Sacramento daily record-union. [volume] (Sacramento [Calif.]) 1875-1891, 1882-04-15

Cldtlf III VI SPAA
lowed by very perceptible rise in the
| temperature Of the flower. The organs of
the flower which most rapidly consume
oxygen are the vital ones-stamens and
pistils. Oxygen is also absorbed by ripen-
ing fruit.
THE FUNCTIONS OF FREE OXYGEN GAS
Seem to be that of an assimilating agent
rather than that of building up the plant by
direct combination of inorganic matter to
form the ingredients of the vegetable
structure As has been said before, oxygen
is an agent in the transfer of nutritive
matter from the seed or parent plant to the
young and growing parts. For instance,
young seedlings. flowers, ripening fruit,
ETC., have no power of assimilating matter
from the atmosphere or soil. but are en-
tirely dependent for their sustenance upon
the substances which they derive from the
seed or parent stem. What makes this
view appear more plausible is the fact that
free oxygen, and oxygen combined with
carbon as carbonic acid, is exhaled by the
plant during certain periods, and IN guam
titles corresponding to those absorbed.
This would seem to point to the conclusion
that the free oxygen has performed the re-
quisite functions in the assimilation pro-
cesses, and has been evolved when its
presence was no longer needed. The leaves
and green parts of plants not only absorb
oxygen from the air, but also exhale it
when they are exposed to sunlight. The
fact that they do exhale oxygen can be
proven by completely immersing an in
verified glass funnel containing some fresh
leaves in vessel of water. Remove all
of tie air from the inside of the funnel by
agitating it; after which tightly cork the
stem of the funnel, and pour off enough OF
the water in the vessel so that it will pro-
trude an inch or so above the surface of the
water. If now this vessel be set in the
sunlight small bubbles of gas will soon
form on the surfaces of the leaves under
the funnel These will soon increase in
size, detach themselves from the leaves,
and rise up into the stem of the funnel.
Enough of this gas will accumulate in sew.
eral hours, so that if the cork be removed
and a glowing splinter be quickly inserted
into the stem of the funnel it will immedl-
ately break out into flame, which is a
conclusive test for the presence OF oxygen
gas.
More will be said of the exhalation of
oxygen when we come to consider carbonic
acid, which is the principal source OF the
evolved oxygen.
NITROGEN.
Nitrogen gas is not food for plants, nor
is it assimilated by them from the atmos-
phere This has been demonstrated by
growing plants in a medium which has
been artifcially freed from all traces of
nitrogen and with their foliage surrounded
by confined volume of atmospheric air.
The amount of nitrogen in the seed and
the nitrogen of the air were then the only
sources from which the plant could obtain
any nitrogen. The development of the
plant was allowed to proceed under these
conditions, and at given time it was re-
moved and chemically analysed for the
presence and quantity of nitrogen. 1t was
found that the native plant contained no
more nitrogen than had been extracted
from the seed, in other words, that it did
not extract any nitrogen from the air
These experiments were made near the end
of the 7th century. Since that time, and
comparatively recently, more perfect meth
DDS have been resorted to, and all of which
gave results confirming the conclusion
previously arrived at. Il o. been proven
also that nitrogen gas is not emitted from
living plants.
WATER.
1t is well-known property of water that
it readily vaporizes or evaporates when ex-
posed to the open air, especially in warm
weather. This vapor of water is readily
absorbed by atmospheric air, OF which it
is an invariable ingredient. 1t can easily
be seen that the rapidity of the vaporiza-
ton of water depends both on the tenn
perature and the dryness of the atmos-
phere. If the atmosphere is exceedingly
dry ice and snow will evaporate to a con-
siderable extent, even if the temperature
be as low as 80 freezing point Fahrenheit
Bodies whose temperatures are consider
ably lower than that of the atmosphere
will condense moisture from the atmos-
phere and cause it to form on the surface
of the colder body in the shape of dew.
Almost every one has noticed that in the
warm summer days glass of ice-water
soon has coating of dew formed over its
outer surface. Steam escaping from the
cylinder is invisible for short time after
it leaves the discharge pipe, but in contact
with the much cooler atmosphere it soon
condolences and forms visible steam or dew.
Fogs and clouds are nothing more than
strata of air saturated with vapor of water,
and which has been rendered visible by
being more or less condensed by coming in
contact with cold currents of air. When
the cooling is sufficiently sudden and great,
drops are formed which are too heavy to
be retained in the atmosphere and they are
then precipitated to the earth as rain. We
have seen that water exists in the atmos-
phere in two distinct notifications, vapor
and liquid. The first is lighter than
air, and hence has a constant tendency to
rise but when it condenses somewhat it
becomes heavier than air, and therefore
must descend. By the physical conditions
produced by alternate cold and hot strata
OF air or periods of weather, but mainly by
the constant difference of temperature be.
tween the strata of the air, the atmospheric
moisture is in a constant state of transi-
ton from lower to higher attitudes, and
vice versa. In general we may say that
the air contains about one per cent. OF
moisture, but the quantity is by no means
constant, and ordinarily varies from one.
half to three per cent. Water or it's vapor
is not directly absorbed by the leaves or
green parts of plants, nor does the plant
imbibe, to any considerable extent, the
water which has been deposited on it in
the form of dew. The whiting of plants is
caused by the loss of water by evaporation
faster than it is supplied by the roots. By
immersing the cuts stems of flowers in
water, the water is sucked up into the
stem almost as fast as evaporated, and the
flowers, therefore, retain their freshness
very considerably longer than they other.
wise would. The fact that willing plants
often speedily revive after fall Of dew or
rain is accounted for, not by the assumption
that the plant directly
ABsoRBs SOME OF THE MOISTURE
Presented to it, but because further evapor.
alton is checked for the time being, and
the accumulation of the normal amount of
moisture greatly facilitated Practically
speaking, all of the water of plants is de.
rived directly from the soil by the roots,
and transmitted up through the stem into
the growing parts. That they do not alb
sorb any moisture from the air is proven
by the fact that plant, if suspended in an
atmosphere which is perfectly saturated
with the yapor of water, will not gain any