The Use of the Electro-magnetic Separator in City Refuse Disposal THE magnetic separator is now largely used in various fields of industry, and is found to be of much efficiency in saving time and labor. It is employed to separate magnetic from non-magnetic material in a mixture of the two. It is of value in handling c03;I, rock, and ore when it is essential that no large pieces of steel or iron should enter the crusher. It is also made use of for removing iron shot from molding sand, for separating brass chips from machine shop turnings, and for separating magnetic ores. This form of separator is also particularly useful in taking out the bits of iron or steel found in all sorts of junk, such as leather goods, rubber and rags, which must be removed before the material is worked over into new products, since if allowed to remain they would deleteriously affect the material or be a source of injury to the machinery. Still another application is the use of the separator in grain elevators, cereal plants and flour mills. Before its installation much damage was caused to mill stones and other apparatus by the fragments of wire found in the grain as a result of the use of modern binders amI reapers. There are various more or 1,less elaborate forms of separators, the simplest being the separator ro'ler. The roller shown in the aecompanying illustration consists of alternate coils and steel disks concentric with the shaft. The eoils are wound on steel spools doweled to the disks, and the disks are in their turn keyed to the ehaft. Each, coil is inclosed and protected by a cylindrical brass coil shield having a tight fit on each, of the two adjacent poles. Current for the coils is obtained through carbon brushes he'd by self-adjusting holders on a pair of slip rings, at one end of tle shaft. These rollers are regularly built 12 inches in diameter, in lengths from 16 to 36 inohes, and are driven by an electric motor mounted on the base of the machine. They have a current consumption of 325 to 750 watts, and capacities of 1,340 to 3,000 cubic feet per hour. They are designed to operate on any direct current voltage up to 250. They are usually installed as a part of a conveyer be t sys tem. The material falls from a hopper upon an endless moving belt below, and is carried along till it reaches the magnetized roller. The non-magnetic material being unattracted, is thrown off by centrifugal force to a bin or upon another conveyer belt, while the magnetic material attracted by the roller is held until it passes beyond the magnetic zone of the same on the under side, where it drops into another receptacle below. A novel and interesting application of this device is its use in garbage reduction plants. All city refuse can tains a very considerable percentage of iron, chiefly in the form of metal cans, etc. It is very desirable to have this eliminated both because of its own value and to rid the other material of it. The Borough of Richmond of the city of New York has recently instared a magnetic separator roller for this purpose, which has been running successfully for several weeks. It is believed to be the only one in the United States used for such a purpose, though several are in use in Great Britain. Mr. .. T. Featherstone, the superintendent of the Street Cleaning Department in Rich- mond Borough, gives some interesting data concerning the practical working of the separator. The dimensions of the separator are 24 inches by 12, all the roMers being 12 inches in diameter. The east of operation is vel y low, since one horse-power or less is sufficient to operate it, while the cost of the roller itself is not much ovcr 0 n e hundred dollars. About thirty tons of raw material daily are used. This is run through a furn ace which melts it down in t ' about twelve tons of clinkers, destroying at the same time the animal and vegetable matter. This, of course, is one of tie main objects in city waste disposal, for sanitary reasons. The clinker is then run through a crusher, and the resuting product passes onto a belt which carries it over the roller. On an average about 600 pounds of iron are recovered from the twelve tons of crushed clinker. The non-magnetic residue is used in the manufacture of concrete to take the place of broken stone and sand, and the process is especially valuable because the iron if allowed to remain would spoil the appearance of the concrete by a peculiar stain. It is probable that this process will be followed in other communities, when its simplicity and efficiency become known. A New Automobile