ncreting 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
entirety or in parts, as is done with caissons. In case they are to remain
wholly or in part in the excavation, they are previously galvanized or
painted with an inoxidizable coating in order to protect them and increase
their durability.

The points of the piles, whatever be their form and arrangement, are
strengthened by means of steel pieces, which assure of their penetrating
hard and compact earth.

[Illustration: FIG. 3.--DREDGING WITHIN A SPACE CIRCUMSCRIBED BY IRON PILE
PLANKS.]

Fig. 2 represents a dredge at work within a space entirely circumscribed
by pile planks. Here, after the excavation is finished, beton will be put
down by means of boxes with hinged bottoms, and the water will afterward
be pumped out in order to allow the masonry to be constructed in the open
air. Fig. 3 shows a transverse section of two of these pile planks united
by mortar joints. This system is the invention of Mr. Papenot.--_Revue
Industrielle._

* * * * *

AN ATMOSPHERIC BATTERY.

Great ingenuity is being shown in the arrangement of new forms of primary
batteries. The latest is that devised by M. Jablochkoff, which acts by the
effect of atmospheric moisture upon the metal sodium. A small rod of this
metal is flattened i