Chapter X: Remarks. Theory. Accomplishments. Maxwell's Hertz's Discovery (1)

THE FUTURE.

The history of wireless telegraphy and telephony is a striking example of how it is possible for scientists laboring in the field of pure research and stimulated by accumulated knowledge and imagination to arrive at discoveries of the most vital importance. Heinrich Hertz and Clerk Maxwell in experimental effort to attain other results unwittingly laid the foundation of this art.

In 1867 Maxwell proposed the theory that light is not mere mechanical motion of the ether, but consists of electrical undulations. These undulations are partly magnetic and partly electrical. Moreover, according to the theory, the phenomena of electromagnetism and also that of light are due to certain modes of motion in the ether, electric currents, and magnetism, being due to whirls, or body displacements in the substance of the ether, while light is due to vibrations to and fro.

Twenty years later Hertz discovered the most convincing experimental proofs of Maxwell's wonderful theory, and succeeded in producing electromagnetic waves in such a manner that their propagation through space could be examined, and it readily showed that while they were much longer than the ordinary waves of light, they possessed the same properties, were capable of being reflected, polarized, refracted, etc., and traveled at the same speed.

The waves that Hertz produced are the electromagnetic or Hertzian waves of radiotelegraphy.

Many thousand commercial wireless stations dot the face of the earth. Daily time signals, weather reports and storm warnings flash to ships far out in the ocean from government observatories. Late at night, in the midnight hours, when the world is asleep, powerful land stations commence to whisper press dispatches, and the next morning the ocean daily, containing the same news as our morning paper, is laid on the breakfast table of the ocean greyhound. A distress signal sends revenue cutters scurrying along the coast, and brings rescue to hundreds of imperiled lives. The Navy Department issues an order, and a few minutes later it is in the hands of the commanding officer of a fleet, a thousand miles away. Wireless links two continents across a table, and yet this wonderful apparatus is so simple that a sixteen-year-old boy can build instruments with a little guidance and listen to a far-distant station, 1,500 miles away, spell out its news.

Wireless telegraphy is part of the established order of things. The wireless telephone is practical for limited distance, but is not a commercial rival of the telegraph. Great distances are claimed, but they are matters for proof and speculation.

There is no immediate possibility that wireless telephony will take the place of local exchanges. If the time ever does come that it in any way tends to supplant the line telephone for some uses, it is more than probable that each subscriber must have his own generating station and call up direct.

There is a very decided field of opportunity for wireless telephony for long-distance work. The present systems of long-distance wires are very expensive to construct and maintain, and are subject to the whims of storms and the elements.

Wireless telephones will not only transmit the speech more clearly and distinctly, but have the further advantages that the initial cost is very much lower than that of wire lines, the maintenance is almost nil in comparison, the depreciation is smaller, the number of employees required is less, and a break-down is limited to the inside of the station, where it could be quickly remedied by the substitution of a duplicate spare piece of apparatus.

Furthermore, no franchises or rights of way would need to be purchased. No serious difficulty would be encountered because of interference.

Wireless telephony, like wireless telegraphy, but to an even greater extent, is peculiarly suited for the conveyance of marine intelligence. Wireless telephony occupies a unique position in this regard-no operator is required. The additional expense of an operator is an objection to the wireless telegraph in many cases, and forbids its installation. Anybody can operate the wireless telephone. It is also much quicker-words can be spoken more rapidly than they can be put into Morse signals and translated.

The wireless telephone enables a passenger on board ship to communicate direct with his home by relaying the message over the line wires. By the same means the captain of a ship can call his home office and communicate with the owner of the vessel.

Telegraphs and telephones are the nerves of the world, carrying swift messages from its brain centers to its hands, annihilating distance in thought. All differences between men as individuals and people as nations can be traced to the lack of close contact. Reduce or annihilate all distance in thought and action, and mankind would possess unbounded opportunities for peaceful economic and healthful development. No force more vital than the possibilities of wireless has ever presented itself or could be demanded to attain such an end. Such a statement, in the light of actual developments, might even be considered conservative, and is neither absurd nor the dream of a vivid imagination. The greatest obstacle to all efforts in radically new directions is the resistance of the human race. The antagonism of prejudice and skepticism can only disappear when the world as a whole grasps a new proof and learns to appreciate it. Inertia must be overcome, and the great masses set to thinking and striving toward an end before the aweing genie finally bursts forth and amazes the Aladdins of science.

Within the memory of older men and women are primers of science, which speculate about the developments of electrical force, and guardedly discuss its possibilities.

And now, electricity—this mysterious agent-has multiplied the muscular strength of man a billion times. The tasks of Hercules are now but chores to be accomplished by the closing of a switch. Mighty rivers roar through intake and turbine to drive the wheels of industry in a distant city and turn the night into day. Any attempt to chronicle all the applications of this wondrous power would be absurd. Such is electricity to-day.

Only a few years ago Langley launched his famous aerodrome over the waters of the Potomac, while the world stood by and sneered, ridiculed a man whose work is now one of the classics of aeronautical literature, and scoffed at a machine whose principles embodied the conclusions of years of careful thought and scientific effort.

A decade later and aeroplanes have become a living reality. A man and a little frame of sticks and canvas can throw off the fetters of gravity and go soaring dizzily two miles up into the blue sky, and daring more, come skimming and diving back to earth with motor dead. Such wonders only came to pass, however, when numbers of men accepted the problem as one to be solved by trying, and bent their energies toward its solution. Science has not reached the limits of its resources. It never will. The art of wireless may always be embarrassed by novelty in many directions.

One of the greatest steps forward toward the day when methods and appliances regarded as permanent as the mountains will pass and be considered only as the curious remnants of a cruder age is the interest of 200,000 wireless amateurs in the United States. Some of these will develop into men who will bring some of the wonders of the future to their full fruition.

