Juniata sentinel and Republican. [volume] (Mifflintown, Juniata County, Pa.) 1873-1955, 1876-01-12
SCIENTIFIC.

RELATION OF neat 10 SekttdtlOns cSpocl-
ally rs to the dynamic influence of
heat ON the growth of plants. He says
that we will elucidate this matter
slowly. in proportion rs physics and
chemistry make progress in the reve-
lation of the nature Of bodies and
forces. Heat has an influence upon
the growth of plants. on the circulation
of the sap. elaboration of the cells. the
respiration, and many otherphenOmena-
The relation of heatto the development
of plants, and particularly the periodic
phases of vegetation, are phenomena
known through the epoch at which they
manifest themselves, the mean dates
OF these manifestations. and the ave-
rage deviation therefrom. After Civ
ing an abstract of the results OF the
labOrs or Schubeler. Hoffman, Fritsch.
Linnsser and Kabsch. Prof. MOrren
states that a problem of high impOr-
tance, and one which has been, per-
haps, too much neglected. is that Of the
relation between heat and the weight
acquired by the plan under the action
of the solar rays. and especially Its re-
lations TO the quantity of carbon fixed
In the organic matter, as Tar as We can
at present estimate that. In temper
ate climate hectare of forest and pral-
rie, or cultivated land, fixes in one year
from 800 to 5000 Kilograms of carbon;
and in order to accomplish this work,
vegetable organisms utilize between
one and four thOusandths of the heat
which has been received by solar radi-
alton upon the surface that they oc-
cupied. 1t is evident that such phe-
nomena as take place periodically,
namely, termination. leating, ETC., are
acts of growth such growth supposes
movement: the fact of the movement
necessitates consumption OF force,
which consumption is but transfor-
nation of heat. If, to fix our ideas, We
suppose an apple TO fall from tree.
we have but to reflect upon the laws
of force in order to see that the apple
must have been previously carried up
into the tree, for it evidently has not
raised itself there. 1t is the power OF
the heat proceeding from the sun which
has effected the development and
growth of the tree. Ii is. therefore.
practicable to determine the mechanical
coefficient of growth. as SAMSON has
determined the mechanical cOefficient
of nourishment for foods. 1t Is the
property of vegetable organisms to u
tilize the heat received by them from
any source, for the conversion OF crude
material into such forms as are needed
by them for their own growth. In this
process, however, force is neither crea-
ted nor lost. although much of it is se-
creted within the body of the plant or
mineral. Other things being equal. the
quantity of carbon fixed in any plant
varies with the average elevation OF
the height of its center OF gravity.
Atmosphere Of Planetary Bodies
Telescope observations appear to leave
no reasonable doubt that the planets.
besides our own, have an encIrcling
atmosphere indeed, the atmOspheres
around the planets are thus made as
palpable to sight as the clouds which
float on our own. Venus and Mercury
are enveloped in thick atmOspheres !;
in the former, the phenomenon Is es-
pecially conspicuous, SO that the morn
ing and evening twilight may almost
be seen in that distant world. The at
mosphere. also of Mars is in like man
ner made apparent, the clouds seen
floating on itallowiDgofno uncertainty
as TO the fact.
Bus the ascertained existence of
clouds in the planets proves more than
the mere presence of atmosphere upon
them. An atmosphere is necessary to
support clouds, but it is not to be in
Identified with them. Water, as is well
known, is converted into vapor by the
agency of the sun and wind. This va
pOr, when it escapes from the surface
of the liquid, is generally lighter, bulk
for bulk, than that portion of the at
mOsphere contiguOustO tit rises into
more elevated regions, where, by the
agency of cold and by electricity, it is
made to resume its liquid state, but in
such minute particles that it floats and
forms those seml-Opaque masses called
clouds. Great difficulties. however,
obstruct inquiries of this nature, with
respect to most of the planets; and
the very presence of those atmospheres
and the clouds with which they are
loaded. offers a serious impediment to
ascertaining the character of their sur
face.
Hudrogeni-ed IrOn.-M. Cailletet, in
a paper presented to the French Acad-
emy, contributed the following inter-
esubg points TO the. literature of this
somewhat obscure subject. If sOlu-
tion composed of mixture of the
chlorides of iron and ammonium is de-
.
be found at the negative pole an ac
|cumulation of metallic iron in masses
of brilliant luster, great brittleness,
and hardness. From this iron after
being washed, either under water or
any other liquid, bubbles up a gas
which is pure hydrogen. In the air
the iron only loses part of the hydro
gen which il contains. A specimen
weighing 90 grm., kept for Is days in
an open tube, gave when heated Is &C.
of gas or more than half of what it
contained atthe moment of preparation.
A fragment of iron placed under test
tube filled with water heated to 60 deg.
or 20 deg. CO. causes tumultuous
disengagement of gas. one volume
of iron contains on an average 2i0 vol
umes of gas. III piece of hydrogen
lzed iron is approached TO burning
body. the disengaged hydrogen burns,
and the metal Is surrounded with a
light flame. If a piece of this galvanic
iron, previously heated, is employed as
the negative pole of a voltameter, the
hydrogen of the decomposed water es
capes in abundance from the surface
of the metal, but none of il appears to
be occluded. Galvanic iron may read
lily be powdered, but after heating il
acquires a certain degree of ductility.
A Gas !ShddoW.-A striking and Gu
rious experiment, showing the supe-
rior weight of carbonic acid gas over
air. may be made by projecting the
shadow of the gas, as il is poured from
its containing vessel, upon a screen.
The latter should be of white paper
and bright sunlight should fall on the
stream of gas. which should be poured
from the spout of pitcher held within
10 inches of the screen. The curious
result, of a shadow produced by appar-
emily nothing, Will be seen. the former
resembling descending smoke, quite
black at the spout of the vessel, but
brightly illuminated whenever the sun
light isconcentratedb by passing through
the gas. -
To Prerent Cine from Crdcking.-
Glue frequently cracks because of the
dryness of the air In rooms warmed by
stoves. An Austrian contemporary
recommends the addition of little
chloride of calcium to glue to prevent
this disagreeable property of cracking.
Chloride of calcium is such dehques-