(12546) F. B. T. says: A short time ago I bought a barometer, which appears to be a very good instrument, but its action is a little puzzling, and I wonder if you can give me a helpful suggestion. The only time that the barometer has gone up to 30 was during the extremely wet weather we had a few days ago; and in the dry season which we experienced during the summer, it ranged around 29'h or thereabout. It has never gone much below 29 in spite of the fact that we have had some very heavy storms. I notice in the daily paper that the government barometer at the Springfield armory seems to agree fairly well with mine in its reading, but in that case, it would seem to me that the lettering, which I have noted, is very misleading. I had the impression that a low barometer stormy, bad weather and a high barometer fair, dry weather. I would be gilad to have you give me any either through your paper, for which I am a regu lar subscriber, or by mail, as you may prefer. A. The words Stormy, Rain, Change, Fair, Very Dry, have no meaning whatsoever upon a barometer, and it is very strange that they should be still pla ced there, since every maker of instruments knows that they are without meaning. The figures around the circles are inches of mercury. In good weather at the sea level “the barometer will be found to indicate about 30 inches. A barometer tes the approach of a storm, a rising barometer indicates the approach of continuance of good weather. A barometer the of the present state of the weather, good or bad. A rapid rise or fall indicates high winds. If you live about 9OO feet above sea level, the barometer will be one inch lower than it is at the same time at sea level, and at 1,650 feet above sea level the barometer will be two inches lower than at sea level at the same time. If your barometer does not agree quite closely with the government instrument in the same neighborhood, it is probably out of order and should be tested. The high school in your city doubtless has a good barometer, and the teacher of physics there wilt be very willing to give you his assistance and advice in the matter. A barometer may be expected to change two inches or thereabout in extremes of weather. The best test for a barometer is to hang it by the side of a reliable barometer and compare the treading of the two for some weeks. (12547) R. N. M. says: Would you please give me a rule or formula for finding the capacity of a cylindrical tank when lying on its side for each inch of diameer ? I desire to make a gage so it can be read at a giving the number of gallons by each inch. The tank is 24 feet long and 9:l inches in diameter, with rounded ends, but for our purpose these ends can be considered as square with the diameter. A. There is no simple formula for the volume of the successive “layers"' of liquid as the tank is filled. There are tables in the pocketbooks, ted from the. mathematical formulas, which give the area of segments in terms of the.area of the circle. The volume of your tank, 93 inches diameter, 288 inches long, is 93 X 93X 0.7854 X 288 —-------------= 8,470 gallons. 231 Now, to find the depth to which 100 .gallons will fill the tank, we must find the height 100 of a segment - of the area of the whole 8470 93-inch circle, or 0.0118 X area of circle. From a table of circular areas and segments (see Kent's “Mechanical Engineer's Pocket-book") we find that a segment having an area of 0.0118 times the area of the circle, would in a circle of l-inch radius, or 3.14 inches area, have an area of 0.0118 X 3.14, or 0.037 inch, and a height of O.073 inch. In a 93-inch circle the height of the segment would be 0.073 X 93 , {>r 6.78 inches; so that filling your tank to 6.78 inches depth will measure 100 gallons. Similarly, you can calculate (with the ai.d of the table) the heights for 150, 200, and all other numbers : of gallons, and make your scale accordingly. LEGAL NOTICES OVER 65 YEARS' EXPERIENCE rade marks Designs Copyrights £.c. INVE-STORS are invited to communicate with Munn&To.. 361 Broadway, New ' ork, or (i-J3 F Street. Washington, D. C” in regard to securing valid patent, protpction for their In-ve n t ions. Trade-Marks and Copyrights registered. Design Patents and Foreign Patents secured A Free Opinion as to the probable 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 communications are strictly confidential. Our Hand-Book on Patents will be sent free on request. Ours is the Oldest agency for securing patents; it was established over sixty-five years ago. MUNN &. CO., 361 Broadway, New York Branch Office. 625 F St.. Washington. D. C. A TrVTC SECURED OR FEE A I E N I C RETURNED D Free report as to Patentability. Illustratt-'d Guide A Book. and What To Invent with Li st of Inventions Wanted and Prizes offered for inventions sent free. VICTOR .T. FlV ANS&CO .. Washington, D.C. Classified Advertisements Advertising- in ibis column ia 7.) cents a line. No less than four nor more than 12 lines accented. Count seven words to the line. All orders must be accom-psmied by a remittance: BUSINESS OPPORTUNITIES YOUR FACTORY AT TULSA will command the Middle West. Natural gas power only$2 to #5 H. P. per year. 26.00 population. Ample labor, materials. Great oil and. coal fields. On large river. Four trunk railways. Sixty three thriving factories already. li'or further particulars write Industry, Bureau of Information. Tulsa, Oklahoma. GOOD BUSINESS OPPORTUNITY. - For sale, a well established business, manufacturing and stlhng a spf'cifilty rapidly coming into general use. A nice, clf an, interesting business which can be expanded indefinitely. No special manufacturing experience necessary. since present trained a'"'d reliable help can r d h i e i tu any young ma who can command $15,000. Address “ Pennsylvania,” Box 773 New York. PATENTS FOR SALE n wondbeater.Patent issued Septembers, 191L lor fall particulars, write Frank Koch, patentee. Arndt's Hotel, Saginaw. Michigan. HELP WANTED. WA NTED—A man orwoman to act as our information renorter. All ur spare time. No experiencenecces-sary. $50 to $00 per month Nothing to sell. Smd s amp for particulars. Hales Association, 6\-13 Association Bldg. Indianapolis, Indiana. LOCAL REPRESENT A i'lVE WAN'lED.-Splendid income assured riebt man to act as our reprf-sentative afi er learning” our businei:!ls thoroughly by mail. b ormer experience unnecessary. All we require is honesty, ability, ambition and willingness to learn a lucrative business. No soliciting or traveling. 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MOTORCYOL ES CHE Ap.