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 ocean steam, which is the cardinal point of interest in marine propulsion.
SECTION IV.
COST OF STEAM: OCEAN MAIL SPEED.
MISAPPREHENSION OF THE HIGH COST OF STEAM MARINE PROPULSION: VIEWS OF THE NON-PROFESSIONAL: HIGH SPEED NECESSARY FOR THE DISTANCES IN OUR COUNTRY: WHAT IS THE COST OF HIGH ADEQUATE MAIL SPEED: FAST STEAMERS REQUIRE STRONGER PARTS IN EVERY THING: GREATER OUTLAY IN PRIME COST: MORE FREQUENT AND COSTLY REPAIRS: MORE WATCHFULNESS AND MEN: MORE COSTLY FUEL, ENGINEERS, FIREMEN, AND COAL-PASSERS: GREAT STRENGTH OF HULL REQUIRED: ALSO IN ENGINES, BOILERS, AND PARTS: WHY THE PRIME COST INCREASES: THEORY OF REPAIRS: FRICTION AND BREAKAGES: BOILERS AND FURNACES BURNING OUT: REPAIRS TWELVE TO EIGHTEEN PER CENT: DEPRECIATION: SEVERAL LINES CITED; USES FOR MORE MEN: EXTRA FUEL, AND LESS FREIGHT-ROOM: BRITISH TRADE AND COAL CONSUMPTION:
THE NATURAL LAWS OF RESISTANCE, POWER, AND SPEED, WITH TABLE: THE RESISTANCE VARIES AS IS THE SQUARE OF THE VELOCITY: THE POWER, OR FUEL, VARIES AS THE CUBE OF THE VELOCITY: THE RATIONALE: AUTHORITIES CITED IN PROOF OF THE LAW: EXAMPLES, AND THE FORMULÆ: COAL-TABLE; NO. I.: QUANTITY OF FUEL FOR DIFFERENT SPEEDS AND DISPLACEMENTS: DEDUCTIONS FROM THE TABLE: RATES AT WHICH INCREASED SPEED INCREASES THE CONSUMPTION OF FUEL: CONSUMPTION FOR VESSELS OF 2,500, 3,000, AND 6,000 TONS DISPLACEMENT: COAL-TABLE; NO. II.: FREIGHT-TABLE; NO. III.: AS SPEED AND POWER INCREASE FREIGHT AND PASSENGER ROOM DECREASE: FREIGHT AND FARE REDUCED: SPEED OF VARIOUS LINES: FREIGHT-COST: COAL AND CARGO; NO. IV.: MR. ATHERTON'S VIEWS OF FREIGHT TRANSPORT.
The foregoing arguments bring us to the conclusion that steam, however desirable, can not be profitably employed in commerce generally as an agent of transport; and that it is best applicable to the rapid conveyance of the mails, passengers, specie, and costly freights only. That this fact may be presented in a clearer light, and that we may see the almost incredibly high cost of rapid steaming, or the attainment of a speed sufficiently high for the carriage of important mails, it will be necessary to make some critical inquiries concerning the working cost of steam power, under any conditions, as applied to marine propulsion. Much misapprehension prevails on this point among nearly all classes of the people, and even among the rulers of the country whose action controls the destiny and uses of this valuable power. It is hardly to be expected, however, that gentlemen engaged actively in the all-engrossing pursuits of business or of public life, with a thousand different sets of ideas to be matured on a thousand different subjects, such as demand the attention of Congress, and the Departments of the Executive Government, should be practically or even theoretically acquainted with a profession which requires years of close application and study, and a wide field of practical, daily observation and experience. It would be as absurd for unprofessional gentlemen of any class, as well from the walks of statesmanship and the Government as from those of quiet private life, to assume an acquaintance with the theory and practice of navigation, and the cost, embarrassments, and difficulties attending steamship enterprise, as it would for any two or three of them to enter an ocean steamer for the first time of their lives, and essay to work the engines and navigate the ship across the seas. The skill and knowledge requisite for such a task would require years of application; and it can not be reasonably supposed that those entirely unacquainted with the theory and parts of an engine, should know much about its capabilities, or the cost attending its use.
But there are approximate conclusions, readily applicable to practice, at which even the unprofessional can arrive with certainty and security on a proper presentation of the prominent facts and theories concerned; and that these may be given to the public in a reliable and intelligible form, for the removal of the doubts and obscurities which have hung around the subject, is the chief object of this publication. This inquiry becomes the more important as the speed of American steamers is proverbially beyond that of any other steam vessels in the world. From the first conception of fluvial and marine steam propulsion by Fitch and Fulton, the public and the inventors themselves regarded the new application of this power with the more favor as it promised to be a means of shortening the long distances between the different parts of our own large country. And the same object has acted as a stimulus ever since to that increase of speed which has placed localities all over this country, hitherto days apart, now, probably, but as many hours. The slow trip through marshes and rivers, over hills and mountains, and by the meandering roads of the country, between New-York and Albany, once required from four to six days; but the attainment of twenty-five miles per hour in our fast river steamers has at length placed that capital within six hours of the Metropolis. And, as in this instance, so has the effort been throughout our whole country, and upon the ocean, until we have attained, both upon the rivers and the high seas, the highest speed yet known, notwithstanding the important fact that steamship building is a new and not fully developed species of enterprise in this country. We have already seen how imperatively the spirit of the age and the genius of our people demand rapid steam mails by both land and sea, and a rapid conveyance of passengers; and it would be unreasonable to suppose that if we required these for the development of our youth, they would be less necessary for the fruitful uses of manhood and maturity. It is abundantly evident that the American people are by nature and habit a progressive and unusually hurrying people; and it is not to be supposed that they will reverse this constitutional law of their nature in their attempts at ocean navigation.
To answer the question, "What is the cost of high, adequate mail speed?" requires something more than an inquiry into the quantity of fuel consumed; although this is the principal element of its cost. We must consider that the attainment and maintenance of high speed depend upon the exertion of a high power; and that,