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