-Send to- day for free catalog 01 new and used motorcycles. AI ..o motorcycle accessories and attachable nirtor outfits tor converting bicycles into motorcvcles ;;haw Manufacturing Company, Dept 24. Galesburg. Kans. GIN1'lENG Raising is tbe surest way to make Big Money on Little Capital. One acre will yield 5000lbs. Sels at $6 a lb. 1 will buy all y. u raise. Gro<;{s anywhere. R quires your spare time only. 1 f you are not satisfied with your pr sent income, write me today.. T. 1:1. Sutton, 780 Sherwood Ave., Louisville, Ky. MAKE BIG MONEY operating a Daydark Post Card, Machine. Photo postal cards made and delivered on. the spot in ten minutes in the open street. No dark room necess ry-- it does not require an experienced photographer to make first- class pictures. Pays a gross. profit of 500 per cent. rite-today for free sample andi catalogue. Daydark Specialtv Co.. Dept. 2 V, St. Louis. FREE-'TNVESTING FOR PROFIT'' Magazine. Send me your nam and [ will mail you this magazine: absolutely free. Before you invest a dollar anywhere —get this magazine it is worth $lu a copy to any man who intends to invent *5 or more per month. 'tells you how $1,000 can grow to $22.000 —how to judge different classes of investments; the Real Warning Power of your money. This magazine sir months free if you write today. H. L. Barber. Publisher, 42,3. '28 W. Jackson Blvd.. Chicago. I N QUIR Y COLU M N October 7, 1911 SCIENTIFIC AMERICAN 325 The Current Supplement TRUE economy is based, not on a mere policy of doing things cheaply, but on a systematic and scientific plan of controlling value received against price paid. How the Pennsylvania Railroad guards against loss by poor materials is told us in a valuable article in the current issue of the Supplement.— Prof. Turner's article on The Great Star Map reaches its sixth instalment. Bal-loonists have observed that to them the surface of the earth appears bowl-shaped. The cause of tins is explained by Dr. Charles Forbes of Columbia University. —The sewage purification industry is far from having become standardized, A new apparatus which has been found to give much satisfaction is described by our Berlin correspondent.—In a very excellent article Mr. A. J. Jarman gives practical instructions for the amateur, which will enable him to prepare and mount photographs upon watch lids and the like,—. The farmer will find in this number useful information regarding the construe tion of concrete silos. In these days of remarkable technical development and substitution of all sorts of artificial products for the natural, it is 'refreshing to note occasionally that for some particular purpose some simple product of nature is still found indispensable. The use of spiders' threads in optical instru ments is discussed by W. F. Rigge, who tells us how, on a certain occasion, an entire department of Creighton University Observatory was put out of commission for want of a spider's thread.—Many are the attempts made by amateurs to solve certain mathematical problems, such as the trisection of the angle. It is unfortunate that much ingenuity should be wasted upon such efforts, and discussion of this topic by N. P. Dupuis, should prove very beneficial in clearing up an unfortunate misunderstanding. The problems as ordinarily stated are incapable of solution, not because of any intrinsic bar to such solution, but because of the artificial restrictions imposed by the injunction that the problem shall be solved entirely by Euclidian methods. Remove this restriction and the problems can l')e solved without difficulty. Insist on this restriction and it can be proved that the problem is incapable of solution.—The influence of the mercury vapoi lamp upon the eye is discussed in a note by Dr. W. H. Williams.—We think of surgery as a destructive measure, which may remedy an ill by removing a part of the body which nature intended to be retained. Some of the newest uevelopments bear the promise of constructive work, in which a deficient organ is replaced by a healthy one derived from some external organism. This subject is discussed in an article derived from La Nature.— Some interesting new light has recently been shed upon the process of fertilization by' researches on the influence of radium upon the frog embryo. A short account of this work is given in the current issue. —From the fertile mind of Svante Arr-henius we have an article on the Fate of the Planets. The Disposition of Guns in the Dreadnoughts (Concluded from paffe 3181.) The second turret from forward is superposed, as is also the second from the stern, the object in each case being to increase the volume of fire along the line of the keel. The fourth turret from aft is also superposed above the third, but here the saving of length was the object in view, as these guns d'l not bear aft. (Fig. 12.) The only other six-turret “Dreadnoughts” with a 100 per cent broadside are the Argentine ships “Moreno” and “Rivadavia.” These vessels, with twelve 12-inch guns, have- four turrets on the middle line and two echeloned (Fig, 13). There has been, and probably will continue to he, much controversy as to which is the mare effective arrangement; but the fact remains that the “Wyom-ings” can cover an arc of 95 degrees on either beam with all twelve guns, while in the case of the Argentine ships this is 1 0 degrees less. For ten guns the respective figures are 120 degrees and 1 05 degrees, and for eight, 135 degrees and 120 degrees. The Brazilian battleships “Sao Paolo” and “Minas Geraes” have their guns arranged on a similai plan to the Argentine vessels, but the superstructure divides the echeloned turrets, which are therefore. not available on both broadsides. For practical purposes the French battleships “Jean Bart,” “Courbet,” “France,"- and “Paris” are similar to the Brazilian, two turrets being mounted forward and aft (with one superposed in each case), and two abreast amidships. (Fig. 13.) We now come to a striking variation in design. The German battleships “Rheinland,” “Posen,” “Nassau,” and “Westfalen” all have twelve ll-inch guns as their main armament; but they are so disposed in their six turrets that only eight guns bear on the beam. (See Fig. 15.) It was at first thought that this system was due to a misapprehension as to the system of naval tactics which the “Dreadnought” principle involved, but this is hardly borne out by the fact that the arrangement is being strictly adhered to. The, “Thuringen,” “Helgoland,” “Ostfriesland,” and “Oldenburg” are armed with twelve 12.2-inch guns apiece; but the distribution remains the same. Although, therefore, these ships carry as many big guns as the “Wyoming,” the latter is 50 per cent superior on the broadsides. The German vessels, with their twelve guns, are no better as line-ahead broadside fighters than the “Michigan,” the British “In-vincibles,” or even the 15,500-ton Spanish Espanas—leaving questions of speed and protection out of consideration. Curiously enough, the Japanese have also adopted this