rejecting post cards. photo
graphs and other pictures or designs so that they
may show as sharp and brilliant as the views
projected by the ordinary transparent lantern
Slides The new magic lantern resembles the
ordinary one in general appearance, but the
picture is placed at the back where 3,000-can
die power beam of light is concentrated upon 1t
by two refiectors. and the image is retransmtted
through the lens to the screen. Though other
powerful lights may be used, gas. with special
high pressure burners and incandescent man
ties, has been found to give the steadiest and
most penetrating beam. The operation of the
high pressure gas system costs about half cent
an hour: specially prepared slides are not needed,
the colors and details of the reflected pictures
are shown wildly on the screen and magnifed
as required, and book pages or other letterpress
printing may be exhibited as well as all kinds of
pictures.
A novel competition is to be decided by Hal
ley's comet. which is expected soon to come in
sight for few months of its 75-year circuit
around the sun. wealthy European amateur
astronomer offered prize for best computation
of this comets orbit submitted before the close
of 1908. and a competing ephemeris for this year
and next indicates very different route from
that expected. showing the perihelion passage
in the middle of June, instead of the middle of
April, 1910.
Accommodating evidence shows that lightning
flashes may have much more.varied structure
than was formerly supposed photographs by
A. Larsen, Danish photographer, indicate that
flashes may be made up of small electric dis
charges or rushes, of which forty may follow
along nearly the same path in half minute.
ars
Considering the industries of the American
aborigines, ]. L. Cowan finds that basketry is
the chief and Oldest. and was well advanced
when Friar Marcos de Mia visited Arizona and
New Mexico in 1889. The designs, instead of be-
ing accidental or representing personal tastes,
have traditional significance. The cobweb pat
tern is associated with the spider deity the deer
hunt with gods of the chase. and even break in
the design is intended to give exit to evilspirits
that is not desirable to keep confined. Colors
also have their meanings, red-the most impor-
tant and sacred-typifying the life of man. The
evolution of pottery from basketry can be traced,
the basket being covered with clay as protec
ton against fire, but the old artistic decoration
and perfection Of form and workmanship in
pottery are to be found only among the Hopi
and Zuni communities. Blanket weaving is the
latest of the Indian manufactures. Plating
and weaving were known before the Europeans
came. but only after the introduction of sheep
and goats was the skill developed that has en-
abled the Navajos to weave the finest blankets
produced in the world.
A%s
A curious result of the fy-pest investigation
in London has been the discovery that the num-
Der of flies in house varies greatly from day to
day, the cooking operations and greater use and
warmth of the rooms causing a large weekend
increase. The daily average noted by one OBJ
server was 20 for Friday to Monday, IA from
Monday to Wednesday, and from Wednesday
to Friday. Washing days have marked in
fuence, and in one instance wedding prepare
lions decidedly increased the flies. Horse refuse
is the chief breeding ground of horse flies. The
number in some localities is almost incredible,
and the bulk of summers catch with fly paper
in one small room would have been an apprecia-
BILE percentage of the rooms capacity. With hot
weather and many flies are associated preya-
lence of summer sickness.
A+s
In the telephone hunt for fishing in Norway, a
microphone in water-tight steel box is lowered
into the sea, and transmits to the telephone re-
ceiver in the boat a whistling sound if herring
are about and kind of grunting If cod are near.
-.
Plates of aluminium alloy used as electrodes
form new kind of electric lamp that seems
to promise efficient and economical lighting.
| Trial was made with an alloy much used for
motor castings, and containing 80 per cent. of
| aluminium, the remaining 10 per cent. being
| chiefly copper and tin. with some manganese,
| iron and zinc. and traces of silicon. Immersed
| in solution of common borax. such electrodes
stand a current gradually brought up to $50
volts. The current caused the electrodes to
| glow like white-hot iron in water, without the
| sparkling of pure aluminium, and with lowered
voltage an opal colored light was produced Civ
ing the effect of a building; lighted with many
concealed lamps. Beyond 200 volts, small shift
| ing sparks appeared over white surface. The
| glow resembles the light sometimes seen about
wires carrying currents of very high tension,
but in this case there is static discharge of
electricity through the very thin film of alumni
mum oxide coating the plates.
sts
The elasticity and hardness of rubber are now
determined by an apparatus akin to the schlero-
scope. which shows the hardness of steel by the
rebound of pointed steel hammer. sharp
point is forced into the rubber, and the force
exerted and the depth of penetration are auto
| matically recorded on graduated circles, a COM
| bination of these Indications giving the degree
of hardness. The elasticity is shown by the
height of rebound of a steel ball when dropped
| upon the rubber from measured height. The
apparatus is simple, and easily and rapidly tests
the relative value of different specimens of
| rubber.
| The elusiveness to chart makers of some dan
gers to navigation in familiar waters is ilustra-
/ ted in a new work by G.. r. Putnam. In the
much traversed Blue Hill Bay, Maine. was lately
| discovered a pinnacle rock that rises from q
depth of rs feet to within seven feet of the sur
! face, with almost perpendicular sides and top
only six feet in diameter.
CASTORIA
For Infants and Children.
The Kind You Have Always Bought
Bears the N <