The New York herald., 1921-11-20

in order to determine both the thick
ness of a dust blanket and likewise It's
density, that is. the number OF dust
particles in a given volume Of air.
All this is wholly within the range Of
possibility.
Now it is pretty certain that vol
cano may shoot dust to height of more
than twenty miles Above height
roughly of seven miles there Is practi-
cally no moisture to bring floating dust
to the earth, nor are there winds to dis
tribute and scatter It. In this region.
therefore. IL very fine dust falls at all.
it is brought to the earth by its own
gravity; in all probability some Of 1t
does not fall at all. In any case 1t
falls so very slowly that perhaps a year
or more may be required to bring 1t to
the lower air, where wind and moisture
condensation quickly take care Of 1t and
carry 1t to earth. In the future, there
FORE dust surveys of the air may enable
the forecaster to determine whether the
temperature of coming year will be
above or below an established average.
Not all cold winters are due to dust
blankets Our winter cold waves ride
with northwest winds For the greater
part they are the overflow OF very high
barometric pressure which forms in
northerly regions. Many meteorologists
are inclined to the opinion that the air
descends from high altitude as we'll as
from a high latitude, and the fact that
IL differs slightly in composition from
surface air bears out such an opinion.
Cold waves usually follow winter
storms. and II the number of such
storms exceeds the average the num-
ber Of cold waves will be likely to ex-
ceed the average. A winter below the
average temperature may therefore re-
suit. Now. high barometric pressure
In Arctic regions indicates a very low
temperature in the air covering circum-
polar regions. Humanity has learned
that polar high pressure is followed by
cold weather, not during a cold winter
but in the following spring. The estab
lishment Of radio station in Greenland
will be very great aid In making fore
casts of probable winter conditions one
or two months ahead Of time. But in
casts of winter weather will not reach
a high degree Of accuracy until meteor
ologists have learned a lot more about
the upper air than is known at present.
The belief that our winters are warmer
now than when grandfather was boy
is as firmly ingrained as the doctrine
Of original sin. Here are one or two
facts worth considering:
The winter average for the ten years
beginning in 1922 Is almost precisely
the same as that for the ten years end
ing 1920; the yearly averages are ex-
actly the same. In the last five years
temperature has occurred a greater num-
Der Of times than in the ninety-five
years preceding. Local temperature
averages covering only a century of
time are inconclusive, but an instance Of
broader application Is set forth In the
botanical history of the grapevine, a
matter covering twenty-five centuries.
Theophrastus of Athens lived about
$50 B. c. His regular business was the
teaching OF ethics to Athenian cubs
whose surplus time was not measurable
in drachma. Between times he devoted
himself to scientific research and inter-
SoehA6Ay ho WAOu6hN Avn Va AiiS WOAhS
survive. "rhe History Of Plants" and
1.-THE Causes of Plants" A scholar of
the present day might be Justly proud
Of the record of Theophrastus.
Concerning the geographic distribu-
ton of the Mediterranean grape Theo-
phrastus gives us information In minute
details. The grape was then the most
important fruit crop in Europe so it
is to-day. The wine grape Of southern
Europe is semi-hardy. It will grow In
the milder climate Of southern Europe,
but it does not thrive in the northern
and eastern parts. 1t survives the win
ters Of California. but not those of New
York. 1t was cultivated to It's geo.
graphic limits twenty-five centuries ago !;
1t Is 50 cultivated now. But the limits
Of cultivation are the same to-day as
they were In the time Of Theophrastus
Let us assume. as one climatologist
incautiously puts 1t, that an increment
Of temperature at the rate of one de-
gree a century has actually occurred.
The absurdity of such an assumption
is apparent when one realizes that, ac-
cording to this theory, the climate of
region fertile almost beyond belief
for 1900 years must have been about
that Of the Arctic shores Of Russia in
the time of Theophrastus.
-