There is a rational distinction between the necessary and the unnecessary which we must learn to make, and a limit which safety assigns to every operation. There are some things which must be done rapidly, and others which may be done at leisure. Between the freight cargo, and the correspondence which controls it there is a great difference. Rapid transport of letters, intelligence, and passengers, and leisure transport of freight, is the law of nature, and to attempt to reverse it is but to attempt that which will never be successfully done, simply because wholly unnecessary in any permanent economic sense. And not only is higher speed than that of clippers unnecessary in ordinary freight transport, but it is clearly impossible in any normal condition of trade. Circumstances may, and doubtless often will exist, which will require some sluggish article to be transported a long distance in a short time, as in the case of the famine in Ireland, and which may insure rates at which steam vessels can take small quantities of such freights; but such occasions will ever be accidental, and the support of vessels depending on them the questionable support of expedients, and capricious in the extreme. It will ever be just as impossible to hurry gross freights across the ocean in a healthy state of commerce as it will to prevent rapid mails, or forego the comforts of quick passenger transit. To say nothing of a vessel which is half filled with its own power, attempting to compete, in the ordinary freights of the world, with one which fills every square foot with paying cargo, it is equally important that we should look at the question of fuel. The coals of the world are not so plentiful or so cheap that we should consume whole pits in a year in unnecessary and unproductive service. They are already beginning to fail in many parts of the world, or to the same effect, are mined and brought to market at such increasing cost, and applied to so many new purposes day by day, that in a few years the price will place them entirely beyond the reach of commercial purposes upon the ocean. It is contended, however, that the science of engineering is also rapidly advancing, and that we shall soon have some discovery by which we can have heat without fuel, and power without heat. But I have heard of those imaginary engineering hopes so long that I begin to believe them vague, and that we shall yet for a few generations measure the power applied by the number of pounds of coal consumed. From past experiences and present indications we can predicate nothing with more certainty of fuel than that it will indefinitely increase in price. I am satisfied, therefore, that with all of the capabilities of steam it can never be applied to general ocean transportation; first, because undesirable; and second, because impossible even if desirable. But to show more clearly that it is impossible, I will now make some inquiries concerning the cost of