mmittee of the "British Association for the Advancement of
Science," this year, by Rear-Admiral Moorsom, 750,000 tons of coal.
The difficulty and cost of mining coal, its distance from the
sea-shore, and the multifarious new applications in its use among our
rapidly increasing population, as well as its almost universal and
increasing demand for marine purposes, all conspire to make it more
costly from year to year; while, as a propelling agent, it is already
beyond the reach of commercial ocean steam navigation. Coal has gone
up by a steady march during the last seven years from two and a half
to eight dollars per ton, which may now be regarded as a fair average
price along our Atlantic seaboard. And that we may see more clearly
how essentially the speed and cost of steam marine navigation depend
upon the simple question of fuel alone, to say nothing further of the
impeding causes heretofore mentioned, I will now present a few
inquiries concerning

THE NATURAL LAWS OF RESISTANCE, POWER, AND SPEED,

WITH TABLES OF THE SAME.

The resistance to bodies moving through the water increases as the
square of the velocity; and the power, or coal, necessary to produce
speed varies or increases as the cube of the velocity. This is a law
founded in nature, and verified by facts and universal experience. Its
enunciation is at first startling to those who have not reflected on
the subject, and who as a general thing suppose that, if a vessel will
run 8 miles per hour on a given quantity of coal, she ought to run 16
miles per hour on double that quantity. I think that it may be safely
asserted that in all cases of high speed, and ordinary dynamic or
working efficiency in the ship, the resistance increases more rapidly
than as the squares. The _rationale_ of the law is this: the power
necessary to overcome the resistance of the water at the vessel's bow
and the friction increases as the square; again, the power necessary
to overcome the natural inertia of the vessel and set it in motion,
increases this again as the square of the velocity, and the two
together constitute the aggregate resistance which makes it necessary
that the power for increasing a vessel's speed shall increase as the
cube of the velocity. But whatever the _rationale_, the law itself is
an admitted fact by all theoretical engineers, and is proven in
practice by all steamships. In evidence of this, I will give the
following opinions.

In his treatise on "The Ma