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that power, whether workmen or employers, will, and in most cases must, find purchasers for it; and as the possessors of all other saleable articles do, when they meet with any difficulty in disposing of their goods, they must find such purchasers through new openings, or by lowering the price in the old market.

"The sole question to be determined, therefore, is, whether it is better to export machinery, or the makers of machinery? At present each machine sent abroad will work under great disadvantages; through the misnamed protective system adopted by most continental states, the produce of that machine is inevitably confined to its own market; but if that machine had remained in England, it would have come into equal competition with its neighbours, and its produce would have gone side by side with theirs into all the markets of the world. In exporting machinery, it is true that the means of making a certain quantity of an article like that made here, are sent away, but it by no means follows, that if it were not made abroad, it would be bought from England, or even bought at all. But by driving away her makers of machinery, England furnishes to the continental states the means of making any quantity of competing machinery, without the important countervailing advantage of retaining here the skill and experience by which it had been constructed. Of course the best workmen will be selected for emigration, and every one at work abroad will teach ten others.

"It would be by no means difficult to shew, that rising manufactures are the inevitable consequence of a long cessation from war, of security of person and property, and preeminently of the extension of constitutional freedom;-that these improving interests need not occasion either envy or alarm;and that as it is impossible to confine manufactures to England; the surest, and indeed the only way to secure our manufacturing superiority, is to allow the free exportation of machinery.

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"An unsound principle generally shows its fallacy and mischievousness when supposed to be extensively applied. What reason is there for prohibiting the exportation of machinery, which the makers of machinery might not urge for that of iron and brass? The bleachers, dressers, runners, purlers, spotters, &c, &c., might equally exclaim against the exportation of nets in the brown. The cushion lace makers may next claim protection against machinery, and hand machinery against power. Are the committee aware to what an extent they are preparing future restraints for themselves? The spinners and doublers, on the same

principle, may be required to keep all their thread at home, that foreigners may not have the employment which we ought to have in working it up; and it is right that the manufacturers of thread should know that this proposition was made at a recent meeting at Loughborough, and generally approved; it was deferred solely because it was judged inexpedient to press it JUST NOW. In the same manner, the worsted spinner may demand a restriction on wool; the hosiers a similar one on yarn; the stockingmaker requires a charter and a minimum of wages; and the landowner insists that neither shall mechanics emigrate, nor foreign corn come to them; the wiseacres of all other trades follow each other in the same round of restraint, and if perchance, each obtains an additional price for his own goods or labour, he pays through the same process that additional price or more to others; while so much energy is wasted by the scheme, that foreigners find they can produce the goods they want cheaper at home. Thus schemes of imaginary protection, at the expense of others, out-general their own wisdom; this narrowness of view leads only to profitless, selfish effort, and in good time we reap the marvellous advantages of a people who rob each other all around, and then duly dividing the spoil, think themselves wonderfully enriched by the process."

RECENT AMERICAN PATENTS. (Selected from the Franklin Journal.) PULP SIFTER-S. A. Sweet, Tyringham, Massachusets.-Instruments for the purpose to which that before us is applied, have been usually called pulp-dressers. That now patented is very simple in its character, operating like the common sieve. A plate of metal is to have slots or openings made through it, of such width as will permit the finely-ground pulp for paper to pass through, whilst it will detain the knots and lumps which may exist in it. This plate is to be surrounded by a wooden frame, of such height as will allow the prepared pulp to be passed into it, and to this strainer is to be given a jarring motion up and down, by which it is to be made to strike upon any hard substance. The mode of filling it with the pulp, and of giving to it the requisite motion, is left to the determination of the user, as it is stated that these things may be effected in various and obvious ways.

REVOLVING SPINNER-W. Allen Potter, Rhode Island. This is a new and peculiar arrangement of the rings used instead of flyers in what has been called the ring spinner. The rings surrounding the bobbins are to have grooves on their outer edges, a light band carried by a horizontal

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pulley at the end of the frame being employed to drive them. This band is to be borne up against the rings by pairs of small friction rollers situated between each of the rings, and sustained on the same horizontal metallic plate which sustains them; the pins upon which these rollers turn, pass through slots in the plate, in order to increase, or to diminish, the pressure of the band upon the revolving rings, and consequently the strain upon the thread which passes over a hook or pin on each ring.

