Southern standard. (McMinnville, Tenn.) 1879-current, 1881-04-23
SCIENCE AND INDUSTRY.

Statistics collected by Prof. G. g.
lockwood show that since March l, 1880,
there have occurred on the American
continent forty-five earthquakes-thirty-
five on the North American continent,
four on the West India Islands, and six
in South America.
"A correspondent of the Michigan
Medical NeaOS cites two instances which
tend to show that door and Windows
screens protect the inmates OF houses
provided with them from malaria. 1t
IS certainly precaution worth trying
by those compelled to live in malarial
districts.
The works for the proposed tunnel
from Dover to Calais have made such
satisfactory progress that its promoters
are now able to employ three shifts of
men constantly throughout the twenty
four hours, and are sanguine of being
able to bore about thirty feet per day
when all the machinery is completed. y
In a paper on dew and fogs, Herr
Dimes says that morning fog along a
river course arises when the water is
warmer than the air over it, the evap-
Grafton going on more quickly than the
vapor can be carried away, and is, there
fore, condensed and spread as o fog.
The evening fog on moist, low-lying
meadow land he attributes to lower
ing of temperature of the grass surface
by radiation, and conseqent condensa-
ton of the acqueous vapor in the lowest
layers of the atmosphere.
The explorations recently made OF
deep-sea bottoms show novel constitu-
ent of such bottoms to be pumice dust,
arising, it is presumed, from submarine
volcanic action; SO general is it, in fact,
that it rarely fails to appear when care
fully looked for in any of the dredgings,
and it is believed to be the chief origin
of the deep.sea clays. An additional
element, which appears to have been
detected at great depths, is "cosmic
dust, or dust formed of aerolites. An
other interesting point in these explora-
tions is the finding of manganese perox-
ide in nodules inclosing organic remains
sharks teeth and pieces of bone.
The works for the Paris Exhibition
of electricity will soon begin. A via
duct will be built for the English elec-
trical railway by Siemens, which will
convey visitors from the Place de la
Concorde to the Palais de l'Industrie.
The internal arrangements will only be
made at the end of the Art Exhibition,
which will take place from May TO July.
The French exhibitors of the electric
light Ihave come to an agreement in or
der to combine for the illumination OF
the nave and other parts. They are
trying to obtain from the High Commis-
sion an idemnity for their working ex-
penses.
Mr.. Shelford Bidwell describes in
Ndturet he result of some experiments
in sending pictures by the telegraph.
This he accomplished by using an ap-
paratus resembling Bakewell's we'll
known copying telegraph. In the trans
mitter the image was focused upon a
revolving cylinder, to which a selenium
cell is attached. At the other end OF
the wire a platinum point presses
against the surface of sensitive paper
prepared by passing it through strong
solution of equal parts of iodide of po-
tassium and water. The arrangement
is such that the selenium cell, by inter-
cepting the current, causes white spot
to appear on the receiver corresponding
in shape and size to the picture focused
) on the transmitting cylinder. The ex-
periments are as yet crude, but full OF
promise.