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Why the roots should have inclined downward more in 
the plat covered with a mixture of sand and soil than when 
the sand or soil was used alone does not appear. 
8rd. Several plants were grown in three inch drain tiles, 
set full length in the earth, with the bottom open, and the 
space within filled with garden soil. Plants of bean, cab- 
bage, corn, egg-plant, tomato and watermelon made a fair 
or good growth, and in every case, the roots were found to 
have penetrated to the bottom of the tile, when a portion 
of them turned upward, growing in this direction until 
within three to six inches of the surface, where they grew 
horizontally in the usual manner. Other roots entered the 
soil beneath the bottom of the tile but did not grow upward. 
It was observed in those that grew upward that they 
branched more and more as they approached the surface. 
Plants of lettuce, pepper and strawberry-tomato (Phy- 
salis), grown in tiles made a poor growth, and on washing 
out the roots, it was found that the roots had not grown 
upward as in the other plants, though in the pepper they 
had started in that direction. 
From these observations it appears that the distribution 
of roots may be influenced to some degree by treatment of 
the soil, but that compelling them to grow deep, asin the 
tiles did not in the majority of cases prevent them from 
rising at last to the more fertile and mellow soil near the 
surface. 
_ It would appear from other observations that the direc- 
tion assumed by roots in the soil is governed as much by 
circumstances as by an inherited tendency to grow in a par- 
ticular manner. This view is strengthened by the fact that 
a plant of barley set in the bottom of a suspended flower 
pot, the stem passing downward through the drainage hole, 
filled the soil in the pot with roots, some of which protruded 
at the upper surface. An examination of the roots showed 
that the growth was apparently exactly similar to that 
formed when the plant is set in the pot in its natural position. 
It was also observed in a plant of potato growing under 
a bell-glass where the moisture exhaled from the leaves 
was all confined, that the rootlets which: started from 
almost every node of the stem as often inclined upward as 
downward. 
Botanists tell us that a certain degree of warmth, mois- 
ture, and oxygen are indispensable to the development of 
roots, and that when these are present, the rapidity of growth 
and the number of the branches are dependent upon the 
amount of available plant food. In that stratum of the soil 
in which the balance of these four conditions is on the whole 
most favorable to root growth, the roots develop fastest, and 
this is doubtless one law that governs their distribution. 
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