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DAMPER SUGAR FURNACE-Joshua Jordan, Boston. The patentee states that his furnace comprises an improvement in the mode of constructing sugar furnaces and setting kettles for manufacturing sugar, so as to prevent the sugar from burning during the operation of striking, or removing the same from the granulating kettles to the coolers, and for other purposes therewith connected." The principal object in view, however, is the preventing of the burning of the sugar in striking. In constructing the furnace, the fire is made to pass directly under and through a flue around the granulating kettle, before it reaches that for evaporating, so that, by means of the damper, it can be prevented from acting on the granulating, without interfering with its operation on the evaporating and clarifying kettles, while the striking is going on. tween the bottom of the granulating kettle, and the fire, a damper of a peculiar construction is to be introduced during the striking. This damper is a vessel of copper, made flat in the form of an oblong square, of sufficient width and length to cover the fire, and hollow so as to contain water in the cavity formed between its flat sides, which water cannot escape excepting through a safety tube, extending up from its outer end. Above the furnace door there is another close to the bottom of the kettle, and of such size that when open the damper can be passed through the opening. This damper is placed upon a carriage, which runs upon a railway in front of the furnace, and when wanted it is brought up and slid in through the opening from off the carriage, the same serving to remove it when it is no longer wanted. Another damper, similarly constructed, is placed vertically between the granulating and evaporating kettles. When this is down in its place, the fire passes freely through a suitable opening in it for that purpose; but when raised, by the aid of pulleys, the opening between the two kettles is closed by an imperforated part of the damper. There are in the drawing a number of the parts of the furnace represented which are without written references; the general plan, however, is sufficiently. apparent, although no specific claim is made.

IMPROVED MODE OF GENERATING STEAM ―Isaiah Jennings, Philadelphia.—The improvement here patented is stated not to be in any way dependent on the particular form of the boilers used, but upon the manner in which such boilers are filled or charged with water, in combination with other substances. "My invention," says the patentee," principally consists in the placing within a boiler spongy, porous, or solid substances of various kinds, so as to fill, or nearly to fill, its internal cavity, with the exception of the spaces between, or within such substances. As, for example, I prepare globular or irregular lumps of wood, of such diameter as may be found convenient, say from 3 inches to 1 foot, or more, in diameter; or, instead of balls, I use pipes, or round sticks of wood, perforated with holes; which sticks, or pipes, are to be piled within, and along the boiler, until it is filled, or nearly so. Instead of wood I sometimes employ reeds, canes, or stalks of various kinds; taking care, however, that the substance be such as will not be readily reduced to pulp by boil ing in water. I sometimes prevent the ve getable or other substances so placed within the boiler from coming in direct contact therewith, leaving a cavity all around them to be occupied by water, which may be done in various ways. Let there, for example, be cylindrical boilers, in which this is to be done. I make a cylindrical vessel of wood, cut and fixed together like the staves of a barrel; this cylinder may be 3 or 4 inches less in diameter than the interior of the boiler; it should be perforated with holes, and is to have spikes or pins, driven into it, over its outside, extending out, so as to bear against the sides of the boiler; this will leave a space, as above mentioned, of from 1 to 2 inches, more or less, between the wood and the metal. The wooden cylinder is to be filled with blocks of wood, or other materials, in the way already described. For steamboilers used on land, where an increased weight is not objectionable, I sometimes use more solid materials than wood; such, for example, as large pebble stones, which, although they do not possess all the advantages of porous substances, yet, from their durability, will, in many cases, be preferred. The increased surface obtained by thus charging the boilers, especially when the softer and more porous woods are employed, occasions a great increase in the production of steam, exceeding, it is believed, that which can be safely obtained by any other arrangement, where the actual quantity of water within the boiler is so small as in that above described. For filling with water, I use such supply pumps, or other means, as are already known, and add a steam-chamber, or such other appendages, as may be found convenient,"

In 1776 and 1778, the French Academy instituted some experiments to ascertain the laws of resistance to bodies passing through water, which were conducted by Bossut and others. The principal object of the experiments made in 1776 was to ascertain the resistance of bodies of known dimensions moving at certain velocities. The experiments appear, upon the whole, to have been conducted with care, and the results are useful, as approximations to the truth, though they contain a source of error, arising from the mode of ascertaining the resistance by means of weights attached to a silken cord, which passed from the model under one pulley near the surface of the water and over another at a considerable elevation. The length and weight of the line, its exposure to the currents of air, and its varying friction through the water, together with the friction of the pulleys or sheaves over which it passed, would affect the results, and prevent the correct indication of the ratio between power and velocity. The moving power, in no case, appears to have exceeded 24lbs., nor the velocity 2 miles per hour: yet general result was that the resistance was in the duplicate ratio of the velocity." The experiments of 1778 were conducted by Bossut and Condorcet, whose object was to ascertain the resistance to bodies of different forms at the same velocities, but being made with the same machinery as those in 1776, the results are open to the same objection.