system, at least for their first two all-big-gun ships, the “Ka-wachi” and “Settsu,” for the distribution of the 12-inch guns in these ships is the same as that of the ll-inch and 12.2-inch in the German vessels. The average student of the naval war between Japan and Russia will be hard put to it to find any justification for this subordination of the broadside; and it is more difficult to understand since it has been reliably stated that all the data gleaned by the Japanese were- placed at the disposal of the British authorities. The same tactical data could hardly justify the “Orion” (Fig. 7) and at the same time excuse the “Kawachi” (Fig. 15.) Summarizing these, details, it will be found that the total number of heavy guns mounted in the 69 ships of the “Dreadnought” era whose details are known is 723, a total that could not have been attained with fewer than 181 ships of the pre-"Dreadnought” era. The ownership of the guns, as well as certain other details, is shown in the following table: . j Guns Mounted (Inches Caliber). | 0 i--;---------------- :n I '14-Inch 13.5-1n. 12-Inch. ll-Inch Countries. °0 ^____ E c5 a)' a.l d PJ 's -= ^ rri' ^ --' ^ —' 13 c^oc- O ^ O ^ o ........ cq s e « Great Britain. 88 27 ....... 104 104 21)2 238 United Stak> 12 10; 8 ) 20 100 100 Germany. .., 21; 9'..... .... 48 3-3 56 40 Italy........ 4 4............ 51 51 Russia........ 4 4 ... 48 48 France ... 4 4...... W 49 Spain....... 3 3.. _ 24 24 . . [ Argentine . 2 2.., I ... 24 24 Brazil . . 3 2.,. , ... 24 20 ..... Japan ____ 7 2.. . ' 24 ]6 ...... Austria..... 4 I 2...... i . . 24 24 . .. Turkey. 2,( ... . ! ' ' Chili..... 2 ' 0...... ; | _ ... Totals........ 100 69 20 104 543 56 Number of guns in three-gun turrets...... .. Ill Number of guns in center-line turrets. 20 104 407 20 _____I_I_ It will be noted that as the caliber increases so does the desire to place all the guns on the middle line. A Political Laboratory APOLITICAL laboratory has been established at Columbia University through the generosity of Patrick F. McGowan, ex-president of the board of aldermen, and will be available at once for the 150 students of politics at the university. Sufficient money has been given by Mr. McGowan to maintain the labora- There is an air of substance that distinguishes wearers of "CORRECT STYLES FOR MEN Absolutely correct styles, splendid workmanship, fine materials and trimmings unite to give these hats a tone that is instantly recognized. Wear guaranteed. Prices, $3, $% and $5. At your dealer's, or if he cannot supply you, write for Fall and Winter Style Book II , and we will fill your order direct from factory if you indicate style wanted and give hat size, your height, weight, and waist measure. Add 25 cents to cover expressage. We Makers of the Factories: Danbury, Conn. Niagara Falls. Ontario, Canada. 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It contains articles written by the most famous men connected with the Science of aerial flight. At the present time all progressive men are studying this great Itew art of flying. tj AIRCRAFT is generally recognized by the leading authorities on the subject as being the organ of the movement itself. q I TIS PUBLIS H E D M O NTHL Y Its subscription price is $1.50 per year, or $1.00 for eight months THE LAWSON PUBLISHING CO., 37-39 East 28th St., New York, N. Y. SCIENTIFIC AMERICAN October 7, 1911 About Remembering By ELBERT HUBBARD FOR a long time I have been promising myself to write up my good friend, Mr. Henry Dickson, of Chicago, and I have not forgotten. Mr. Dickson is teaching a Science or System, which I believe is of more importance than the entire curriculum of your modern college. MR. DICKSON teaches HENRY DICKSON memory. America's Foremost And or- Good memory is necessa- ilyonM*movy-Tr»irjingaii4 to a|| achievement Priorip»lDick.oiiScl]ooiof ry to al1 achievement. M",mor?. Auditorium BoiM- I know a man who is a graduate of three colleges. This man is neither bright, interesting nor learned. He's a dunce. And the reason is that he CAN NOT REMEMBER. He can not memorize a date or a line of poetry. His mind is a sieve. Education is only what you remember. Every little while I meet a man who has a memory, a TRAINED MEMORY, and he is a j oy to my soul. The manager of a great corporation never misses a face. If he sees you once the next time he will call you by name. He told me how he did it Hestudied memory training with Prof.Diekson. He said a lot of nice things about Prof. Dickson, that 1 hesitate to write here lest my good friend Dickson object. i i i f wantto enlarge yourarm, youexercise it. The samewith your mind. You mustputyour brain through a few easy exercises to discoVer its capacity. You will be surprised how quickly it responds. Youdo not know when you win be calleduponto tell what you know; andthen a trained memory would help you. To the man orwoman whosememory plays tricks I recommend thatyou write to Prof. Dickson, and ifhis facts do not convince you. you are not to be convinced. Write today for FREE hooi/er and facts. Address. Prof. HENRY DICKSON 700 AUDITORIUM BUILDING CHICAGO RISK 25c It will be the best investment in smoking tobacco you ever made. Royal Flush Mixture It's the tobacco you have been looking for. Carefully blended—Pure, delicious and cool. 17vf-«*AA«*j!M«.«*«r H your dealer will not supply you, send EXiraOrainarY his name and 25c for large can. Send today and ask for FREE booklet: “How to Smoke o Pipe. “ I %: oz. 25c; oz. 50c; M lb. $1; 1 lb. $2 prepaid. E. HOFFMAN COMPANY, Manufacturers 175 Madison Street, CHICAGO lllBRlCATCSVo"? Anything *-:^:tw _ H8-124North Clinton St. B ESlI.Y II CO f.V!f.ioff.l>SA WIN THIS $1200.00 ! Thousands Already Won—Going on Daily TEN PEOPLE GET $40,000 They 7efl You How to Win. 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Devoto all or BV'ire time* Means phenomcufll earnings: no competition fascinating, high-sraJ&bu&ineaa-&rdquo; edit given aetlve ulstrlbutQrtfi Send no nsuu-ey — inTeFtl-ate flrAt« ENERGIZE” ^<Jr^Tn Send to-dor far remarkable offer—It's valuable butfree. Address ALLEN MFG. CO,, 3391 Allen Building, TOLEDO, OHIO tory” for two years. Its purpose is to bring the students in contact with the documentary sources of information, and in addition to place the collection of materials at the disposal of the debating teams of the university. The laboratory will consist of a select library covering the field of American government and politics. Newspapers from all parts of the country will be kept on file for a certain period and afterward clipped and indexed. A large number of weekly and monthly magazines will be kept on file. Then there will be such books of reference as the American Year Book, the Cyclopaedia of American Government, Beard's Digest of Short Ballot