Tire Pump ODR illustration shows a new form of portable four-cylinder hand pump especially adapted for inflating automobile or motor-cycle tires. The aim which the inventor had in view in designing this pump was to* provide a portable apparatus which. could be read ily attached to a suitable support such as the step of an automob i Ie. The pump is fur-thermore so constructed as to combine great strength with simplicitY of structure, so that it can be manufactured at a low cost, and is efficient and reliable in operation. The air passages are so formed as to avoid joints, which would be apt to become loose and to leak. With these objects in view the frame has been made in one single casting, consisting of a vertically disposed wall and cyl- inders integral therewith on opposite sides of the wall, the cylinders being disposed in axial alinement. Pistons reciprocate in these cylinders, being actuated by a handle A which is journaled centrally with respect to the cylinders in the central vertical plate; suitable valves D admit air to the cylinders for compression and permit the escape of the air when properly compressed. 'he passages for conveying the compressed air from the cylinders to the point of consumption are formed directly in the casting constituting the frame of the [Jump. Valves G are arranged in 'these passages for the purpose of preventing the return of the compressed air to the cylinders, and these vahes as well as the intake valves D are so constructed that the use of ample lubricating oil in ¦ the cylinders will not result in the incomplete closure of the valves. The air inlet. valves D are mounted upon each of the pistons and are automatically opened by suction by a friction-operated piston ring E, during the return stroke of the piston. All four cylinders are arranged in opposite pairs with separate head plates. A powerful screw clam, is formed integral with the cylinder casting by which means the pump is readily attached to the running board. The pistons are operated by means of pinions C, C, which have twice the number of teeth as the intermediate pinion B. so that the clamp motion is geared down to the ratio of two to one. Each of the driving gar wheels is screwed to a crank shaft and from the crank pins, connecting rods secured to pistons on opposite cylinders. The two crank pins are arranged at right angles to each other, so that when one pair of pistons is at the end of the stroke the other pair is approximately at mid stroke. The gears are cut gears. The connecting rods are made of manganese bronze. The bore of the cylinders is 1'4 inches and the stroke 2 inches, equivalent to an 8-inch single stroke, and as the pump is so arranged that the compression strokes come at equal intervals, the pump is remarkably easy to operate, especially since the crank handle is quite long. Notes for Inventors The Money in Little Things. -The profits resulting from patents af limited scope frequently come to the notice of patent attorneys in active practice. The writer recalls an instance in which the patentee of a harvester knife grinder submitted the patent for an opinion as to its scope. When told that the patent waa limited very closely to the structure it presented and that almost a “Chinese copy” would have to be made to infringe it he said “That may be so, but I have made seven thousand dollars out of that patent in the last three months in the territory west of the Mississippi.” Possibly his wits had been sharpened by the grinding operation, for we recall an itinerant scissors grinder of the Irish persuasion who opened the office door one day and called out “Has yez anything to sharpen up to-day?” to which one of the office force replied, “No! unless you can sharpen up our wits,” and the answer came quickly back, “I have no stones small enough for that." The One Millionth Patent. -Patent number one million will issue shortly, probably about the middle of August. The first patent of the present series was issued July 28th, 1836, to John Ruggles (antedated July 13th, 1836) of Thomas-ton, Me., for a locomotive engine. One hundred and nine of the patents or the present issue were issued prior to January 1st, 1837, but these one hundred and nine patents were not regularly numbered on the patents themselves, although the original drawings and the specification in the Patent Office are regularly numbered. On January 1st, 1837, however, the patents began to be regulally numbered with pabt one hun dred and ten issued on that day , and the numbering has con- 86 SCIENTIFIC AMERICAN July 22, 1911 tinued until the present time. It will thus require only a little over seventy-fve years to complete the issue of one million patents. Prior to July 28th, 1836, 9,957 patents had 'been granted. These 'patents have never been officially numbered but were numbered in their order by Examiner-in·Chief Skinner when he was in charge of the elassification division of the Patent Office. It has been suggested, some ceremony be attached to the delivery of the one millionth patent, but nothing definite along this line has as yet been decided. A Woman's Patent.