It shows clearly all parts of a typical four-cylinder gasoline engine of the four-cycle type.

It outlines distinctly all parts liable to give trouble and also details the derangements apt to interfere with smooth engine operation.

Valuable to students, motorists, mechanics, repairmen, garagemen, automobile salesmen, chauffeurs, motorboat owners, motor-truck and tractor drivers, aviators, motor-cyclists, and all others who have to do with gasoline power plants.

It simplifies location of all engine troubles, and while it will prove invaluable to the novice, it can be used to advantage by the more expert. It should be on the walls of every public and private garage, automobile repair shop, club house or school. It can be carried in the automobile or pocket with ease, and will insure against loss of time when engine trouble manifests itself.

This sectional view of engine is a complete review of all motor troubles. It is prepared by a practical motorist for all who motor. More information for the money than ever before offered. No details omitted. Size 25x38 inches. Securely mailed on receipt of 25 Cents

This shows clear sectional views depicting all portions of the Ford power plant and auxiliary groups. It outlines clearly all parts of the engine, fuel supply system, ignition group and cooling system, that are apt to give trouble, detailing all derangements that are liable to make an engine lose power, start hard or work irregularly. This chart is valuable to students, owners, and drivers, as it simplifies location of all engine faults. Of great advantage as an instructor for the novice, it can be used equally well by the more expert as a work of reference and review. It can be carried in the tool-box or pocket with ease and will save its cost in labor eliminated the first time engine trouble manifests itself. Prepared with special reference to the average man’s needs and is a practical review of all motor troubles because it is based on the actual experience of an automobile engineer-mechanic with the mechanism the chart describes. It enables the non-technical owner or operator of a Ford car to locate engine derangements by systematic search, guided by easily recognized symptoms instead of by guesswork. It makes the average owner independent of the roadside repair shop when touring. Must be seen to be appreciated. Size 25x38 inches. Printed on heavy bond paper. Price 25 cents

This chart presents the plan view of a typical six-cylinder chassis of standard design and all parts are clearly indicated that demand oil, also the frequency with which they must be lubricated and the kind of oil to use. A practical chart for all interested in motor-car maintenance. Size 24x38 inches. Price 25 cents

This chart shows all parts of a typical pressure feed fuel supply system and gives causes of trouble, how to locate defects and means of remedying them. Size 24x38 inches. Price 25 cents

In this diagram all parts of a typical double ignition system using battery and magneto current are shown, and suggestions are given for readily finding ignition troubles and eliminating them when found. Size 24x38 inches. Price 25 cents

This composite diagram shows a typical automobile power plant using pump circulated water-cooling system and the most popular lubrication method. Gives suggestions for curing all overheating and loss of power faults due to faulty action of the oiling or cooling group. Size 24x38 inches. Price 25 cents

A chart showing sectional view of a single-cylinder gasoline engine. This chart simplifies location of all power-plant troubles. A single-cylinder motor is shown for simplicity. It outlines distinctly all parts liable to give trouble and also details the derangements apt to interfere with smooth engine operation. This chart will prove of value to all who have to do with the operation, repair or sale of motorcycles. No details omitted. Size 30x20 inches Price 25 cents

A practical work containing valuable instructions for aviation students, mechanicians, squadron engineering officers and all interested in the construction and upkeep of airplane power plants.

The rapidly increasing interest in the study of aviation, and especially of the highly developed internal combustion engines that make mechanical flight possible, has created a demand for a text-book suitable for schools and home study that will clearly and concisely explain the workings of the various aircraft engines of foreign and domestic manufacture.

This treatise, written by a recognized authority on all of the practical aspects of internal combustion engine construction, maintenance and repair fills the need as no other book does.

The matter is logically arranged; all descriptive matter is simply expressed and copiously illustrated so that anyone can understand airplane engine operation and repair even if without previous mechanical training. This work is invaluable for anyone desiring to become an aviator or aviation mechanician.

The latest rotary types, such as the Gnome, Monosoupape, and Le Rhone, are fully explained, as well as the recently developed Vee and radial types. The subjects of carburetion, ignition, cooling and lubrication also are covered in a thorough manner. The chapters on repair and maintenance are distinctive and found in no other book on this subject.

Invaluable to the student, mechanic and soldier wishing to enter the aviation service.

Not a technical book, but a practical, easily understood work of reference for all interested in aeronautical science. 576 octavo pages. 253 specially made engravings. Price $3.00 net

A complete, well illustrated volume intended to facilitate conversation between English-speaking and French aviators. A very valuable book for all who are about to leave for duty overseas.

Approved for publication by Major W. G. Kilner, S.C., U.S.C.O. Signal Corps Aviation School. Hazelhurst Field, Mineola, L. I.

