The Project Gutenberg eBook of How Two Boys Made Their Own Electrical Apparatus, by Thomas M. (Thomas Matthew) St. John

This book contains 141 pages, 125 illustrations, and directions for making 152 pieces of apparatus. Size, 5×7½; red cloth.

CONTENTS: Chapter I. Cells and Batteries.—II. Battery Fluids and Solutions.—III. Miscellaneous Apparatus and Methods of Construction.—IV. Switches and Cut-Outs.—V. Binding-Posts and Connectors.—VI. Permanent Magnets.—VII. Magnetic Needles and Compasses.—VIII. Yokes and Armatures.—IX. Electro-Magnets.—X. Wire-Winding Apparatus.—XI. Induction Coils and Their Attachments.—XII. Contact Breakers and Current Interrupters.—XIII. Current Detectors and Galvanometers.—XIV. Telegraph Keys and Sounders.—XV. Electric Bells and Buzzers.—XVI. Commutators and Current Reversers.—XVII. Resistance Coils.—XVIII. Apparatus for Static Electricity.—XIX. Electric Motors.—XX. Odds and Ends.—XXI. Tools and Materials.

"The author of this book is a teacher and writer of great ingenuity, and we imagine that the effect of such a book as this falling into juvenile hands must be highly stimulating and beneficial. It is full of explicit details and instructions in regard to a great variety of apparatus, and the materials required are all within the compass of very modest pocket-money. Moreover, it is systematic and entirely without rhetorical frills, so that the student can go right along without being diverted from good helpful work that will lead him to build useful apparatus and make him understand what he is about. The drawings are plain and excellent. We heartily commend the book."—Electrical Engineer.

"Those who visited the electrical exhibition last May cannot have failed to notice on the south gallery a very interesting exhibit, consisting, as it did, of electrical apparatus made by boys. The various devices there shown, comprising electro-magnets, telegraph keys and sounders, resistance coils, etc., were turned out by boys following the instructions given in the book with the above title, which is unquestionably one of the most practical little works yet written that treat of similar subjects, for, with but a limited amount of mechanical knowledge, and by closely following the instructions given, almost any electrical device may be made at very small expense. That such a book fills a long-felt want may be inferred from the number of inquiries we are constantly receiving from persons desiring to make their own induction coils and other apparatus."—Electricity.

"At the electrical show in New York last May one of the most interesting exhibits was that of simple electrical apparatus made by the boys in one of the private schools in the city. This apparatus, made by boys of thirteen to fifteen years of age, was from designs by the author of this clever little book, and it was remarkable to see what an ingenious use had been made of old tin tomato-cans, cracker-boxes, bolts, screws, wire, and wood. With these simple materials telegraph instruments, coils, buzzers, current detectors, motors, switches, armatures, and an almost endless variety of apparatus were made. In his book Mr. St. John has given directions in simple language for making and using these devices, and has illustrated these directions with admirable diagrams and cuts. The little volume is unique, and will prove exceedingly helpful to those of our young readers who are fortunate enough to possess themselves of a copy. For schools where a course of elementary science is taught, no better text-book in the first steps in electricity is obtainable."—The Great Round World.

While only 40 pieces of simple apparatus were shown in this exhibit, it gave visitors something of an idea of what young boys can do if given proper designs.

"HOW TWO BOYS MADE THEIR OWN ELECTRICAL APPARATUS"
Gives Proper Designs—Designs for over 150 Things.