-Patent No. 838,053 should be of interest to women because it is for a com bined bread toaster and warming oven for use on gas stoves. Apart from any particular interest in the invention itself, the patent is notable because it was issued to a woman inventor, Minnie Agnes Phelps of Chicago, prosecuted by . a woiman attorney of Chicago and witnessed by two women. Storing Patent Assignments.-The neeessity of fireproof storage faciliUes for the assignment records of the United States Patent Office was called to rttenHon in our issue of May 27th. The Fire Marshal, P. W. Nicholson, of the District of Columbia has just submitted to the Distriot Commissioners an extended report on the hazardous conditions existing practically throughout the Patent Office building. As to the general conditions in the Patent Office, the Fire Marshal has this to say: "'rIle vYorst conditions are on the third floor, lth Street wing. The entire floor and conidOl'S arc taken Ull with comlmstible matter, wood shelving, fijled with official docnments. The corridor is used by the puhlic in the examination of records and the position of the clerical foreps is obstructed by dfsks and tables. "There are two balconies extending from the floor to the ceiling filled with” wood shelving, in which are stored official documents with small aisles hardly wide enough for one per80n to pass. the conditions arc n1uch COlgested. In the event of a fre the fre depat'tment would be much hampered by tho obstructions from the corridors, besides encountering a regular wall of fre. The stairways are hidden from view by the wood shelving and are not properly located. There are two wit'e gates In this corridor, separating two different bureaus, that are kept locked at night. This should not be allowed." ConcernIng the storage Df gasoline in a manner prohibited by the District regula tions, the report says: mhere is a small l'oor in the basement, 7th Street wing, which is used for the storage of oils. I found in this room two wooden barrels, oue containing kerosene and one containi:1g gasoline. The manner in which gasoline is stored should be abolished at once, as it is vpry dangerous. A leak is liable to occur at any time, and if some person, not knowing the volatile conditions, should strike a match, a fre and probably an explosion would he the result. The regulations prohibit the storage of gasoline iI this manner." New Westinghouse Brakes.-A brake meehanism has been prt,ted which has two winding drums. One of the drums takes up the slack in the chain and applies the brake shoes to the wheels, while the other drum applies the brake shoes to the wheels, with the maximum braking power. Means are provided which are operated at a predetermined degree of braking pressure to cut the first drum out of action. The patent, No. 994,286, was issued to the Westinghouse Air Brake Oompany as- assignor (f Richard C. Swartzwelder of Edgewood, Pa, In a patent, No. 994,220, Walter V. Turner of Edgewood, Pa., assignor to the Westinghouse Air Brake Company, provides an air brake in which a number of brake valves act in connection with a single equalizing discharge valve device for the train pipe, which is adapted, to be operated by either brake valve, the brake va'ves having ports and connections so they can .control the pressure in Ithe .equalizing chamber. Caffeinless Coffee. -Three reissues, Nos. 13,261, 13,262 and 13,263, have been granted of original patent, No. 897,84(, for the preparation or treatment of coffee in which the urubroken green cofee beans originally containing caffeln, but freed therefrom, have their remaining natural constituents substantially unimpaired. In removing the eaffein, the green coffee beans are treated with dry steam to loosen the molecular structure, then treated with gaseous chemicals to liberate the caffein from its salts, wHer which the caffein is extracted by a volatile solvent and the beans are subjected to eurrents of dry steam at different pressures. The Cuspidors in the Patent Office.