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At the close of the last century, the Society for the Improvement of Naval Architecture made a very extensive series of experiments to ascertain the velocities and resistance of bodies of various forms and sizes. Fulton availed himself of their results, in his calculations for the application of steam to navigation in North America; and it is worthy of remark, that, erroneous as they are, they yet furnished him with a clue by which he arrived at an approxima

These Notes were committed to paper before the writer had an opportunity of perusing the criticism on Mr. Macneill's Treatise, published in the Mech. Mag. of the 30th November last, or had any reason to anticipate so strong a coincidence of opinion as exists between them. Only so much, therefore, of these Notes are now published, as contains some new information on the points at issue, or places in some new point of view the pretensions of the author of the work under consideration.ED. M. M.

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tion to the truth, as proved by actual experience.

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In 1799, some very interesting experi ments were made by Charles Gore, Esq., with the apparatus of the Society, for the purpose of ascertaining the comparative resistance of fluid water on floating bodies of different forms applicable to the construction of ships.' He made use of a constant motive weight of 1 lb., with models of different forms and weight. After showing the advantage of great length and slight immersion of the body in the fluid, he remarks,"the form best calculated for velocity. long parallel body, terminating at each end in a parabolic cuneus, and having the extreme breadth in the centre. Also, making the cuneus more obtuse than is necessary to break with fairness the curve line into the straight, creates a considerable degree of impediment. And I am inclined to think, from what I have stated, that the length of ships, which has already been extended with success to four times the breadth, is capable, with advantage, of still further extension-perhaps to five, and in some cases even to six times."

In 1827 (May 31), Mr. James Walker, civil engineer, read to the Royal Society of London a paper on the laws which regulate the resistance of fluids, in which he observes" It has lately acquired a new importance from the introduction of steam in navigation, rendering the ratio between power and velocity essentially necessary to be known. The comparison between canals and rail-roads, to which public attention has of late been much directed, depends also upon the ratio between the resistance and velocity by each of these modes of conveyance.

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It has been demonstrated and proved, in the most satisfactory manner, by various experiments, the resistance from friction to a carriage upon a rail-road is the same at all velocities. I know, therefore, that the same strain upon a waggon which has the effect of moving it upon a railroad at the rate of 1 mile an hour, will (after the inertia is overcome) be indicated at any other velocity at which the power is made to move; but I have not found any theory or experiment by which, after knowing the strain upon a boat moving at the rate of 2 miles per hour, I have been able to fix satisfactorily the strain that is exerted upon it when moving at the rate of 4 miles per hour. The resistance of the fluid, per se, increases in the duplicate ratio of the velocity. Ex

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periment has amply confirmed this theory in the abstract; but there are other elements of resistance caused by viscidity, by friction, by the accumulation of water in front and depression towards the stern of the boat, for which our ignorance of the laws which govern the internal motion of the fluid, has prevented any correct theory from being suggested; and the experiments from their disagreement, and from the way in which they have been made, have not done much to supply the defect." Such was the deliberate judgment of a gentleman of no small experience, after having made a number of experiments himself to obtain correct data upon which to reason, The experiments were made by Mr. Walker under the most favourable circumstances for obtaining a correct and useful result. They were not made in a narrow trough, with but little more than sufficient space for the model to pass (as in Mr. Macneill's experiments in the Adelaide Gallery), but in the East India Import Dock, which is 1,410 feet in length, 560 feet wide, and 24 feet deep, with two boats of the ordinary construction, one 18.6 long, the other 28 feet.

Let us now see how far Mr. Macneill has succeeded in supplying the deside rata which Mr. Walker represents to be wanting.

Mr. Macneill affirms (page 1,) that the practical application of the laws founded by the mathematician has failed in producing any form which will rival the skiff of the Indian, the canoe of the Esquimaux, or the junk of the Chinese;" and he adds, "the boat-builder seems to have studied how he could best keep his vessel ploughing her way."

Now, the fact happens to be precisely the reverse. The study of "the boatbuilder," in this, and, indeed, in all countries, has uniformly been to get the floating capacity of the vessel as near the surface as possible, in all vessels designed for fast sailing. Mr. Phineas Pett, who was master shipwright of the Royal Navy of England towards the close of the 17th century, advocated an adherence to this principle in every case as far as practicable; and it will be found, on reference to the models or drawings of all the fast sailing vessels which have been since constructed, that it has been

adhered to with almost undeviating fidelity.

We are further told, that it cannot "be satisfactorily shown that even seagoing ships would not be improved by such a build as would enable them to rise to the surface of the water." In our boyish days we were accustomed to indulge in the usual amusement of youths in a sea-port, and we well remember the quandary in which we once found ourselves for want of ballast to put our little boat down in the water. She would neither bear up nor luff, but drove bodily to leeward, to the imminent peril of our lives. If we had had Mr. Macneill with us, however, he would have told us to be at our ease, since we were only showing "satifactorily how much a vessel may be "improved" by being rendered unmanageable!