Charters, a.nd the like. The laboratory will also contain a large number of federal, state, and municipal publications, which will include the Congressional Directory, Congressional Record, Labor bulletins, consular reports, reports of civil service commissions, the constitutions of all states, legislative manuals, sample ballots, election laws, and, in fact, everything that the student in politics needs. Special subjects will also be cared for as well and extensive collections 'in the field of politics will be made. A New Opportunity in Industrial Education THE first requisite of education should b e that it helps the b oy to make a livelihood. Whatever else it may do it should at least train him properly for some occupation. Education which thus ministers to self-support is attracting wide attention, and the need for the development of trade schools in all important industrial centers has become everywhere recognized. In this matter of trade schools, Boston merits particular attention as it is especially in advance in this direction. The most recent accession to the list of existing educational institutions is the New Wentworth Institute. This most important addition to the present educational facilities of the Commonwealth, which are so amply provided and so excellent in many other directions, furnishes new and very much needed opportunities in the industrial field where at present there are none. The new Trade School was founded by the late Arioch Wentworth, a citizen of Boston, who left over three and a half million dollars for the purpose of “Furnishing Education in Mechanical Art." The aim of the new school is to give young men practical instruction which will enable them to enter industrial life prepared to do and earn from the moment of graduation. These courses are for those who wish to become skilled and intelligent artisans and industrial workers, and also for those who wish to prepare themselves for more responsible positions in mechanical and manufacturing plants. "T'o furnish education in mechanical arts'' is the statement of purpose made by Mr. Wentworth tn his bequest. This phrase defines both the general field of education which the new school occupies, and it also defines with equal defi-niteness many of its essential characteristics. It is a school to furnish -i-tion in mechanical arts; in other words, a school to train young men for a higher degree of efficiency in mechanical trades requiring both skill and intelligence than they may attain through any opportunl-ties which are now open to them. The End of the British Naval Airship THE first naval airship built for the British government by Vickers, Sons&Maxim, at a cost said to be $400,000, was wrecked in Barrow in Furness on September 24th. It seems to have been ruined from the same-cause that brought about the destruction of so many Zeppelin craft, namely, the impossibility. of preventing the airship from being battered against its own shed when ' half drawn out. The new dirigible, which has been fully described in these columns, never really flew. It was taken out on May 22nd, but failed to ascend. The builders thereupon undertook to lighten it, and the Admiralty finally accepted it on September 22nd, Electricity Queen Mary's Fan. —An electric fan has recently been made by the General Electric Company for Queen Mary of England. It has been designed to harmonize with the royal toilet articles. It is mounted in gold, and is provided with an ebony switch. The fan will be used to dry the Queen's hair, after a shampoo. Electric Lamps Here and Abroad.— There are in Boston, says the Electrical Review and Western Electrician, the equivalent of 1,232 sixteen-candle power electric lamps per .thousand of population, in New York 859, in Chicago 730, and in San Francisco 660. European cities show much smaller figures, St. Petersburg having 440, Vienna 246, Paris 185, and London only 4. Electrocuting the Codling Moth.—The owner of an apple orchard in Spokane has constructed an apparatus with which he hopes to rid his orchard of the codling moth. He uses electric incandescent lamps, surrounded by a metal netting, which is charged with electricity. The moths attracted by the light strike the wire and are instantly killed. 'The cost of the storage battery and lamps is comparatively small. Electricity from Peat in Canada.—The Canadian government, wishing to arouse interest in the utilization of peat, has built a plant at Ottawa. and secured a peat b og of th ree hundred acres near Alfred, Ontario. The plant is equipped to make producer gas from tho> peat, which will be used in a 60-horse-power four-cycle gas engine, directly connected to a 50-kiIowatt dynamo. It is estimated that there are 36,000 square miles of peat in Canada, which would yield 28,000,000,000 tons 'of air-dried peat, which would be equivalent to 14,000,000,000 tons of coal. To demonstrate the commercial practicability of utilizing peat for power purposes a building adjoining the Ottawa plant will be fitted up as an ore-dressing laboratory and will be operated by the electricity generated from the peat. Wireless Telegraphy in the Congo.—A recent consular report states that within five years there will probably be 200 wireless telegraph stations in operation in the Congo. A Telefunken station is in operation at Boma, the capital of Belgian Congo, and a station of the French Ferrier type at Banana, the principal seaport. Each of these is of 1% kilowatts, but the latter will shortly be increased to 5 kilowatts. The Telefunken engineers expected to erect in September a 5-kilowatt station at St. Paul de Loanda, in the adjoining Portuguese territory at Angola, after which a station was to be established at Leo-poldville, on the Congo River. If these stations prove successful, an extensive series of stations will be erected all along the Congo and Kasai rivers. The French company expects in the near future to erect a station at Loango, French Congo, and later stations in all the French West African colonies. Electrical Fires in Chicago.