- 'hose who have visited the Patent Office will remember the large cuspidors that adorn the halls at intervals. It is told of a prominent Philadelphia lawyer of the old time that on one Dccasion he was sitting on the steps of the Patent Office nursing a lame foot. A Washington attorney asked what was the matter. He replied that he had been in and had a very unsatisfactory interview with a Patent Office examiner and it had been his habit when discussing patent matters before CongreSSional committees, if the results were unsatisfactory, to kick the rubber cuspidors then in use of the U. S. Capitol along the halls. On leaving the examiner's room after the unsatisfactory interview, he pursued the same tactics, thinking that the cuspidors in the Patent Office halls were also rubber, but he said with an exclamation: “I found them to be cast iron and almost broke my foot." The Need of an Easily Set Rat Trap.- Wasn't it Jay Gould who laid the foundation of a great fortune by the sale of rat traps? If so, and you have ever trier to set one of these five or ten cent affairs they sell in the department stores, you .may well wonder why sOime one does not follow his example with a mouse trap that ean be set without losing all one's religion. Ross Turner as a Patent Office Draftsman.-A celebrity who was at one li mej an attache of the Patent Office is Mr. Ross Turner, the prominent water color-lst. Prior to his European studies, Mr. Turner was a draftsman in the draftsmen's division. This, of course, was many years ago, but Mr. Turner is well remembered by some of the older officials. Legal Notes Color and Trade-marks.-ln ex parte Austin, Nichols&Co., the CommissiDner of Patents has held, affirming the decision of the trade-mark examiner, that where the applicant states that the color of the trade-mark is not claimed, the special lining of the drawing to indicate color should be omitted. Also that coffee and .ocoa are goods of the same descriptive properties. An Unfair Competition Decision.-The Supreme Court O'f the United States by Mr. Justice Holmes has delivered an opinion in the unfair competition case of Jacobs vs. Beecham, affirming the dedsion below and holding that the burden rests upon the defendant when sued for an unfair use of uhe plaintiff's name to justify his use Of the name; also that the use of the name of a manufacturer of pills under a secret formula upon pills made by a competitor is not saved from being unfair because the name of the manufacturer is accompanied by a statement that the competitor makes the pills,' even H it be conceded that he is using the ouher's formula. The dedsion also refers to the use of the word “patent” as applied to proprietary medicines and holds that the use of the word “patent” to indicate a medicin! made by a secret formula when the medicine- is in fact not patented, is not such a fraud as defeats the right of the manufacturer to lielief in equity against unfair competition. In the decision it is said “l'he use of the word 'patent' to indicate medicines made by secret formulas is Wide spread and 'Well known. It is mentioned in the die-tionaries and it occurs in the plaintiff's circulars." RECENTLY PATENTED INVENTIONS. 'hese columns are open to all patentees. ''he notices are inserted by special arrangement with the inventors. Terms on application to the Advertising Department of the Scientific American. Pertaining to Apparel. HAT.-D. SteRn, New York, N. Y. ''his invention relates to hats, and it has for its object the provision of one having a separate crown membcl', which lllay be readily mounted on a brim member, So that hats of many different styles may he quickly provided by the selcction of the desired crown member, to be used with the brim member which has been previously selected. Electrical Devices. SIGNALING DEVICE FOJ TEI,EPI-NE SYSTEMS.-A . ,T. Dunron, Ketchikan, Alaska. ''he main objec. here is to provide a signaling system in which the signals may be sent to a considerable distance, as far as the line is likely to be used for talking purposes. A fHrther object is to provide a system with simple apparatus, including a relay for producing audible signals. Of Interest to Farmers. AFETY CHECK FOR CUTTER BARS OF MOWING MACHINES.-N. Rogers, Wolfboro, N. H. The object of this inventor is to provide novel means for automatically and instantly stopping the action of the cutter bar while the mowing machine is progressively moved, at the time the driver vacates the seat on the machine when said vacation is effected purposely or accidentally. LEGAL NOTICES Of Heneral Interest. MARKING STAKI-M. F. NoGrse, Cement, Wash. 