A and B are two upright pieces of brass, or wood faced with brass, through the centre of each of which, and between the letters CCCC, a longitudinal cut is made, sufficient to admit to the number of one hundred steel wires (size No. 17, or smaller if required,) to pass freely. EE are two iron finger screws, inserted in the tops of the upright pieces A and B, and passing a little way into the longitudinal cuts at CC; by means of which the wires are tightened or secured when the pattern to be taken is finally adjusted. I is a slab of wood, into the surface of which the lower ends of the upright pieces are inserted when

G

the pattern of a vase, or any other moveable article, is required to be taken. G is a small instrument for advancing each wire forwards separately.

N. B. The wires, if cut precisely of the same length, will delineate the required pattern, both convexly and invexly, with the greatest possible accuracy.

LEESON'S PATENT SAFETY SPRING

LOCK.

Sir,-The liberality you have always evinced in your ably-edited work, the "Mechanics' Magazine," convinces me that apology is quite un

necessary in soliciting your notice of an invention, which I trust will be as beneficial to the patentee as it will be useful to the public, and in some cases aid the cause of humanity; for, hy the simplicity of Mr. Leeson's "patent safety spring hook," a horse that should happen to fall down under a stage, gig, or carriage, can be instantly released from such a distressing situation. This I think of some importance; as, in nine cases out of ten, the animal (particularly a spirited one) receives more injury from his struggling than from the fall itself; and the accident is often attended with great danger to the driver, passengers, and any persons who from motives of humanity volunteer their services.

At first, Messrs. Taft and Leeson took out their patent for driving reins only, thinking that the timid driver would feel more confidence in their "spring hook," than the usual dependence on the tongue of a small buckle; but subsequently they have applied it to various parts of harness: such, for instance, as the tug of the loop that supports the shafts (often so

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much curved as to render it difficult and even dangerous for one man to harness or unharness a spirited horse). By this simple contrivance expedition and security are at once obtained, and the general appearance of the harness rendered much neater. It is also applicable to traces, pole-pins, coupling rings, &c.; and will be found very useful to mail and stage contractors, as much time is thus saved in attaching the horses to a vehicle.

Having thus disposed of this invention as applicable to harness, I beg leave to point out one or two other instances where it may prove equally useful. The fair sex might adopt the "safety spring steel loop" for the greater security of valuable necklaces, bracelets, &c.; and gentlemen who carry valuable watches, would find it admirably suited for watch-guards.

I send you drawings of the invention, should you deem them worthy a place in your valuable work; and am, with great respect,

Sir, your obedient servant,
T. REILLY.

15, Finsbury-place,
Dec. 18, 1829.

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Fig. 2 shows the slide-tube drawn back.

Fig. 3. A the shaft of a gig; B the hook, or tug, to receive the shaft; C the safety slide-tube; D the springcatch; F the back-band.

WINANS' PATENT WHEEL.

Since we last took notice of this wheel, (p. 211.) Mr. Winans has enrolled his English specification; which does not, we find, differ in any material respect from the one he had previously lodged in the Patent-office at Washington. We shall in preference, however, to giving either specification, now lay before our readers the description of the wheel given by Mr. Winans' American partner, Mr. Sullivan, in the "Journal of the Franklin Institute," (No. for April, 1829,) because, in the first place, it is shorter; and, secondly, because it is to this description the very able report, which we also subjoin, by the Committee of Mechanics of the Franklin Institute, on the merits of the invention, bears reference.

Mr. Sullivan's Description.

The wheels of common cariages operate as levers of the second class, because the wheel turns on the axle, but when the axle turns with the wheels, it operates as of the first class, or as a windlass.

The main travelling wheels of Mr. Winans' carriage are of the latter kind. The fixed axles pass through the wheels, and extend about nine inches from them; the last three inches thereof being converted into smooth gudgeons. These enter under the upper part of the rims of the secondary wheels, (those of the second class of the lever,) which, in this modification, are placed outside the large wheels, but do not touch the ground, and are about half their diameter. They have short axles each, which apply in brasses under the double side pieces of the frame, between which they are lodged. Their rims hanging on the gudgeons, their short axles bear up the load frame, and when the primary wheels roll forward on the railroad, their axles turn, and the gudgeons roll in, on and under the smooth surface of the rim of these outside wheels, which of course revolve slowly, and turn perhaps once, while the large wheels and axle turn ten

times; the bearing or rubbing axles moving thus very slowly, perhaps no attainable speed of the carriage would cause them to heat.

