OUT nothing, nothing comes. This is really a wonderful axiom. Men will grant it at once as an abstract proposition. But when they apply it to real things, some seem to get confused, and entertain expectations which if realized would set this axiom at naught. The same general truth is expressed by the statement, Every efect must have a cause. This, too, will he granted by pretty much everybody, until application to real things is made. Perhaps no one has trouble with a case where there is absolutely nothing at all. From a space where there is no matter, whether solid, liquid or gaseous, no one will expect anything. But juggle matters a little. Put in A, put in B. Suppose it to be known just what A will accomplish, and what B. And suppose, further, that we have found, subsequent to our combination of A and B, that we can trace these accomplishments of A and B. Call them a and l. Now right here is where some seem to go astray. They seem willing to believe that in addition a new thing, c, might somehow turn up. Well, if it should, then we will have a case of something coming from nothing. We might, just as well, expect that sometimes 2 and 2 would produce 5. The additional unit he"e would be no more wonderful than c. This is the trouble with the seekers after perpetual motion. They really expect something from ' nothing; they expect an efect without a cause to produce it They take a machine (A) and a certain amount of energy (Bl and expect that somehow the combination will give rise not merely to the machine itself (a) and a total of energy (l) equivalent in amount to what they put in (B). They expect not merely a and b; they look for an additional energy c. I they get it, they will get something out of nothing; they will get an efect without a cause behind it. It is just as ridiculous as expecting to get 17 separate ounces of metal by cutting up a pound of steel. Just as soon as one thoroughly grasps the idea that energy is a real thing, he is prepared to understand that it cannot be increased by manipulating it. He is then ready to see that, if he puts 2 foot-pounds into a machine, he cannot expect to get 21 foot-pounds out. Indeed, he may apparently get less than 2, because some of the >nergy will be transformed into heat and will be radiated of and thus may escape observation. However, men have been working at the impossihle problem of getting something out of nothing for hundreds of years. And, some are probably still at it. No doubt, there are to-day, men in the United States who think that a machine can somehow be made, which will run without energy being constantly put into it. It is just as if they expected to cut the 8-inch square into two separate parts, and get a 5 x 13 inch rectangle by putting these parts together in a diferent way. That the possibility of a perpetual motion machine has not been entirely given up will be understood when it is learned that 575 application for patents for suC'h apparatus were made to the British Patent Ofce in the period 1855 to 1903. This is about ten patents a year. In FIg. 1 we have an example cited by Mr. F. F. Charlesworth of the British Patent Ofce. An endless band or chain is arranged to mesh with two sprocket wheels. The band carries a series of cups, or rather dippers so attached that the handles are continually perpendicular to the band. Heavy balls are fed one by one to the open dippers on the descending side. When the dipper nears the bottom, a projecting horn intercepts the ball and guides it away. It will be seen that this machine will run as long as the balls are fed in at the top. In the form shown, an elevating screw is used to bring the balls to the top and permit their use over again. This endless screw is driven by mechanism connected with the shaft of the upper sprocket wheel. The thing lost sight of here is the fact that it will require as much energy to lift the ball to its initial position as it will develop by falling. It was proposed, apparently for this same machine, to proviae for the return lift of the balls by conducting them along an incline to a hollow tower filled with quicksilver or some othe[ liquid. Once a ball had entered the base of the tower, it would rise to the surface of the quicksilver because of the difference in specifc gravity. It could then be recovered by a lifting device, dropped onto an incline and fed into the machine again at the top. A very fine scheme—the only diffculty lay in getting the balls into the bottom of the quicksilver column. Consider now FIg. 2. We have here a similar arangement to that shown in Fig. 1. However, the endless band is here of rubber and hollow. Instead of dippers, there are hollow rubber projections or alms. On the following