'he intention of this invention is to provide a stake having a weight near its pointed end for steadying the stake, and so arranged that it cannot slip on the stake, even should it become loosened. A further object is to provide an improved holding means for the stake when not iI use, with which the stakes may bc easily connected and disconnected. PACKEH 1,'OR WELLS.-A. C. Graham, Oilfields, Cal.-One object here is” to provide a packer which may be inserted within the casing already in position and which is left in place in the casing after the insertion of the cementing material. The cementing material will firmly lock the packer in place, and the lowering device may be disconnected from the packer without disarranging it in its position at the end of the casing. DISprAY STAND.-Wal'J'er GllbeUt, St. Louis, Mo. Among the principal objects which the - present invcntion has in view are : To provide a revolving stand arranged and constructed to facilitate the handling and display of merchandise packed in cartons ; to provide a simple and efficient means for deliver- ing the cartons so that the same may be handled for the delivery of the goods therein contained; and to provide a display stand the construction of which is simple, economical, durable, and efficient. The illustratiol herewith, shows a perspective view of a vertically disposed rotary stand constructed and arranged in accordance with, the invention descrihed. TRUSS.-p. S. Haehn, Youngsville, Pa. In this invention the construction confers resilient support for single or double ruptures in the inguinal region, adapts the truss for yielding conformity in the movements of the body, avoids excessive pressure upon the tissue neal' the rupture, but exerts such a constrneting pressure upon the defining wall of the hernia as will have a tendency to dose the edges ther<of and facilitate a healing action tbat will ('ure the samp. LOADING WIRE FOR THA VELER DISPENSERS.-.. S. Drake, Lancaster, S. C. The object here is to provide means for supplying travelers to the dispensing device, by means PATEN TS INVENTORS are invited to communicate wit u niunn&Co., 3(H Broadway, New York. or 025 F Street, “·ashington, D. C., in regard to securing valid patent protectiun for their inventions. Trade-l[arks and Copyrights registered. Design Patents and Foreign Patents secured. A }ree Opinion a. to the p r ob a b l e patentability of an invention will be readily given to any inventor furnishing us with a model or sketch and a brief description of the device in question. All commullicatiolls a r e strictly confidentia1. Our Hand-Book OI Patents will be seut free on request. Ours is the Oldd ett a gency for secu nng patents j it was est,ablished ove r sixty-five years ago. MUNN&CO., 361 Broadway, New York Branch Office. 625 F St., Washington, D C. P AT E N T S SEC U l E Or FEE /* 1 U 11 1 O RETURNED Free report as to Pa tentability. IJlustrated Guide Bo ob, and What To InvenL with Liit of InvelltieO us Want e d and Prizes offered for inventions sent free. VICTOR J. FV ANS&CD .. W as h i n g ton. D.C. Classified Advertisements Advertising in this column i, 7;·) cents a Ime. No less than tour nor more than J2 Jines accepted. Count seven words to the line. AI) orders must be accompanied by a remittance . Further informa l ion sent on request. FOR SALE. FOR SALE.-Complete set Patent Office Reports for the year IS36 to 1871 inclusive. bound volumes of Official Gazette from 1872 to. 1900 inc l usive, unbound volumes 10.01 to date. All in g oo d condition. Address P. O. Box B” Ma maro necl kl , N. Y. HELP WANTED. WANTED-GENERAL SUPERINTENDENT^ take charge of a s h e e t metal stove shup employing 10 t 0 men. Must be th or oug h l y familiar with sbeet metal work, factory management and equipment . He must be strictly sob er . efficient and have gswso d constru ctive ability. and be able to tu rnish frst·class re ferences as to cbaracte1', experien ce and ability. Only th0se who can fully qualify need apply. Address Box 773, New York, N.Y. SUP ERINTENDENT.-Metal Department of “ lar/e manufacturing concern. One who thoroughly under· stands the making and fnishing of articles from sheet : etals. fo oee who is nS thoroughly expe;ienced nee3 apply. Per: : ne di positi on to rih t party. lddress Metal Expert, Box 773, N. Y. PATENTS FOR SALE. FOR SALE.-Outri/bt, U. S. latent 948280- combination or keyless padlock, and locking device for anv style lock. Simple, attractive. durable. Small capital re quired. Unquesti(.nable saJe. John Junkulc, P. O. box 523, Pocatello, Ida. FOR SALE.