VOL. XXII.
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INDIANAPOLIS, IND., SATURDAY, SEPT. 3,1887.
NO. 36
THE   WEATHER   FOR   FIFTY   YEARS.
The Influence of Drainage on the Crops.
:r utrtrihution of Prof. I. n. Baker, of the Illinois
Industrial UnivHi-sity to th* DrainSKe anil Farm
Journal.]
The state of the weather has probahly
always been a fruitful source of disctts-
slon, but recently, and as far as the writer
has observed mainly within the past year,
the discussion has taken a new phase. At
present there are a considerable number
who, in private conversation and in the
public press, contend that the wholesale
drainage of the Mississippi valley during
the past few years has materially changed
the climatic conditions of that region, that
the drouth and intense heat of the present
summer are due to this cause, and that if
something is not done to counteract this
effect the prairie country will become a
desert.
The question whether the effects of the
works of man will change the aspect of
that portion of the earth's surface inhabited by him is one of the greatest scientific interest, as well as of the highest practical value. It is universally known that
our earth passed through powerful transformations during its earlier periods, and
it Is possible that, even at present, important changes are taking place on its
surface. Such changes are, however, no
longer on so grand a scale nor so powerful,
anttif now taking place are probably so
gradual as to be scarcely perceptible to the
living generation and * can only lie established by the closest observation of the
facts and by correct reasoning therefrom.
Drainage is only one of the ways,although
in some respects, at least the most important, in which the works of man may possibly affect tke climatic conditions of the
region which he inhabits.
It is asserted that the drainage of swamps
and lakes has decreased the surface of
water exposed toevaporation,that this has
diminished humidity of the atmosphere
and consequently decreased the rainfall.
It is probably true that the drainage of
swamps and lakes has decreased the surface exposed to evaporation, but it will be
interesting to inqu re how much this may
affect the moisture in the air and the rainfall. It is impossible to even estimate the
amount of 'this decrease of the surface of
water exposed to evaporation, but it must
be exceedingly small and insignificant in
comparison with the land immediately
surrounding it, or even in comparison
with the area of the rivers and large lakes
in its vicinity. Let anyone, who thinks
this win have an appreciable effect upon
the rainfall stop and consider two things.
First, that about three-fourths of the
earth's surface is water from which the
evaporation goes on unceasingly. .Second, that the moisture lifted up to the
clouds from the surface of water is continually wafted over the land by the
winds. How utterly insignitlcant. then
must be the effect of a few little ponds,
more or less.
If this argument were true, then a place
upon the ocean or lake shore,or even upon
a large river, should have a much greater
rainfall than places situated inland. To
test it, compare the annual rainfall in
inches as given by the United States
Weather Bureau, at the following places:
Cleveland, O., 30.09 and Columbus, O.,
44.62; or Cincinnati, 45.2*5 and Columbus,
44.U2; or Chicago, 111., 37.57 and Indianapolis, Ind., 47.59; or St. Louis 38.02 and
Springfield, 111., 48.61; or Davenport, la.,
35.96 and Des Moines 42.75; or Chicago 37.57
and Dubuque 39.41, or the mean for Chicago, St. Louis and Cincinnati 40.58 with
the mean for Indianapolis and Springfield, 111., 48.10. The list of places showing
essentially the same thing could be considerably extended. The facts were unexpected and a great surprise to the writer; he attempts no explanation further
thun to suggest that possibly the differ-
e ice between the lake and the inland
cities is due to the fact that rainfall is dependent upon change of temperature as
well as upon moisture, and that a large
body of water diminishes changes of temperature.   As  between the  river and in
land  towns the difference is inexplicable, the annual   rainfall, and for "long grass"
These data illustrate the complexity of the under the same conditions the%excess was
causes producing a change in the weather. 100 per cent. In England "during the time
Even if  the air  were always still, then of ahright hot sun when there haa been rain
the decrease of  moisture in the air due to for a month,tire evaporation from grass was
the drainage of ponds and lakes would be attherateof 0.36 lne_ in 12hrs. These results
very  small as  compared   with   the large arenotvery valuable,buttheymaybetaken
quantity of moisture which is continually as giving a* rough measure of  the amount
given off by the much larger area of  till- of moisture given off by vegetation.  They
able  land.    The  evaporation    from   the certainly   show   how   insignificant is the
surface of  water is very variable;   under effect of a few pounds to increase the  hu.
