be used as a base-line, from which to find, by
measuring offsets, other points near it.

The object of this staking is, to find, in an inexpensive and easy way,
the precise position of the drains, for which it would be otherwise
necessary to grope in the dark, verifying our guesses by digging four-foot
trenches, at random.

If there is a silt-basin, or a junction a short distance below the point
where the water shows itself, this will be the best place to dig. If it is
a silt-basin, we shall probably find that this has filled up with dirt,
and has stopped the flow. In this case it should be cleaned out, and a
point of the drain ten feet below it examined. If this is found to be
clear, a long slender stick may be pushed up as far as the basin and
worked back and forth until the passage is cleared. Then replace the tile
below, and try with the stick to clean the tiles above the basin, so as to
tap the water above the obstruction. If this cannot be done, or if the
drain ten feet below is clogged, it will be necessary to uncover the tiles
in both directions until an opening is found, and to take up and relay the
whole. If the wetting of the ground is sufficient to indicate that there
is much water in the drain, only five or six tiles should be taken up at a
time, cleaned and relaid,--commencing at the lower end,--in order that, when
the water commences to flow, it may not disturb the bottom of the ditch
for the whole distance.

If the point opened is at a junction with the main, examine both the main
and the lateral, to see which is stopped, and proceed with one or the
other, as directed above. In doing this work, care should be taken to send
as little muddy water as possible into the drain below, and to allow the
least possible disturbance of the bottom.

If silt-basins have been placed at those points at which the fall
diminishes, the obstruction will usually be found to occur at the outlets
of these, from a piling up of the silt in front of them, and to extend
only a short distance below and above. It is not necessary to take up the
tiles until they are found to be entirely clean, for, if they are only
one-half or one-third full, they will probably be washed clean by the rush
of water, when that which is accumulated above is tapped. The work should
be done in settled fair weather, and the ditches should remain open until
the effect of the flow has been observed. If the tiles are made thoroughly
clean by the time that