The Donaldsonville chief. [volume] (Donaldsonville, La.) 1871-current, 1882-10-07
sCIENTIFIC MISCELLANY.

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SCIENTIFIC MISCELLANY.
Polished silver absorbs less than three
per cent of the rays of light striking it,
and is the most perfect rejecting metal
known.
It has been estimated that the North
American continent is being reduced in
height ut the rate of foot i'll every
$500 years by the erosiye action Of
water.
The delicacy Of the spectroscope i'll
chemical analysis is remarkable. Swan
found that the sodium lines are visible
when solution is employed containing
less than two-millionth part Of a grain
of sodium.
A London architectural authority at
tributes the great durability Of mortar
in Italy to the fact that the lime re-
mains covered with water in a pit for
two years, whereas in England it is APP
piled at once after shaking.
A new method of utilizing certain
marine plants has been devised in
France, gum being extracted from
them which is found to be valuable in
the arts in various ways, particularly in
the manufacture Of . substitute for
leather.
Many singular creatures are known to
science, but probably none of the lower
animals have more remarkable method
of securing prey than the chactodan, a
beautiful Japanese fish. Seeing a fly
lighted near the surface of the water,
this fish gently approaches and with un-
erring aim projects drop of water at
the unsuspecting insect, knocking it
from its perch, when it is easily secured.
An experiment by Mr.. John Eite], Il
Sacramento chemist, proves that only an
exceedingly small supply of oxygen is
necessary to the life of toad. After be-
ing kept for three or four days under the
receiver of an air-pump from which the
air had been exhausted as nearly as
practicable, one of these reptiles APP
peared to have suffered no injury. A
mouse, put under the same receiver, was
quickly suffocated at the third or fourth
stroke of the pump.
The body l,eat.of birds is greater than
that of any other class of animals, rang.
ing from LOG to liz degrees Fahrenheit
Among the mammala it is from IS tx
los degrees, varying in adult man from
90 to 100. In sleep it is about u degree
and half lower than when awake, and
in fevers it rises several degrees above
the normal temperature. In the young
of all animals the body heat is greater
than in the adult-the difference being 9
few degrees.
Lecturing upon the storage of cleo
tric;ty, Prof. sylvanus Thompson has de
clared the two great recent discoveries
in science to be that the Gramme ma
chine is reversible and that the Voltait
battery is reversible. Tho former ha:
solved the problem Of the electrical
transmission of power, and the other til.
problem Of the electrical storage o
energy. Such storage, however, mus
not be mistaken for the storage Of the
electricity itself.
Mr.. Robert E. c. Stearns has sngges
ted the possibility Of making valuabl.
Investigations into the periodicity o
climates and the direction and effects, Of
prevailing winds by systematic study
of the annual rings of trees. It may bt
found, for exalp ple, that thick aud thil
rings record VI Jet aud dry years, and tina
a greater grow h OIL one side of layer
than on the other may be traced to /:
difference in the amount Of heat striking
the two sides. The record of some tree:
covers long period.
German statistics concerning the vital
ity of children under different method:
of feeding have shown that 1872 per cent
of the infants nnrsed by their mothers
have died the first year; of those nnrsei
by vet nurses, 1888 per cent died; d
those artiticially fed, GO per cent died
and of those reared in institutions, &
per cent died. Further statistical com
parsons show that poverty has smaller
chance for lie than competence. TAX
ing 1000 &ell-to-do persons and loot
poor persons, there were living at the
end of five years 943 of the prosperou.
and only 655 ofthe poor; after fifty year:
557 were left of the prosperous, and onl.
90. of the poor at seventy years Of agt
23o of the prosperous remainca, and bni
Go of the poor. Among the wcll-otf class
che average length of life was found tt
i,e fifty Years. and among the poor only
thisty-two,