Should some of the competitors for the first cash prize of $300 fall short of obtaining the requisite names to entitle th81 to it, the second prize—$250—will be worth striving for; and if they fall short of that, the third—$200—will be gained by some one. And should circumstances prevent a competitor getting a sufficient number of subscribe to obtain either of the fifteen cash prizes, he will have no difficulty in ohtaining names enough to entitle him to one or more of the large and elegant steel-plate engravings, containing superb likenesses of NINETEEN of the most distinguished American inventors. The lowest pricethese engravings are furnished, single, is $10, and for the size and quality are the cheapest steel-plate engravings published. These engravings can only be had at this office, the plate from which they are printed (valued at $4,000) being owned by the publishers of this paper. Send for printed prospectuses and circulars. Improired Malvay. The object of this inyention is to enable cars to be run with safety at great speed, to give sure warning of their approach to a station, and to permit the ready ascension of steep grades. Our readers are well aware that the smooth traction wheel, though answering admirably for such ordinary grades as are employed on railways, fail when applied to the ascension of very steep grades, examples of which are found in the Mount Washington railway in New Hampshire, and Fell's railway over Mont Cenis, in Switzerland. They are also aware that the danger of running off the track increases with the speed of the train ; any slight obstruction or unevenness in the track under such circumstances causing the wheels to bound, as it were, vertically. For the ascension of steep grades many devices have been employed, among which may be mentioned a central toothed rail with horizontal wheels gearing into both sides. This device necessitates considerable complication in the construction of the locomotive, which it is desirable to avoid. The plan shown in our engraving, while it does not require much variation from the form of locomotive employed at present, so that the wheel s may be used as ordinary smooth traction wheels on level or slightly ascending grades, provides for additional tractive power when steep grades are reached. The lirst object desired to be attained in this form of construction, is to secure safety at high speed. To this end the locomotive is provided with extra wheels, A, attached to a shaft connected with the en.2*ine in the manner shown, or in any other suitable and convenient manner; which wheels run along the grooved under side of elevated rails, B, connected with and supported from the sleepers just outside the principal rail upon which the locomotive runs. Gars are provided with wheels attached to and playing upon the ends of the axles, to which the ordinary wheels are attached. At stations and other places where these rails are not required, they may be interrupted ; the entrances to their grooves being made flaring to insure the easy entrance of the wheels, A. The adaptation of locomotive and track to tho ascent of heavy grades is accomplished by placing toothed rails on the inner sides of the ordinary rails at such grades, into which toothed wheels fixed to the axles of the driving wheels, and on the inner sides of the driv. ing wheels, mesli and prevent slipping which would otherwise occur. On exceedingly steep grades, where even the toothed wheels would otherwise be liable to slip from the teeth of the rails, the elevated rails above described hold them to their work. To give warning of the approach of a train to a station, wires running parallel to the track and extending a mile or more from the depot, but interrupted at intervals and connected with systems of levers, C D, are employed; the end of the wire at the station being connected with a bell. The levers are pivoted to a support placed along the side of the track and are joined by a connecting rod, E,in such a manner that when the projecting end of the axle, F, strikes the one more remote from the station, D, it draws the one at C nearer to the station, into a vertical position which in its turn is depressed ; and thus a reciprocating movement is imparted to the wire, and through it to the bell at the station, which is thus sounded. The length of time through which the bell will ring, depends, of course, upon the number of the pairs of levers, and the frequency of its strokes upon their proximity to each other. A patent on this improvement was obtained through the Scientific American Patent Agency, October 5, 1869, by David Harrison, of Fayette, Mississippi, the inventor of the railway supply apparatus illusti'ated and described in our last issue. Improvement in. Velocipedes. In. the ordinary method of applying the power of the feel to the propulsion of velocipedes, each foot has to pass through the arc of a semi-revolution of its respective crank beneath the center of the shaft, during which time it can exeru no proptil-sive force upon the veliicle, while a large proportion of muscular Ibrce is required to carry tlie leg imigh ihiB arc. If this motion could be utilized in propulsion, it is clear there would be a great gain. This cannot be done, however, with the ordinary crank, and with a loop over the foot so that the force of the liexor muscles could be applied to the crank, there would be but a slight gain, as these muscles are very weak in comparison to the extensors. The loop i$, however, inadmissible for several reifjons, The invention we herewith illustrate is a novel and unique method of applying the power of the foot to a crank motion, and might perhaps be called a radially-expanding and contracting crank motion. It has for its object the application of the extensor muscles of the leg, with the advantage of a long leverage, while the circumferential motion of the foot and crank wrist is not increased. The method employed to secure this result is ingenious and will be admired for the simple manner in which the required motion is attained. A grooved circle is attached to the standard, as shown in the engraving, eccentric to the action of