It would be interesting to refer to the embankment of the Bann, or Lough
Island Reavy reservoir, Fig. 8, designed by Mr. Bateman, now nearly fifty
years ago, where a layer of peat was adopted both on the slope, 15 in.
thick, and in front or on the up stream side of the puddle wall, 3 ft.
thick. The object was, that should the puddle become fissured and leaky,
the draught so created would carry with it particles of peat, which would
choke up the cracks and so reduce the leakage that the alluvial matter
would gradually settle over it and close it up. On the same diagram will
be noticed curved lines, which are intended to delineate the way in which
the earthwork of the embankment was made up. The layers were 3 ft. in
thickness, laid in the curved layers as indicated.

It is a moot question whether, in making an earthwork embankment,
dependence, as far as stanchness is concerned, should be placed upon the
puddle wall alone or upon the embankments on either side, and especially
upon the up-stream side in addition. Supposing the former idea prevails,
then it can be of little moment as to how or of what material the bank on
either side is made up--whether of earth or stone--placed in thin layers
or tipped in banks of 3 ft. or 4 ft. high; but the opinion of the
majority of engineers seems to be in favor of making the banks act not
merely as buttresses to the puddle wall, and throwing the whole onus, as
it may be termed, of stanchness upon that, but also sharing the
responsibility and lessening the chances of rupture thereby. But to
insure this, the material must be of the very best description for the
purpose. Stones, if allowed at all--and in the author's opinion they
should not be--should be small, few, and far between. Let those that are
sifted out be thrown into the tail of the down stream slope. They will do
no harm there, but the layers of earth must not approach 3 ft. in
thickness nor 1 ft.--the maximum should be six in., and this applies also
to the puddle. Let the soil be brought on by say one-horse carts, spread