This form of the cariage thus requires no fixtures; but the essential parts are combined naturally together, and work without any liability to separate. Nor is there any friction but that of the small axles, which it is the object of the leverage to overcome.

Thus the compound leverage of this carriage conquers the resistance of friction, and allows of augmenting the quantity of load. The horse carries the instrument of his power as a part of his burden. His speed, like that of a steam-engine, would accelerate till the force and the resistance balance each other, or steadiness is attained.

There are sundry incidental advantages, besides, in this form of the carriage. In passing along curves, the outer wheels will turn as much on their axles as the outer line is longer than the inner line of the track, instead of slipping thus much. They will yield to this resistance; but ordinarily the weight of the load alone fixes the axis in the naves, because they meet with more resistance there than at the gudgeons.

In turning curves of the road, the manner in which the gudgeons are lodged, capable of a little retrocession, allows the flanch which touches the rail to turn off from it. The flanches are, therefore, on the outside the wheel; and even in great velocity, it cannot gain upon the rail, because it must be turned off with force equal to that with which it acts.

To enable this railway-carriage to go temporarily on streets, I make the secondary wheels of greater diameter, so that they may reach below the primary wheels and below the level of the rail. When the carriage arrives at the end of the road, the pavement being there raised to its level, nearly, the secondary wheels take the ground and bear the load. The main wheels being thus relieved, their axles fall a few inches into scores in blocks, placed on the side frames to receive them. They are thus suspended from use, but remaining in place, when the carriage returns to the railroad and enters thereon, they rise from their repose, and take the bearing of the new load.

But to enable the carriage conveniently to traverse streets, and be guided. I make the frame in two divisions, and connect them with the bottom of the load body frame by pivot boits, &c. and

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apply a tongue which shifts to either

of the railway, there would be no question about the amount of the second

Another mode mentioned in my specification of the improvement, of converting this carriage to street use, is, to adapt to it a pair of trucks, on which a lever or screw is placed, whereby to lift the fore part of the waggon, and let the hinder part run on the hind secondary wheels.

Report of the Committee of Mechanics of

the Franklin Institute.

The committee beg leave to report :—

That they have attentively considered the subject assigned to them, both with reference to the model before them, and to the description contained in the Journal of the Institute. They have, likewise, duly weighed the remarks of Mr. Sullivan, contained in a letter which accompanied the model, and which invited the closest scrutiny into the merits and defects of the principles of construction, and of the mode in which it is proposed to apply them to practice.

The resistances to be overcome in drawing a load over a common turnpike, or other road, arise from several causes; first, from the inequalities of the road itself, which allow the wheels to sink at one moment into cavities, and require them, and of course the load also, at another, to rise over prominences. Secondly, from the friction of the axles in the naves of their wheels. Third, from the adhesion of the wheels to the materials of the road. Fourth, from the air in which the vehicle and all connected with it must ever be placed. To these causes of resistance we may add that of the inertia of the carriage and its load when commencing its motion; and finally, the inclination of the plane of the road, which will be in concurrence with, or in opposition to, the above-mentioned causes, according as the carriage is ascending or descending, and of course, on a horizontal plane, is equal to zero. The primary object of all railroads is, to conquer the first mentioned cause of resistance; namely, the inequalities of surface. To do this completely, the materials composing. the rails, and the wheels which pass over them, must be perfectly hard, smooth, inflexible, and free from the most minute particles of foreign matter. If this were practically, as well as theoretically, characteristic

of turning on their axles, would then slide on the rails without revolving at all, as they are sometimes observed to do upon very smooth ice; and this, too, however small, might be the friction at the naves of the wheels, because the friction at the periphery would be still less, that is, absolutely nothing. The car would, in fact, become a sledge. But since the imperfection of materials, and the unavoidable inaccuracy of all strictures formed by human art, forbid us to expect such a railway will ever exist, it becomes necessary to compute the amount of the second resistance, and, if possible, to devise means to reduce or to overcome it. The friction is reduced by making the nave and its axle as smooth as possible; by forming the two different metals; by reducing the diameter of the axle as far as may be consistent with proper strength; and finally, by the lubrification of the rubbing surfaces with such oily substances as are found effectual for this purpose. By these expedients, and by duly defending the interior of the naves from dust and from water, it is found that in practice the friction due to the axles may be reduced to about of the load.