This book should be in every Aviator’s and Mechanic’s Kit for ready reference. 128 pages. Fully illustrated with detailed engravings. Price $1.00

A large chart outlining all parts of a typical airplane power plant, showing the points where trouble is apt to occur and suggesting remedies for the common defects. Intended especially for Aviators and Aviation Mechanics on School and Field Duty. Price 50 cents

The only book that shows you just how to handle any job of brazing or soldering that comes along; it 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 formulæ for all kinds of solders and fluxes have been added. Illustrated. Price 25 cents

A large chart outlining all parts of a typical airplane power plant, showing the points where trouble is apt to occur and suggesting remedies for the common defects. Intended especially for Aviators and Aviation Mechanics on School and Field Duty. Price 50 cents

It shows clearly all parts of a typical four-cylinder gasoline engine of the four-cycle type. It outlines distinctly all parts liable to give trouble and also details the derangements apt to interfere with smooth engine operation.

Valuable to students, motorists, mechanics, repairmen, garagemen, automobile salesmen, chauffeurs, motor-boat owners, motor-truck and tractor drivers, aviators, motor-cyclists, and all others who have to do with gasoline power plants.

It simplifies location of all engine troubles, and while it will prove invaluable to the novice, it can be used to advantage by the more expert. It should be on the walls of every public and private garage, automobile repair shop, club house or school. It can be carried in the automobile or pocket with ease and will insure against loss of time when engine trouble manifests itself.

This sectional view of engine is a complete review of all motor troubles. It is prepared by a practical motorist for all who motor. No details omitted. Size 25x38 inches. Price 25 cents

This chart presents the plan view of a typical six-cylinder chassis of standard design and all parts are clearly indicated that demand oil, also the frequency with which they must be lubricated and the kind of oil to use. A practical chart for all interested in motor-car maintenance. Size 24x38 inches. Price 25 cents

This chart shows all parts of a typical pressure feed fuel supply system and gives causes of trouble, how to locate defects and means of remedying them. Size 24x38 inches. Price 25 cents

In this chart all parts of a typical double ignition system using battery and magneto current are shown and suggestions are given for readily finding ignition troubles and eliminating them when found. Size 24x38 inches. Price 25 cents

This composite chart shows a typical automobile power plant using pump circulated water-cooling system and the most popular lubrication method. Gives suggestions for curing all overheating and loss of power faults due to faulty action of the oiling or cooling group. Size 24x38 inches. Price 25 Cents

This chart simplifies location of all power-plant troubles, and will prove invaluable to all who have to do with the operation, repair or sale of motorcycles. No details omitted. Size 25x38 inches. Price 25 cents

This shows clear sectional views depicting all portions of the Ford power plant and auxiliary groups. It outlines clearly all parts of the engine, fuel supply system, ignition group and cooling system, that are apt to give trouble, detailing all derangements that are liable to make an engine lose power, start hard or work irregularly. This chart is valuable to students, owners, and drivers, as it simplifies location of all engine faults. Of great advantage as an instructor for the novice, it can be used equally well by the more expert as a work of reference and review. It can be carried in the toolbox or pocket with ease and will save its cost in labor eliminated the first time engine trouble manifests itself. Prepared with special reference to the average man’s needs and is a practical review of all motor troubles because it is based on the actual experience of an automobile engineer-mechanic with the mechanism the chart describes. It enables the non-technical owner or operator of a Ford car to locate engine derangements by systematic search, guided by easily recognized symptoms instead of by guesswork. It makes the average owner independent of the roadside repair shop when touring. Must be seen to be appreciated. Size 25x38 inches. Printed on heavy bond paper. Price 25 cents

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

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. Price 25 Cents

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. Price 25 Cents

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 25 Cents

A chart showing the anatomy of a steel Hopper Bottom Coal Car, having every part of the car numbered and its proper name given in a reference list. Price 25 Cents

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. Price 50 Cents

Shows the horse-power of any stationary engine without calculation. No matter what the cylinder diameter of stroke, the steam pressure of 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. Price 50 Cents

A chart—size 14x28 inches—showing in isometric perspective the mechanisms belonging in a modern boiler room. 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. Price 25 Cents

This, the standard work on the subject, has just been revised. It is a practical work 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 one which shall be of use and benefit to those who are associated with, or interested in, the modern developments of the industry. Among the Chapters contained in Volume I are: Introduction; Classification of Fuels; Impurities of Coals; Coal Washing; Sampling and Valuation of Coals, etc.; Power of Fuels; History of Coke Manufacture; Developments in the Coke Oven Design; Recent Types of Coke Ovens; Mechanical Appliances at Coke Ovens; Chemical and Physical Examination of Coke. Volume II covers fully the subject of By-Products. Price, per volume $3.00 net

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. Price $5.00

Half Morocco. Price $6.50

A new automatic wall clamp is illustrated with working drawings. Other types of wall forms, clamps, separators, etc., are also illustrated and explained. (No. 1 of Series) Price 50 cents

The molds for molding squares, hexagonal and many other styles of mosaic floor and sidewalk blocks are fully illustrated and explained. (No. 2 of Series) Price 50 cents

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. (No. 3 of Series) Price 50 cents

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. A number of ornamental designs of chimney construction with molds are shown in this valuable treatise. (No. 4 of Series.) Price 50 cents

The proper proportions of cement and aggregates for various finishes, also the method 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. (No. 5 of Series.) Price 50 cents

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 are also fully treated. (No. 6 of Series.) Price 50 cents