What is this great change that can be coolly and precisely forecast? Along what lines will these wonderful developments come? The answer is "wireless"-not the wireless of a Marconi or a De Forest, but the wireless of a Tesla--of "high potential magnifying transmitters"-of "nodes" and "loops"--of oscillatory currents that leave their conductors behind-the "wireless" of the day when a system is introduced enabling any person to reach any other on the globe, not simply through a spoken word or thought conveyed, but visually a perfect transmission of images which will enable one person to see another, as though that other were by his side-"wireless" of a time when the great operations of commerce and industry will be vitalized by huge wireless power stations, turning the machinery of factories, lighting cities, or sending swift aeroplanes and ships darting to the farthest points of the earth.

Of course, there may be something of the dramatic in such assertions, but they are founded upon scientific facts, and, if imaginary, are scientifically imaginary. The wonderful mysteries of oscillatory currents, whose natural medium is the ether, currents which object to being confined to wires and cables, and defy all ordinary laws; currents that will melt masses of metal with the violence of an explosion, but yet pass through the human body without producing any sensation; currents that will instantly manifest themselves 2,000 miles away from their source, with no visible means of propagation, are the open sesame to the treasures of a wonderful future.

There are many places in the world where water power is available capable of generating almost unlimited electrical energy. The present difficulty lying in the way of its utilization is the limitation of electrical transmission by wire, for not only is the cost of long lines of copper tremendous, but power can only be carried in this manner for limited distances. Central distributing wireless power stations could send the power of Niagara, which alone might be made to supply a fifth of all the power in the United States, and the energy of Victoria to the ends of the earth with little loss. The Great Falls of Zambesi, in the heart of Africa, could be made to run the subway trains, the factories, lights, railroads, ferries, trucks, heaters, etc., in that vast, most complex, most bewildering and inspiring city of the Western World, the City of New York. Ocean vessels would no longer carry thousands of tons of coal, locomotives would not wheeze and cough a trail of soot and smoke through the country, chimneys would cease to belch, and aeroplanes would travel silently and swiftly overhead.

It is easy, in the face of certain facts, to conjure up situations which would be pleasant and make for the betterment of the world. Any one whose imagination is vivid enough can make a prediction, but when the great truth is accidentally revealed, or experimentally confirmed, as the case may be, and rendered absolutely sure of accomplishment, will its incalculable consequences continue to baffle the imagination and carry us further into the land of wonderment? Only the future knows.

THE END.

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AUTOMOBILE

THE MODERN GASOLINE AUTOMOBILE-ITS DESIGN, CONSTRUCTION, MAINTENANCE AND REPAIR. By VICTOR W. PAGE, M. E. The latest and most complete treatise on the Gasoline Automobile ever issued. Written in simple language by a recognized authority, familiar with every branch of the automobile industry. Free from technical terms. Everything is explained so simply that anyone of average intelligence may gain a comprehensive knowledge of the gasoline automobile, The information is up-to-date and includes, in addition to an exposition of principles o construction and description of all types of automobiles and their components, valuable money-saving hints on the care and operation of motor cars propelled by internal combustion engines. Among some of the subjects treated might be mentioned: Torpedo and other symmetrical body forms designed to reduce air resistance; sleeve valve, rotary valve and other types of silent motors; increasing tendency to favor worm-gear power-transmission; universal application of magneto ignition; development of automobile electric-lighting systems; block motors; underslung chassis; application of practical self-starters; long stroke and offset cylinder motors; latest automatic lubrication systems; silent chains for valve operation and change-speed gearing; the use of front wheel brakes and many other detail refinements. By a careful study of the pages of this book one can gain practical knowledge of automobile construction that will save time, money and worry. The book tells you just what to do, how and when to do it. Nothing has been omitted, no detail has been slighted. Every part of the automobile, its equipment, accessories, tools, supplies, spare parts necessary, etc., have been discussed comprehensively. If you are or intend to become a motorist, or are in any way interested in the modern Gasoline Automobile, this is a book you cannot afford to be without Nearly 600 6 x 9 pages—and more than 500 new and specially made detail illustrations as well as many full page and double page plates, showing all parts of the automobile. Including nine large folding plates. Price $2.50

BALLOONS AND FLYING MACHINES

MODEL BALLOONS AND FLYING MACHINES. WITH A SHORT ACCOUNT OF THE PROGRESS OF AVIATION. By J. H. ALEXANDER. This book has been written with a view to assist those who desire to construct a model airship or flying machine. It contains five folding plates of working drawings, each sheet containing a different sized machine. Much instruction and amusement can be obtained from the making and flying of these models. A short account of the progress of aviation is included, which will render the book of greater interest. Several illustrations of full sized airship and flying machines of the latest types are scattered throughout the text. This practical work gives data, working drawings, and details which will assist materially those interested in the problems of flight. 127 pages, 45 illustrations, 5 folding plates. Price $1.50

BRAZING AND SOLDERING

BRAZING AND SOLDERING. By JAMES F. HOBART. The only book that shows you just how to handle any job of brazing or soldering that comes along; tells you what mixture to use, how to make a furnace if you need one. Full of valuable kinks. The fifth edition of this book has just been published, and to it much new matter and a large number of tested formulas for all kinds of solders and fluxes have been added. Illustrated. 25 cents.

CHARTS

MODERN SUBMARINE CHART WITH 200 PARTS NUMBERED AND NAMED. A cross-section view, showing clearly and distinctly all the interior of a Submarine of the latest type. You get more information from this chart, about the construction and operation of a Submarine, than in any other way. No details omitted-everything is accurate and to scale. It is absolutely correct in every detail, having been approved by Naval Engineers. All the machinery and devices fitted in a modern Submarine Boat are shown, and to make the engraving more readily understood all the features are shown in operative form, with Officers and Men in the act of performing the duties assigned to them in service conditions. This CHART IS REALLY AN ENCYCLOPEDIA OF A SUBMARINE. It is educational and worth many times its cost. Mailed in a Tube for 25 cents.

BOX CAR CHART. A chart showing the anatomy of a box car, having every part of the car numbered and its proper name given in a reference list. 20 cents.