- l h ave inv ented a lead ring for ca ttle. Patent No. ,lE81. 1 des i r e to sel l toiB patent . For full particulars about tbis invention and oth er information. addres8, K. P. Williams, Houte 3. Burling ton , Kansas. FOR SALE. -Patent N fl. 991[:89. This is a join1-fAstene r . “Invisible” for win dow sc r pen, Ecreen doors. etC. No nailS or screws used. D. A. W n.ght, 318 4th St ., San Anton i o , 'I'ex. THE PATENTF1E of No. 937733, a metal device for ho l ding paper targets. especially useful for indo n r prac t ice, wisbes TO have same manufactured. or will seil patent or inves t it in a factory. C. P. Worrell, Zanesville, Ohi o. _________________ WANTED. LOCAL REPRESENTATlVE WANTED. Splendid incom e assured rig ht man t o act as ou r represe ntative atte r learning our bus iness th oro ugh ly b V m S il. Former expe r ience unneCeESary: All we r eqUlre is honesty, ability, amotion and will.ngness Lo learn a lucrat.e business. No t<ol If Urn? or traveling. This is an exceptiona) opportunity for&man in yp our section to get i nt o ·n big pay ing bURiness , ithout capi tal and become Inde* peddent for life. Write at once for full particular:. Address, E. K Mar den, Pres. The Natfgg art J -9p:ra-ti ve Rea l J\tate Comp a ny. L 378. Marden BuIlding, Wasbinjton. D.C.______________— MISCELLANEOUS. FRE1-"INVESTING foR PROFIT” Malazlne. Send !e your name and [ :ill mail you th lB Wag8:ine absofutilv free. g e l ore you lin:est b dollar anywhere-get this magazine- it is worth $1 a c opy to any man who in tends to i nve s t *'5 or more p er montb. '! 'ells you bow $1.000 can grow to *2? nOO -bow to judge different classes of in"e"tments the Real learning :ower of loir money. Th.s majzazibe six mcnthB free if yoi write to_da;. i. l t: rbe: p u;lis i er, 423. 28 W. Jackson Blvd . . Chicago. CIVIL SERVICI EXAMINA''IONS open tbe way to gao od Go vernm ent p ositions. I can coach you by mail at sm all cost. P'u ll particulars fr e to an y A m eriaa nn citizen of eilhteen OT over. \Vrlte to-day for Booglet E 40. E a rl Hopkins. Wasbinlton, D. C. FOOLISH! FOOLISH! is the man wbo neglects bis Health to p r omote bis busin ess. Send :2.5Ufer Lor a nd's “O ld Age D ef erred” or post ss l fo· o e s c r ip t ive cir cula r. M'. A. Davis Co. . rDrept . S, P ublish ers . Philadelph ia. Pa. META] POLISH. Will send tbe complete formllla tor making it. Decidedly the best on the market. On recetpt of twenty-five cents in COlliS I will send same9 complete. J. Duval, Grand Junction, Colorado. LISTS OF MANUFACTURERS. COMPr.E''IE LIS'IB of manufacturers ill all linps supplied M, short notice aT, mOllerare r a Les . Small and special lists compiled to ( rde l at Vnl'iOU 8 prices “s· timates shOUld be o b t a in ed Iu a d va nc e . .Addres s .unn&Co .,. Inc.. List DeLurtment. Box 773. Iew York. INQUIRY COLUMN READ ''HIS COLUMN CAREFULLY.-Yon will Hnd iuquiries for certain classes of a r tic l es numbered il consecutive order. If you manufactnre theBe foods wrlte ns at once and we will send you The n ame and address of the pa r t y deSiring the information. ffhere is no charge for t h is serVice. In every case' it is necessary to aive the number of tlte iIquiry. Wtere ma o u t actu rer s do not respond promptly tbe inquiry Juay be repeateo. it UNN&CO., Inc. Inquiry No. 92;H. Wanted addresses of p arties having Pitchblende deposits. if able to ship p re. Inquiry No. 92:'. Wanted addresses of firms !elling second-hand water turbines. Inquiry No. !l25S.-Wanted addresses of parties having jzem materials to offer in any part of the world. Inqniry No. 925!.-Wanted to buy a machme for rehoving the .oa!lng of a Albert. In;uirib No. 99'fOa :J !nt ' ddresseB of par ties able to shin corundur, garnet. flint, emery or any mate rial suitabYe as anabrasive. July 22, 1911 SCIENTIFIC AMERICAN 87 of which the travelers will be held in propel' position for dispensing, and supplied to the device in such position. With the improved loading wire, the travelers may be placed on the magazine in proper position for dispensing, and they cannot become disarranged during transfer, neither can they be lost from the wire, if the pins are retained in place, until the loading wire is centered. ROLLER BEARING.