t man calls "too high," or, "too
low." An inch or two of filling maybe beaten sufficiently hard with the
back of the scoop, but if several inches should be required, it should be
well rammed with the top of a pick, or other suitable instrument, as any
subsequent settling would disarrange the fall.

[Illustration: Fig. 31 - SIGHTING BY THE BONING-RODS.]

Fig. 31 - SIGHTING BY THE BONING-RODS.

As the lateral drains are to be laid first, they should be the first
graded, and as they are arranged to discharge into the tops of the mains,
their water will still flow off, although the main ditches are not yet
reduced to their final depth. After the laterals are laid and filled in,
the main should be graded, commencing at the upper end; the tiles being
laid and covered as fast as the bottom is made ready, so that it may not
be disturbed by the water of which the main carries so much more than the
laterals.

*Tile-Laying.*--Gisborne says: "It would be scarcely more absurd to set a
common blacksmith to eye needles than to employ a common laborer to lay
pipes and collars." The work comes under the head of _skilled labor,_ and,
while no very great exercise of judgment is required in its performance,
the little that is required is imperatively necessary, and the details of
the work should be deftly done. The whole previous outlay,--the survey and
staking of the field, the purchase of the tiles, the digging and grading
of the ditches--has been undertaken that we may make the conduit of
earthenware pipes which is now to be laid, and the whole may be rendered
useless by a want of care and completeness in the performance of this
chief operation. This subject, (in connection with that of finishing the
bottoms of the ditches,) is very clearly treated in Mr. Hoskyns' charming
essay,(19) as follows:

"It was urged by Mr. Brunel, as a justification for more attention and
expense in the laying of the rails of the Great Western, than had been
ever thought of upon previously constructed lines, that all the
embankments and cuttings, and earthworks and stations, and law and
parliamentary expenses--in fact, the whole of the outlay encountered in the
formation of a railway, had for its main and ultimate object _a perfectly
smooth and level line of rail_; that to turn stingy at this point, just
when you had arrived at the great ultimatum of the whole proceedings, viz:
the iron wheel-track, was a sort of saving which