—Some interesting facts gathered from the annual report of the city electrician of Chicago are quoted by the Electrical World. These relate to the electrical inspectors' reports on electrical fires in that city during the year 1910. A table is given to show that there were eighty such fires, with a total loss of $37,550, a small amount compared with the total Are loss. Of this amount, one fire caused a loss of $30,000, the' cause in this case being the breaking of a lighted portable incandescent lamp, the sparks from which fell into gasoline and oil on the floor. The next largest loss was caused by a fire due to sparks from a defective socket falling on chemicals. This defective socket was suspended over the chemicals by lamp cord extended through a metal hood. The loss was estimated by the inspector at $5,000. In all other cases the loss was comparatively slight. Of the eighty electrical fires, fifteen were due to low-tension wires short-circuited, nine to motor. burn-outs, seven to sparks from motors, five to overheated flatirons, five to wires grounded In conduits, four to low-tension wires grounded, four to defective rheostats, four to lightning, four to short-circuits at fixture outlets, four to breaking of incandescent lamps and the rest to a variety of causes. i;Cf /id” fmtrm"« ,11 ,-1iv Screw Cutting Automatic I ITHrC Cr™ F»d LillllLd For Fine, AccuraSe \f oris Send for Catalogue B SENECA FALLS MFG. CO. 695 Water Street Seneca Falls, N. Y., U. S. A. SEBASTIAN LATHES 9 to 15 Inch Swing HigA Quality Low Prices Co/olog Free THE SEBASTIAN LATHE CO., 120 Culvert St., Cincinnati, O. The “BARNES” Positive Feed Upright Drills 10 to 50-inch Swing Send far Drib Catalogue W. F.&Jno. Barnes Co. \ (Established 1872) 1999 Ruby Street Rockford, Illinois THE MOST USEFUL PLYER MADE Drcp i'"r£ml F,t«H : Itaml ta tiruck till trOTH hftrtVV etorfc tru-fl unusual atreugLb. Jtfrt inkv w ]W In. Grip* TfflUlid or tftp*i:*d <j}.]e<:t*. EffecH™ piim wench. Hf>Jrt orini-n send jvt j-a$« aalahn, jfy, is-B. STAlCliETT CO.. AthoIt V.^s., U.S.A. THE BEST EQUIPPED SHOP For Mechanical and Electrical Manufacturing Special Machinery, Jigs, Tools, Repairs, Experimental Devices IH'.lenLuK and Cuiiiinvrt'lullziiifr n Sprcliitty THE UNIVERSAL TELEGRAPHIC COMPANY *Mttsai>« 1,1 Th. Itoirlniol Trlrcrniflilr Co. TUI/riflOrtP, 111*. Mannfartiinn« of Special Machinery, Metal lUcUlUldllUrillg Specialties, patented Devices, Dies and Tools, Stampings, Screw Machine Work. Model and Experimental Work. M. P. SCHELL MFG. CO. 509-511 Howard St. .... San Francisco, Cal. WAWTCTl To manufacture METAL SPECIALTIES, 20 year, experience in making Dies, Tools and Special Machinery. Expert work. Complete equipment. NATIONAL STAMPING&ELECTRIC WORKS D.ut, 2, 412 So. Clinton Street, - Chicago. Ill. Patented Articles and Metal Specialties MANUFACTURED BY CONTRACT Stamping Dies, Metal Stampings and Screw Machine Work H. CARSTENS MFG. CO., 567cScr.tGo St. NOVELTIES 8r PATENTED ARTICLES By CONTRACT PUNCHINS DIES. SPECIAL MACHINERY. E.KONIGSLOW STAMPING & lOOL WORKS. CLEvE land. O. Models&Experimental Work INVENTIONS DEVELOPED SPECIAL MACHINERY .. . E.V. BAILLARD CO., 24 Frankfort St.,N. Y. MECHANICAL-^ SUPPLIES in* MATERIAL Qf -il “In Hp. ;:.nrrn m tntm. and m::,f-i r mjwh sil WORK la ori*t. 132 MILK STH££T BOSTfiH Manufacturers of Metal Specialties, Stampings, Dies and Tools. Thirty Power Presses at your service. Hoeft&Company, inc. CHuIc;.Al°' 141-143-145 West Michigan Street, corner La Salle Avenue Corliss Engines, Brewers VILTER MFG. CO. 899 Clinton Street, Milwaukee, Wis. DURYEA BUGGYAUT u may simplicity with many. but for id (_[unjiil_i!y-you will use a Buggyaut. experiment lilicity and (liinUluv: _________________... "ITS THE ULTIMATE THING c:s ST DURYEA AUTO CO., SAGINAW, MICH. Your PATENTS and BUSINESS in ARIZONA Incorporate Laws the most liberal. Expense the least. Ho Id meetings. transact business anywhere. Blanks. By-Laws and forms for making stock fuil-oaid for cash. property or services. free. President Stoddard. FORMER SECRETARY OF ARIZONA, resident agent for many thousand companies. Reference: Any bank in Arizona. STODDARD INCORPORATING COMPANY, Box8000 PHOENIX, ARIZONA BIG MONEY FOR YOU Felling our metallic letlers for office windows, store fronts, and glass sig'us. Any one, nn put them on. Nice, pleasant business. Big demand everywhere. Write toby for fnje sample and full particulars. BIETAIJJC SIGN IF.TTEU to., 438 North Clark Street, Chicago BAKELITE (REG. U.S. PAT. OFF.) the new synthlitic substance of many applieations. Write for booklet.,. GENERAL BAKELITE COMPANY, 100 William St., New York, N. Y i and Bottlers' Macblnery October 7, 1911 "Red Devil” No. 024 Far Famed as a GLASS CUTTER MzY/zons ha'Ue heen sold It will cleanly cut a maximum number of feet of glass with a minimum effort — and the tool will prove it. “It's all in the wheel.” At all dealers. 10c. It's one of the “Red De'Uil” Tool Family. Smith&Hemenway Co. 150 Chambers Street New York City r-DON'T PAY TWO PRICES^ Save $18.00 to $22.00 on HOOSIER HEATERS&RANGES Why not buy the best when you can buy them at such low. unheard-of Factory Prices? THIRTY DAYt'l FREE TRIAL BEFORE YOU BI'Y. Our new improvements absolutely surpass anything ever produced. POSTAL TODA Y FOR OUR FREE CATALOG AND PRICES Hoosier Stove Factory 357 State St.. Marion. Ind. WELL DRILLING MACHINES Over 70 sizes and styles, for drilling either .deep or shallow weU in any kind of soil or rock. Mounted on wheels or on sills. With engines or horse powers. Strong, simple and durable. Any m echanic can operate them easIly. Send f\ir catalog. WILLIAMS BROS., Ithaca, N. Y. A Home-Made 100-Mile Wireless Telegraph Outfit Read Scientific Am ° lean Supplement 1605 for a thorough clear description, by A. Fred'k Collins. Numerous adequate diagrams accompany the text. Price 10 cents by mail. Order from your newsdealer or from MUNN&CO., Inc. 361 Broadway, Nevr York -n Z3- ,_,_ L Enormous saving of VhRtAOXOgrapn time in makingtrac-ings from mechanical drawings. Circular free. THE LOXOGRAPH INSTRUMENT CO., Wilmington, Delaware , Solders and Soldering f1l If you want a complete text book on Solders and the art of Soldering, giving practical, working recipes and formulae which can be used by metallurgist, the goldsmith, the silversmith, the jeweler, and the metal-worker in general, read the following Scientific A merican Supplements: I I 12, 1384, 148 I , 1610, 1622, 1434, 1533, price 70 cents by mail. f1l Order from your newsdealer or from ( MUNN&COMPANY, Inc. 'Publishers, 361 Broadway, New York LEARN A TRADE BEYOUR OWN BOSS ly, 'big (WivinK work if you learn Elec. il Work, i'iumlmig', Bricklaying, Paint-ins and Decorating, by our praeticitl, personal nstniction. Act-.ial wort takes place ot books. We help graduates to good positions. Easy payments. Low Jiving expenses. Tools and lniiterials furnished free. Write to-day ior free cfit:ilncn« (101 M MIIOMI IIUI> ^ IIOCII x 60 V. 