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قراءة كتاب History of Steam on the Erie Canal

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History of Steam on the Erie Canal

History of Steam on the Erie Canal

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دار النشر: Project Gutenberg
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reach of capital and beyond the reach of known resources, and no adequate knowledge had been developed to solve the problem. Therefore, after suffering failures for several years, the State wisely volunteered to add extraordinary inducements by a large appropriation to encourage success. It could not have been to encourage the reproduction of former failures by the repetition of former trials.

The inquiry is therefore proper, as a lesson from the history of the early era of steam, what are the difficulties? Why has steam failed so absolutely and so universally? Why did the State subsequently offer a large bounty to foster and develop steam.

Obviously there is some hidden difficulty, some unknown inability, because steam is the arbiter of the age, it is the great supreme motor of man's agencies throughout the world, hence we come from the sublime to the ridiculous when we use it to load boats at Buffalo, to be towed 350 miles by horses.

The lessons of the early era are worthless for repetition. There is no better screw-propelling machinery known than was then tried and abandoned; but the lessons are of value to discover the difficulties which must be remedied; to teach that the success of steam lies beyond the reach of publicly known mechanical resources.

The trials establish plainly and incontrovertibly that the failures were owing to the want of mechanical adaptation to required duty; to a mechanical inability to utilize the power of the steam; to a mechanical waste of power beyond their ability to control or remedy; and that the wasted power was extravagantly large and the utilized insignificantly small. A very intelligent captain of one of the best and most powerful steamers known to the Erie Canal, who had a full and carefully-kept log, stated that when his engine exceeded a hundred horse-power of steam, he could only equal twelve horses on the tow-path. Thus over seven-eighths of his power was wastefully developed in order to render one-eighth useful. But this occurred when he was moving only two loaded boats—the steamer and one in tow—but when moving four boats—three in tow—the percentage of utility was lessened, and he could not exceed eight to ten per cent. of his steam, as shown in slower movement, when fewer horses on the tow-path could equal him.

The steamer is a reservoir, and its rotatory power is free to be developed "inversely as its resistances." Hence, when fastened to a pier, it is all developed in its receding currents, and per contra when moving; if its machinery had a perfect fulcrum, it would all be developed in the run of the boat; consequently, on rivers and lakes, with fine-lined steamers, that cut the water like a knife, it is like standing in a small boat and pushing from a large one, but on canals, with their full bows, it is like standing in a large boat and pushing from a small one; the little one runs away with the power. The more than 100 square feet area of immersed section of the full bow represents the large boat, and the dozen square feet effective area of propeller blades, set at an easy angle for spiral motion and recession velocity, is the little one that squanders the power so extravagantly. Increase in number of boats increases this contrast. The propeller blades of a good canaller will move twelve to fifteen miles, in their line of spiral movement, to get two to three miles headway for the boat.

A correct scientific analysis can trace the developments of the eighty-five to ninety per cent. of the inherent power of the steam that is wasted on the common canal-boat, and that has no resultant effect whatever in the motion of the boat, just as positively as it can trace the co-developments of fifteen to ten per cent. that is utilized and that moves the boat.

The practical man sees the truths of these statements. He sees steam used with small, medium and large engines for canal purposes, and sees them all fail to meet the economy of transportation established by horses; but he would just as soon put men on the tow-path to compete with horses as to put horses into his elevators to compete with steam; and that, because in the elevators the power of the steam is chiefly utilized, whilst on the canal it is chiefly wasted.

It is therefore conclusive that there is an absolute necessity for a new mechanical system, for a radically different system of transmissive mechanism, for a system that can develop a considerable portion of the power of the steam in the movement of boats.

The variations of the old systems of propulsion that are being continuously tried are worthless, in the very nature of the case, because they are in no sense a remedy for existing inabilities, and because they do not, in any sense whatever, meet the difficulties.

STEAM IN 1871 AND 1872.

Screw Propellers.

Soon after the Act of April, 1871, to foster and develop the inland commerce of the State, the steam canal-boat Cathcart was tried. She is like the Niagara of 1859, and has not been continued in the trade.

The canal-boat George Barnard, afterward called the Andrew H. Dawson, was tried, and has run through the season of 1872. She has a common propeller in her bow, with a recess from the water-line inclined to twenty feet aft to the bottom. Her propeller, therefore, forces the current against this incline and along the bottom in retardation of its progress. Hence, she cannot be expected to excel former trials.

The Eureka is an iron boat, built at Buffalo, with twin-propellers at her bow, set in recesses, at a diverging angle, to throw the water from the bow along the sides of the boat. She is built, by men of canal experience, with compound engines, and was designed to be a superior boat for canal purposes. But her mechanical currents at and against the bow must have a retarding tendency, not compensated by any other considerations.

The George A. Feeter is also a twin-propeller, with diagonal, channel waterways on each side for about twenty-five feet, when they merge into a larger channel about five feet forward of the rudder. Her propellers are set in these channels, about ten feet aft of their side openings. With her propellers thus housed, the mechanical currents against the aft-sides of her channels are very damaging to her efficiency.

The Wm. Baxter is also a twin-propeller, like the P. L. Sternburg, of 1858, and with compound engines, like the Eureka and the Dawson. She is built of yellow pine, with easy lines, and so low as to be unable to carry five-sixths of a horse-cargo of wheat or corn below deck, so that her lightness gives help to cargo, and her sharp bow and stern to speed. But her construction and model were long since abandoned by canal-boat builders.

The Wm. Newman is a common propeller and double-deck boat, and carries two hundred and ten tons. She is much like the Ruggles of 1858, but has less steam capabilities.

The Charles Hemjee was built upon the Western Division, with a tunnel-shaped encasement to her propeller. Of course she is reported as "very slow."

The John Durston had a propeller built in with her rudder, and driven with a vertical shaft, extending down through a cylindrical rudder-post, but was unfit for service.

Paddle Wheels.

The Port Byron is a stern, paddle-wheel boat, with vertical or eccentric acting paddles, and is like the Viele of 1858. She has a recess the entire length of her bottom of several square feet area, intended to facilitate a flow of water from the bow, but the flow does not occur; the mechanical

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