GONDOLA CAR CHART. A chart showing the anatomy of a gondola car, having every part of the car numbered and its proper reference name given in a reference list. 20 cents.

PASSENGER CAR CHART. A chart showing the anatomy of a passenger car, having every part of the car numbered and its proper name given in a reference list. 20 cents.

WESTINGHOUSE AIR-BRAKE CHARTS. Chart I.—Shows (in colors) the most modern Westinghouse High Speed and Signal Equipment used on Passenger Engines, Passenger Engine Tenders, and Passenger Cars. Chart II.—Shows (in colors) the Standard Westinghouse Equipment for Freight and Switch Engines, Freight and Switch Engine Tenders, and Freight Cars. Price for the set 50 cents.

TRACTIVE POWER CHART. A chart whereby you can find the tractive power or drawbar pull of any locomotive, without making a figure. Shows what cylinders are equal, how driving wheels and steam pressure affect the power. What sized engine you need to exert a given drawbar pull or anything you desire in this line. 50 cents.

HORSE POWER CHART. Shows the horse power of any stationary engine without calculation. No matter what the cylinder diameter of stroke; the steam pressure or cut-off; the revolutions, or whether condensing or non-condensing, it's all there. Easy to use, accurate, and saves time and calculations. Especially useful to engineers and designers. 50 cents.

BOILER ROOM CHART. By GEO. L. FOWLER. A Chart-size 14 x 28 inches-showing in isometric perspective the mechanisms belonging in a modern boiler room. Water tube boilers, ordinary grates and mechanical stokers, feed water heaters and pumps comprise the equipment. The various parts are shown broken or removed, so that the internal construction is fully illustrated. Each part is given a reference number, and these, with the corresponding name, are given in a glossary printed at the sides. This chart is really a dictionary of the boiler room--the names of more than 200 parts being given. It is educational-worth many times its cost. 25 cents.

CIVIL ENGINEERING

HENLEY'S ENCYCLOPEDIA OF PRACTICAL ENGINEERING AND ALLIED TRADES. Edited by JOSEPH G. HORNER, A. M. I. E. M. This set of five volumes contains about 2,500 pages with thousands of illustrations, including diagrammatic and sectional drawings with full explanatory details.. This work covers the entire practice of Civil and Mechanical Engineering. The best known experts in all branches of engineering have contributed to these volumes. The Cyclopedia is admirably well adapted to the needs of the beginner and the self-taught practical man, as well as the mechanical engineer, designer, draftsman, shop superintendent, foreman, and machinist. The work will be found a means of advancement to any progressive man. It is encyclopedic in scope, thorough and practical in its treatment of technical subjects, simple and clear in its descriptive matter, and without unnecessary technicalities or formulae. The articles are as brief as may be and yet give a reasonably clear and explicit statement of the subject, and are written by men who have had ample practical experience in the matters of which they write. It tells you all you want to know about engineering and tells it so simply, so clearly, so concisely, that one cannot help but understand. As a work of reference it is without a peer. $6.00 per single volume. For complete set of five volumes, $25.00

COKE

COKE-MODERN COKING PRACTICE; INCLUDING THE ANALYSIS OF MATERIALS AND PRODUCTS. By T. H. BYROM and J. E. CHRISTOPHER. A handbook for those engaged in Coke manufacture and the recovery of By-products. Fully illustrated with folding plates, It has been the aim of the authors, in preparing this book, to produce ore which shall be of use and benefit to those who are associated with, or interested in, the modern developments of the industry. Contents: I. Introductory. II. General Classification of Fuels. III. Coal Washing. IV. The Sampling and Valuation of Coal, Coke, etc. V. The Calorific Power of Coal and Coke. VI. Coke Ovens. VII: Coke Ovens, continued. VIII. Coke Ovens, continued. IX. Charging and Discharging of Coke Ovens, X. Cooling and Condensing Plant. XI. Gas Exhausters. XII. Composition and Analysis of Ammoniacal Liquor. XIII. Working-up of Ammoniacal Liquor. XIV. Treatment of Waste Gases from Sulphate Plants. XV. Valuation of Ammonium Sulphate. XVI. Direct Recovery of Ammonia from Coke Oven Gases. XVII. Surplus Gas from Coke Oven. Useful Tables. Very fully illustrated. Price $3.50 net.

COMPRESSED AIR

COMPRESSED AIR IN ALL ITS APPLICATIONS. By GARDNER D. HISCOX. This is the most complete book on the subject of Air that has ever been issued, and its thirty-five chapters include about every phase of the subject one can think of. It may be called an encyclopedia of compressed air. It is written by an expert, who, in its 665 pages, has dealt with the subject in a comprehensive manner, no phase of it being omitted. Includes the physical properties of air from a vacuum to its highest pressure, its thermodynamics, compression, transmission and uses as a motive power; in the Operation of Stationary and Portable Machinery, in Mining, Air Tools, Air Lifts, Pumping of Water, Acids, and Oils; the Air Blast for Cleaning and Painting, the Sand Blast and its Work, and the Numerous Appliances in which Compressed Air is a Most Convenient and Economical Transmitter of Power for Mechanical Work, Railway Propulsion, Refrigeration, and the Various Uses to which Compressed Air has been applied. Includes forty-four tables of the physical properties of air, its compression, expansion, and volumes required for various kinds of work, and a list of patents on compressed air from 1875 to date. Over 500 illustrations, 5th Edition, revised and enlarged. Cloth bound, $5.00. Half Morocco, price. $6.50

CONCRETE

ORNAMENTAL CONCRETE WITHOUT MOLDS. By A. A. HOUGHTON. The process for making ornamental concrete without molds has long been held as a secret, and now, for the first time, this process is given to the public. The book reveals the secret and is the only book published which explains a simple, practical method whereby the concrete worker is enabled, by employing wood and metal templates of different designs, to mold or model in concrete any Cornice, Archivolt, Column, Pedestal, Base Cap, Urn or Pier in a monolithic form-right upon the job. These may be molded in units or blocks, and then built up to suit the specifications demanded. This work is fully illustrated, with detailed engravings. Price $2.00

CONCRETE FROM SAND MOLDS. By A. A. HOUGHTON. A Practical Work treating on a process which has heretofore been held as a trade-secret by the few who possessed it, and which will successfully mold every and any class of ornamental concrete work. The process of molding concrete with sand molds is of the utmost practical value, possessing the manifold advantages of a low cost of molds, the ease and rapidity of operation, perfect details to all ornamental designs, density, and increased strength of the concrete, perfect curing of the work without attention and the easy removal of the molds regardless of any undercutting the design may have. 192 pages. Fully illustrated. Price $2.00

CONCRETE WALL FORMS. By A. A. HOUGHTON. A new automatic wall clamp is illustrated with working drawings. Other types of wall forms, clamps, separators, etc., are also illustrated and explained. 50 cents.