Simple molds and instruction are given for molding many styles of concrete bathtubs, swimming-pools, etc. These molds are easily built and permit rapid and successful work. (No. 7 of Series.) Price 50 cents

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. (No. 8 of Series.) Price 50 cents

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. (No. 9 of Series.) Price 50 cents

The molds for producing many original designs of flower-pots, urns, flower-boxes, jardinieres, etc., are fully illustrated and explained, so the worker can easily construct and operate same. (No. 10 of Series.) Price 50 cents

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. (No. 11 of Series.) Price 50 cents

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

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 for the Farm and in the Shop” is a new book from cover to cover, illustrating and describing in plain, simple language many of the numerous applications of concrete within the range of the home worker. Among the subjects treated are: Principles of Reinforcing; Methods of Protecting Concrete so as to Insure Proper Hardening; Home-made Mixers; Mixing by Hand and Machine; Form Construction, Described and Illustrated by Drawings and Photographs; Construction of Concrete Walls and Fences; Concrete Fence Posts; Concrete Gate Posts; Corner Posts; Clothes Line Posts; Grape Arbor Posts; Tanks; Troughs; Cisterns; Hog Wallows; Feeding Floors and Barnyard Pavements; Foundations; Well Curbs and Platforms; Indoor Floors; Sidewalks; Steps; Concrete Hotbeds and Cold Frames; Concrete Slab Roofs; Walls for Buildings; Repairing Leaks in Tanks and Cisterns; and all topics associated with these subjects as bearing upon securing the best results from concrete are dwelt upon at sufficient length in plain every-day English so that the inexperienced person desiring to undertake a piece of concrete construction can, by following the directions set forth in this book, secure 100 per cent. success every time. A number of convenient and practical tables for estimating quantities, and some practical examples, are also given. (5x7.) 149 pages. 51 illustrations. Price 75 cents

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 follow: Introductory. Kinds of Cement 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 of 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 Draining Works. Concrete Tanks, Dams and Reservoirs. Concrete Sidewalks, Curbs and Pavements. Concrete in Railroad Construction. The Utility of Concrete on the Farm. The Waterproofing of Concrete Structures. Grout of 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

WHAT IS SAID OF THIS BOOK:

“The field of Concrete Construction is well covered and the matter contained is well within the understanding of any person.”—Engineering-Contracting.

“Should be on the bookshelves of every contractor, engineer, and architect in the land.”—National Builder.

Modern Methods of Waterproofing Concrete and Other Structures. A condensed statement of the Principles, Rules, and Precautions to be Observed in Waterproofing and Dampproofing Structures and Structural Materials. Paper binding. Illustrated. Price 50 cents

The lists contained are confined to essentials, and special folding plates are included to show all important airplane parts. The lists are divided in four sections as follows: 1.—Flying Field Terms. 2.—The Airplane. 3.—The Engine. 4.—Tools and Shop Terms.

A complete, well illustrated volume intended to facilitate conversation between English-speaking and French aviators. A very valuable book for all who are about to leave for duty overseas.

Approved for publication by Major W. G. Kilner, S.C., U.S.C.O. Signal Corps Aviation School, Hazelhurst Field, Mineola, L. I. This book should be in every Aviator’s and Mechanic’s Kit for ready reference. 128 pages, fully illustrated, with detailed engravings. Price $1.00

An indispensable work to all interested in electrical science. Suitable alike for the student and professional. A practical handbook 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

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 of 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 515 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. 6th Revised and Enlarged Edition. Price $3.00

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. 2d Edition. Price $4.00

This is a practical treatise on Modern Shop Practice, Processes, Methods, Machine 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-forgings, 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

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. 4th Edition. Price 50 cents

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. There is included a self-explanatory chart which gives all information necessary for the thorough understanding of perspective. This chart alone is worth many times over the price of the book. 2d Revised and Enlarged Edition. Price $2.50

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 fly-wheels, have been treated in such a way as to make possible the use of the work as a text-book 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 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.

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

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. 4th Edition. Price 25 cents

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 Punching. 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.

A complete treatise for the practical worker in Installing, Operating and Testing Bell Circuits, Burglar Alarms, Thermostats, and other apparatus used with Electric Bells.

Both the electrician and the experimenter will find in this book new material which is essential in their work. Tools, bells, batteries, unusual circuits, burglar alarms, annunciator systems, thermostats, circuit breakers, time alarms, and other apparatus used in bell circuits are described from the standpoints of their application, construction and repair. The detailed instruction for building the apparatus will appeal to the experimenter particularly.

The practical worker will find the chapter on Wiring, Calculation of Wire Sizes and Magnet Winding, Upkeep of Systems, and the Location of Faults, of the greatest value in their work. Among the chapters are: Tools and Materials for Bell Work; How and Why Bell Work; Batteries for Small Installations; Making Bells and Push Buttons; Wiring Bell Systems; Construction of Annunciators and Signals; Burglary Alarms and Auxiliary Apparatus; More Elaborate Bell Systems; Finding Faults and Remedying Them. 124 pages, fully illustrated. Price 50 cents