-Lu'heR Badger, St . J ohns, Ore. This roller bearing is designed for general purposes, as, for example, car, locomotive, automobile and other vehicle whpcls, and also machines of various characters. The invention is shown in the engraving which represents a c('ntral longitudinal section of the bearing, and the improvement contemplates an anti-friction bearing capable HOLLER BEARING. of free working under end thrust in either direction or a lateral strain, as that occasioned by the weight of the load, the bearing consisting of an inner and outer bearing member, and an internally threaded bear· ing support, the inner beul'lng member increasing in dia meter in passing from the ends toward the center and the outer bearing member composed of two sections threaded into the bearing support from the opposite sides thereof. Hard,vare and Toohi. WRENCH.-ChaRLes Kane, National MiIitary Home, Tenn. 'rhis wrench is provided with difflerent sized jaws, any one of which can be readily moved into act! ve position and securely locked therein. Usc is made of a jaw head mounted to turn on the end of the wrench handle and having a plurality of integral jaws of diffeJ'ent sizes, and a bolt slidable lengthwise on the handle and having its outer end reduced in step form co engage and fit any one of the jaws, to hold the jaw head against tuming in either direction on the handle. The en!raving shows a plan view of the wrench having two jaw heads. It is all steel and durable, the jaws and locking bars are tempered cold steel and contain neither rivets nor threaded screws in the locking parts. The revolving jaws respond readily to the movement of the push button, and the angle at which the head locIs, enables an operator to reach nuts or bolt heads in narrow and intricate spaces. Heatlng: and L!glltlng. OVEN THERMOMETER AND VENTI LATOR.-Henay C. Fe«brache, Bonners Ferry. Idaho. This device wiii automatically regulate the draft of an oven, whereby to maintain a predetermined temperature, will indicate the temperature and may be regulated to operate at different temperatures. The engraving shows a front view of a portion of the oven, with the improvement in place. Superposed strips and damper are so arranged that between certain predetermined temperatures, the damper is not affected. When, however, heat exceeds predetermined high temperature, the damper is closed, the composite bar being flexed toward the lamina having the lowest coefficient of expansion. As soon as the damper is closed, temperature rises, and the damper again gradually 0Jens and is held open until the hi:h temperature falls. When the dawper Is OJen or closed, some little varia- OVEN THERMOMETER AND VENTILATOR. tion in temperature is permittl'u before the damper operating mechanism again comes into play. Machines and IUccitanical Devices. PICTURE DISPLAY CABINET.-MaRk C. Phillips, State Agricultural College, Corvallis, Ore. Among the principal objects which this invention has in view are: To provide an automatic mechanism to expose successively pictorial exhil'its to attract attention and to PICTURE DISPLAY CABINET. please passers by; and to provide a flashlight mechanism for periodically illuminating the said exhibits. The illustmtion shows a vertical longitudin&1 section of a machine which in operation gives an attractive and continuously interrupted display of pictolial designs, interspersed with entertainL'g advertising matter. RAZOR STROPPING MACHINE.-A. FoR' “andeR, New York, N. Y. This machine may be operated alternately by motor or manual power. The blade is addressed in approved position to the stropping member; the blade is oscillated to present opposite sides thereof to the stropping member; the stropping device has a continuously moving double belt adapted to receive there between the blade to be stropped; the double and face butted stropping member is arranged to receive between the faces thereof the blade to be stropped; the device holds the blade in inclined position when stl'opped, and means provide for varying the helt tension. AUTOMATIC GATE.-LouIS A. Laas, Maxwell, 'l'exas. This invention relates to automatic gates, and more particularly to gates that are unlatched and opened by a vehicle approaching along the road and closed and latched again through the same agency, all of which is done automatiCally. An object is to avoid encumbering the swinging gate itself with many or heavy operating parts. The gates is shown in the accompanying engraving, which pictures the various feature. O'f the construction, among which is the provision at each side of the swinging gate of separate vehicle-engaged road members, preferably in the nature of fulcrnmed running boards, and located at opposite sides of the road, one of which controls the opening and the other the closing of the gate, Note.