plain steel or copper pipes convey the steam to the whirling blades of
the enclosed turbine wheels, but enormous power has been generated and
marvellous speed gained. In the modern turbine a glowing coal fire, kept
intensely hot by an artificial draft, has taken the place of the blazing
sticks; the coils of steel tubes carrying the boiling water surrounded
by flame replace the bronze-figure boiler, and the whirling, tightly
jacketed turbine wheels, that use every ounce of pressure and save all
the steam, to be condensed to water and used over again, have grown out
of the crude machine invented by Branca.

As the engines of the _Arrow_ are but perfected copies of the engine
that drove the _Clermont_, so the power of the _Turbina_ is derived from
steam-motors that work on the same principle as the engine built by
Branca in 1629, and his steam-turbine following the same old, old, ages
old idea of the moss-covered, splashing, tireless water-wheel.




THE LIFE-SAVERS AND THEIR APPARATUS


Forming the outside boundary of Great South Bay, Long Island, a long row
of sand-dunes faces the ocean. In summer groups of laughing bathers
splash in the gentle surf at the foot of the low sand-hills, while the
sun shines benignly over all. The irregular points of vessels' sails
notch the horizon as they are swept along by the gentle summer breezes.
Old Ocean is in a playful mood, and even children sport in his waters.

After the last summer visitor has gone, and the little craft that sail