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steamship Princeton, and two revenue

cutters.

Among the steps contemplated in the advancement of ocean steam navigation in Europe, that which has attracted most public notice, is the iron steamship built by the Great Western Steamship Company. This vessel and its machinery are said to have been planned and constructed under the superintendence of J. K. Brunel, the engineer of that company, and of the railway connecting London with Bristol. This stupendous structure is remarkable as being not only the largest ship ever constructed of iron, but the largest of any kind that ever floated on water. She is three hundred and twenty-one feet in length, fifty-one feet six inches in width, and thirty-one feet six inches in depth; she measures three thousand six hundred tons.

One of the difficulties which have presented themselves in the adaptation of the endless screw to the propulsion of steamships is, that the velocity necessary to be given to the screw is in every case much greater than the speed with which the engines can be worked. Several expedients were proposed to surmount this. Some suggested the use of engines similar to locomotives; others proposed to convey the power of the engines to the screw by toothed gearing, by which the velocity might be increased in any desired proportion; while others again proposed that the engines should act upon a drum or cylinder of greater diameter than the shaft of the screw, and that this drum and the shaft should be connected by an endless band or chain. In this way the velocity would be increased in the ratio of the diameter of the shaft to the diameter of the drum. The last is the expedient adopted in the present case. The drum and shaft (constructed like a rag-wheel) are connected by an endless chain. The drum is placed on the main shaft driven by the engines, and this shaft carries upon it two cranks, each of which is driven by

two cylinders. These cylinders are placed two at each side of the vessel, in an inclined position, leaning towards the centre of the vessel. The piston rods, moving in guides, are connected with the cranks by long links or connecting rods. Each of the cylinders eighty inch diameter and six feet stroke, and they are supplied with steam by eight boilers. This machinery is said to have the nominal power of twelve hundred horses.

The machinery and other appointments of this leviathan of the deep being long since completed, and all being ready for sea, it will naturally be asked why she is not afloat?-why this grand project is not in practical operation?why this stupendous production of art and science stands immovable in the dock in which the builder put her together? Will it be credited that those in whom this company put their trust for guidance in this novel experiment, have actually either miscalculated or omitted to calculate at all, the space requisite for the vessel to move through in passing from the dock! And that she now lies encaged, crying, like Sterne's Starling, "I cannot get out!" Bent on astonishing the Yankees, and filling the human race with amazement at such a monster-ship as eyes never before beheld, the aspiring engineer was either unable or unwilling to calculate the conditions necessary to liberate the megatherion! To do this it would have been necessary to compute certain matters of a very sublunary kind, such as the immersion, the width and height of the works, and to take into account the dimensions of the dock. Such calculations, it is true, were not as likely to startle as the exhibition of a ship the sixteenth of a mile long, nor were they as likely to draw upon the engineer the wondering eyes of mankind; but, humble as they were, they were indispensable, and they were neglected or wrongly executed.

It was not until all the arrangements for the first voyage were made, and the day and hour advertised at both sides of

Not, as is sometimes erroneously supposed, the inventor of the block machinery and engineer of the Thames Tunnel, but a son of that distinguished man.

There are now (August, 1844) two steamboats on the Hudson of greater length, though less in their other dimensions. The "Empire" measures 330 feet, and the "Knickerbocker" 324 feet in length. These are truly magnificent vessels in every point of view, and we may possibly on a future occasion scize an opportunity of giving some information to our "neighbors" on the other side of the Atlantic respecting their performances, which will open their eyes to what has been already and may be hereafter accomplished by American engineering.

the Atlantic, not for the first voyage only, but for the second, and the third, and the fourth, that it was discovered that the dock obstinately refused to open itself wide enough to eject the monstership, and that the rigid material of the vessel just as pertinaciously resisted the contraction necessary to escape. In vain was expedient after expedient suggested. It was easier to astonish the world by producing an enormous vessel, than to get it practically afloat when built.

We cannot refrain from expressing our admiration of the forbearance and good-natured indulgence with which this piece of unparalleled professional ignorance or culpable negligence has been treated by the engineering profession and by the press in this country. Reverse the case, and suppose that instead of occurring at Bristol, it happened at New York; instead of being committed by a British, it had been chargeable upon an American engineer,-how endless, how unmitigated would have been the ridicule, what sneers against American engineering, and what self-complacent references to the British steam navy would have followed. But seriously, it is too bad to see capital and property ignorantly and rashly trifled with after this fashion. At the time we write this we learn that no expedient has yet been suggested to surmount this difficulty, except one which would cost the company the sum of fifteen thousand pounds sterling to carry into effect!

