$$ 




7 
the soul upon the soil temperatures. It should include a 
study into the forces expressed in evaporation and most 
particularly those expressed by the term capillarity. Capil- 
lary water, or that amount of saturation which capillarity 
is capable of effecting, seems one of the most beneficial in- 
fluences toward promoting plant growth that we are ac- 
quainted with, while what we may call water in the soil, 
2. €., a saturated condition such as exists below the water 
table, is exceedingly detrimental to vegetable life. In the 
greenhouse, in order to have healthy growth, we are per- 
fectly well aware of this distinction between what we will 
call soil water and capillary water. The earth, which 
becomes soggy, and which holds water in excess over that 
which is retained by capillarity, makes a healthy growth 
nearly impossible for the majority of our plants; while on 
the other hand, keeping the land fully supplied with capil- 
lary moisture is found extremely beneficial, and one of the 
main efforts of the gardener is to get his soil into a con- 
dition of perfect drainage. One of the most beneficial 
actions of tile draining is to prevent the access of this soil 
water, or stagnant water, to the soil above, allowing only 
the water of capiliarity to remain in the cultivated portion. 
A single rain, in our locality, rarely penetrates the soil to 
the depth of the drain tile, the water which appears in the 
drain being either a displacement of the capillary water by 
the water of the rainfall, or else the raising of the water 
level which supplies the drain below. To measure this cap- 
illarity in its relations to the character of the soil and in its 
relation to our power to profitably change the character of 
the soil, is one of the most important problems in agricul- 
ture, and one which seems to have received comparatively 
little attention. 
We have already done some work, scarcely complete 
enough for record, but yet sufficient to indicate the impor- 
tance of this character of investigation, at various times 
during the last few years. The work of our Horticulturist 
has been especially fruitful of clues, as will be seen by his 
report. The majority of our agricultural plants do not form 
root-hairs in any appreciable quantity in clear water, while 
these hairs are oftentimes produced abundantly in a perfect- 
ly saturated atmosphere. The same fact has been observed 
as between saturated soil, and soil kept moist through cap- 
illary attraction. As these root-hairs furnish very largely 
the food resources of the plant, the importance of this ob- 
servation can scarcely be overestimated. 
The color of the soil influences the reception of heat 
during the sunlight and the radiation of it into space during 
the night. Durimg most of the growing season the balance 
seems to be in favor of the absorption of heat, but we 
“4 