side of eaeh of the arms, conceiving the whole to turn with the hands of a watch are air-sacks. To these weights are attached. When an arm is rising and the weight is consequently underneath, there will be a distension of the sack. This entire apparatus is immersed in water. It is expected that it will now begin to move clockwise. The rising side is lighter than the descending one because the distention of the air-sacks has decreased the specifc gravity on the one side. All air compartments communicate with the main tube. There is no change in the tension of the air. As a weight at the top passes into the position where its sack collapses, another sack will be distended at the bottom, and so the air required will have the same volume. At any rate, this is the general scheme. But why won't it work? The reason lies in the progressively increasing pressure of water as one passes downward beneath the surface. It is this that should raise the distended side. But it is also this that resists the movement of air from the top to distend an air·sack at the bottom. The distension of the air-sack at the lottom is broadly the same problem as introducing a metal ball into the bottom of the column of quicksilver. Refer now to Fig. 3. This represents what appears to have been a French “solution.” An air-tight bellows DFE is arranged on an axis perpendicular to the paper. The total length of the bellows is about 40 inches. There is an aperture at E', by means of which and a suitable tube there is a communication between the interior of the bellows and a vessel of mercury G. This vessel is fxed in position at about the level of the shaft on which the bellows turns. B is a counterpoise, while C is a clasp which serves to retain the bellows in position with a moderate amount of strength. Suppose now the lellows to be forced open, say, to a third of its capacity. Quicksilver will fow from G and after a time, so it is claimed, the weight within the bellows will exert a turning efort suf. fcient to cause it to break away from the dasp. The lower end of the tube E will eontinue in the mercury bath. The f:ntire movement will be arrested at the position shown in Fig. 4, and another clasp H will engage the bellows. The mercury rose before, because of the height of the tube E being less than that of the usual barometric column. The mercury now will run out from the bellows and the latter will collapse. The counterpoise B then operates to bring the bellows back to its initial position. Arrived here, whatever mercury remains within, falls to ahout 27 inches height, whereupon mercury from the reservoir will rise to fow into the bellows, because the length of the tube E is considerably less than 27 inches. This is essentially Dr. Papin's account of this scheme. What is wrong with the device? Consider now Fig. 5. Here we have a drum flled with water or other liquid and arranged on trunnions. Upon one of the trunnions, a fy wheel is mounted and a suitable belt carries the power from the generator of perpetual motion. By means of stufng boxes two rods pass through the drum. These rods are mutually perpendicular. Weights are arranged on the ends of these. It will be understood that if we could always have the same amount of weight on the two sides of a drum or wheel, but the weight on one side so managed as to be further from the axis of rotation, the wheel or drum would turn. The excess of leverage on one side would cause that side continually to descend. To manage this shifting of the weights, the inventor provided the rods with cork spheres centrally arranged. Evidently when the one rod is vertiC'l, its cork foat will, if suitably dimensioned with respect to the two weights, cause the upper weight to rise and so project from the drum at a maximum distance. There will be no tendency for this position to be lost until after this vertical rod has taken up a horizontal position. The condition shown in the figures is where one rod is vertical and the other horizontal. The vertical rod and its weights will, apart from previous movement, exert no turning effort. But the horizontal one will, since one of its weights is farther from the axis than the other. Motion will be set up in the direction of the arrow. Of course the rods must be so arranged as to prevent interference between their cork foats. A simple device is shown in Fig. 6. An endless chain passes around two 'vheels BB. A trio of idle wheels COD deflects the chain from the vertIcal on one ,side. The result hjre is that I greater length and consequently a greater weight of chain are continually on the right-hand side. Presumably, we have a clockwise movement here. The difficulty is that the deflected portion, although