On the question of the ultimate success of this experiment, opinion, as necessarily must occur in such a case, is somewhat divided. Her extraordinary magnitude is in some respects a disadvantage. A traffic in passengers is always inore successful with frequent trips and smaller loads than with long intervals requiring accumulated supplies. The convenience of the public is obviously better consulted by the former species of arrangement. Besides, in this case opportunities will be offered, twice a month, of sailing by the Cunard line. Will the large accumulation of cabinpassengers which is indispensable to make this huge vessel pay, wait for her? Again; nautical men express grave doubts whether, (supposing her to succeed in a commercial sense,) she will stand the Atlantic. They contend that she will strain herself until her joints will be loosened ;-that her length is at the same time too great, and not great

enough for the swell of the ocean;—that she may stretch over the trough of the sea and balance herself on the crest of the wave, but that the weight of her centre in the one case and of her extremities in the other, will produce a destructive strain upon her;—that, in short, without being large enough to convert the waves of the ocean into a ripple, she is too large to glide along their acclivities like a sea-fowl. It is a question, however, on which it is vain to theorize, either in a commercial, nautical, or mechanical sense. Experience alone, and that not of one but many voyages, can give us data on which we can safely reason. Meanwhile we are glad to see so grand an experiment tried, and equally glad that we have ourselves no capital invested in it.

The United States steamship Princeton is an experiment in some respects similar to that to which we have just adverted, but presenting to the world a much more promising result, and indicating in its progress and details the presiding influence of a master hand. This splendid ship is, like the former, supplied with a subaqueous propeller. A wheel, fourteen feet in diameter, is placed on an axis projecting in a horizontal direction from the stern of the vessel parallel to the line of the keel. The face of the wheel is therefore presented sternwards, and is vertical when the ship floats in calm water. The thickness of the wheel or the space included between its face and under surface, is forty-two inches. The material is a metallic composition which resists oxidation. With a motion of continued rotation this propeller, by a series of spiral plates or vanes attached to the circumference of a hoop twenty-six inches broad and eight feet diameter, supported on the shaft by a number of twisted arms, acts upon the water so as to drive it sternwards, on a principle nearly similar to that by which the sails of a wind-mill are affected by the atmosphere, only that in the latter case the air is the agent and the sails the object acted on; whereas in this case the propeller is the agent and the fluid the object acted on. Suppose the atmosphere quiescent, and the arms of the wind-mill made to revolve by a steam-engine within the building. A current of air would then be produced by the action of the sails contrary in direction to that current which would have imparted to those sails the motion which

they are here supposed to receive from an internal power. Imagine, then, the fluid acted on to be water instead of air, and the revolving sails to be augmented in number, diminished in length, and increased in speed, and we have an apt illustration of the principle of this propeller. The engines which give rotation to the shaft of the propeller consist of two semi-cylinders placed with their axes horizontal and parallel to the shaft, and their convex surfaces downward. On the axis of the semi-cylinder is placed a solid parallelogram equal in length to the cylinder, and in breadth to its radius. This parallelogram being suspended on the axis of the semi-cylinder, would hang in the vertical position when not acted on by the steam, and being movable in each direction, is capable of being raised on either side to the height of the flat top of the semi-cylinder. Thus this parallelogram is susceptible of a pendulous motion from side to side, through an angle of 90 degrees. It is this parallelogram which discharges the functions of the piston. Steam is admitted and discharged by proper valves on each side of it, and it is thus driven from side to side alternately with a corresponding force. The discharged steam passes to a condenser, where in the usual way it is converted into water, and the piston is suddenly relieved from its reaction.

These semi-cylinders are placed symmetrically on each side of the shaft, parallel to the keel, and in the bottom of the vessel. The action of the vibrating pistons is transmitted to the shaft of the propeller by short connecting rods attached to vibrating crank levers on the axis of the vibrating pistons, so as to convert the reciprocating pendulous motion into one of continuous rotation. This mechanical arrangement, which we could not hope to render intelligible without a model, presents a singularly happy combination of elegance and simplicity.

In the Princeton, the entire machinery as well as the propeller is below the water-line; the draught of the furnaces being produced by small separate engines acting the part of blowers, a funnel is not needed. A short one with the telescope tube motion is used in the present case, which may be raised or lowered at pleasure. The fuel used is hard

coal of the species commonly called anthracite, which having an inconsiderable proportion of bitumen, is consumed without flame or smoke.