-Copies of any of these patents wlll be fnrnlshed by the Sc ientific A merican for ten cents eaeh. Please state the name of the patentee, title of the invention, and date of thia paper, .O have a Warner Auto-Meter un your car is more important to you than the top, the glass front, or any other accessory. It's almost as important as the car itself. This statement may at first seem overdrawn-but Consider These Points- No matter what top or glass front you select, you cannot go far wrong-all are good. There is no definite standard of value. The Warner is recognized as the Standard of Speed Indicator Values because of its Sup(ere Quality and enduring accuracy. You can go away wronf if you select the wrong Speed Indicator, for not all arc good. * * * The Speed Indicator is the most-looked-at thing on an automobile. The driver refers to it constantly every instant the car is in motion. Other car owners and those who pass your car when drawn up at the curb, look fir the Speed Indicator when deciding for themselves or for others whether you are driving a good car or not. It is com m 0 n knowledge among Motorists and Laymen that the Warner is the Highest-!uality Speed Indicator and that it is used on the best cars_ Therefore, if the car carries a Warner on the dash, they unhesitatingly brand that car as Good. If it is an inferior and unreliable Speed Indicator, the Quality of the car is open to suspicion in their minds_ Our Branch Managers and Salesmen in every important city report having many times heard people on the sidewalk, who have stopped beside a car, say in almost the same words: ” I do not see the name of the car, but it must be a good one for it has a Warner Auto-Meter on it." > * * We are stating facts when we say that the Quality Warner is accepted by the General Public as a reliable index of the Quality of the car which carries it on the dash. New Model M2, $125 Equipped with Warner large figure odometer-electric light ullderglass bezel-outside trip reset and extra detail tri p reset. Has electric lighted Chelsea c1ock-outside wind, and set. Price $125. There are other Warner models varying in price from $50 to $145. .. The Aristocrat of Speed Indicators “ The Warner can be secured through reputable Automobile dealers In any city or town in the United States. Warner branches are maintained in all the principal cities for the convenience of these dealers and their customers. Inquiry to Beloit or at our branches is invited for Warner literature. Warner Instrument Company Main Offices and Factory 1166 Wheeler Avenue, Beloit, Wisconsin Branch Houses Maintained at Atlanta Chicago Detroit New York San Francisco Boston Cincinnati Indianapolis Philadelphia Seattle Buffalo Cleveland Kansas City Pittsburg St. Louis Denver Los Angeles Portland, Ore. 88 SCIENTIFIC AMERICAN July 22, Elll THE SMOOTHEST TOBACCO^ Do you realize what a "smooth” tobacco really is? One that can't bite? If not, try Velvet, It means cool smoking. And, it means a whole volume 01 enjoyment besides-a rich, mellow fragrance that is peculiar to the carefully selected and carefully matured Burley leaves. Try it today and you'll never be content with other tobaccos. At your dealer's, or if h” is sold out, we7I sendyou a can for a dime, to any address zn the U. S. A. SPAULDING & Dept. 7. MERRICK ChicBuo, 111. -m it mm TOBACCO ^=£*-,tfA" Maxim Silencer l«_-J_—\X-\SGSOSBBOOL Checks the muzzle blast, preventing report noise and recoil. Makes rifle practice possible anywhere. Adopted by U. S. Government. ·'onderful aid to marksmanship. Couplings furnished for attaching immediately to any rifle. Write us make, model and calibre of your rifle. We will tell you what Silencer you need, price, etc. Give your dealer's name. WRITE TODAY MAXIM SILENCER, Hartford, Conn. Specify Silencer equipment on yom' new 'ie sw« A Fascinating Booklet: "WAYS AND MEANS IN PHOTOGRAPHY" Full of helpful hints.-Write Burroughs Wellcome&CO. 35, West :3rd St.. New Yor k . or 101, Coristine Building, Montreal ' |"'T|J|',I>,LM^ JTT" Typew Ot er TYPE T y pe Making writers and Other Machines Using Steel Type. Makers of Steel Letters, Metal Stamps, Stencils, Etc. NEW YORK STENCIL WORKS, 100 Nassau St. , N. Y. Veeder Counters to register reciprocating movernellts or revol\1tialls. Cut full size. Booklet Free. VEEDER MFG. CO. 18 Sargeant St., Hartford. Conn. Cyclometers, Odometers. Tachometers. Counters and ]'ne CastinfS. Represented in Great Britain by 1 ark t&Co., Liml'l'IW, n City Roiid, Fioshury Square, London, E. C; }ran:e,by Ma:k;b o.: LimitIW. 10' Avellue Parmentier, Paris; Germany, Aus trint-H)nn Ka:ltY aud Sc andinavian>w . l.OKwl&Co., Hutte*. Strnsse 17 . 20, Berlin.