On the Rain and Drainage -Waters at Rothamsted. 3 
The drains lie generally about 2 feet below the furrow under 
which they are placed ; the depth is greatest towards the middle 
of the field, where it reaches about 2^ feet. The lower ends of 
the drains were originally connected witb a main drain, 4 inches 
in diameter, lying across the headland at the bottom of the 
field ; by this main drain the water was conveyed to a ditch at a 
considerably lower level. 
Early in December 186G the connection of the drain-pipes 
from Plots 2-16 with the main drain was severed, and small 
pits dug at the previous points of junction. The drain-water 
flowing from the pipes was now discharged into the pits, and 
samples could be collected from the pipes before the water was 
carried off by the main drain. The ends of the pipes from 
Plots 17-19 were not uncovered till November 1878. 
The arrangements just described for collecting the drainage- 
waters were at first by no means perfect. During heavy rains 
a considerable amount of surface-water collected in the inter- 
- mediate furrows* at the bottom of the field, chiefly towards the 
left-hand side ; this was in extreme cases reinforced by a flood 
coming through the hedge from Saw-pit Field. To remove this 
surface-water a furrow was opened across the bottom of the field, 
starting at the hedge-green by Saw-pit Field, crossing the lower 
edge of Plots 19 and 18, and coming out on to the headland at 
the bottom of the field at the furrow separating Plots 2 and 1. 
After some time, the point of exit of this surface-drain was 
altered to the furrow separating Plots 3 and 2, it being thought 
that the drainage from Plot 2, which is always very scanty, 
was affected by the water thus brought over its drain-pipe. In 
the autumn of 1877 a surface-drain was constructed along the 
hedge by Saw-pit Field ; and in the following autumn a large 
soak-pit was dug in Saw-pit Field ; both with the object of 
protecting Broadbalk from flood-water. This object is now 
fairly accomplished. Surface-floods occur at present only from 
the melting of snow, or in storms of very exceptional character. 
Another difficulty at first experienced was due to the small 
outfall provided by the drains. In heavy rains the pits into 
which the drains delivered quickly filled above the level of the 
pipes, and it was necessary to bale out the water in each pit 
before a collection from the pipe was possible. The water 
filling any pit being to some extent a mixture of the drainage- 
waters of all the plots lying to the left of it (the same main 
drain passing through all the pits), there was some danger of 
* In heavy rain surface-water runs down the alternate furrows in considerable 
quantity, it rarely appears in the furrow occupying the centre of each plot, 
owing to the action of the drain-pipe beneath. 
B 2 