The inventor claims that these engines occupy only one eighth of the tonnage necessary for British marine engines of the common kind, of equal power, and are only half the weight.

The design of this fine vessel and its machinery was complete before a single plank of it was laid, and that design has been carried into effect without a single deviation-a striking proof of the clearness of the views, and the consistency of the objects of the inventor. No blunder was made in her construction. She was completed and put afloat, and is now and has been for many months in successful practical operation.

The propeller and the other machinery of this vessel are the invention of Captain Ericcson, and have been constructed altogether under his direction, and according to his drawings-copies of which are now before us. The propeller is not an untried expedient, now for the first time essaying its wings. It was first promulged by Captain Ericcson, in England, before his visit to this continent. He constructed, in England, two experimental boats of about twenty horse power each, besides the iron steamer Robert F. Stockton, which crossed the Atlantic in the year 1839, and has ever since been continually in operation, as a steam-tug, on the Delaware and Schuylkill. It has also been three years in practical operation, in a considerable number of vessels of various tonnage, carrying freight and passengers, on the lakes, the principal rivers, and along the coast in the United States and British provinces. The number of vessels now in operation, driven by Ericcson's propeller, at this side of the Atlantic, is above seventy. It is the more necessary to state this distinctly, as a general impression prevails that the Princeton is the first and only vessel so propelled, and therefore to be regarded as an experiment on a new principle, rather than the adoption of one on which experience so extensive has been obtained.

It will be naturally asked why advantages so great and obvious as those obtained by this invention, may not be equally secured by the screw-propeller

*It has often been proposed to adopt expedients for raising and lowering the funnels of war steamers; but this is, we believe, the only instance of the principle having been brought successfully into practical application.

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adopted in the Great Britain. We answer, that Captain Ericcson has succeeded in imparting to the shaft of the propeller the power of the piston by a simple connecting rod, without the intervention of any mechanism by which the smallest portion of that power can be lost or intercepted; that he has thus obtained all the requisite velocity without resorting to any of the usual expedients for multiplying the revolutions. Whereas, on the other hand, the screw requiring a velocity from four to six times that of the engine, the interposition of cogwheels, leather straps, rope bands, or chains, becomes unavoidable.

In the Great Britain, the engineer, with a curious infelicity of instinct, has out of all this catalogue of objectionable expedients, selected that which is transcendently the most objectionable, namely, an endless chain working round a drum of twenty-four feet diameter, attached to the main shaft of the engines. The surface of this drum is cut into cavities or notches corresponding with the links of the chain. The smaller wheel, or pinion, driven by the chain, is fixed on the shaft of the propelling screw, and is what is called a rag-wheel, having a surface similar to that of the drum, being about one-fourth of the diameter of the latter. Let any practical mechanic imagine for a moment a chain of this kind moving at the rate of twenty-five feet per second!--and conveying the power of twelve hundred horses!! The bare mention of this, without going into the multifarious consequences which it will readily suggest to the mind, will, we conceive, be enough to demonstrate the extravagance of this monstrous project.

The superior claims of Ericcson's propeller have at length forced their way to the notice of the governments of England and France, which are not easily moved to venture on novel or untried projects. In these countries two frigates are now in preparation, in which these propellers will be used.

On the 20th of last October, when the Great Western was starting from New York for Liverpool, the Princeton was stationed in the North River, and a trial of speed took place between these two ships. It is stated, that in leaving the Battery the Great Western was about a quarter of a mile ahead, but was soon overtaken by the Princeton, which passed her, sailed round her, and passed her a second time before leaving the bay. The

G.Western had all her sails set on this oc-
casion. The Princeton put up no canvass.

Independently of the superiority claim-
ed for her machinery, the Princeton has
obvious advantages over all steamers
propelled by the common paddle-wheels.
She may be rigged and worked as a
sailing vessel as effectually as if she were
not propelled by steam at all. No mat-
ter what position she may take in the
water; no matter how she may pitch or
roll, her wheel will exercise the same
propelling power.

As a vessel of war, she has great advantages. All her machinery being under the water line, is protected from shot. She exposes no chimney to an attacking force. She can sail with a fleet without consuming her fuel, and can therefore preserve all her powers as a steamer in the longest voyage.