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certain conditions the water will condense
moisture from the air, while on the other
hand if the water is shallow the evaporation is more than the annual rainfall. As
a general rule the vaporization from a surface of water is taken as equal to the annual rainfall. The only experiments concerning the evaporation from vegetation,
which the writer has been able to find, are
some' made in Europe by engineers in
connection with questions relating to wa-
jTJiui jirx jjijs Qjrj?
tnidity of the atmosphere, in comparison
with the vastly greater area of land with
its vegetation.
As far as crops are concerned, the rainfall is not tlie only source of moisture; as
is well known, tile drainage opens the soil
swamps to be soon lifted into the air by
evaporation and wafted entirely away
by the winds. With underdrained land a
small part of the water reaches the water
courses   rapidly, causing   sudden   rises of
flit. :t.
great hight, but short duration in the
smaller ones, at least, while a very large
proportion is held in the soil to be given
out slowly to the vegetation and the water
courses, and through both channels to the
atmosphere. Thc drainage of a swamp
usually includes the tile drainage of a
much larger area, and hence it is by no
means certain that drainage does not actually increase the amount of moisture in
the atmosphere, and also increase, or at
least make more uniform,the dry weather
How of streams.
In \ iew rrf rlic above is it certain that the
drainage of swamps and lakes has decreased the surface of water exposed to
evaporation? Whether drainage may
Increase or decrease the amount of moisture in the air, it is certain that the effect
is wholly inappreciable.
In this connection, perhaps the accom-
panying diagram, Fig. 1, showing the annual variation in rainfall for the territory
extending from Western Pennsylvania
to Eastern Missouri may be of interest.
The data used in ihe construction of the
diagram was collected and arranged by the
Smithsonian Institute, Washington, D. C,
and published in Vol. 24, of Smithsonian
Contributions to Knowledge, page 224.
The data includes that of 34 places, and
represents in the aggregate 249 years of
observations. The average rainfall over
the territory is 40.88 inches, and the diagram shows the per cent that the rainfall
for each year exceeds or falls short of the
mean. A glance shows the succession of
wet and dry years. It is interesting to
note that from 1832 to 1844 the rainfall was
below the average. About 1837 would have
been a suitable time for some one to dem-
t'-t-
t'i**-. ».
ter supply.   As   the result   of continuous
observations during eight years at I "open
hagen,  (annual   temperature  46°   P.) the
evaporation   from  a   "saturated   plot   of
short  grass" was 37 per  cent in excess of
to the circulation of the atmosphere which
deposits! ita moisture in the pores of the
soil in tlie form of dew. Tile drainage actually increases the amount of moisture
available for crops. This phase of the
subject is too well known to need further
discussion. However there is another
phase that is frequently forgotten. The
tile drainage of land renders it porous to
greater depths than before; consequently
a greater proportion of the rain falling
apon drained land will be absorbed and
lielil iii the soil, than of that falling on un-
drained land. In the latter case a large
part of the water either finds its way into
the water courses and runs entirely off, or
is   impounded    in   shallow    ponds   and
onstrate that the rainfall had been permanently decreased, particularly as 1837
seems to have been a very dry year over
the entire United States, 'similarly from
1S44 to isi'4 the rainfall was above the average. This alone shows how foolish it is
to contend that the precipitation has been
fiermanently decreased because we have
one or two dry years.
The diagram also shows that the average annual rainfall over the entire region
stated may be 15 per cent below the average or the same amount above. If instead
of plotting the averages for the whole region, the values for a single station had
been used, the  variation from   the mean
lonrlttSeS oit page IS.