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Write for illustrated booklet: “GETTING A UNE C11* THE CIVIL ENGINEER.” It will tell you how. AMERICAN SCHOOL OF CORRESPONDENCE Dept. 320 Chicago. Ill. Engineering A Sewer System for Tokyo. —A consular report from Japan states that the city of Tokyo will install a complete system of modern sanitary sewerage before the opening of the world's exposition, which is to commemorate the fiftieth anniversary of the crowning of the Mikado. Tokyo has a very large area in proportion to its population, viz., about 100 square miles; hence the installation of sewers will be an immense undertaking. The cost is estimated at from $17,000,000 to $20,000,000. The Dreadnought “New York.” —Fol. lowing the “Connecticut” and the “Florida,” the keel of the largest of our battleships, the “New York” has been laid at the New York Navy Yard on the same ways on which the two first-named ships were built, and excellent progress is being made upon the ship's floor. A touch of sentiment was lent to the occasion by the fact that the first bolt was put in place by the young grandson of the late Rear Admiral Sampson. The “New York” will be 573 feet long, 95 feet, 2 inches broad, will displace 27,000 tons, and will carry ten of the new and very powerful 14-inch rifles. Heat of Exhaust. —Experiments were recently made by one of the leading Swiss firms as to utilizing the waste heat of exhaust gases from internal combustion motors. In the present case the Sulzer-Diesel motor was used. Water is heated by the exhaust, and the exhaust gases are sent through a set of tubes placed inside a water tank. Air for various purposes can be readily heated, for drying ovens or other purposes. One of the main difficulties was to make the tubes of a suitable material so that the exhaust gases would not attack it. However it was found that certain special kinds of cast iron will serve the purpose very well. "Spotting” by Camera.—At present the ' fall of the shots in target practice is observed from the tops of the cage masts of our battleships and cruisers; the “spotter” noting through his glasses whether the shot falls short or over, or has a deflection to right or left. Lieut. Com. Cleland Davis, whose torpedo has been illustrated in this journal, has invented a method of spotting by the aid of the camera. The splash is photographed and in a few seconds the negative is developed. The necessary corrections in the range and deflection are then made, and it is stated that the operations are so speedy that there is practically no delay as compared with the present methods of spotting. Lubricating Oil Tests. —From the fact that it is a common practice to use lubricating oil again after filtering it, Messrs. Sabatie and Pellet found it of interest to see whether such used and filtered oil showed any great difference from fresh oil. Analyses showed tha following results. The density of the oil is somewhat increased, this being no doubt due to the evaporation of volatile portions of the oil. The flash point and combustion are a few degrees higher. About the same viscosity was observed in both cases. The acidity of oils is not changed, but the percentage of vegetable or animal oil ! in mixed oils is. considerably lessened. From a practical standpoint the used and filtered oil keeps all its lubricating qualities, provided that care is taken to secure a good filtering so as to remove all the solid particles. Double-decking a City Street. —Chief Engineer Goodrich of the Bureau of Encumbrances, of the Department of Highways, New York, has proposed a plan for the double-decking of 42nd Street, New York, between 5th and Lexington Avenues. The street is one of the most congested in the city, there being probably no place in the world where so many systems of transportation center as here. The double-decking of the street will give an opportunity for separating the. traffic, to say nothing of at once doubling the capacity of the street. Here is a problem which will have to be met and successfully solved as the modern office. building twenty to thirty stories in height gradually replaces the older building. Some of the down town streets of New York are already congested almost to a standstill. Science An Anthropological Expedition to New Guinea.—The Geographical Journal announces that the Committee for Anthropology at Oxford is about to send an expedition for anthropological research to the little known D'Entrecasteaux group, off the eastern end of New Guinea. It will be under the leadership of Mr. D. Jenness, of Balliol, who won distinction at the University of New Zealand before proceeding to Oxford, and who has had practical experience of life in the bush. Ostia.—Director Marino Vaglieri of the •National Museum at Rome has opened several Republican tombs in the course of his researches at Ostia, once the chief port of Rome at the mouth of the Tiber. A fountain statue of Aphrodite came to light in the Roman theater. It is recalled that the Townley Venus in London was found at Ostia. The new one resembles another statue of equally Praxitelean style which the late Professor Furtwaengler coupled with the London figure, namely, the Venus of Arles. Horace's Villa. —The exploration of Horace's villa in the valley of the Li-cenza near Mandela has been resumed by A. Pasqui. Two sites claim the honor of this name and have divided the pilgrims to the Latin poet's home into ('amps. Both offer scanty remains of Roman country houses. Whether Pasqui will find any relics as old as the reign of Augustus is very doubtful. But his villa ruin will serve a purpose if it only entices more tourists out of the hot streets of Rome to the outdoor charm of the Sabine Hills. Distribution of the Elements in the Earth's Crust.—The solid crust of the earth, with a specific gravity of only about 2.5, as against 5.7 for the entire globe (crust and liquid or semi-liquid interior) is said by Rosenbusch to consist of the various elements in the following proportions by weight: Oxygen, 47.29 per cent; silicon, 27.21; aluminium, 7.81; iron, 5.46; calcium, 3.77; magnesium, 2.68; sodium, 2.36; potassium, 2.40; hydrogen, 0.21; titanium, 0.33; carbon, 0.22; chlorine, 0.01; phosphorus, 0.10; manganese, 0.08; sulphur, 0.03; barium, 0.03; chromium, 0.01. To Remove Tattoo Marks.——Once tattooed, always tattooed, was formerly the rule; but a French army surgeon, Dr. Tranchant, has discovered a method of removing tattoo marks, whether made with India ink or lampblack. According to La Nature, the process consists of first rubbing the skin until a thin layer of the surface is worn away, then applying a mixture of lime, slaked just before use, and powdered phosphorus. The tattooed part having been coated with this paste, a piece of gauze is laid over it, covered with a bandage. The dressing is removed after forty-eight hours. The scab is allowed to dry in the air, and comes away in about a fortnight, without leaving a scar. If any trace of the tattooing then remains, the treatment is repeated. Dr. Tranchant claims to have applied this treatment in a great many cases, with perfect success. A Cold Winter in the Levant. —According to a report from the American consul at Aleppo, last winter in that vicinity was one of almost unprecedented severity. The snow was from two to four feet deep on the level, and covered the plains of the