The Baltimore County union. [volume] (Towsontown, Md.) 1865-1909, 1890-11-22
Correspondence Baltimore County UssiOn.
SCIENTIFIC MISCELLANY.
ooLoRs OF TEMPERED STEEL

Annealing colors have been supposed to be
due to oxidation of the iron, and this theory
has now been confirmed by Herr >. Stein.
Carefully cleaned pieces Of iron and steel were
put into glass tube, the air was exhausted,
and nitrogen was introduced and pumped out
in order to ensure complete removal OF the
Oxygen. On heating the tube white preclpl-
tate of unknown nature formed ON the inside,
but the usual temperatures failed to bring out
the annealing colors, which, however prompt
lv appeared on the admission ofoxygen. Other
German chemists have proven that the colors
do not always appear at the same temperatures.
Increased hardness of the steel makes neces-
sary an increased heating to produce the same
annealing color, and difference OF composition
produces a still greater difference in the tenn
perature required for any color. Length of
heating also has an influence. A piece of soft
steel heated to $50 degrees f. became purple af-
ter 68 hours, violet after 49, and dark blue after
100. whereas piece of hard steel turned light
orange after so, and purple after 1OS. At higher
temperatures, the colors appear with shorter
intervals
DURABILITY OF CONSUMPTION.
In late series of experiments, DIR. Koch
found that certain bodies, such as volatile oils.
and metallic salts, such as nitrate of silver and
preparations of gold, even in very small doses
Il to 600 OO0 and even less), destroy the bacilh
of consumption in very short time. Hethere-
fore concludes that in course of thine some drug
may be discovered that will cure the disease by
destroying the bacili without injury to the
body.
SOUND AT DIFFERENT ANGLES.
In some recent experiments on the range OF
human hearing, the ticking of a watch was
distinctly audible at distance of 10 feet on
line at right angles to the head. On moving
the watch Is degrees in front of the line, the
tick could be heard IA feet away; at an angle
of 40 degrees only feet and at 55 degrees,
only 8 feet. Placed IS degrees back of the line,
the watch could not be heard beyond 6 feet.
iSs y greatest scmseness being Is de-
grees in front of the imaginary line through
the ears. Descending from the horizontal, the
hearing distance increased from 10 feet to
maximum of IL feet at IS degrees, and then de-
creased until reduced to feet at 80 degrees.
On carrying the watch upward, the sound de-
creased steadily until at an angle OF 90 degrees
it could be heard only feet away.
MILITARY AGRICULTURE.
instruction in agriculture and forestry has
been introduced into the Belgian army. intend
ed for such soldiers as expect to return to the
farm on retirement from military service.
Land for experimental and practical purposes
is acquired near garrison towns. The scheme
offers the double advantage of turning out
scientific farmers and providing supplies for
the army.
PROMISING FIBRE-PLANT.
An official report to the Belgian Govern
ment states that the 'guimbobo" or "angu,"
of the Mexican State of Vera Cruz, possesses
fibre finer and stronger than silk, and OF
similar lustre. Experiments already made are
said to indicate that the guimbobo differs es-
sentially from ramie, cotton and hemp in
having the plant covering around the fibre in
stead of mixed up and interlaced with it. This
makes it practicable to separate and remove
the bark by means of machinery. The plant
grows luxuriantly with little care, and pro-
duces highly-esteemed food in addition to the
fibre.
SMALLPOX IN GERMANY.
The law of Germany makes vaccination COM
pulsory and provides for re-vaccination at
stated periods. As result smallpox is rap
deaths for the whole empire as only 1877 in 1886.
1853 in 1887. and ITO in 1888. OF the deaths IN
1888, about four-ifths occurred in parts of the
empire Immediately bordering countries not
protected by vaccination. Comparing the
deaths of the larger cities with those of cities in
other countries, the death-rate from smallpox
was 136 times as great in Austria, 30 times as
great in Hungary, 16 times as great in England,
"a times as great in Belgium, and twice as great
in Switzerland
MISCELLANEOUS.
It has been noticed that liability to cancer
diminishes from about As to IS onward, and
that after 20 there is little to fear from this dis
ease. Only one centenarian is known TO have
died from it.
Cowhide horse-shces are reported to be grow
ing IN FAVOR IN England ana OLner parts OF Eu-
rope. They have the advantages of lightness,
great durability, superior adhesion and avoid
ance of split hoofs. The japanese are said to
have used straw horse-shoes for centuries, the
straw being treated by an unknown chemical
process.
Electric currents of 500 horsepower will be
supplied the International Electrical Exhibit
ton at Frankfort from generators 140 miles
distant.
French Psychologists have found that alcohol
produces the same effects-including derange-
ment similar to delirium tremens- dogs as
on men.
A nautical ball-seven feet in diameter and
-Garable of holding four persons-has been
made and tested by an italian inventor. 1t
sinks when closed, and has screw and rudder
for propelling and steering. 1t is provided
with windows and grapplers, and may be used
in warfare as well as for fishing up articles
from the bottom.
In some 80 species of plants growing both on
the coast and in the interior of France, NJ.
Pierre Lesage has found that proximity to the
sea causes thickening of the leaves. Artifi-
cially sailed soil produces the same result.
According TO DIR. Chaille, woman's average
life is longer than MANS and in most parts of
the United States her expectation of life IS
greater.