St. Landry democrat., 1881-12-10
SCIENTIFIC MISCELLANY.

found valuable in fOgs and snow storms,
when ordinary signals often escape
notice.
Some time ago Pf 81. Forel, expert
menting with the alblmenized paper of
photographers, reached the conclusion
that light cannot penetrate in water Ito
a greater depth than about 1876 feet.
More recently, however, M. Asper has
exposed more sensitive Photographic
plates at depth of 800 feet under
water, and the traces of light were dis
tinctly left on the plates. Light must
therefore pentrate clear water at least
800 feet, while rays so feeble as to es-
cape detection by any means at our
commandment yet so powerful as to
exert an influence upon some forms of
sub-aqueous life-may reach still greater
depths.
The President of the American
Society of Mechanical Engineers, Mr..
X. II. Thurston, points out three fields
Tor invention, in which success must
mean fame and fortune. The first is
some plan for producing electricity,
without loss, directly from burning coal,
with no Intervention of special and
costly apparatus such as is now en-
ployed. The worker in the second field
must find q plan to produce the soft
light Of the freely in such manner as
to be a practical and commercial sue
cess. Recent progress has nearly
solved this problem. The third great
field for invention is the navigation OF
the air.
Prof. Stillman has excavated, at
Gnosso, in Crete, the remains Of what
he supposes to be the historical labyrinth
famous from the story of Theseus and
the Minotaur.
Concerning the moons effect on titles
the Astronomer Royal for Ireland recent
ly stated that, while the day is gradually
lengthening through lunar action on
tides, the earth reacts on the moon
and drives it away farther and farther.
Looking backward, the moon must have
been nearer and nearer the earth, and
at one epoch in the remote ages of the
past-perhaps about 100000 of years
ago-the two bodies must have been
very close together. Then the day was
but three hours long instead of twenty
four. At that distant period, the earth
rotated once every three hours, and
the moon revolved with it in the same
time. So near was the moon that, if
there had been oceans in those days as
now, the tides must have been 216 times
as great as at the present time; and,
rising to an immense height, would
have swept over the whole of England.
Animal life in the Sahara is some I
what peculiar to the region, and,
according to NJ. Vogt, the traveller is .
struck with the absence Of all bright
colors in the animals of the desert. AS {
a rule, their hue approaches that of the .
and the adaptation is most re-
in birds, reptiles, grasshop-
pers, etc. Black and white exist in
some animals-for instance, the male
have nothing to fear .
from enemies; and a single exception e
to the rule occurs among insects-the t
Coleoptera are nearly all black. To 8
explain the existence in safety Of these 4
insects whose color must make them Il
conspicuous, M. Vogt states that they e
Feign death on approach of danger and i
IN that state closely resemble the ex- d
of gazelles, goats and sheep. q
This deception, with their disagreeable q
odor, gives them sufficient protection. d
The general color Of the ground in the pl
iesert is, of course, that of sand. b
The number of varieties of insects c.
vastly greater than that of all other " =.
living creatures. The oak supports $50 I'll
pecies OF insects, and 200 are found in hi
he pine. Humboldt, in 1849, calcula- pa
ed that between 10000 and 10000
pecies were preserved in collections, !.
ut recent estimates place the present he
lumber at about 100000 species. bl
1t is a very general belief that great di
arial places exert noxious influence, 3;
hich must render the localities very m
nhealthy as places of residence. This an
ea is shown to be mistaken one by an
e results Of an inquiry into the sani- h ha
ny condition Of the cemeteries of Paris. Bi
he composition Of the air in the ceme- TIN
ries is reported to be indistinguishable Ia
ON that of arabic lands. H
AT the Crystal Palace, London, al Pc