With this reduction the horse may, without difficulty, draw a load of 8 or 9 tons over a perfectly level railway. With the same reduction an inclination of 30 feet per mile would, on a descending plane, be sufficient to overcome the friction, and cause the car to descend by its own gravity. The irregularities of the rails and the slight obstructions from foreign matter would be the same in all cases, and increase the necessary inclination. But in addition to the reduction of friction by the means already mentioned, there may be an application of the mechanical powers to overcome the remaining resistance, wherever the pur pose to be accomplished will warrant an additional expense in the construction of the car; and where the additional machinery will not, on account either of its weight or complication, prove more detrimental than useful.

One of the most obvious expedients to augment the power of the wheel to overcome friction, would be to increase its diameter, while the diameter of the axle remained constant; because as the friction is proportionate to the weight, it would, for a given load, remain the

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same on an axis of given size and materials, however high the wheel should be on which that load might rest. But, if the radius of the wheel be increased, the length of the arm of lever which overcomes this constant resistance is proportionally increased. Those who prefer the principle of virtual velocities for explaining mechanical powers, may consider, that with a wheel of double diameter the load will be conveyed over a double space on the rail, while the force applied is overcoming that amount of friction which results from a single revolution of the wheel on its axle. This mode of overcoming friction has, however, the disadvantage of carrying the axles too high, and of exposing them to the injurious effects of a powerful lateral pressure when the two rails are not precisely of the same height. The changes of form in the wheel itself would likewise require attention, when its height should be greatly augmented. But it is not necessary to dwell on the defects of the high-wheeled carriage. The committee have only referred to it as one of the expedients by which it has been attempted to overcome, in part, the friction on the axle.

The description of Winans' railroadcarriage, contained in the Journal of the Institute for April last, is so full, as to require but little explanation from your committee. The mode of overcoming the friction of the axle, by causing the ends of it to revolve within the rims of friction-wheels whose axes are below that of the travelling wheels, is certainly a very ingenious device.

It is not perceived by your committee, that the mere circumstance that the first and second orders of the lever are combined in the forms of the wheels of this carriage, is of any peculiar advantage in overcoming friction, since the principle of action and amount of power gained by the two orders is precisely the same. All the superiority which this circumstance imparts to the car before us, arises, therefore, from the convenient arrangement of the parts. It is a decided advantage in point of firmness and compactness of structure, that the friction-wheels require no additional fixtures with which to attach them to the load frame, except such as constitute in fact a part of that frame itself.

The liability of common railway-carriages to heat the gudgeons when moving with great speed, is a practical

difficulty, which appears to be entirely removed by transferring the rubbing surface from the axes of the primary to those of the secondary wheels. The latter will always move so slowly as to preclude the idea of much increase of temperature from friction.

It will be observed, that the load now rests on eight bearings instead of four; the number found in every fourwheel carriage of the simplest construction. This allows the gudgeons of the secondary wheels to be less in diameter to support a given load, than those of the primary. A single revolution of the secondary wheel will, therefore, present a less number of rubbing points to any part of the bearing, than would a revolution of the primary wheel, whose axis is of double diameter to that of the former. And the leverage is greater where the diameter of the gudgeon is less; so that if the strength and other properties of materials allowed a very great diminution of the axle, the smaller it could be made the better.

The friction is, doubtless, as stated in the description above referred to, nearly proportional to the weight; but when the weight is constant, and the motion of the rubbing surfaces uniform for each case, the sum of all the resistances due to friction is proportional to the number of units of rubbing surface brought into contact during a given time. If this be true, it is of great importance to form the pivots of the secondary wheels in such a manner as to rub on their bearings through the least possible space, while the carriage passes over the greatest possible space on the road.

The model performs in a manner sufficiently decisive of the advantage which the principle of its construction has over that of the simple car in overcoming friction; but your committee would hesitate to receive the performance of this model as a certain indication of what may be expected from the machine of full size on a common railway.

Nothing but actual experiment on a large scale will fully develop the precise amount of advantage of a machine of this nature, because it is not possible to foresee all the circumstances which will attend its construction and use. If confined to a straight, level road, there can be no doubt that the power of the mover would be greatly increased by the addition of friction-wheels. The same may be said where the carriage is employed solely in transporting loads