n 1856, page 436, says: "_The power in similar
vessels, I here take for granted, at present varies as the cube of the
velocity._" The power simply represents the coal; in fact, it is the
coal.

Mr. Charles Atherton, the able and distinguished Chief Engineer of Her
Majesty's Royal Dock Yard, at Woolwich, has published a volume, called
"Steamship Capability," a smaller volume on "Marine Engine
Classification," and several elaborate papers for the British
Association, the Society of Arts, London, the Association of Civil
Engineers, and the Artisans' Journal, for the purpose of properly
exposing the high cost of steam freight transport as based on the law
above noticed, and the ruinous expense of running certain classes of
vessels of an inferior dynamic efficiency. When but a few weeks since
in London, I asked the Editor of the "Artisan," if any engineer in
England disputed the laws relative to power, on which Mr. Atherton
based his arguments. He replied that he had never heard of one who
did. I asked Mr. Atherton myself, if in the case of the newest and
most improved steamers, with the best possible models for speed, he
had ever found any defect in the law of, the resistance as the
squares, and the power as the cubes of the velocity. He replied that
he had not; and that he regarded the law as founded in nature, and had
everywhere seen it verified in practice in the many experiments which
it was his duty to conduct with steam vessels in and out of the Royal
Navy. I think, therefore, that with all of these high authorities, the
doctrine will be admitted as a law of power and speed, and
consequently of the consumption of coal and the high cost of running
steamers at mail speeds.

It is not my purpose here to discuss this law, or treat generally or
specially of the theory of steam navigation. It will suffice that I
point out clearly its existence and the prominent methods of its
application only, as these are necessary to the general deduction
which I propose making, that rapid steamships can not support
themselves on their own receipts. The general reader can pass over
these formulae to p. 69, and look at their results.

I. TO FIND THE CONSUMPTION OF FUEL NECESSARY TO INCREASE THE SPEED OF
A STEAMER.

Suppose that a steamer running eight miles per hour consumes forty
tons of coal per day: how much coal will she consume per day at nine
miles per hour? The calculation is as follows:

8^3 : 9^3 :: 40 : required consumpt