heavier, does not exert the full efect of its weight. The gravitation of the chain operates downwardly in an exactly vertical direction. But since this gravitative action is compelled to act, say, on the topmost wheel, at an angle, there is some loss. To make this perfectly clear, suppose a chain to hang precisely vertical. At the point of tangency the gravitative pull will be in the direction of the tangent and therefore most efective. Defect the chain in or out, and the gravitative pull will be at an angle to the tangent and so at some loss. In point of fact the axles of the wheels BCB sustain a certain fraction of the weight of the chain. Consider Fig. 7. Three rotatable shafts are arranged horizontally so that a verUcal section would show the shaft sections at the vertices of a right-angled triangle, as disclosed in the fgure. Suppose now that an endless chain be arranged to envelop these rollers. It might be thought that, since the hypothenuse is longer than the vertical side, a uniform chain would set up a clockwise movement. The explanation just given, however, prepares us to understand that this will not be the case. In fact the disadvantage under which the gravitative pull of the hypothenuse is delivered is just compensated by its excess of weight. Such an arrangement will be a well-balanced, immovable one. But suppose that the metal chain be replaced by a band to which sponges are attached, the whole being enveloped hy a string of evenly distributed weights. Suppose, in addition, that the horizontal portion of the apparatus be immersed in water. We now have a device conceived by Sir William Congreve, probably about 1827. Sir William was a member of the British Parliament and the inventor of the celebrated Congreve rockets. This machine was expected to turn counterclockwise. The modus operandi was conceived to be as follows: On the vertieal side a sponge as it entered the water would be uncompressed by the string of weights and therefore free to absorb water by capillary attraction. As a sponge emerged from the water at the lower end of the hypothenuse, the line of weights would operate to compress it and thus keep it comparatively dry. Because of the diference in weight on the dry and wet sides, the whole system would move. Perhaps the most celebrated eforts in the direction of perpetual motion have been made in connection with the continued distribution and r0distribution of weights within or about a wheel movably mounted upon an axle or trunnions. The purpose is to have the same number of weights upon the downgoing and upgoing sides, but to have the average distance from the axis of rotation greater upon the downgoing side. It is conceived that, on the principle of a diference in leverage exerted by the two groups of weights, we should get a never-ceasing motion, if this relation could be perpetually maintained. One of the most distinguished of those who gave attention to this matter was the second Marquis of Worcester who fourished about the middle of the seventeenth century. This gentleman wrote in his “Century of Inventions” of a device whose purpose was “to provide and make that all ye weights of ye de/cending syde of a wheele shal be perpetualy further from ye center, then tbofe of ye mounting syde, and yett equall in number and heft on ye one syde as ye other. A mo/t incredible thing if not scene, butt tryed before ye late King of happy and glorious memorye in ye Tower by my directions, two gxtraordinary Embaf fadors accompanying his Matie and ye D. of Richmond, D. Hamilton, and moft part of ye Court attending him." He goes on to relate that the wheel, or drum, was 14 feet in diameter and was provided with 40 weights of 50 pounds each, When this wheel was put in motion, it was claimed, so it seems, that as the weights successively passed the vertical diameter above they hung a foot further from the center, and that as they passed this diameter on the lower side they would hang a foot nearer. It would seem that the predse method by which this result was accomplished is not certainly known. However, it is thought to be substantially as indicated in Fig. 8. It will be seen that the distribution to right and left is about equal, so that so far as mere weight is concerned, we have a halance. But there is i preponderance of leverage on one side. The view represents the position at a certain defnite instant. And we may grant that this instant displays conditions in a fairly typical manner. It would seem then that tbe Marquis was perhaps justifed when he said, “Bee pleafed to judge ye confe-quence." Half a century or thereabouts later, a celebrated apparatus was constructed more than once by Jean Ernest Elie-Bessler Orphyrreus upon