The Baltimore County union. [volume] (Towsontown, Md.) 1865-1909, 1904-04-30
Correspondence Baltimore County Union.
SCIENTIFIC MISCELLANY.


SCIENTIFIC MISCELLANY.
Dark Rays Of Gaslight--Slag Cement
Electric Arc Burns-Carbon Wool-A
New Oxygen Process-Novel Develop
ment Of Hearing-A Mechanical Drill
Enthusiastically for Consumption
Silver for Wounds.
The N-rays of r. Blondlot should interest us
especially because they are so common about
us. They were discovered while the light from
welsbach burner was being concentrated by
quartz lens on a sulphide of calcium screen.
the lens causing the luminosity of the screen TO
persist after the light was removed. They are
now known to exist not only in the incandescent
gas but also in the ordinary gas flame burning
without chimney, and in the radiation from
red-hot place Of silver or tale, and they excite
radioactivity in the various substances, such as
q place Of lead. The invisible rays can be de-
tected by the slight increase of luminosity Of a
phosphorescent screen or Of very small gas
flame. These rays seem to be given of by the
human body, and D'Arsonval has shown that a
screen Of platinocyanide of barium, made slight
~ luminous by radium, lights up on approach to
muscle. and is so sensitive that it can show the
course of nerve under the skin.
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W uliC uyuIhuilC CCkuCub AAOnA DAa6s~AdAAoSS
Stag was made in London many years ago, the
industry does not seem to have become perma-
nent The manufacture of Portland cement
from Stag and limestone has now been begun in
Germany and Belgium, and the product is
claimed to be cheaper and more trustworthy
than that from the usual materials. Mortar of
one part of Stag cement to three of sand had
tensile strength Of 3e3 pounds per square inch
after days, increasing to ISL pounds in rs days.
s's
In late experiments of Jensen. isolated can
Ger cells retain their vitality for Is days at 10 to
80 c., IL days at room temperature, and persisted
in "a hours at body temperature. Bright light
was rapidly destructive, as was also carbolic
aofd.
still unexplained effect of the electric light
somewhat resembles mild sunburn and sum
stroke. The heat Of the electric arc employed
in the reducing furnace is so concentrated that
it melts steel like tallow, but the thermometer
a dozen yards away is scarcely affected. Even
at this distance from the heat, however, per-
sons experience burning of the face and other
exposed skin much like that produced by in
tensely hot sunshine. The skin becomes deeply
bronzed. and there is temporary blindness in
natural light, with pain in the eyes, followed by
headache and insomnia.
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In certain open coke furnaces, where air is
admitted through openings and the gas from
the bituminous coal is burned in the apparatus,
carbon is deposited in the singular form of
masses of fine threads. These deposits, which
they call carbon wool, are found by two French
chemists to occur in geode-like cavities in the
coke, and the finer filaments are about O00O8
inch in diameter while the coarser ones range
from O.O012 to 0.0O35 inch, the length being
usually about inches. The lllaments are
formed Of rings, of which six were seen in
1-250th of an inch.
Oxygen has been obtained from liquid air by
distillation, the nitrogen passing of first and
the last 10 per cent. being about 80 per cent.
oxygen. The oxygen volatilizes first but also
condenses while the nitrogen is still in gaseous
form, and NJ. Georges Claude has devised new
apparatus In which partially frozen stream of
air is made to return against fresh air, when 1t
gives up nitrogen and takes oxygen. One end
Of the apparatus is thus made to give out near
ly pure nitrogen and the other nearly pure oxy-
gen, 1900 cubic feet of 90 per cent. oxygen per
hour having been obtained.
"a
Radium has been found to have distinct but
variable influence on the growth of tadpoles,
development being slowed, quickened, or per-
verified.
-.
To train deaf mutes to hear and to measure
their sense of hearing have been subjects of
experiment in Europe by DR.. Marage. A siren
giving vowel sounds was used, and the intensity
of the sound as 1t became audible became pro-
gressivcly less, many cases of complete deaf
ness being thus made to give place in six weeks
to the power of hearing ordinary sounds. The
treatment proved to be pleasing instead of IA
tiguing or painful. The hearing was measured
at different stages of the treatment by the air
pressure necessary to make the siren audible,
and the results claimed izaaiaa4e- taat