CONCRETE FLOORS AND SIDEWALKS. By A. A. HOUGHTON. The molds for molding squares, hexagonal and many other styles of mosaic floor and sidewalk blocks are fully illustrated and explained. 50 cents.

PRACTICAL CONCRETE SILO CONSTRUCTION. By A. A. HOUGHTON. Complete working drawings and specifications are given for several styles of concrete silos, with illustrations of molds for monolithic and block silos. The tables, data and information presented in this book are of the utmost value in planning and constructing all forms of concrete silos. 50 cents.

MOLDING CONCRETE CHIMNEYS, SLATE AND ROOF TILES. By A. A. HOUGHTON. The manufacture of all types of concrete slate and roof tile is fully treated. Valuable data on all forms of reinforced concrete roofs are contained within its pages. The construction of concrete chimneys by block and monolithic systems is fully illustrated and described. А number of ornamental designs of chimney construction with molds are shown in this valuable treatise. 50 cents.

MOLDING AND CURING ORNAMENTAL CONCRETE. By A. A. HOUGHTON. The proper proportions of cement and aggregates for various finishes, also the methods of thoroughly mixing and placing in the molds, are fully treated. An exhaustive treatise on this subject that every concrete worker will find of daily use and value. 50 cents.

CONCRETE MONUMENTS, MAUSOLEUMS AND BURIAL VAULTS. By A. A. HOUGHTON. The molding of concrete monuments to imitate the most expensive cut stone is explained in this treatise, with working drawings of easily built molds. Cutting inscriptions and designs is also fully treated. 50 cents.

MOLDING CONCRETE BATH TUBS, AQUARIUMS AND NATATORIUMS. By A. A. HOUGHTON. Simple molds and instruction are given for molding many styles of concrete bath tubs, swimming pools, etc. These molds are easily built and permit rapid and successful work. 50 cents.

CONCRETE BRIDGES, CULVERTS AND SEWERS. By A. A. HOUGHTON. A number of ornamental concrete bridges with illustrations of molds are given. A collapsible center or core for bridges, culverts and sewers is fully illustrated with detailed instructions for building 50 cents.

CONSTRUCTING CONCRETE PORCHES. By A. A. HOUGHTON. A number of designs with working drawings of molds are fully explained so any one can easily construct different styles of ornamental concrete porches without the purchase of expensive molds. 50 cents.

MOLDING CONCRETE FLOWER POTS, BOXES, JARDINIERES, ETC. By A. A. HOUGHTON. The molds for producing many original designs of flower pots, urns, flower boxes, jardinières, etc., are fully illustrated and explained, so the worker can easily construct and operate same. 50 cents.

MOLDING CONCRETE FOUNTAINS AND LAWN ORNAMENTS. By A. A. HOUGHTON. The molding of a number of designs of lawn seats, curbing, hitching posts, pergolas, sun dials and other forms of ornamental concrete for the ornamentation of lawns and gardens, is fully illustrated and described. 50 cents.

CONCRETE FOR THE FARM AND SHOP. By A. A. HOUGHTON. The molding of drain tile, tanks, cisterns, fence posts, stable floors, hog and poultry houses and all the purposes for which concrete is an invaluable aid to the farmer are numbered among the contents of this handy volume. 50 cents.

POPULAR HANDBOOK FOR CEMENT AND CONCRETE USERS. By MYRON H. LEWIS, This is a concise treatise of the principles and methods employed in the manufacture and use of cement in all classes of modern works. The author has brought together in this work all the salient matter of interest to the user of concrete and its many diversified products. The matter is presented in logical and systematic order, clearly written, fully illustrated and free from involved mathematics. Everything of value to the concrete user is given including kinds of cement employed in construction, concrete architecture, inspection and testing, waterproofing, coloring and painting, rules, tables, working, and cost data. The book comprises thirty-three chapters, as follows: Introductory. Kinds of Cements and How They are Made. Properties, Testing and Requirements of Hydraulic Cement. Concrete and its Properties. Sand, Broken Stone and Gravel for Concrete. How to Proportion the Materials. How to Mix and Place Concrete. Forms for Concrete Construction. The Architectural and Artistic Possibilities of Concrete. Concrete Residences. Mortars, Plasters and Stucco and How to Use Them. The Artistic Treatment of Concrete Surfaces. Concrete Building Blocks. The Making of Ornamental Concrete. Concrete Pipes, Fences, Posts, Etc. Essential Features and Advantages of Reenforced Concrete. How to Design Reenforced Concrete Beams, Slabs and Columns. Explanations of the Methods and Principles in Designing Reenforced Concrete Beams and Slabs. Systems of Reenforcement Employed. Reenforced Concrete in Factory and General Building Construction. Concrete in Foundation Work. Concrete Retaining Walls, Abutments, and Bulkheads. Concrete Arches and Arch Bridges. Concrete Beam and Girder Bridges. Concrete in Sewerage and Drainage Works. Concrete Tanks, Dams and Reservoirs. Concrete Sidewalks, Curbs and Pavements. Concrete in Railroad Constructions. The Utility of Concrete on the Farm. The Waterproofing of Concrete Structure. Grout or Liquid Concrete and Its Use. Inspection of Concrete Work. Cost of Concrete Work. Some of the special features of the book are: 1. The Attention Paid to the Artistic and Architectural Side of Concrete Work. 2. The Authoritative Treatment of the Problem of Waterproofing Concrete. 3. An Excellent Summary of the Rules to be Followed in Concrete Construction. 4. The Valuable Cost Data and Useful Tables given. A valuable Addition to the Library of Every Cement and Concrete User. Price $2.50

WATERPROOFING CONCRETE. By MYRON H. LEWIS. Modern Methods of Waterproofing Concrete and Other Structures. A condensed statement of the Principles, Rules, and Precautions to be Observed in Waterproofing and Damp-proofing Structures and Structural Materials. Paper binding. Illustrated. Price 50 cents.

