has
virtually been the means of forcing sail-power to resign its supremacy
to steam.

For checking the rocker in time of heavy weather special appliances
are necessary, which, of course, must be easily operated from the
deck. Wedge-shaped pieces with rails attached may be driven down by
screws upon the sides of the vessel, thus having the effect of
gradually narrowing the amplitude of the rocking motion until a
condition of stability with reference to the hull has been attained.

In the building of steel ships, as well as in the construction of
bridges and other erections demanding much metal-work, great economies
will be introduced by the reduction of the extent to which riveting
will be required when the full advantages of hydraulic pressure are
realised. The plates used in the building of a ship will be
"knocked-up" at one side and split at the other, with the object of
making joints without the need for using rivets to anything like the
extent at present required. In putting the plates thus treated
together to form the hull of a vessel the swollen side of one plate is
inserted between the split portions of another and the latter parts
are then clamped down by heavy hydraulic pressure. This important
principle is already successfully used in the making of rivetless
pipes, and its application to ships and bridges will be only a matter
of a comparatively short time. Through this reform, and the further
use of steel ribs for imparting strength and thus admitting of the
employment of thinner steel plates for the actual shell, the cost of
shipbuilding will be very greatly reduced.

Hoisting and unloading machines will play a notable part in minimising
the expenses of handling goods carried by sea. The grain-elevator
system is only the beginning of a revolution in this department which
will not end until the loading and unloading of ships have become
almost entirely the work of machinery. The principle of the miner's
tool known as the "sand-auger" may prove itself very useful in this
connection. From a heap of tailings the miner can select a sample, by
boring into it with a thin tube, inside of which revolves a shaft
carrying at its end a flat steel rotary scoop. The auger, after
working its way to the bottom of the heap, is raised, and, of course,
it contains a fair sample of the sand at all depths from the top
downwards. On a somewhat similar principle the unloading of ships
laden with grain, ore, coal, and all other