List No.	List Price
R1—FUN WITH MAGNETISM. A book and complete outfit of apparatus for sixty-one experiments. Weight 4 ounces.	$0.35**
R2—FUN WITH ELECTRICITY. A book and complete outfit of apparatus for sixty experiments. Weight 1 pound.	$0.65**
R3—FUN WITH PUZZLES. A book and complete outfit for four hundred puzzles with key to them. One pound.	$0.35**
R4—FUN WITH SOAP-BUBBLES. A book and complete outfit of apparatus for fancy bubbles and films. One pound.	$0.35**
R5—FUN WITH SHADOWS. A book and complete outfit of apparatus for shadow pictures, pantomimes, etc. One pound.	$0.35**
R6—FUN WITH PHOTOGRAPHY. A book and complete outfit of apparatus for amateur work. One pound.	$0.65**
R7—FUN WITH CHEMISTRY. A book and complete outfit of apparatus for forty-one experiments. One pound.	$0.65**
R41—ELECTRIC SHOOTING GAME. Absolutely harmless; fascinating. Paper bullets shot by electricity. One pound.	$0.35**
R42—ELECTRIC AIR-SHIPS AND OTHER GAMES. Great fun. Get into the game; be an aviator at home; for two players. One pound.	$0.35**
R43—ELECTRIC FORTUNE-TELLER tells a lot. Mysteriously electric. Comic and otherwise. In preparation. One pound.	$0.35**
R51—HOW TWO BOYS MADE THEIR OWN ELECTRICAL APPARATUS. A book containing complete directions for making many kinds of electrical apparatus. Seventh edition; 141 pages; cloth.	$1.00**
R52—THE STUDY OF ELEMENTARY ELECTRICITY AND MAGNETISM BY EXPERIMENT. A text-book for students and others. Systematic course for home or school. 220 pages; 200 experiments; cloth; fourth edition. This book with 105 pieces of apparatus complete, by express $6.25	$1.25**
R53—THINGS A BOY SHOULD KNOW ABOUT ELECTRICITY explains in simple language things a boy wants to know, things he should know. Seventh edition. 180 pages; cloth.	$1.00**
R54—REAL ELECTRIC TOY-MAKING FOR BOYS contains complete directions for making and using many electrical toys. Over 100 original drawings, diagrams and plates. Second edition; 140 pages, cloth.	$1.00**
R55—WIRELESS TELEGRAPHY FOR AMATEURS AND STUDENTS contains theoretical and practical information, together with directions for performing numerous experiments on wireless with simple home-made apparatus. Third and enlarged edition in preparation.	$1.00**
R56—ELECTRICAL HANDICRAFT contains complete directions for making and using nearly 150 pieces of electrical apparatus, including various devices and outfits for experimental purposes. New ideas and inexpensive supplies. Cloth; 252 pages; 250 drawings. Second edition.	$1.00**
R57C—THE STUDY OF ELECTRIC MOTORS BY EXPERIMENT contains sixty experiments that bear directly upon the construction, operation and explanation of electric motors, together with much helpful information upon the apparatus required. Over 100 pages; paper cover.	$0.35**
R58—THINGS A BOY SHOULD KNOW ABOUT WIRELESS contains much practical and some theoretical information on the operation and explanation of wireless outfits, together with numerous wiring-diagrams. Third edition; 126 pages; cloth.	$1.00**

Ask your Bookseller, Toy-dealer or Electrical Store for our Books, Games, Toys and Electrical Apparatus.

The book contains 180 pages, and 260 illustrations; it measures
5 × 7½ in., and is bound in cloth.

CONTENTS: Chapter I. About Frictional Electricity.—II. About Magnets and Magnetism.—III. How Electricity is Generated by the Voltaic Cell.—IV. Various Voltaic Cells.—V. About Push-Buttons, Switches and Binding-Posts.—VI. Units and Apparatus for Electrical Measurements.—VII. Chemical Effects of the Electric Current.—VIII. How Electroplating and Electrotyping are Done.—IX. The Storage Battery and How it Works.—X. How Electricity is Generated by Heat.—XI. Magnetic Effects of the Electric Current.—XII. How Electricity is Generated by Induction.—XIII. How the Induction Coil Works.—XIV. The Electric Telegraph, and How it Sends Messages.—XV. The Electric Bell and Some of its Uses.—XVI. The Telephone, and How it Transmits Speech.—XVII. How Electricity is Generated by Dynamos.—XVIII. How the Electric Current is Transformed.—XIX. How Electric Currents are Distributed for Use.—XX. How Heat is Produced by the Electric Current.—XXI. How Light is Produced by the Incandescent Lamp.—XXII. How Light is Produced by the Arc Lamp.—XXIII. X-Rays, and How the Bones of the Human Body are Photographed.—XXIV. The Electric Motor and How it Does Work.—XXV. Electric Cars, Boats and Automobiles.—XXVI. A Word About Central Stations.—XXVII. Miscellaneous Uses of Electricity.