entire country around Aleppo, as far south as Bagdad, and north and east to Diarbekir and Mosoul, while the mountainous districts and the railway from Aleppo to Beirut were entirely blocked for a period of about two months, not even the mails arriving for some lour weeks. If, as we infer from this statement, snow fell in Beirut, it was the first since meteorological observations were begun there upward of thirty-five years ago. It is stated that drivers and travelers were frozen to death on the roads, many flocks of sheep perished together with the herders, and numerous families of Bedouins were found frozen in their tents. It is estimated that between 50 and 60 per cent of the sheep were frozen or starved to death, so that there will be a great reduction in the export of skins, wools and stock for meat purposes during the next year or two. The olive orchards were also badly damaged. Your best negatives deserve and your poorest negatives require VELOX The one paper made expressly to give the best results from the average amateur negative. If you do your own printing use Velox because it is simplest, if you have your work done for you insist on Velox, because it is also best. Velox offers a wide variety of surfaces and qualities from which to choose. The Velox Book, free at your dealers or by nmil, tells all about them and explains in ful l the methods of handling the paper. NEPERA DIVISION, EASTMAN KODAK CO., Rochester, N. Y. The kind of true stories young folks love, and parents approve. Stories of Useful Inventions By S. E. FORMAN Profitable and entertaining stories of the beginnings of everydaythings—the match, stove, lamp, plow, etc.—tales which make the most of all the history and humanity wrapped up in these inventions. A regular picture hook oj useful inventions, too. $1.00 net, postage 11 cents Published by THE CENTURY CO., New York INVENTORY We build models, do INTLNIURS experimental w o r k , light manufacturing dies and tools. G. SCHWARZ&CO., 123 Liberty St., N.Y. M P Pens that have l^^H elasticity—make either a fine or a coarse stroke—and don't stay wHH spread—retain perfect writing H points after long, hard use. ;Spencerian : ™ STEEL PENS ™ Sfee/, tempering, grinding—they do it. ^^II Sample card of 12 different styles with II 2 good penholders sent for 10 cents. SPENCERIAN PEN CO.. 349 Broadway, N.Y . %. . ......... i 0j|l A Permanent Edge “ You can keep your razor constantly keen. so it will give you a close, comfortable shave every day, if you use our New Torrey Honing Strop You don't need any experience or any special skill—the new strop will do it all. The sharpening side is prepared with our newly discovered sharpening dressing. This is oursecretand no other strop intheworldhasit. That is why the New Torrey Strop keeps your razor in so much better condition than any other strop. If your dealer cannot show you the New Torrey Honing Strop—write us for full information. Booklet, all about shaving, sent free on request. . Prices 50c, 75c, $1.00, J $1.25, $1.50, $2.00 and $2.50 Get a Torrey Razor - the Best Made. Every dealer who is not )low selling the New Torrey Honing Strop should write at once for our special proposition. J. R. TORREY CO.. Dept. G • Worcester, Mass. 328 SCIENTIFIC AMERICAN October 7, J 911 The letters that have sold the most goods, collected the most money, settled the hardest complaints, won the best j obs, had the strongest influence—analyzed and dissected for you to learn from, to adapt to your needs, or to develop an original style of your own—with the best examples actually reproduced as they were used and graphically explained point by point. Here in these three volumes—672 pages—are packed the success-secrets back of the letters that are actually winning the biggest results today, that are bringing orders from you and me, and making other men' s fortunes. Two years of investigation by a staff of experts employed by SYSTEM, the Magazine of Business, were spent collecting the letters of firms and individuals ; investigating the actual results; analyzing the comparisons of costs and profits; studying the difference in results obtained by differences in arrangement, wording, enclosures, etc. Every striking idea found in use by mail order house, wholesaler, manufacturer, retailer, real estate or insurance man, bank, collector, individual salesman or complaint clerk was followed out and its returns studied. This mass of information, this wealth of ideas, this gold mine of absolute fact was then charted and diagrammed—and developed into one complete, yet concise, library so clear and simple that from it any busy man can pick out for any sort of proposition, an idea or suggestion that he can know in advance to be successful; or can turn to for original inspiration. It is a work that will show any man how to write or dictate the kind of letter that arouses attention, tingles with convincing strength, and carries its point; how to conduct a follow-up campaign, how to key results, how to compile and index names, how fit schemes and plans to any proposition. Would Yoi j Like tt ) See Actual E xamples of How Othe r Succes: sful iMen Havt : Written- DOWN SYSTEM, the Magazine of Business, conducted this exhaustive investigation only for its subscribers. It was not to be given to the general public until But the subscribers' edition has caused a public knowledge of the tremendous value of the contents, and an extra advance edition has been made imperative. 2640 special sets have been hastily printed. To make its distribution fair and equitable to all business men, SYSTEM has made the terms as simple as writing your name and as easy as buying your cigars. $1 with this coupon brings to you the complete “Business Correspondence Library “—3 volumes— 672 pages, transportation prepaid. $2 per month for 4 months thereafter —less than 7 cents a day—pays for them complete and in addition brings you SYSTEM, the Maga- zie of Business, every month for two full years—24 numbers of this remarkable business magazine, inc: uding a copy of —Letters to Follow-Up Inquiries see Vol. I, pp. 138, 139; Vol. III. pp. 75, 84. —Nine Main Angles for Follow-Up Letters see Vol. I II, pp. 63, 64, 78. —Letters to Accompany Catalog see Vol. II, p. 35. —Opening Paragraphs to Get Attention see Vol. I, pp. 34, 35, 36, 37, 38, 39, 84, 85. —Interest-Holding Paragraphs see Vol. III, pp. 149, 150. —Arguments to Clinch the Sale see Vol. I, p. 47; Vol II, pp. 47, 136. —Schemes to Get New Customers see Vol. II, pp. 169. 214, 224, 225, 227; Vol. III, pp. 29, 31, 137. —Money-Getting Collection Letters see Vol. I, p. 135. —Clever Answer to Complaints see Vol. III, pp. 189, 198. —Arguments to Advance Prices see Vol. III, pp. 159, 161, 174. —Paragraphs to Prompt Action see Vol II, pp. 16, 17, 71, 72. 