whwt are conceived to have been substantially the foregoing prinCiples. It is related that Orffyreus, as he is generally called, made one machine about 1715, but broke it up because of the tax imposed upon it by the government of Hesse Cassel. A second apparatus was made and exhibited to the Landgrave. It is said that this machine, which outwardly appeared to be a drum 12 feet in diameter and 14 inches between faces mounted upon an iron axle, upon being started with a smart impulse-in either direction-would rotate faster and faster until the periphery wa, moving at the rate of about 16 feet per second. It was claimed, so it would seem, that the wheel having been set in motion in the chamber of the Landgrave and kept there under seal, was still going after the lapse of two months. The machine was stopped, so it is said, to prevent undue wear. However, the inventor kept his secret very close. The Landgrave, having made him a fine present, was shown the interior. But he had to promise not to tell what he had seen nor to make use of his knowledge. Ln fact, Orffyreus demanded a payment of about $100,000 for his secret. Prof. 's Gravesand of Leyden was employed by the Landgrave to investigate the machine, in so far as one might be able to do so without opening up the interior. In a letter to Sir Isaac Newton in connection with this matter, he describes it as made of “several cross pieces of wood framed together, the whole of which is covered over with canvas, to prevent the inside from being seen. Through the center of this wheel or drum runs an axis of about six inches diameter, terminated at both ends by iron axes of about three-quarters of an inch diameter upon which the machine turns. I have examined these axes, and am firmly persuaded that nothing from without the wheel in the least conlributes to its motion. When I turned it but gently, it always stood still as soon as I took away my hand; but when I gave it any tolerable degree of velocity, I was always obliged to stop it again by force; for when I let it go, it acquired in two or three turns its greatest velocity, after which it revolved for twenty-fve or twenty-six times in a minute. This motion it preserved some time ago for two months, in an apartment of the castle; the door and windows of which were locked and sealed." It seems that no one who had the $100,000 ever agreed to pay it over upon the condition that the apparatus should be “found to be really a perpetual motion.” Whether Sir Isaac Newton repUed to Prof. 's Gravesand or not, I do not know. A device probably similar to that just described is illustrated in Fig. 9. There is a rotatable wheel upon whose circumference arms are hinged at equal intervals. Weights are attached at the outer ends. Stops are so arranged that the movement of an arm on its hinge is limited to an angle one side of which is a prolongation of a radius. All the arms are arranged to swing from a radial direction in a circular direction contrary to the hands of a clock. By attending to the figure, it will readily be seen that on the right the weights A, B and a are advantageously situated to produce a clockwise motion, even though somewhat resisted. Because of a preponderant advantage which it might seem reasonable to suppose continually to attach to the weights on th! right, we might look for perpetual motion. What may be regarded as a variation from this device is exhibited in Fig. 10. Here the arms consist each of a number "Red Devil"-No. 470 Sm. prton ast. “dDevilrdquo; Gln Cuttest Wl male. A drop forged steel plier. Guaranteed quality. Money back if defective_ All standard sizes 7 to 12". A pair of 8” direct to you for 60c. Ifyourlocaldealercan'tsupplyyou,remitto Smith&Hemenway Co., 148 Chamben SL,NewYork $60 GOES LIKE StXTY SELLS LIKE SIXTYj SELLS FOR SIXTY GILSON GASOLENE ENGINE 'For Pumping, Cream ^Separators, Churns, Wash Ma- .^chines, etc. FREE TRIAL _______________________ Askfor catalog-all sizes GILSON MFG. co. 308 Pari St. Por* Washington, Wis. te£ETf5J*!!« ENGINES FROM 2 TO 40 H.P. PALMER BROS-, :K COS COB, CofJ* ^)m^ AIR GAS! Latest Invention Standard Vacuum Gas Machine makes gas automatically! Uses97% ordinary air! Cheapest, safest, most hygienic for lighting', heating and cooking! All conveniences of city gas! Non-poisonous non-asphyxialing, inexplosive andin-odorotis! Machine always ready'. Gas can bemad© forl5e per 1000cu.fl.! 25 times cheaper than acetylene! Cheaper than kerosene lamps, electricity or city gas! Saving will pay for the machine in a few months! Agents wanted everywhere in the United States and abroad! Machine of 25 light capacity. $125.00. Standard-Gillette Light Co., 10 H Michigan St., Chicago, U. S. A, Nulite Gasoline lable Lamp A beauttful lnmp for homes, hotels, o fi ces, stores, bank. cafes. Portable, safe; can be tur ned up side down or rolle d on the lloor without danger or aiecting the light .. 