DICTIONARIES

STANDARD ELECTRICAL DICTIONARY. By T. O'CONOR SLOANE. An indispensable work to all interested in electrical science. Suitable alike for the student and professional. A practical hand-book of reference containing definitions of about 5,000 distinct words, terms and phrases. The definitions are terse and concise and include every term used in electrical science. Recently issued. An entirely new edition. Should be in the possession of all who desire to keep abreast with the progress of this branch of science. Complete, concise and convenient. 682 pages. 393 illustrations. Price $3.00

DIES-METAL WORK

DIES: THEIR CONSTRUCTION AND USE FOR THE MODERN WORKING OF SHEET METALS. By J. V. WOODWORTH. A most useful book, and one which should be in the hands of all engaged in the press working of metals; treating on the Designing, Constructing, and Use of Tools, Fixtures and Devices, together with the manner in which they should be used in the Power Press, for the cheap and rapid production of the great variety sheet metal articles now in use. It is designed as a guide to the production of sheet metal parts at the minimum of cost with the maximum of output. The hardening and tempering of Press tools and the classes of work which may be produced to the best advantage by the use of dies in the power press are fully treated. Its 505 illustrations show dies, press fixtures and sheet metal working devices, the descriptions of which are so clear and practical that all metal-working mechanics will be able to understand how to design, construct and use them. Many of the dies and press fixtures treated were either constructed by the author or under his supervision. Others were built by skilful mechanics and are in use in large sheet metal establishments and machine shops. Price $3.00

PUNCHES, DIES AND TOOLS FOR MANUFACTURING IN PRESSES. By J. V. WOODWORTH. This work is a companion volume to the author's elementary work entitled "Dies, Their Construction and Use." It does not go into the details of die making to the extent of the author's previous book, but gives a comprehensive review of the field of operations carried on by presses. A large part of the information given has been drawn from the author's personal experience. It might well be termed an Encyclopedia of Die Making. Punch Making, Die Sinking, Sheet Metal Working, and Making of Special Tools, Sub-presses, Devices and Mechanical Combinations for Punching, Cutting, Bending, Forming, Piercing, Drawing, Compressing and Assembling Sheet Metal Parts, and also Articles of other Materials in Machine Tools. 2nd Edition. Price. $4.00

DROP FORGING, DIE SINKING AND MACHINE FORMING OF STEEL. By J. V. WOODWORTH.

This is a practical treatise on Modern Shop Practice, Processes, Methods, Machines, Tools, and Details, treating on the Hot and Cold Machine-Forming of Steel and Iron into Finished shapes; Together with Tools, Dies, and Machinery involved in the manufacture of Duplicate Forgings and Interchangeable Hot and Cold Pressed Parts from Bar and Sheet Metal. This book fills a demand of long standing for information regarding drop forging, die-sinking and machine forming of steel and the shop practice involved, as it actually exists in the modern drop forging shop. The processes of die-sinking and force-making, which are thoroughly described and illustrated in this admirable work, are rarely to be found explained in such a clear and concise manner as is here set forth. The process of die-sinking relates to the engraving or sinking of the female or lower dies, such as are used for drop forgings, hot and cold machine forging, swedging and the press working of metals. The process of force-making relates to the engraving or raising of the male or upper dies used in producing the lower dies for the press-forming and machine-forging of duplicate parts of metal.

In addition to the arts above mentioned the book contains explicit information regarding the drop forging and hardening plants, designs, conditions, equipment, drop hammers, forging machines, etc., machine forging, hydraulic forging, autogenous welding and shop practice. The book contains eleven chapters, and the information contained in these chapters is just what will prove most valuable to the forged metal worker. All operations described in the work are thoroughly illustrated by means of perspective half-tones and outline sketches of the machinery employed. 300 detailed illustrations. Price $2.50

DRAWING-SKETCHING PAPER

LINEAR PERSPECTIVE SELF-TAUGHT. By HERMAN T. C. KRAUS. This work gives the theory and practice of linear perspective, as used in architectural, engineering, and mechanical drawings. Persons taking up the study of the subject by themselves will be able by the use of the instruction given to readily grasp the subject, and by reasonable practice become good perspective draftsmen. The arrangement of the book is good; the plate is on the left-hand, while the descriptive text follows on the opposite page, so as to be readily referred to. The drawings are on sufficiently large scale to show the work clearly and are plainly figured. The whole work makes a very complete course on perspective drawing, and will be found of great value to architects, civil and mechanical engineers, patent attorneys, art designers, engravers, and draftsmen. $2.50

PRACTICAL PERSPECTIVE. By RICHARDS and COLVIN. Shows just how to make all kinds of mechanical drawings in the only practical perspective isometric. Makes everything plain so that any mechanic can understand a sketch or drawing in this way. Saves time in the drawing room, and mistakes in the shops. Contains practical examples of various classes of work. 3rd Edition. 50 cents.