The prospectus of a project for another direct line of steamers has been recently offered to the public. It is proposed to form a company with the title of the "American Atlantic Steam Navigation Company," to be under the directorship of a body of our most respectable merchants. It appears that a charter was granted to this company about five years ago, since which time it has been, wisely as we conceive, dormant, watching, doubtless, the progress and collecting the results of the experience so dearly paid for by the English companies. The directors now think that the period has at length arrived when they may advantageously take the field. "The experience," they say, "we have had in Atlantic steam navigation,-the more economical construction of steamships,the skill acquired in navigation and general management, have furnished practical data for our guidance, and developed the subject so fully, that we have only to adopt what is useful and reject what is not, to insure success."

It is proposed that the company shall commence operations by the construction of a steamship of two thousand tons, having accommodation for seventyfive cabin-passengers and eight hundred tons of measurement goods. The projectors expect that whether she gets passengers or not, she cannot fail to make a freight.

It is proposed that subscribers shall be allowed five per cent. discount on their freight bills. The subscribers may therefore, if they desire, monopolize the use of the ship for their own business.

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"All the support the company deem it necessary or expedient to ask of the general government is the privilege of receiving postage upon letters carried by their ships." This, we presume, is a privilege which they need not ask. It is a right that they may assume.

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"The grand effects of carrying into execution the designs of the company,' they observe," are too obvious to need any comment. If it be important to retain in the hands of American citizens their own European carrying trade; if the prosperity and extension of commerce depend in any degree upon the facilities of carrying it on; if the advancement of this great city to opulence and commercial rank are dear to every American citizen; then he will with alacrity seize any and every opportunity to realize such vast and permanent results."

On these abstract propositions no difference of opinion can exist. If they can be attained without loss to the individuals who devote their talents, labor, and capital to carry them out, they ought to be, and without doubt will be, encouraged and supported. But the only practical view which can be taken of this enterprise must exclude mere patriotic considerations. It must after all be regarded, as it really is, a commercial speculation, in which men will engage with a view to profit; and it is only by the fair expectation of profit which it may hold out, that it can be tested.

It is stated in the prospectus that the cost of the British Queen was ninety thousand pounds, and that of her machinery twenty-four thousand pounds. Whether the latter sum is included in the former is not distinctly stated, but we presume it is. It is estimated, however, that a similar vessel, similarly equipped and propelled, may now be completed for little more than half cost. How far the privilege of carrying freight at five per cent. below the rate charged to non-subscribers may operate favorably on the interests of the subscribers, we do not at present very clearly see. If the rate of freight charged to non-subscribers be such as would insure full loads, then it is clear that the privilege is delusive, for the owners will lose in their character of shareholders exactly what they gain in their character of merchants. If the rate charged to non-subscribers be higher than that which would insure full loads, and

the vacant tonnage be filled at the lower rate by subscribers, it becomes a nice matter of calculation whether the company as a body would not profit more by bringing down the freight to the limit which would insure fair loads at full price, and abandoning the plan of reducing the freightage to each other, which we fear will prove to be an expedient more adapted to attract unwary subscribers, than to secure any substantial and permanent advantage.

It would be extreme weakness if this company were wilfully to close their eyes on the facts we have stated in the preceding pages. Unless they can greatly improve on the Great Western, they will be surpassed in expedition by the Cunard steamers. Can they hope to stand against the formidable subsidy of the British post-office enjoyed by that line? Is it really "unnecessary and inexpedient" to seek some support from the general government, like that which is given to the Halifax line by the English government? If such support, or any, is likely to be accorded, we say that so far from being unnecessary and inexpedient," it would be most necessary and most expedient, and would, in our judgment, prove to be the very life and soul of the enterprise. In fine, it is to our apprehensions as plain as light, that if some measure be not adopted to compensate to such a company for the want of that aid thus extended to the competing line, it cannot be reasonably expected that a profitable and permanent result will ensue; and we frankly confess that we see nothing in the published prospectus likely to produce such an effect.

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After what has been stated regarding the Princeton, it is scarcely needful to say, that the serious attention of all parties interested in projects dependent on steam navigation, should give serious consideration to what has been effected, and is likely to be effected, by the improvements of Captain Ericcson. But this is especially incumbent on a body like the present, which avowedly looks to freight as the main source of profit. The machinery of Ericcson will not only leave a large amount of tonnage available for freight, but will give the vessel increased sailing power, and diminished expenses of the mechanical propelling power. We should say that if the project prove eventually successful at all, its best chance is through the agency of these improvements.

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