Evening star., 1939-01-24
Of Stors, Men
And Atoms
Notebook Of Science Progress
In Field, Laboratory
And Study

In Field, Laboratory
And Study
By Thomas r. Henry.
About .O3 of one per cent Of the at
mosphere is the gas carbon dioxide.
Upon this depends all life on earth. It
is absorbed by green plants, combined
with the hydrogen in water through the
energy OF the sun, and thus converted
into the substance of plants, which is
the fuel of organic crestion-7in the form
of sugars and starches for the body en-
gines of animals, in the form Of coal and
oil for the artificial engines man has
created.
But it is not quite so slender thread
as might appear. according to DR.. H. A.
Spoehr, head of the plant biology di-
vision of the Carnegie Institution Of
Washington, in an article prepared for
the memorial volume presented to DR..
John C.. Merriam, the institutions re-
tiring president That .03 of per
cent amounts, he calculates, to approxi-
mately 2,2OO ,OOO, 900 900 tons in the air
alone, and probably Is to IS times as
much is locked up in the sea to be re-
actually so great that all the carbon
dioxide poured into the atmosphere in
the past so years through the burning
of coal and oil has not made any meas
urable difference in the atmospheric con-
centration. he points out.
DR.. Spoehr gives some astronomical
figures on the power essential to keep the
earth-life engine running. Pouring
against the outer atmosphere of the
planet every year is an amount of energy
from the sun calculated at approximately
1,34O 900 600, ,OO0, 900 900 900 calories About
$40, 600 900 900 0O0, ,000,0 900 calories of it
are used up in the evaporation of water,
which is thus transformed into the en-
ergy of rains, of flowing streams and, In
one way or another, into about every con-
ceivable form of natural energy except
that of life itself.
The next greatest use made of the
suns energy-requiring about l62,0OO,-
basic life process of photosynthesis. 1t
is absorbed by the green leaves of plants
and used, by means of the pigment
catalyst chlorophyll, to combine the car
bon dioxide breathed by the plants and
the water taken up by their roots into
the fuel substances for animal life.
The earth, it appears from the calcula-
tions, is not very efficient transformer
of the solar energy it acquires. The en-
ergy of all the flowing water on earth is
calculated at $4,000 900 900 900 calories-
most of which is lost by being in inacces-
sible places and through the inefficiency
Of the devices man has invented for
changing it into still more usable forms.
In fact there are less than 5000 900 ,O00,-
600 900 calories of utilizable water power
and only about 80, 600, 600 900 900 calories
which actually are made use of. This is
just little more than is calculated for
the total work capacity of the human
race-about 10 900 O0O, 900 900 calories. All
this human capacity is retransforma-
ton of the solar energy originally caught
and locked up by photosynthesis.
This is by all odds, DR.. Spoehr points
out, the most important process on earth.
1T is important to bear in mind he
says, that while the total output of
this process is enormous, it is all done by
piece work. Every plant represents an
individual, itself dependent on a COM
plex of envlronmental forces, each leaf
of the plant semi-independent factory
of the system, and within each factory
millions of units in which the process is
actually going on These units are
microscopic organs, the chloroplasts,
usually many in each single cell, so that
an ordinary sunflower leaf contains
about 10000 900 900 of these individual
units in which the photosynthetic proc
ess occurs. The rest of the plant-the
roots the stem and the pores are merely
organs which supply the raw materials
and carry of the manufactured product.
"A characteristic of outstanding i'm
portance is that the chloroplast is liv-
ing organ of apparently extraordinary
sensitivity. The slightest injury results
in cessation Of its functioning. Its
structure, or perhaps the collodial rela-
tionships of its chemical components, is
absolutely essential to its operation. This
is not only true for the photosynthetic
reaction itself, but has been found to
apply to other reactions"
| The exact mechanism of photosyn-
thesis, DR.. Spoehr points out, is still far
from being understood by science, al
though of late considerable progress has
been made along divergent lines. One
field of investigation has been that of
isolating all the chemical constituents
of the chloroplast, other than those of
the green coloring matter, chlorophyll.
This investigation has been hindered
by the fact that all these constitu-
ents are very complex and are likely
to undergo changes in the very process of
extraction. OF only the more obvious Of
them is there fair knowledge Even
the finer aspects of chlorophyll remain to
be worked out and there is little doubt,
DR.. Spoehr Says, that the substance ex-
tracted and studied in the laboratory
differs in some way from that which is
actually present in the plant.