What is to be done with the next passage? "But to pursue our reductio ad absurdum: there are many cases in navigation where a sharp cut-water shape to a boat would be as unphilosophical as a knife-edged fellow would be to a wheel intended for ploughed land." "Many cases!" Is there a single case? And in what respect would a sharp cut-water shape be unphilosophical? Mr. Macneill has not furnished us with any means of answering these questions, but, on the contrary, with evidence of a directly negative description; for on reference to the plan of the trough and model, with which he made some experiments of his own at the Adelaide-street Gallery, we find the model has, what sailors are accustomed to term, a razor face, and that carried to a great extreme.

He proceeds to tell us that "at a time when it was generally held that the resistance to a vessel in the water increased in the duplicate ratio of the velocity of the vessel through the water, the now keenly-contested merits of railway transport and canal transport were brought under public discussion." This question of comparison is the point upon which Mr. Macneill evidently wishes to bring all his experiments to bear; his grand aim is to prove that railways are useless and unprofitable things when compared with canals. He writes as a partisan and not as an inquirer after truth-his object is not so much to correct the mistakes into which his predecessors in this line of ex

Mr. Macneill informs us that "experiments were instituted in order to confirm this law of resistance, but that it occurred to none of the experimentalists, although they could not increase the density of water and harden it, as has been done with roads for carriages, they could still increase the relative resistance of water by giving the boat such velocity that she could not penetrate fast enough, and thus that she would rise out of the fluid." They might, he adds, "have reasoned by a perfectly fair analogy between conveyance on land or on snow and conveyance on water, and have legitimately concluded that as their object was not to cut through gravel, but to get on it in the one case, so at high velocities in the other they should not have endeavoured only to cut through the water, but also to raise the boat to the surface, and make her skim thereon," even as the schoolboy makes a stone skim the surface of the water. To show that there is nothing absurd in this notable scheme of sending first-rate men-of-war skirling along the surface of the ocean, Mr. Macneill tells the following most marvellous story :

"Fourteen years ago Mr. Robison, Secretary to the Royal Society of Edinburgh, was informed by Mr. Perkins that upon one of the rivers of the United States he had observed a barge (length sixty feet, and ten feet of beam) loaded with hay so acted upon by a strong wind, that the barge appeared to rise about three feet above the water-line, and to skim with very great velocity upon the surface of the water."

Now the reader will please to bear in mind that a barge of the above-named dimensions is about 4 feet deep on the side, and when light (empty) would draw 9 or 10 inches water; if loaded with hay in the manner that our river barges are, she would then draw from 2 ft. 3 in. to 2 ft. 6 in. water, so that Mr. Perkins' barge must have been raised actually 6 in. above the surface of the water!!!

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of eight experiments made under the same circumstances, we find a variation in the force of traction between the theory laid down and the actual experiment amounting to .059 lbs.-the force of traction or weight on the towing-line during each experiment, being 0.468 lbs.; and the force of traction calculated as the squares of the velocities is in the 3rd experiment 0.508 lbs., and in the 5th experiment 0.449 lbs. We are left to account for such different results in the best manner we can, as the column entitled "General Observations" contains no remark on the subject. It appears probable that the weight of the line and its friction through the fluid affected the results very considerably in the first or standard experiment, so that .468 lbs. is not the true value of the "force of traction" acting on the boat. If this supposition be correct, it follows that the deductions from the standard experiment are erroneous, and that we must commence de novo from more correct data.

In the 68th experiment, with a motive power of 20 lbs., the velocity of the empty boat appears to have been 6.392 miles, and "the force of traction during the experiment" 3.156 lbs.-In the 63rd experiment, with the same motive power as in No. 68, the velocity of the empty boat appears to have been 7.053 miles; a difference of of a mile under apparently the same circumstances. In the higher velocities similar discrepancies are to be found. Examples 88 and 91, with the same motive power, gave, the one 10.765 as the velocity, and the other 12.784 miles; whilst No. 92, with the same motive power only, attained a velocity of 10.227 miles Again, in experiment No. 93, with a motive power of 80 lbs., a velocity of only 10.765 miles was obtained, whilst, with the same power, Nos. 98, 99, 100, and 101, a velocity of 12.784 miles was obtained, or upwards of 2 miles

more.

We are afterwards presented with the details of some experiments made on the Paddington Canal with one of the Paisley Canal Company's quick boats, which are thus pompously introduced::

"The important effects which they are calculated to produce in the minds of the unprejudiced, not only upon inland navigation, but to nautical science in general, have determined me to publish them in the fullest