The Salt Lake herald. [volume] (Salt Lake City [Utah]) 1870-1909, 1884-05-02
WHERE DID LIFE BEGIN?


one time an intensely hot globe to-
tally destitute of organic life, one OF
the principal and Indispensable con-
ditions Of rendering it habitable for
plants and animals evidently would
be the radiation into space of its ex-
cesslve and d sIuctive heat. The
accomplishment of this, with the
train of concurrent effects which
would follow, or at least ever
have followed the gradual
reduction of temperature, is
all that would be necessary
to render the earth a suit
able place for the maintenance Of
vegetal and animal life. At any
rate this is precisely what has taken
place since the commencement Of
the Azoic age, and is still taking
place on parts of the earth's sur
face to day, visible and obvious to
any observer.
Our inquiry, therefore is reduced
to this question: What part or parts
of this earth surface first became
sufficiently cooled by radiation to be
habitable by plants and animals?
A supposed case may help rs in
reaching a correct answer to this
question. Let US assume, then, that
the earth, at the time it was q
molten mass. had been and was re-
vOlving In an orbit so near the sun
that the amount of heat it would
have been receiving from the sun
would have just equalized the
amount hOf heat 1t was losing by
radiation. Under these conditions
it would have cooled as the sun
cooled-neither faster nor slower.
This helps US to understand that
the heat received by the earth from
the sun is, and ever has been. an
Offset, so far as it goes. to the heat
lost from the earth by radiation. A
statement OF the loss of heat from
the earth during any definite time
may be formulated in this way
From the heat lost by the
earth by radiation during a
given period subtract the
heat received by the earth from
the sun during the same period, and
the remainder viii be the earth's net
or actual loss of heat. Sidereal heat
received by the earth being infinit-
esimal in comparison, is not here
taken into the calculation But,
were it more considerable, 1t would
not be important in this connection,
for it falls upon all parts OF the
earth about equally.
1t is evident, from the present
condition Of the esrth's surface, that
at the time it was molten mass,
and for a long time thereafter, it
heat ietO space much more
rapidly than it received heat from
the sun; but nevertheless the heat
of the sun is, and always hss been,
the loss of heat from the
earth by radiation to the full extent
of the heat which the earth had been
receiving from the sun during the
time.
But this sun heat, this offset to
has not been received by
ali parts of the earth equally. The
belt, or torrid zone, has al
ways received the most per square
foot, or in proportion to its srea.
The two intermediate or temperate
ZONES have received the next largest
amount per Fquare foot, or in proper
ton to their area; while the polar
Or frigii zones have received the
least per square foot, or in proper
ton to their area. II the amount of
sun>hS at received st the equator be
rated at LOCO, then, upon the same
basis, the average Ct sun-heat
the torrid zone seoulC
be rated at 975, the average sun
hest throughout the temperate
zoDes at ISL, and the average sun
beat throughout the frigid zones at
i54, or less than one-half that Of the
orrid and less than two thirds that
# the temperate zones. We speak |
lere, aud shall hereafter; OF the
geographical zones Of the earth for
he sake of convenience.
The greatest Amount Of heat re-
;eived from the sun and eff tting
sdiation from tue earth, other |
hings beipg equal, is Of course, as |
We have seen, at TIE equator, and
ess and less every degree north and
outh of this line TO the poles. If, |
hen, the frigid zones have been |
Turing all this time receiving the
east neat from the sun-the least
,ffset to their own loss of heat by
'sdiation- does it not follow that
hey were the first parts Of the ear b ]
cooled to maintain vege-
al and animal life? The inference
seems inevitable.-G. II Scribner
n Popular Science Monthly for