SELF-TAUGHT MECHANICAL DRAWING AND ELEMENTARY MACHINE DESIGN. By F. L. SYLVESTER, M.E., Draftsman, with additions by ERIK OBERG, associate editor of "Machinery." This is a practical treatise on Mechanical Drawing and Machine Design, comprising the first principles of geometric and mechanical drawing, workshop mathematics, mechanics, strength of materials and the calculations and design of machine details. The author's aim has been to adapt this treatise to the requirements of the practical mechanic and young draftsman and to present the matter in as clear and concise a manner as possible. To meet the demands of this class of students, practically all the important elements of machine design have been dealt with, and in addition algebraic formulas have been explained, and the elements of trigonometry treated in the manner best suited to the needs of the practical man. The book is divided into 20 chapters, and in arranging the material, mechanical drawing, pure and simple, has been taken up first, as a thorough understanding of the principles of representing objects facilitates the further study of mechanical subjects. This is followed by the mathematics necessary for the solution of the problems in machine design which are presented later, and a practical introduction to theoretical mechanics and the strength of materials. The various elements entering into machine design, such as cams, gears, sprocket wheels, cone pulleys, bolts, screws, couplings, clutches, shafting and flywheels have been treated in such a way as to make possible the use of the work as a textbook for a continuous course of study. It is easily comprehended and assimilated even by students of limited previous training. 330 pages, 215 engravings. Price. $2.00

A NEW SKETCHING PAPER. A new specially ruled paper to enable you to make sketches or drawings in isometric perspective without any figuring or fussing. It is being used for shop details as well as for assembly drawings, as it makes one sketch do the work of three, and no workman can help seeing just what is wanted. Pads of 40 sheets, 6 x 9 inches, 25 cents. Pads of 40 sheets, 9 x 12 inches. 50 cents; 40 sheets, 12 x 18, Price $1.00.

ELECTRICITY

ARITHMETIC OF ELECTRICITY. By Prof. T. O'CONOR SLOANE. A practical treatise on electrical calculations of all kinds reduced to a series of rules, all of the simplest forms, and involving only ordinary arithmetic; each rule illustrated by one or more practical problems, with detailed solution of each one. This book is classed among the most useful works published on the science of electricity covering as it does the mathematics of electricity in a manner that will attract the attention of those who are not familiar with algebraical formulas. 20th Edition. 160 pages. Price $1.00

COMMUTATOR CONSTRUCTION. By WM. BAXTER, JR. The business end of any dynamo or motor of the direct current type is the commutator. This book goes into the designing, building, and maintenance of commutators, shows how to locate troubles and how to remedy them; everyone who fusses with dynamos needs this. 25 cents.

DYNAMO BUILDING FOR AMATEURS, OR HOW TO CONSTRUCT A FIFTY-WATT DYNAMO. By ARTHUR J. WEED, Member of N. Y. Electrical Society. A practical treatise showing in detail the construction of a small dynamo or motor, the entire machine work of which can be done on a small foot lathe. Dimensioned working drawings are given for each piece of machine work and each operation is clearly described. This machine, when used as a dynamo, has an output of fifty watts; when used as a motor it will drive a small drill press or lathe. It can be used to drive a sewing machine on any and all ordinary work. The book is illustrated with more than sixty original engravings showing the actual construction of the different parts. Among the contents are chapters on 1. Fifty Watt Dynamo. 2. Side Bearing Rods. 3. Field Punchings. 4. Bearings. 5. Commutator. 6. Pulley. 7. Brush Holders. 8. Connection Board. 9. Armature Shaft. 10. Armature. 11. Armature Winding. 12. Field Winding. 13. Connecting and Starting. Price, paper, 50 cents. Cloth. $1.00.

ELECTRIC FURNACES AND THEIR INDUSTRIAL APPLICATIONS. By J. WRIGHT This is a book which will prove of interest to many classes of people; the manufacturer who desires to know what product can be manufactured successfully in the electric furnace, the chemist who wishes to post himself on the electro-chemistry, and the student of science who merely looks into the subject from curiosity. The book is not so scientific as to be of use only to the technologist, nor so unscientific as to suit only the tyro in electro-chemistry; it is a practical treatise of what has been done, and of what is being done, both experimentally and commercially with the electric furnace. In important processes not only are the chemical equations given, but complete thermal data are set forth and both the efficiency of the furnace and the cost of the product are worked out, thus giving the work a solid commercial value aside from its efficacy as a work of reference. The practical features of furnace building are given the space that the subject deserves. The forms and refractory materials used in the linings, the arrangement of the connections to the electrodes, and other important details are explained. 288 pages. New Revised Edition. Fully illustrated. Price $3.00

ELECTRIC LIGHTING AND HEATING POCKET BOOK. By SYDNEY F. WALKER. This book puts in convenient form useful information regarding the apparatus which is likely to be attached to the mains of an electrical company. Tables of units and equivalents are included and useful electrical laws and formulas are stated. One section is devoted to dynamos, motors, transformers and accessory apparatus; another to accumulators, another to switchboards and related equipment, a fourth to a description of various systems of distribution, a fifth section to a discussion of instruments, both for portable use and switchboards; another section deals with electric lamps of various types and accessory appliances, and the concluding section is given up to electric heating apparatus. In each section a large number of commercial types are described, frequent tables of dimensions being included. A great deal of detail information of each' line of apparatus is given and the illustrations shown give a good idea of the general appearance of the apparatus under discussion. The book also contains much valuable information for the central station engineer. 438 pages. 300 engravings. Bound in leather pocket book form. Price $3.00

ELECTRIC WIRING, DIAGRAMS AND SWITCHBOARDS. By NEWTON HARRISON. A thoroughly practical treatise covering the subject of Electric Wiring in all its branches, including explanations and diagrams which are thoroughly explicit and greatly simplify the subject. Practical every-day problems in wiring are presented and the method of obtaining intelligent results clearly shown. Only arithmetic is used. Ohm's law is given a simple explanation with reference to wiring for direct and alternating currents. The fundamental principle of drop of potential in circuits is shown with its various applications. The simple circuit is developed with the position of mains, feeders and branches; their treatment as a part of a wiring plan and their employment in house-wiring clearly illustrated. Some simple facts about testing are included in connection with the wiring. Molding and conduit work are given careful consideration; and switchboards are systematically treated, built up and illustrated, showing the purpose they serve, for connection with the circuits, and to shunt and compound wound machines. The simple principles of switchboard construction, the development of the switchboard, the connections of the various instruments including the lightning arrester, are also plainly set forth. Alternating current wiring is treated, with explanations of the power factor, conditions calling for various sizes of wire and a simple way of obtaining the sizes for single-phase, two-phase and three-phase circuits. This is the only complete work issued showing and telling you what you should know about direct and alternating current wiring. It is a ready reference. The work is free from advanced technicalities and mathematics, arithmetic being used throughout. It is in every respect a handy, well-written, instructive, comprehensive volume on wiring for the wireman, foreman, contractor, or electrician. 272 pages; 105 illustrations. Price $1.50