00 C . P . of soft, brilliant light, o ne-third cent per hour. Als o 20 0 d Ufer e nt styles of lamps and siystems. ACENTS-We want towu, county, and traveling; salesme n, l::: t i:?po!r!ID fer of l1 ered. Sells every-where. Write for Special Offer. National Stamping&Electric Works 412 So. Clinton St. CHICACO m"EE * TO ALL A Fascinating Booklet “WAYS AND MEANS IN PHOTOGRAPHY" Full of helpflll hints.-Write BURROUGHS WELLCOME&Co. 35, “West 33rd St., New York, or 101, Coristine Building, Montreal tggJQggj THE EDISON S Concrete o use How it is CODtructed, how much it will coat. i. it practical from an architectural and enRineering standpoint ) Th .. and other imPortant questioll relating to the structure are disus in a good, thorough, illustrated article published in Scientific A merican Supplement 1685. Price 10 cents by mail. Order from your newsdealer or from MUNN CO., Inc., Publishers, 361 Broadway, N. Y. PENCEMAN STEEL PENS Tempered for high elasticity, ground for smooth writing—the perfection of pens. For every style of writing. Sample card of 12 different styles and 2 good penholders Bent for 10 cents. SPEHCERIAH PEH GO., 349 Broadway, New York I ncorporate Your PATENTS and :USINESS in ARIZC:i Lawi lbe most liberal. Expense tbe least. Hold meetinE!. transact busine ss an y whe re . Blanks . B y -Laws ami fo r m s for ma k in2 st ock fl llJ-pa id fo r cas h. p roperty o r se rvices. free . P r esidd en t Stod d ard. FORM ER SEC R E TARY O F ARIZ ONA. re ,iden! afen t for many th ou sand c om panies. R eferenc e: A n y b ank in Ariz o na. STODDARD INCORPORATING COMPANY, 80: 8000 PHOENIX, ARIZONA BAKELITE (aHG. v. S. PAT. OFF.) the new synthetic substance of many applications. Write for booklet. GENERAL BAKELITE COMPANY, 100 William St., New York, N. Y. No. A. Wizard Monorail Jumping Top No 9. Wizard 6 Minute Jumping Top One Pu ll of the Curd. colored she ll and c ontinues spinning. on the tip of finger, end 8f nose, e Travels 50 Feet on Inelined Wire. Revolves 10,000 Times i\ Blinute with J1u mps from thhe Spins ge of tumbler, etc. Each Outfit contains: Top, Polished Jumping Shell, Monorail Carriage, Wire, Cords, I. lastra:ed Directions. No. 9 Either Ontfit, eomplele. 50c, p ostage, '60 • Outf le ts, $1.00. <#- 1 WIZARD CO., 129 W. 31st St., N.Y. November 18, 191 1 SCIENTIFIC AMERICAN 467 WOOD-WORKING MACHINERY For npping;, cross ('utting _ mitering;, grooving;. boring 8crol1-stlwing;, td'.e moulding, mortising; tor working wood in al.Y m: Sew for ('atnloglle A. SENECA FALLS MFG. CO. 6 95 W at er S treet Seneca Falls, N. Y .. U. S. A. SEBAS!IAN LA!HES 9 to 15 Inch Swing High Quality Low Prices Catalog Free THE SEBASTIAN LATHE CO .. 120 Culvert St . Cincinnati. O. WORK SHOPS of Wood and Metal Workers, without steam power, equipped with BARNES' Foot Power MACHINERY allow lower bids on jobs and give greater profit on the work. Machines sent on trial if desired. Catalog free. W. F.&JNO. BARNES CO. 1999 Ruby Street Established 1872. Rockford, Illinois The Elkins Saw Filer and Clamp is a useful Tool in every carperr perfection, is v complete in Itself. shop. It holds and files a Saw It is light, strong and durable, no loose parts to get lost or out of order. A. J. WILKINSON&CO. MACHINERY&TOOLS 184-188 WSfhinuton St., Boston, Mafs. Saves time and saves flies. Adapted to all saws except circular. $2.50 STARRETT'S PLANER AND SHAPER GAGE :ll ti; any me asm e ! % to ;y2 ilches. ' accurately set (ut;er, :Yaner or st!per tool to plane o; mill any dlsired thlclmes1 without ^ finS recourse to “cui nnd try” method As a pluwb can be otten used where ^[]^]^J^^Jj^f|r]j^^^JQ4r|^[]l|][ nothing else is possible. Great time and material saver. Price *S.16. Send for 274 page catalog, No.I9B. TlIE L. S. STARRETT CO., Athol, Mass., U. S. A. ^fJyS^AX/ A IVITF 1*1 To manufacture METAL ilk-L- , »” /^.l^l I dl-/ SPECIALTIES, 20 years experience in making Dies, Tools and Special Machinery. Expert work. Compiete equipment. NATIONAL STAMPING&ELECTRIC ^ WORKS Dept. 2, 412 So. Clinton Street, - Chicago, Ill . Manufacturers of Metal Specialties, Star pings, Dies and Tools. Thirty Power Presses at your service. Hoeft&Company, Inc. ™1.^.0. 141·143·145 West Michigan Street, corner La Salle Avenue DIES, FINE TOOLS I ^RY METAL SPECIAL TIES.C,I I di &F t INVENTIONS! MOORE&CO., iisi™ Chicago'. PERFECTED, Models&Experimental Work INVENTIONS DEVELOPED SPECIAL MACHINERY . . . E. V. BAILLARD CO., 24 Frankfort St.,N. Y. NOVELTIES&PATEnTED ARTICLES MANUFACTURED B'V CONTRACT. P UNCHING DIES. SP ECIAL MA CHINER Y. E.KONIGSLOW YTAMPING&TOOL W ORK S, CLEV E LAND. O. Patented Articles and Metal Specialties MANUFACTURED BY CONTRACT Stamping Dies, Metal Stampings and Screw Machine Work St. H. CARSTENS MFG. CO., 56CHICAGO A .hop 01 i,.'