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The first attempt, consciously a rude one, consisted in 
burying common bricks about eight inches deep in the soil 
in autumn, to be taken up from time to time during the 
following season, and the per cent. of water in them deter- 
mined by drying. This method besides being very incon- 
venient, proved entirely unreliable. The bricks were found 
to be incapable of taking up more than half the percentage 
of water that the soil in which they were buried would 
contain. 
Samples of a very porous kind of brick were obtained 
through the courtesy of the International Terra Cotta 
Lumber Co., of Chicago. This material obviated the objec- 
tion noted above, as it was found to contain quite as much 
water to a given bulk, as would the soil. Another objec- 
tion appeared, however. The terra cotta had a stronger 
affinity for water than the soil, in consequence of which it 
would become saturated during rains and would not part 
with its water as rapidly as would the soil. 
Pieces of pine wood were also tested to see if the degree 
of expansion by absorption of moisture would represent the 
water content of the soil, but these appeared to offer the 
same objection as that noted for the terra cotta. 
A method that it was thought must prove reliable was to 
take actual samples of the soil and determine the moisture 
by drying. This proved unsatisfactory for various reasons. 
The soil as a rule is neither homogeneous nor level. It is 
thus unequally wet by rains. The water flows from the 
- ridges and settles in the hollows. The amount of organic 
matter the sample happened to contain would also exercise a 
a marked influence upon its water content. Again, the act 
of taking the sample would necessarily loosen the soil more 
or less at that place and hence cause it to dry out more 
rapidly than elsewhere in dry weather and to retain more 
moisture during rains. This made it impracticable to take 
samples from the same locality from day to day, and hence 
the results secured were not comparable. 
At last a clue was found that appears up to the present 
time to obviate the objections noted. It is well known that 
the rapidity of evaporation from a moist surface exposed to 
air is in proportion to the dryness of the surrounding 
atmosphere, modified by temperature. Does a similar rule 
apply to the soil, 7. ¢., is the rapidity with which the soil 
absorbs water from a moist surface in contact with it, in 
proportion to its degree of dryness? A variety of experi- 