ELECTRIC TOY MAKING, DYNAMO BUILDING, AND ELECTRIC MOTOR CONSTRUCTION. By PROF. T. O'CONOR SLOANE. This work treats of the making at home of electrical toys, electrical apparatus, motors, dynamos and instruments in general, and is designed to bring within the reach of young and old the manufacture of genuine and useful electrical appliances. The work is especially designed for amateurs and young folks. Thousands of our young people are daily experimenting, and busily engaged in making electrical toys and apparatus of various kinds. The present work is just what is wanted to give the much needed information in a plain, practical manner, with illustrations to make easy the carrying out of the work. 19th Edition. Price $1.00

ELECTRICIAN'S HANDY BOOK. By PROF. T. O’CONOR SLOANE. This work of 768 pages is intended for the practical electrician who has to make things go. The entire field of electricity is covered within its pages. Among some of the subjects treated are: The Theory of the Electric Current and Circuit, Electro-Chemistry, Primary Batteries, Storage Batteries, Generation and Utilization of Electric Powers, Alternating Current, Armature Winding, Dynamos and Motors, Motor Generators, Operation of the Central Station Switchboards, Safety Appliances, Distribution of Electric Light and Power, Street Mains, Transformers, Arc and Incandescent Lighting, Electric Measurements, Photometry, Electric Railways, Telephony, Bell-Wiring, Electro-Plating, Electric Heating, Wireless Telegraphy, etc. It contains no useless theory; everything is to the point. It teaches you just what you want to know about electricity. It is the standard work published on the subject. Forty-one chapters, 610 engravings, handsomely bound in red leather with title and edges in gold. Price: $3.50

ELECTRICITY IN FACTORIES AND WORKSHOPS, ITS COST AND CONVENIENCE.

By ARTHUR P. HASLAM.

A practical book for power producers and power users showing what a convenience the electric motor, in its various forms, has become to the modern manufacturer. It also deals with the conditions which determine the cost of electric driving, and compares this with other methods of producing and utilizing power.

Among the chapters contained in the book are: The Direct Current Motor; The Alternating Current Motor; The Starting and Speed Regulation of Electric Motors; The Rating and Efficiency of Electric Motors; The Cost of Energy as Affected by Conditions of Working, The Question for the Small Power User; Independent Generating Plants; Oil and Gas Engine Plants; Steam Plants; Power Station Tariffs; The Use of Electric Power in Textile Factories; Electric Power in Printing Works; The Use of Electric Power in Engineering Workshops Miscellaneous Application of Electric Power; The Installation of Electric Motors; The Lighting of Industrial Establishments 312 pages. Very fully illustrated. Price $2.50

ELECTRICITY SIMPLIFIED. By PROF. T. O'CONOR SLOANE. The object of "Electricity Simplified" is to make the subject as plain as possible and to show what the modern conception of electricity is; to show how two plates of different metals immersed in acid can send a message around the globe; to explain how a bundle of copper wire rotated by a steam engine can be the agent in lighting our streets, to tell what the volt, ohm and ampere are, and what high and low tension mean; and to answer the questions that perpetually arise in the mind in this age of electricity. 172 pages. Illustrated. Price $1.00

HOUSE WIRING. By THOMAS W. POPPE. This work describes and illustrates the actual installation of Electric Light Wiring, the manner in which the work should be done, and the method of doing it. The book can be conveniently carried in the pocket. It is intended for the Electrician, Helper and Apprentice. It solves all Wiring Problems, and contains nothing that conflicts with the rulings of the National Board of Fire Underwriters. It gives just the information essential to the Successful Wiring of a Building. Among the subjects treated are: Locating the Meter. Panel Boards. Switches. Plug Receptacles. Brackets. Ceiling Fixtures. The Meter Connections. The Feed Wires. The Steel Armored Cable System. The Flexible Steel Conduit System. The Ridig Conduit System. A digest of the National Board of Fire Underwriters' rules relating to metallic wiring systems. Various switching arrangements explained and diagrammed. The easiest method of testing the Three and Four-way circuits explained. The grounding of all metallic wiring systems and the reason for doing so shown and explained. The insulation of the metal parts of lamp fixtures and the reason for the same described and illustrated. 125 pages. Fully illustrated. Flexible cloth. Price 50 cents.

HOW TO BECOME A SUCCESSFUL ELECTRICIAN. By PROF. T. O'CONOR SLOANE. Every young man who wishes to become a successful electrician should read this book. It tells in simple language the surest and easiest way to become a successful electrician. The studies to be followed, methods of work, field of operation and the requirements of the successful electrician are pointed out and fully explained. Every young engineer will find this an excellent stepping-stone to more advanced works on electricity which he must master before success can be attained. Many young men become discouraged at the very out-start by attempting to read and study books that are far beyond their comprehension. This book serves as the connecting link between the rudiments taught in the public schools and the real study of electricity. It is interesting from cover to cover. Fifteenth edition. 202 pages. Illustrated. Price $1.00