73, 74, 75, 76, 77, 78, 79; Vol. III, pp. 92, 93. —Letters to Dealers' Clerks see Vol. III, p. 32. —Educational Letters to Dealers' Customers see Vol. III. pp. 8, 9, 12, 13, 138. —Sales Letters to Dealers' Customers see Vol. III, pp. 18,19, 21, 22. —Letters to Follow-Up Real Estate Sales see Vol. III, pp, 77, 86, 87, 88. —Letters to Illustrate Demonstration Offers see Vol. III, p. 157. —Effective Descriptions in Letters see Vol. 1, pp. 44, 45. —Salesmen's'Letters to Dealers s{-e Vol. III, pp. 41, 42, 43, 44. — Unusual Sales Letters see Vol II, p. 12. —Letters to Answer Specific Inquiries see Vol. II, pp. 37, 38. —Clever Schemes to Get Replies see Vol. II, pp. 22, 26, 27, 28; Vol. III, pp. 167, 168. -Paragraphs to Increase Effectiveness of Enclosures see Vol. III, p. 148. —Business -Getting Postals see Vol. II. p. 63, —Schemes to Get Line on Prospects' Needs see Vol. III, p. 136. —Plans for Offering Premiums see Vol. III, pp. 100, 175. —Effective Summaries see Vol. I, p. 46. —Their Best-Pulling Letters see Vol. II, pp. 108, 109. —Letters Emphasizing the “ You “ Element see Vol. II, pp. 133, 134. —Special Inducements to Retailer see Vol. II, pp. 128/129, 141, 178. —Letters Emphasizing Special Prices see Vol. I, p. 149; Vol. III, p. 158. —Dealer's Trade-Getting Letter see Vol. II, pp. 186, 187,. 188, 189, 190, 191, 197, 198, 205, 206, 207, 208, 211, 214, 217, 218, 219, 220, 221, 222, 226, 228; Vol. III, p. 25. —Trade-Getting Letters to Consumers see Vol. II. p. 147. —Letters Asking-Credit Information see Vol. I, pp. 185, 186, 187. —Letters to Poor Credit Risks see Vol. I, p. 185. —Letters Taking Reader Into Confidence see Vol. III, p. 181. —"Last Resort* * Collection Letters see Vol. I, pp. 160, 164. —"True Note” Collection Letters see Vol. I, pp. 190, 193, 194. —Retailers' Collection Letters see Vol. I, pp. 147, 148. —Instalment Collection Letters see Vol. I, pp. 154, 155. - Ol Uglier Letter Offering Inducement see Vol. I, pp. 156, 157. —Tactful Collection Letters see Vol. I, pp. 140, 141. 161, 162, 163, 164. —Collection Letters Quoting from Delinquent's Letter see Vol. I, p. 176. —Letters to Bring Cash With Order see Vol. 1, pp. 189, 191. —Collection Letters Containing Salesmanship see Vol. I, p. 188. —Letters for Collection Agencies see Vol. 1, pp. 158, 159. —Letters Based on Current Events see Vol. I, pp. 91, 92, 147, 173. —LettersIllustrating"Man-to-Man' ' Attitude see Vol. I, pp. 86, 89, 90. —Letters Backed With Proof see Vol. II, p. 15. —Letters Backed With Inducement see Vol. I, p. 47; Vol. II, pp. 49, 136. —Letters Appealing to Women see Vol. 11, pp. 87, 89, 91, 92, 93, 95, 96, 97. —Letters Appealing to Merchants see Vol. 1, p. 149. —Letters to Revive Old Customers see Vol. 111, p. 182. —Letters Offering Investments see Vol. TI, pp. 102, 107, 110, 111. —Letters Appealing to Farmers see Vol. II, pp. 118, 119, 120. —Letters With Appeals That Get Attention see Vol. II, p. 26. —Letters With Effective and Clever Appeal see Vol. I, pp. 101, 103, 104; Vol. II, pp. 101, 102, 103; Vol. Ill, pp. 172, 178, 179. I5c a Copy ISc a Copy AVIATION The October Magazine Number of the Scientific American Issue of October 14th, 1911 The next mid-month number of the Scientific American will bear the date, October 14th, 191 I. (j[ A large part of the number will be devoted to the more practical aspects of flying. (j[ Besides these articles on aviation, the mid-month number for October will contain the usual Scientific American material. abstracts from current periodicals, the inventor's department, and articles on recent achievements in science and industry. (j[ The whole number will be enclosed in a beautiful colored cover by Mr. Wm. H. Foster. Please note the change 0/ price of Magazine Numbers—now fifteen cents on all news stands MUNN&CO., Inc., 'Publishers, 361 Broadway, New York JUST PUBLISHED .J/ :J\[ew andA uthor/taf/ve :Book MONOPLANES and BIPLANES THEIR DESIGN, CONSTRUCTION&OPERATION The Application of Aerodynamic Theory, with a Complete Description and Comparison of the Notable Types By GROVER CLEVELAND LOENING, BJSc., A.M.. C. E. CRITICISMS "The first treatise upon aviation which we have seen whicl- may De styled really complete.....Actual aeroplane designing is the central themeof the volume..... The prominent types are exhaustively compared..... The illustrations are a notable feature." —Rochester, N. Y., Chronicle. "A very complete account of the theory of heavier than air flying machines with a technical description of nearly all the present types of aeroplanes.....Presents in compact shape the substance of aerodynamic theory..... Easily comprehensible to the reader who can concentrate his attention.....It is the most scientific popular book on the aeroplane that we have come 'across so far." —New York Sun. ” Many writers have failed to realize the demand which exists for aero literature in which mathematical deductions are a necessary but not predominant part of a comprehensive exposition of the entire subject. For a writer to steer a straight course between the mazes of trigonometry on the one hand, and the superficialities of mere discussion in a popular vein on the other is to accomplish what can be done only by one who is himself a thorough student in the finer details, but who can sufficiently divorce himself from the mathematical atmosphere as to present the whole subject from a broad standpoint, making it readily intelligible and informative to the less erudite seeker after knowledge." —Phila. Inquirer. ” Students learned in aerodynamics and laymen ordinarily interested in aviation will find equal delight in reading ' Monoplanes and Biplanes.' The book is a welcome addition to the libraries of those who have realized the future of aerial navigation, and desire a work treating solely of the heavier than air machines written by an acknowledged expert and with no hobbies hidden in the discussion." —Boston Journal. ” While enthusiastic in his interest as becomes one who has written so superb a volume, Mr. Loening is also rigidly accurate as the most exacting scientist could demand. Here is a work which is at once a history and textbook which may be depended upon for ^verythinjf that is within the range of actual know ledjsc. To say that ' Monoplanes and Biplanes* is at once new and authoritative with reference to the entire subject and that it is practical in the highest degree is the just praise due to this volume ;Buffalo News. ; Mr. Loening has written, in fact. for the man who wishes to apply practically the experience that has already been gained." —New York Times. 12mo. (6x8%; inches ) 340 Pages, 278 Illustration*. Attractively bound in cloth. Price $2.50 net, postpaid A n illustrated descriptive circular will be sent free on application. MUNN&CO., Inc., Publishers 361 Broadway New York