Seattle daily post-intelligencer. [volume] (Seattle, W.T. [Wash.]) 1881-1888, 1884-07-16
wngRE DO LIFE BEGIN .

Regarding the earth "a Al one time an
intensely hot globe. totally destitute of
organic life, one of the principal and
Indispensable conditions of rendering
il habitable for plants and animals EVIL
IDENTIFY would be the radiation into
space of its excessive and destructive
heat. The accomplishments of this, with
the train of concurrent effects which
would follow, or, at least, ever have fol-
lowed the gradual reduction of temper
ature. is all that would be necessary to
render the earth q suitable place Tor the
maintenance of vegetable and animal
life. At any rate, this Is precisely what
has taken piece since thu commence
ment of the aZotic age, and is still
taking place on parts Of the earth's
surface today, visible and obvious TO
any observer.
Our inquiry, therefore, is reduced to
this question: What part Of the earth's
surface first became sufficiently cooled
by radiation to DO habitable by plants
and animalsf
A supposed case may help us in reach
ing a correct answer to this question.
Let us assume, then, that the earth, at
the time il was a molten mass, had been
aud was revolving ia IA orbit 50 near
the sun that the amount of heat ii would
have been receiving from the san would
havs Just equaliZed tue amount of heat
il was losing by radiation. Under these
conditions it would have cooled as the
sun eooled-neither faster nor slower.
This helps as to understand that the
heat received by the earth from the sun
is and ever has been an offset. IS far
AZ ID 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 given period subtract
the heat received by the earth from the
sun during the same period, and the
remainder will be the earth's net or
actual loss of heat. Sldereal heat re-
oeived by the earth, being infinitesimal
in comparison, Is not here taken into
calculation. But, were it more con-
siderable. it would not be important
in this connection, for it falls upan all
parts of the earth about equally.
Ii is evident, from the present condi-
ton of the earth's surface, that at the
time IL WAS molten mass, and for long
time thereafter, IL radiated heat into
NhrsCo AnOhp AnRsabf thNA ~ ACoCANNa dfat
from the sun; but nevertheless the heat
of the sun is, and always has been, Off
setting tho loss of heat from the earth by
which the earth has been receiving from
the sun during the time.
But this sun heat, this Offset to radia-
ton, has not been received by all parts
of the earth equally. The equatorial
belt, or torrid zone, has always received
the most per square foot, or IN proper
tion to It's area. The two intermediate
or temperate zones have received the
next largest amount per square foot, or
in proportion 10 their area; while the
polar or frigid zones have received the
least III proportion to their area. II the
amount of SUI heat received at the
equator be rated at 1000, then, upon the
same basis. the average of sun-heat
throughout the torrid zone should be
rated at 975; the average sun-heat
throughout the temperate zones at 757,
aud the average sun-heat throughout
the friRld Ron, s at 454, or less than one
half that of the torrid, and less than
tvo-thirds that Of the temperats zones.
We speak here of the geographical
zones of the earth for the axe OF con-
ysnience.
The greatest amount of heat received
from the sun and offsetting radiation
from the earth, other things being equal.
is of course, as we have seen, AZ the
equator, and less aud less every degree
north and south of this line to the poles.
Ii, then, the frigid zones have been. dur
ING all this time. receiving the least heat
from the sun, the least Offset 20 their
own loss Of heat by radiation, does il
not follow that they were the FIRST parts
Of the earth sufficiently cooled 70 main
tain vegetable and animal life7 The
inference seems inevitable.