.--Mi/-.I .I.MI.I,,,^ III \ UIIIH.1 The Universal T elegra;hic Company Electricians an M,^»,.«:.». Inventon' de FREE SAMPLE Goes With First Letter Something new. Every firm wants it. Orders $1.00 to $100. Big demand everywhere. Nice p l easan t business. Write at once. METALLIC SIGN CO., 438 N. Clark, Cbicago 'TE LsC w 0 e O G E I PLAINFJELD . N. J RUBBER Expert Manufacturers Fine Jobbing Work PARKER, STEARNS & CO., 288-290 Sheffield Ave., Brooklyn, N. Y. M anuf act un·ng of SIp eci a I Machinery, Metal ITiallUIaCllliing Specia lties , patented D evIces, Dies and Tools, Stampings, Screw M achin e Work. Modt l and Expen mental Work. M. P . SCH EL L MFG. CO. 509·511 Howa rd St. - - - - Sa n Francisco, Cal. WELL DRILLING MACHINES Over 70 SIzes and !tyles. for drilling either deep or shallow wells in any kind at soil or rock. Mounted on wheels or on SIlls. \Vitb engines or horse powers. StrO"g. sImple and durable. Any mechanic can operate the .' easily, Sen(i tor catalo;, WILLIAMS BROS.. Ithaca. N. Y. of links hinged together. A trough D C is arranged to permit the weights, which are here loose balls, to roll from one side to the other. This trough is fixed in position. By these means, the weights of the upper left-hand quadrant are entirely removed or brought in close to the vertical diameter. When a weight rises to the point D it rolls off by way of a trough to an arm previously crumpled up but now outstretched. The great thing overlooked in such devices is the question of velocity. A ball which falls from top to bottom will acquire, apart from friction, just so much momentum. This is due to the vertical distance passed over, and will not vary however tortuous the real path may be. The reason that it is due to the vertical distance is because that is the direction in which gravitation acts. Similar considerations apply to thf upward movement. It is the vertical distance that counts because that is the direction in which gravitation has to be overcome. Of course, this is precisely the same from top to bottom as from bottom to top. I may be permitted to call attention to a device somewhat similar to those just described. (See Fig. 11.) The figures to right and left of the vertical diameter are the same in number. As it is obvious that a number of 9's preponderates over an equal number of 6's, the wheel must, of course, turn clockwise. Study this device well; it is as good as any of the others. The devices described so far all aimed at gaining a balance of power from the effect of gravity. Other inventors have sought to utilize the properties of a magnet for the same purpose. The oldest of devices of this kind (Fig. 13) offered in 1570 by the Jesuit priest, Johannes Theisner, had a lodestone on a pillar, sUPlosedly drawing iron balls up an incline. When they reached the top they were to drop into a curved tube which would let them out at the bottom of the incline through a trap dQor. The other three types are all based on what seems to have been the most popular notion of perpetual motion schemes, namely, on overbalancing one side of a wheel to make it rotate. Stephan's plan (Fig. 14), dating back to 1799, was to have four cylindrical magnets sliding in holes bored radially into a square wooden block which was mounted so as to rotate between two pivoted magnets of opposite polarity. All of these sliding magnets had their north poles pointing away from the center, hence they would be attached by the pivoted magnet with the south pole at its free end, but repelled by the other. Then the corners of the wooden block were supposed to tilt the magnets so as to carry the movement beyond the dead points. Instead of using such a wooden block, the writer in his high-school days proposed (Fig. 15) a brass drum rotating close to a horseshoe magnet, with two rods running radially through the drum at right angles to each other. Each of these rods was to carry heavy knobs at its outer ends and a soft iron armature inside the drum. Then the magnet was to attract the armatures so as to draw out one knob after the other, leaving gravity to return them. Somewhat allied is the still more recent proposal of Kort-ing and Hoepe (Fig. 12) that a magnet be used to attract one after another of a series of soft iron pieces connected at their ends by brass links to form a ring and supported by rods which can slide in and out on the spokes of a wheel. Of course none of these devices ever worked and some of our readers may be interested in figuring out why.