The Baltimore County union. [volume] (Towsontown, Md.) 1865-1909, 1904-01-02

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Correspondence Baltimore County Union.
SCIENTIFIC MIS- CELLANY.
Lighting Enaciency-Street Paving-A
Safe xplosive-Japanese 5word-Mak-
in9-Red Rain in Observation-Disclosures
ton With Alcohol-Why the Intestines
Are Not Digested-The Tropical Prob
lem-Another Metalloid.
The electric discharge between two vessels of
mercury IN partial vacuum is the most eff
cient form Of artificial lighting yet discovered.
In q recent test by W. C. Geer. the terminals
were about four-nfths Of an inch apart, and an
arc Of two inches in length was produced by
direct current Of ITO volts. Nearly 50 per cent.
Of the energy supplied was converted into wish
BILE light. Turning to other lights, the Geissler
tube showed an efficiency Of 80 per cent; the
ordinary arc lamp. 10; acetylene gas. 10; the in
candescent electric lamp, 9, and the Argand gas
burner, 1.0.
An investigation Of paving stones has been
undertaken in Ireland by Prof. Jolly. He finds
that resistance to wear varies directly with the
amounts of quartz and felspar contained. the
completely crystalline igneous GRANTEES, etc.,
being as rule the toughest. Rocks that are
decidedly porphyritic, porous or CLASSY are to
be avoided. A certain coarseness of grain is
usually desirable, as fne-grained rocks, like
certain Welsh diorite. are liable to become
slippery.
Ammonia. a new mixture of powdered alumni
mum and nitrate of ammonia, is claimed to be
one Of the safest of explosives. 1t is not liable
to explosion by shock or friction, is not readily
fired. is especially free from spontaneous de-
composition, and is even credited with the rath-
er surprising PROPERTY of being unaffected by
moisture. It is fired with the usual percussion
cap.
-
The temperature limits of life are much more
widely separated than we once supposed. Bac-
terra are now known to develop and multiply at
72oC.. and Prof. A. Macfadyen. Of London, has
exposed such organisms to 1000. below zero for
six month without harming them. while they
even survived 250oC. below zero.
AZ
One of the most interesting Of metallurgical
processes is the manufacture of Japanese
swords. recent description states that the
steel is produced in thin laminae from magnetic
upon the weapon begins with the fixing of one
Of these plates to an iron rod, which serves as a
handle. Other sheets are soldered on until the
mass has length of six to eight inches, width
Of two inches, and thickness of one-fourth to
four-hfths Of an inch. Brought to white heat,
the bar is doubled upon itself and hammered to
its original form. the process being repeated
fifteen times and four similar bars are then
heated and soldered, this process being repeat
ed five times. These operations give superim-
posed layers so thin that sabre is estimated to
contain thousand sheets Of metal. Alternate
layers of iron and steel are sometimes soldered
together, and veined appearance is thus given
to the blade.
In their investigation Of the rains OF red mud
that fell in Victoria early this year, F. Chap
man and H. J. 9rayson have found that the de-
posit in one case reached fifty tons per square
mile. Much limonite was included, with many
mineral fragments and diatioms. The material
seems to have been carried by the winds from
the vicinity Of certain swamps and salt lakes,
which exist from 80 to 800 miles north and west
of Melbourne, and whose margins had been
made unusually dry by a season of drought.
-
with his improved lamp, L. Denayrouze, a
French physicist, claims to obtain light with
pure alcohol at third of the cost per candle
power of petroleum lighting. and with carbu-
reted alcohol at fifth of the cost. A wick con-
ducts the liquid by capilarity into a chamber.
where it is vaporized by the heat from copper
bar reaching into the fame. The vapor passes
into a kind of Bunsen burner, over which is
fixed mantle.
A puzzling fact Is that the walls of the intes-
tines and the parasites often living on them are
never digested by the ferments that attack, de-
stroy and transform the food. Frenzel in 1891,
suggested that protective anti-ferments are Sc
GREETED by living tissues. In some late expert
ments, M. Weinland, French Psychologist,
sought to digest f1brine in trypsine or pepsin
after first adding a little juice from lntesti-
nal worms. but the ferment had no effect
upon the hbrine in the presence of the anti
ferment juice. It is thus proven that the juices
secreted by and impregnating living tissues
instead Of the tissues acknowledgements diges-
ton. The anti-ferment extract is exceedingly
powerful and retains its resisting power for
months. but it loses its property on boiling.
AZ
The war against malaria and mosquitoes is to
be fought out in tropical Africa. DR.. button,
in a report to the Liverpool School of Tropical
Medicine, states that 30 per cent. OF the native
children examined in British Gambia showed
the malaria parasite in the blood, and that the
liability of infection by Europeans continues
during the rainy season, the time of mosquitoes.
The breeding places of the insects include wells,
canoes, boats, lighters barrels, tubs and various
disused household utensils, and grass-clogged
street trenches. Bathurst, the capital of the
colony offers an unusual field fora test of exter-
mination plans, as the land to be dealt with has
an area Of only a square mile and is isolated by
broad expanse of sea water, while rain occurs
In only four months of the year. The removal
of breeding places, now sevaral months In pro-
gress, is aided by grant of 920O a year.
Ars
Tantalum has been known hitherto as a some
what impure powder having density of 1880.
Henri Moissan has now reduced tantalic acid in
the electric furnace with carbon, and the fused
tantalum obtained has a brilliant metallic ap
pearance and density of 1919. It scratches
quartz, is infusible in the oxyhydrogen blow
pipe. has crystalline fracture, and is classed
with the metalloids.