MANAGEMENT OF DYNAMOS. By LUMMIS-PATERSON. A handbook of theory and practice. This work is arranged in three parts. The first part covers the elementary theory of the dynamo. The second part, the construction and action of the different classes of dynamos in common use are described; while the third part relates to such matters as affect the practical management and working of dynamos and motors. The following chapters are contained in the book: Electrical Units; Magnetic Principles; Theory of the Dynamo; Armature; Armature in Practice; Field Magnets; Field Magnets in Practice; Regulating Dynamos; Coupling Dynamos; Installation, Running, and Maintenance of Dynamos; Faults in Dynamos; Faults in Armatures; Motors. 292 pages. 117 illustrations. Price $1.50

STANDARD ELECTRICAL DICTIONARY. By T. O'CONOR SLOANE. An indispensable work to all interested in electrical science. Suitable alike for the student and professional. A practical hand-book of reference containing definitions of about 5,000 distinct words, terms and phrases. The definitions are terse and concise and include every term used in electrical science. Recently issued. An entirely new edition. Should be in the possession of all who desire to keep abreast with the progress of this branch of science. In its arrangement and typography the book is very convenient. The word or term defined is printed in black-faced type which readily catches the eye, while the body of the page is in smaller but distinct type. The definitions are well worded, and so as to be understood by the non-technical reader. The general plan seems to be to give an exact, concise definition, and then amplify and explain in a more popular way. Synonyms are also given, and references to other words and phrases are made. A very complete and accurate index of fifty pages is at the end of the volume; and as this index contains all synonyms, and as all phrases are indexed in every reasonable combination of words, reference to the proper place in the body of the book is readily made. It is difficult to decide how far a book of this character is to keep the dictionary form, and to what extent it may assume the encyclopedia form. For some purposes, concise, exactly worded definitions are needed; for other purposes, more extended descriptions are required. This book seeks to satisfy both demands, and does it with considerable success. Complete, concise, and convenient. 682 pages. 393 illustrations. Twelfth edition. Price $3.00

SWITCHBOARDS. By WILLIAM BAXTER, JR. This book appeals to every engineer and electrician who wants to know the practical side of things. It takes up all sorts and conditions of dynamos, connections and circuits and shows by diagram and illustration just how the switchboard should be connected. Includes direct and alternating current boards, also those for arc lighting, incandescent, and power circuits. Special treatment on high voltage boards for power transmission. 2nd Edition. 190 pages. Illustrated. Price $1.60

TELEPHONE CONSTRUCTION, INSTALLATION, WIRING, OPERATION AND MAINTENANCE. By W. H. RADCLIFFE and H. C. Cushing. This book gives the principles of construction and operation of both the Bell and Independent instruments; approved methods of installing and wiring them; the means of protecting them from lightning and abnormal currents; their connection together for operation as series or bridging stations; and rules for their inspection and maintenance. Line wiring and the wiring and operation of special telephone systems are also treated. Intricate mathematics are avoided, and all apparatus, circuits and systems are thoroughly described. The appendix contains definitions of units and terms used in the text. Selected wiring tables, which are very helpful, are also included. Among the subjects treated are Construction, Operation, and installation of Telephone Instruments, Inspection and Maintenance of Telephone Instruments; Telephone Line Wiring; Testing Telephone Line Wires and Cables; Wiring and Operation of Special Telephone Systems; etc. 100 pages, 125 illustrations. $1.00

WIRELESS TELEGRAPHY AND TELEPHONY SIMPLY EXPLAINED. By ALFRED P. MORGAN.

This is undoubtedly one of the most complete and comprehensible treatises on the subject ever published, and a close study of its pages will enable one to master all the details of the wireless transmission of messages. The author has filled a long felt want and has succeeded in furnishing, a lucid, comprehensible explanation in simple language of the theory and practice of wireless telegraphy and telephony. Among the contents are: Introductory; Wireless Transmission and Reception—The Aerial System, Earth Connections—The Transmitting Apparatus, Spark Coils and Transformers, Condensers, Helixes, Spark Gaps, Anchor Gaps, Aerial Switches—The Receiving Apparatus, Detectors, etc.—Tuning and Coupling, Tuning Coils, Loose Couplers, Variable Condensers, Directive Wave Systems-Miscellaneous Apparatus: Telephone Receivers, Range of Stations, Static, Interference Wireless Telephones, Sound and Sound Waves, The Vocal Cords and Ear—Wireless Telephones, How Sounds are changed into Electric Waves Wireless Telephones, The Apparatus-Summary. 200 pages. 150 engravings. Price $1.00

WIRELESS TELEPHONES AND HOW THEY WORK. By JAMES ERSKINE-MURRAY.

This work is free from elaborate details and aims at giving a clear survey of the way in which Wireless Telephones work. It is intended for amateur workers and for those whose knowledge of electricity is slight. Chapters contained: How We Hear; Historical; The Conversion of Sound into Electric Waves; Wireless Transmission; The Production of Alternating Currents of High Frequency; How the Electric Waves are Radiated and Received; The Receiving Instruments; Detectors; Achievements and Expectations; Glossary of Technical Words, Cloth. Price $1.00

WIRING A HOUSE. By HERBERT PRATT.

Shows a house already built; tells just how to start about wiring it; where to begin; what wire to use; how to run it according to Insurance Rules; in fact just the information you need. Directions apply equally to a shop. Fourth edition. 25 cents.

FACTORY MANAGEMENT, ETC.

MODERN MACHINE SHOP CONSTRUCTION, EQUIPMENT AND MANAGEMENT.

By O. E. PERRIGO, M.E.

The only work published that describes the modern machine shop or manufacturing plant from the time the grass is growing on the site intended for it until the finished product is shipped. By a careful study of its thirty-two chapters the practical man may economically build, efficiently equip, and successfully manage the modern machine shop or manufacturing establishment. Just the book needed by those contemplating the erection of modern shop buildings, the re-building and re-organization of old ones, or the introduction of modern shop methods, time and cost system. It is a book written and illustrated by a practical shop man for practical shop men who are too busy to read theories and want facts. It is the most complete all around book of its kind ever published. It is a practical book for practical men, from the apprentice in the shop to the president in the office. It minutely describes and illustrates the most simple and yet the most efficient time and cost system yet devised. Price $6.00

FUEL