the wheel, and strengthened by lateral braces. The arm of the crank passes through a hole in the end of the axle, but is not fastened to it. In the groove of this circle plays a small friction roller attached to the crank behind the foot-piece, which causes the crank to slide through the hole in the axle to and from the center during each revolution; its nearest approach to the center being diiring ijbe time it passe under the center. Thus a gVeraVr leverage is obMndd for th'e fdiwia thrust of the foot, and as the grooved circle can be made of the same size as the circle described by the common velocipede crank, the motion of the leg is no greater than before. But the leg during the forward thrust is more extended and a more advantageous application of the muscular power can be made than when the leg is more flexed. The inventor claims that the increased ease with which a velocipede can be propelled with this attachment, will be found a great aid in ascending grades, and will greatly mitigate the fatigue of velocipede travel on ordinary roads. The inventor of this ingenious device is Mr. Edward A. Lewis, of St. Charles, Mo., to whom was granted a patent for it, through the Scientific American Patent Agency, October 26,1869. The Foot liathe. Thf3 foot lathe—the terms hand and foot lathe are synonymous— is generally used, at the present time, by small machinists, manufacturers of gas fixtures, amateurs, etc.; men who do not work a lathe constantly, but are called to braze or solder, or, perhaps, to fit some detail with a file. For these uses the foot lathe is one of the cheapest of tools ; for the same person that does the work furnishes the power also, so that a man working on a fovot, or hand lathe, as it is often called, ought to have first-class wages. Moreover, a first-rate foot lathe turner is always a good mechanic, for it takes no small degree of dexteri ty to perform the several jobs with ease and dispatch and certainty. To always get hold of the right tool, to use the same properly, so that it will last a reasonable time without being ground or tempered, to rough-turn hollow places with a square edge, to chase a true thread to the right size every time, without making a drunken one, or a slanting one, to make a true thread inside of an oil cup or a box—all these several tasks require good j udgment, dexterity, and a steady hand. Of course, where a slide-rest is used, the case is diflerent. We allude, specially, to a cutting tool managed by the hand. To do all these things, however, it is necessary to have tools, and good ones, or none. It is an old saying, that a bad workman quarrels with his tools, but a good workman has a right to quarrel with bad tools if he is furnished with them through chance or design It is impossible to execute good work v/ith a dull tool, one badly shaped or unsuited to the purpose, and, therefore, it is important to set out right at the beginning. There is no tool more efficient in the hands of a good workman, than the diamond point. For roughing off a piece of metal, for squaring up the end, for facing a piece held in the chuck, for running out a curve, or rounding n.p a globe, it is equally well adapted. It may be truly called the turner's friend.— Watson's Manual of the Hand Lathe. A Yalnsihle Cmente A correspondent, J. M. Benthall, finds the following recipe good. He says : " liave used the compound of glycerin, oxide of lead, and red lead, for mending a large cast-iron kettle that had been fractured across the bottom by allowing water to freeze in it, with the happiest results. It takes some little time to dry, but turns almost as hard as stone, and is fire and water-proof. For mending cracks in stone or cast-iron ware, where iron filings cannot be had, I think, it is invaluable. " My method was as follows : Take litharge and red lead, equal parts, mix thoroughly and make into a paste with concentrated glycerin to the consistency of soft putty, fill the crack and smear a thin layer on both sides of the casting so as completely cover the fracture. This layer can be rubbed off if necessary when nearly dry by an old knife or chisel." " If this will be of any service to the read-, ers of your valuable paper they are welcome to my experience." DuEiNG the gale, on the night of the 19th ult., the water rose in the Niagara River at the rate of two feet per hour till the gale reached its hight. Tho new suspension bridge was severely tried. Some of the guys were broken, and the structure swayed two and fro like a reed, and it was regarded by many as certainly doomed to immediate detmction. It was cloged|against the public, but if it had not been no one would have ventfurb upon it while the gale lasteli.The next namher will termbate the present volume, and with it will expire several thousand subscriptions. We have never had the intention to force our journal upon any one who does not wish it, or who does not feel it. to be money well laid out ; hence we apply, in all cases, the strict business rule of discontinuing the paper when the term paid for runs out. This we think is the best plan. Our subscribers don't want to be dunned to pay up, and we do not wish to undertake a duty so unpleasant as to dun them. We believe that the SCIENTIFIC AMERICAN has been worth during the past year, more than it has cost any one of its subscribers—indeed, it is almost a wonder to ourselves how we have been able to give a weekly journal of the size and quality, at so low a price. We are anxious to 'increase our circulation, and we know that thousands more would be glad to take it, if some, one would but invite their attention to it. 'So other journal hm had l;etter friends in this respect than the BCIBNTII'IC AIEHICAN. We feel gratefiil for all the solid interest whicli las been sliown to US in this respect, and e propose with the new year to rcwa rd our friends for making an extra effort, witli. cash prizes, end an elegant work of art as a premium for club.=i. ead the announcement on flno|hcr'liage, and lie Idnd enough toki us hear froni yon on the Eiubject. Succespful comp'-ditors for the prizes will be sure to get their money when pay-day arrives.