120 
Drought of 1870 and 
showing the extent to which the barley-plant can avail itself of 
the stores of moisture within the soil, than that which was at 
command relating to wheat. 
Before considering the results themselves, to which reference 
is here made, it will be well to describe briefly the circumstances 
under which they were obtained. With a view to the determi- 
nation of what proportion of the rainfall passes to given depths 
in the subsoil, under different conditions of season, manuring, 
and cropping, a series of experiments has been commenced, for 
the cutting off, and the collection, of the drainage-water from the 
land at different depths — an essential condition being that neither 
soil nor subsoil should be disturbed. Leaving out of view for 
the present the questions of the influence of different manures, or 
of the growth of different crops, early in 1870 three plots of un- 
cropped land, each of one-thousandth of an acre area, were 
selected, with a view of determining the amount of water passing 
below the depths of 20, 40, and 60 inches, respectively. The 
plan of operating was, to cut a sufficiently wide trench for men 
to work in, down one side of the plot, to a considerably greater 
depth than that at which the drainage was to be cut off. The 
plot was then carefully undermined and shored up at the depth 
decided upon, until a cast-iron plate, rather more than the length 
of the plot, 8 inches wide, and having small holes for the water 
to drain through, could be got in and fixed underneath. The 
plot was then further undermined, until another plate could be 
put in ; and so on, until the whole was supported at the proper 
depth, without disturbance, by a perforated iron flooring, which 
finally was itself supported on three sides by brickwork, and on 
the fourth and across the middle by iron girders. The three as 
yet undisturbed sides of the plot were then trenched round ; a 
4^-inch brick and cement wall was built round the plot, resting 
on the projecting rim of the iron flooring below, and finished 
level with the surface above. The trench outside the wall was 
then filled in again. Thus, the exact area required was cut off 
from the surrounding soil by brickwork at the sides, and below, 
at the depth required, by a perforated iron flooring. 
The field in which these drain-r/avges were made, had grown 
wheat in 1<S(j9, and was sown with barley in March, 1870, and 
the drill by mistake was allowed to sow two rows of seed on the 
plots along one side of them. As the excavations proceeded, 
barley-roots were observed to have extended to a depth of between 
4 and 5 feet, and the clayey subsoil appeared to be much more 
disintegrated, and much drier, where the roots had penetrated than 
where they had not. Accordingly, it was decided to make careful 
notes on the sections under the two conditions, and also to take 
samples of soil and subsoil to a depth below that at which roots 
