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country, the other is a necessity of existence in an arid country; and yet as all regions 
other than those developing from the Anglo-Saxon civilization have felt it necessary 
to recognize the diversion of water, it is undoubtedly the case that such will be the 
development in the eastern United States as it has been found to be necessary in the 
western. 
Granting, however, that aperson is satisfied that irrigation is worth his consideration, 
the methods both of obtaining water and of application must vary with the situation of 
the land. The purpose of irrigation is not to be lost sight of as is often done. The main 
purpose is to keep the soil with just the proper degreeof moisture for hest production. 
The physical problem is to accomplish this in the best manner possible, and to make 
a uniform distribution of water over the tract to be irrigated — quickly or copiously 
on a sandy or absorptive soil and for a longer time on a clay soil, and in no case for 
a time long enough to damage the crop. Gentle and frequent rains are the most 
efficient and economical distribution. Irrigators do not find it possible to distribute 
small quantities of water uniformly. Hence, irrigations are not so frequent as is 
desirable and are more copious than would best accomplish the purpose. The large 
quantities, however, are a consequence of the difficulty of making a uniform dis- 
tribution. This can be improved by a more perfect preparation of the surface of the 
ground and becomes a matter of greater consideration in the East, where there is 
greater liability of excess. If the surface is uneven the lower spots receive too much 
water in order that the higher ones get enough. Hence, effort and expense need to 
be given to smoothing the tract for irrigation. The more pains taken this way the 
more satisfactory will be the results. In Italy an expense of several hundred dol- 
lars per acre is incurred for preparing the ground for the Marcite or water meadows. 
The basin method is applicable to grades of 10 feet per mile. The furrow system is 
best applicable to slopes of about 20 feet per mile, but a greater slope may be 
used by running the rows diagonally. It may be used up to slopes of even 200 feet 
per mile. The flooding system may be used on ground on any slope by modifying 
the distance between the ditches and using collection ditches. 
A gravity system, for reasons already given, is practically inapplicable to the 
greater part of the East. It requires long canals and costly enterprises, except in the 
case of streams of rapid fall. As the lands justifying the expense are near market 
centers, the last condition is not present and the former is not applicable. Hence, 
for market gardens the question in many cases reduces itself to pumping. 
C. E. Thorne, of Ohio, read the following paper: 
Methods of Conducting Investigations Relating to Maintenance or Increase 
of Soil Fertility. 
There are two principal lines along which the problem of fertility maintenance 
must be attacked, the one lying through the laboratory, the other through the field. 
While the chemist can not yet meet the popular expectation by prescribing a spe- 
cial fertilizer for a particular soil on the basis of a chemical analysis of that soil, yet 
he has been and will ever continue to be an indispensable helper in our pursuit of 
knowledge concerning this great problem. In addition to the fundamental infor- 
mation which he has given us concerning the composition of soils and plants and 
the sources from which plants derive their sustenance, we must turn to him for help 
in determining whether the chemical constituents of a soil are associated in normal 
ratio to each other, and for knowledge concerning the materials with which we may 
most economically reenforce its stores of plant food. 
In. the earlier days of soil investigation it was assumed that this was to be chiefly or 
altogether a chemical problem, but w T e now know that we must call upon the geologist 
for information concerning the origin of the soil and the probable bearing of that 
origin upon its present composition; upon the soil physicist for advice regarding its 
mechanical texture and the effect of that texture upon the availability of its stores of 
plant food, and upon the bacteriologist for knowledge of the minute organisms 
which inhabit the soil, and whose work, unsuspected until a very recent date, has 
been shown to be a most important factor in the daily sustenance of the growing 
crops. 
But after all these have given us all the help in their power there still remain 
unsolved problems of vital importance, whose solution is only to be found in the 
field itself. 
Our soils lie in broad sheets, varying in geologic origin, in physical texture, and 
in chemical composition; they lie upon subsoils equally variable in formation; they 
are exposed to constant changes of temperature and alternations of moisture, to sun- 
light and its imperfectly known influences, and to the still less understood influences 
of that mysterious force which we call electricity. Not only this, but they are occu- 
