The Baltimore County union. [volume] (Towsontown, Md.) 1865-1909, 1906-12-08
Correspondence B0gssmoss County linton.
SCIENTIFIC MISCELLANY.

Correspondents Baysimoss County linton.
SCIENTIFIC MISCELLANY.
Quartz Glass In Quantity Electrifying
the Gas Light-sitsing Lessons Work
The Observation-Disclosures StockiDgs--
Vegetable Sponges-Fog Dispersion.
Teeth Destroying Saliva-Liquid Airs
Real Use-The Suns Temperature.
Glass from pure quartz can be heated to l.0OO0
c. without softening. is not cracked by sudden
changes Of temperature, and is otherwise of
great value for scientific and other purposes.
It Is prepared with great difficulty, however.
the quartz apparatus now in use having been
built up by piecine single crystals together by
means Of the oxyhydrogen blowpipe. When
quantity of crystals is fused the mass is made
Opaque By air bubbles. which cannot be removed.
and varied experiments have made it evident
that clear glass Is not likely to be obtained by
direct fusion at atmospheric pressure. An eff
fort to solve the problem BY other means has
been made at the Carnegie Institution with fair
success. The quartz. in graphite crucible. is
first heated to 2,000o or more. to produce quartz
vapor enough to drive out the afr from between
the grains, then pressure of 5O0pounds or more
il quickly applied and the temperature is low
cred to perhaps 1902 for half an hour, when
Ahcat Nuu REGcSHEC akt bUWly WiIuuEAWUs
~
Raising the temperature of bare platinum
wire from SO00 c. to 500 more than doubles its
brightness. while doubling the temperature Of
white-hot body is estimated to increase the
luminous intensity 1900 times. With this in
mind, Adolf Herr. German. has passed an cleo
trio current through an Auer glover of metal
oxides heated by gas flame, and has thus con-
siderably raised the temperature. The result is
anextraordinary increase in luminous efficiency.
sss
BY means of ergograph measurements, NJ.
Charles Ferre has found that one-tenth more
work can be done standing than sitting but
that the greater intensity of effort during q
long period in the standing position is followed
at the end by more rapid fatigue.
~
In the ''autocarte," novel French touring
map, the road travelled is shown upon band of
paper. which is mounted on the dashboard of the
motor-car, and by automatic unrolling indicates
the exact position Of the car at any moment. 1t
Is especially useful at night, while at present
high speeds sign-boards are not easily read even
in daytime. The scale of the map is sufficiently
large to make clear the exact point of the route
reached, and the chauffeur can read ahead for
i've miles, thus being able to fix in mind all
obstacles, turns descents, etc.. long before they
are reached. At night the chart is always
lighted.
The peculiar substance known as asbestos,
which was regarded as valueless century ago,
10 now in demand for many purposes. 1t is
made into roofing felt, cement theater curtains
and various heat-resisting articles, and has been
recently spun into a light and fairly strong
thread. Even ropes. with or without steel cores,
are made from it for firemen. Anew and rather
surprising application is for army stockings.
which have been shown to be less irritating to
the feet of soldiers on the march than other
stockings and the War Department Of Austria
is considering their general adoption.
~
About ten species of vegetable sponges' are
now cultivated In the warmer parts Of Africa
and Asia. especially in Algeria. The fruit is
edible before maturity, but on ripening the
pulp separates from the 1brous material, which
then becomes an excellent substitute for real
sponge for the toilet. bathroom and many
other purposes. The Algerian sponges are in
large demand in Paris.
~
Fog dissipation by electric discharges has
proven more effective when the fog contains
dust or smoke than when it is water only. the
solid particles seeming to become charged and
10 be then repealed, precipitating particles of
vap0r with which they collide. With bundle
Of spikes as radiator. space of some yards can
be cleared in few seconds.
~
Why the teeth of some people decay early
while those of others continue sound through
out long life is problem that appears to have
been only imperfectly solved A European in
vestigator. Dr. G. Risa. has lately analysed the
saliva Of 219 children averaging ID years of age,
and has confirmed the idea that there Is a rela-
ton between the alkalinity of the saliva and
dental carries. A highly alkaline saliva ensures
good teeth. He has made many experiments to
determine how an acid or slightly alkaline saliva
may be made decidedly alkaline, and has proven
that diet containing much lime has marked
inhSence~apd does much to keep the teeth in
perfect condition.
Cheap oxygen is the one important product
thus far obtained from liquid air, for which
such extravaganza prophecies have been made.
AS the nitrogen and oxygen of the liquid air
return to the gaseous state at different tempera-
lures, it has proven to be possible to separate
them by fractional distillation. and as the evap-
Grafton of the gases cools the air entering to be
compressed in the apparatus, the process is very
economical. An idea of this efficiency has lately
been given by NJ. Georges Claude. His plant
produces 1000 cubic metres of oxygen, with
purity of 96 to 98 per cent? twenty four hours,
and the cost in France is only one-twentieth of
that of oxygen from the electro-lytic decompo-
sition of water.
-.
The electric arc in which titanium has been
distilled has a temperature of about $500 G.
Making allowance for uncertainty as to pressure
in the solar atmosphere, NJ. Moissan concludes
that points on the sun where titanium is seen in
the solar spectrum to be volatized must have
temperature between two estimates of sun-heat
already made-6.59Oo G. and 2OOOO to 5000 G.
The probability is that the latter is nearer the
true heat Of the sun than the former. This is
very much lower than early estimates.