perfectly in twenty feet of water. Other boats are fitted with
pneumatic drills, which are operated by means of air, compressed to a
tension of seven hundred and fifty pounds to the square inch. The
pressure of the compressed air is transmitted by means of water to the
drills, which act by percussion, and work very rapidly. These drills
are curiously automatic in their operation. After boring the holes to
the allotted depth, the machine automatically sets in each a tube,
washes out the dust, inserts a dynamite cartridge, withdraws the tube,
and connects the wire of the electric fuse in the cartridge with the
battery wire in the boat. The cartridges are charged with a pound of
dynamite to each. In hard rock only one charge is fired at a time, but
in softer material four are fired at once. If the water over the work
is deep, the boat is not moved from its position, but in shallow water
it is towed a few yards away from the spot where the explosion is to
take place. The drill holes are about six feet deep, and are spaced at
the rate of about one to every three square feet, something, of
course, depending upon the character of the rock. The whole work is
now under contract, the mechanical engineering firm of Luther, of
Brunswick, having undertaken to complete it in five years, for a
payment of less than four million dollars.

* * * * *




THE NEW GERMAN SHIP CANAL.


The gates which admit the water into the new canal which is to connect