, 1877-11-09
Science.

der storms was considered by NJ. Du
Moncel IN paper lately communicated
to the Paris Academy of Sciences.
Trees, he said, were all Conductors of
electricity, their conductivity increasing
with the quantity of liquid they con,
tanned. An ordinary house, however, Of
tered from sixteen to twenty times as
much resistance to the transmission of
electricity as an ordinary tree, and there
fore the tree might be considered pro-
lection to the house if it equalled or ex-
ceeded the house in height. On the
other hand, when house is wet by rain
its electrical conductivity is so much
augmented that the author thought the
protective value of the tree might then
depend solely upon its excess in eleva-
tfon over the housetop. Although trees
may thus shelter houses to some extent
it is very dangerous for individuals to
take refuge under tree in a thunder
shower, as has been repeatedly demon
strated by many of the numerous light
ming accidents this summer.
DR.. Elliott Cones, of the United States
Army, desires medical officers in the
military service, and other persons who
may be interested in zoology, to cooper.
ate with him in preparing a history of
North American animals belonging to
the mammalia. His circular, which is
issued from the surgeon.general's office,
suggest that observers should make out.
lists of the animals found in specified
localities, with particulars as to the num-
Der of each species, when they come and
go, and the places they frequent. Infor-
nation is especially wanted in respect to
many species which are small and OBJ
scure, and observers are asked to direct
their attention to the habits of squirrels,
hares, rats, mice, moles, weasels, gophers
and bats. Almost any intelligent person
who is interested in natural history, and
resides in the country, can add to the
sum of scientific knowledge by aiding in
this work.
Some experiments lately recorded in
France contradict the prevalent opinion
that copper when taken into the system
with food is highly poisonous. These
experiments were made upon dogs, which
could take as much as two drachms of
metallic copper, or its oxides, a day,
without prejudicial effects. "In many
instances" says the report, "the animals
gained in weight. Small doses of the
acetate, such as may be found in food
that has remained for twenty-four hours
in copper vessel that is not enameled,
do not produce any Of those violent effects
in dogs that are usually attributed to
them in the case of man." However, we
do not think too much care can be taken
to keep copper out of food intended for
human consumption.
Mr.. Henry Gilman writesfrom WaldOr
Florida, to the Naturalist, that the beau.
tiful and varied lizards, SO numerous in
that State, have the chang eleon.like ca
pacity of changing color, in, spite Of any
thing that has been said to the contrary.
He asserts that they possess the power in
remarkable degree, and describes a
lizard which was of yellowish- brown
hue when upon the ground, but assumed
the dull gray color of fence rail when
gliding along it, aud changed to an olive,
and then bright emerald green, as it
passed under the foliage of those colors.
When this lizard returned to the ground
its original yellowish-brown was re-
stored.
Some cartridges on table in an apart
ment in Paris were exploded recently by
the concentrated rays of the sun falling
upon them through window glass, in
which peculiar formation, described as
an eye, made burning lens. The Lon
don scientific journal, Nature, says that
similar accidents are commoner than we
suppose. In Algeria, forests are some
times set on fire by the concentration Of
the solar rays through drops of rain-wa-
ter on the leaves; while in Europe, the
beams passing through the panes Of sta
tionary railway carriages occasionally
ignite the dried plants or leaves near the
track.
One hundred and seven photographs
were taken in the Arctic regions by the
recent British expedition, and about fifty
sets of these pictures have been prepared
for distribution to foreign governments
and institutions, so II is quite probable
that some of them will come to this
country. They include views Of the Pal
@ocrystic Sea, and of the cliff of pure
COAL twenty-five feet thick, which was
near the winter quarters OF
one of the ships. This coal is particu-
larly important in relation to Captain
HJwgates proposed colony near the
North Pole.
A staff surgeon Of the British Army,
Dr Josenh i pope, read paper on
before the Domestic Economy
Congress, lately held at Birmingham, in
which he maintained that white clothing
would really be the warmest in winter
having due regard TO the conducting
power and thickness Of the material oi
which IL is made. lie thought that peo-
pie had been led TO wear dark clothes
principally from motives Of ecouomy In
the use Of soap and water.
The fourth comet detected by astrono-
mers this year is that which bears the
IL A nl