The Baltimore County union. [volume] (Towsontown, Md.) 1865-1909, 1905-10-14

SCIENTIFIC MISCELLANY.
Telegraphic photoeraphy-Air-Carried
Smallpox-The Rust of Bronze-CheeDo
Bacteriology-A Machine to Test OIL
Explosive Rocks - Electric Discharge
Pictures-How Snake Poison Kills.
The picture telegraph of DR.. Korn. Of the
University Of Munich, has been so perfected
that in 10 to 20 minutes q photograph By
inches in size can be sent through resistance
corresponding to 1000 miles. The portrait or
design to be transmitted is on transparentnlm
which il wound around glass cylinder, and
upon which lens focuses point of light that
passes through the film to selenium cell in the
cylinder. The bright and dark portions of the
picture cause the ray Of light to vary the resist
ance Of the selenium cell to an electric current
passing through it, and this variation produces
q corresponding instantaneous Frightening or
darkening Of the glow in Tesla vacuum tube
at the receiving end Of the wire. Except pin
point apcrature, this vacuum tube is covered
with wax or rubber. The light ray from the
aperture falls upon sensitive hlm wound upon
cylinder, and as this cylinder and that Of the
transmitter are moved in unison, the light and
shade Of the original picture are reproduced in
proper place on the second FILM, giving new
photograph accurate in minute detail.
a*s
An outbreak Of II cases of smallpox at New
castle, Eng. last year has mystified the doctors
No ordinary source of infection could be discov
cred, but it has been found that on the days
when II Of the patients probably contracted the
disease the wind was blowing from one or the
other Of two smallpox hospitals-one about
mile away. the other about two miles. 1t is
pointed out that flies. pest Of hospitals, may be
carried long distances by the wind.
~
The moon is usually supposed to have solidi-
fed from the center to the periphery. but lunar
photographs have convinced two leading French
astronomers that the surface hardened first.
This view mobiles various theories.
80
The beautiful patina Of old bronzes is often
ascribed to some secret of composition or man
ufacture that died with the ancient artist.
After long observation and experiment DR.. Otto
N. Witt. a German chemist, finds this notion to
be quite unfounded, and that, while the surface
alteration Of our coppers and bronzes varies
greatly with slight impurities and differences of
composition, the failure to get ancient effects is
largely due to the chemical changes that have
taken place In city atmospheres. The much
priced blue-9reen tint results from the forma-
ton of an unaterable coating of basic cupric
chloride. The chlorides of the sea breezes of
Greece. Rome and Egypt gave this patina, and
even in inland cities, when wood was the chief
fuel. the air contained little to act on copper
cept the hydrochloric acid from ocean winds.
With the burning Of coal great quantities of sui
phur1c acid have been discharged into the at
mosphere. This acid rapidly attacks objects of
copper and bronze, and, as the sulphates are
washed away, unsightly corrosion is produced
instead Of true patination.
"a
The art of the cheese-maker now depends to
an ever increasing degree on bacteriology.
While bacteria seem to play smaller part in
the ripening Of cheese than was formerly sup
posed. Tactic bacteria are found necessary for
acidifying the milk, and specific molds are essen
tial for the fav0rs characteristic Of some kinds
of cheese. The newest discovery is that of GER
tain bacteria, known in Holland as "langvey,"
that tend to prevent deterioration of cheese.
These harmless organisms appear to exhaust the
food of Objectionable forms and thus give good
product where without them no cheese at all
could be made.
A lubricant-testing machine just put to work
at Frankfort. Germany, consists essentially Of q
short shaft running in an ordinary bearing. The
shaft is rotated at speed and under pressure
easily regulated. and the oil, half pint having
been poured upon the bearing, has its effective
ness estimated from the time taken by the shaft
to come to rest from standard speed. The
bearing is cleaned by suitable liquid and
blast of air.
Rocks that explode or fly to pieces spontane-
ously have been reported in recent years from
mines in various parts of the world. Quartz
reefs, hornblende schists, trap-dykes and states
have been included among these kicking"
ole
compression are among the suggested causes of
their popularity. In some cases pieces fly from
the rocks on being drilled or scratched with
pick, in other cases the floor or sides of mine
may split into thousands OF fragments, filling
shaft or tunnel with debris. One of the most
remarkable of these rock bursts occurred few
months ago in the New Hillgrove Proprietary
mine, New South Wales and destroyed much of
the mine at q depth of 1000 feet, affecting an
area 800 feet long and 100 feet in height, and
causing a shock like that of an earthquake for
mile or two around. On investigation Mr.. ]. B.
Jaquet, the Inspector, has now concluded that
this outburst was due to state of molecular
strain, from earth movements, the rock break
ing and disintegrating instead of bending like
many states.
A~a
The name "electrograph" is proposed for the
photograph of an electric spark. since light
plays no part in its production. An ordinary
Photographic plate enclosed In two light-proof
paper bags is placed film upward on an insulated
metal plate, and the pointed dischargers of
large induction coil are made to touch the paper
envelope, when a single discharge is brought
about. The spark decomposes the film in its
path. the negative being developed in the usual
way. The two poles show characteristic tree
shaped and fan-shaped discharges, which may
be much varied by shifting the poles, using
knobs instead Of points, dispensing with che
metal plate. etc.
The poison of the Indian cobra has been sup
posed to act Oh the human system by paralyzing
the respiratory centres. A late investigation
has convinced Surgeon-C Captain Elliot that the
main cause Of death from cobra venom is rise