[Illustration: FIG. 1.--CONSTRUCTION OF A DOCK WALL BEHIND PAPONOTS IRON
PILE PLANKS.]

The system is applicable to at least three different kinds of work: (1)
The making of excavations with a dredge and afterward concreting without
pumping out the water. (2) The removal of earth or the construction of
masonry under protection from water (Fig. 1). (3) The making of
excavations by dredging and afterward concreting without pumping, mid
then, after the beton has set, pumping out the water in order to continue
the masonry in the open air. This construction of masonry in the open air
has the great advantage of allowing the water to evaporate from the
mortar, and consequently of causing it to dry and effect a quick and
perfect cohesion of the materials employed.

[Illustration: FIG. 2.--TRAVERSE SECTION OF TWO PILES CONNECTED BY MORTAR
JOINTS.]

This system may likewise be employed with advantage for the forming of
stockades in rivers, or for building sea walls. A single row of pile
planks will in many cases suffice for the construction of dock walls in
the river or ocean when the opposite side is to be filled in, or in any
other analogous case (Fig. 1).

The piles are driven by means of the ordinary apparatus in use. Their
heads are covered with a special apparatus to prevent them from being
flattened out under the blows of the pile driver. They may be made in a
single piece or be composed of several sections connected together with
rivets. They are designed according to circumstances, to be left in the
excavation in order to protect the masonry, or to be removed in their