Frostburg mining journal. [volume] (Frostburg, Md.) 1871-1913, 1886-01-09
POPULAR SCIENCE.

Traces of prehistoric race have been
discovered in Jamaica by Mr.. r. G.
Halliburton. From the skulls obtained
he judges that they We're people of great
natural intelligence, an he hnds reason
for believing that their habits were
peaceful and Industrious. .
] A new use is found for electricity. In
Russia, now, they bleach cotton by
means of it. Cotton manufacturers near
ST. Petersburg steep their material in
water, which is then decomposed by
electric currents. The oxygen, set free
in this way, at once acts on the fbres.
Careful experiment has disclosed the
fact that single square foot of leaf
surface jim the case of soft. thin ,leafed
plants will, during fair weather, exhale
aqueous vapor at the rate of one and
quarter ounces daily. At night the
rate is only about one-ffth as rapid as
during the day, and during rainy weather
there is absolutely no evaporation.
| The great Mexican volcano Popocat
epetl has Just been remeasured and
found to be II, 500 feet above the sea-
, The crater, which is completely OBJ
scured within by sulphurous vapor, is
about two and one.half miles in circuit
and 1000 feet deep. The entire center
of the top of the mountain seems to be
solid sulphur, which is deposited at the
rate of q ton day.
A new French experiment consists in
placing two similar black paper figures
two crosses. for eXamplc-quite closely
! together, Mt about three inches from the
eyes. When so held before sheet Of
! white paper. three separate crosses will
/ be seen. The phenomenon, illustrating
the principle of the stereoscopc. is ex-
planned by the simultaneous vision of
the two eyes. If figures of complement
airy co!ors, as red and green. are used
upon dark background, white figure
will appear in the middle.
While it is positively known that
plants require carbon, hydrogen, oxygen
and nitrogen as constituents of their
food, there are several other elements
! found in plants whose essential character
is not so certainly established. Some
recent experiments, according to Mr.. +.
| Jameson, an English chem st, furnish
proof that sulphur is not an essential.
that even lime and magnesia are of
doubtful necessity, but that phosphorus
and potassium are indispen sable. Iron
and chlorine occur in plants, but have
little Calm to be regar led rs essentials.
| Remarking upon the apparent phenom-
enon of the unusual large size OF the sun
and moon, in rising or setting, Stroo.
| bant points ont the common error that
intervening objects enable an observer
| to better estimate the rea! size of the
heavenly bodies, in that the same effect
is visible at sea and indicates the fal!acy
of several other theories There are, he
asserts, two real causes of the phenom-
enon in question, both purely physio-
logical one, the greater sensisiveness of
the eye to angular magnitudcs near the
horizon; the other, direct effect of tho
feeber light in the enlargement OF the
pupil. which, it would seem, tends to
magnify objects, even when artiticialy
, produced. Thus it is shown BY expert
ments that the distance between two
luminous points within room suffers
the same appa"e change as in the con-
stellations. when. without altering the
distance from the eye, the altitude is
| gradually increased.