This book explains, in simple, straightforward language, many things about electricity; things in which the American boy is intensely interested; things he wants to know; things he should know.

It is free from technical language and rhetorical frills, but it tells how things work, and why they work.

It is brimful of illustrations—the best that can be had—illustrations that are taken directly from apparatus and machinery, and that show what they are intended to show.

This book does not contain experiments, or tell how to make apparatus; our other books do that. After explaining the simple principles of electricity, it shows how these principles are used and combined to make electricity do every-day work.

By
THOMAS M. ST. JOHN, Met. E.

Author of "Things a Boy Should Know about Electricity," "Fun with
Electricity," "The Study of Elementary Electricity and Magnetism by
Experiment," "The Study of Electric Motors by Experiment," "Electrical
Handicraft," Etc., Etc.

126 Pages—109 Illustrations and Diagrams
Bound in Cloth—Net $1.00

This book contains much practical and some theoretical information regarding the operation and explanation of wireless outfits. It discusses enough of the theoretical side to make the student sure of himself and to give a well-rounded knowledge of this most practical subject.

The author has explained the various pieces of apparatus needed in a wireless station in such a clear manner that the student can not fail to understand how they work and why they work. The numerous drawings and diagrams simplify the discussions to such an extent that the reader will not want to skip a single paragraph.

"Things a Boy Should Know About Wireless" will be welcomed by thousands of enthusiasts and it should find its way into every library.

The book contains 220 pages and 168 illustrations. It measures
5 × 7½ in., and it is bound in green cloth.

CONTENTS: Part I. Magnetism.—Chapter I. Iron and Steel.—II. Magnets.—III. Induced Magnetism.—IV. The Magnetic Field.—V. Terrestrial Magnetism. Part II. Static Electricity.—VI. Electrification.—VII. Insulators and Conductors—VIII. Charging and Discharging Conductors.—IX. Induced Electrification.—X. Condensation of Electrification.—XI. Electroscopes.—XII. Miscellaneous Experiments.—XIII. Atmospheric Electricity. Part III. Current Electricity.—XIV. Construction and Use of Apparatus.—XV. Galvanic Cells and Batteries.—XVI. The Electric Circuit.—XVII. Electromotive Force.—XVIII. Electrical Resistance.—XIX. Measurement of Resistance.—XX. Current Strength.—XXI. Chemical Effects of the Electric Current.—XXII. Electromagnetism.—XXIII. Electromagnets.—XXIV. Thermo electricity.—XXV. Induced Currents.—XXVI. The Production of Motion by Currents.—XXVII. Applications of Electricity.—XXVIII. Wire Tables.—Apparatus List.—Index.

This is a text-book for amateurs, students, and others who want to take up a systematic course of electrical experiments at home or in school. It will give a practical and experimental knowledge of elementary electricity, and thoroughly prepare students for advanced work. Full directions are given for

The experiments and discussions are so planned that the student is always prepared for what follows. Although the experiments may be performed with the apparatus that is usually found in school laboratories, the author has designed a complete set of apparatus for those who want to have their own outfit.

If you want to take up a systematic course of experiments—experiments that will build a lasting foundation for your electrical knowledge—this book will serve as a valuable guide.

Fun With Magnetism and Fun With Electricity have started more young men upon electrical careers than any other scientific outfits ever placed before the public. The thousands upon thousands that have been sold in all parts of the world have furnished fun and science for people of all ages, and the mere fact that they are listed by the New York Board of Education, and recommend to the pupils and teachers of the New York public and private schools is a guarantee of their value. Were it not for the fact that these are made in such large quantities and sold by stores, agents and mail-order houses, the price would be much higher. Don't fail to get these. They have a national reputation.

This outfit contains a 32-page book of instructions, with 45 illustrations, together with a complete set of apparatus for performing 61 fascinating experiments. It will give you some new ideas about magnetism and start you at the right place in your study of electricity. Think what that means—to start right!

The book contains experiments with the horseshoe magnet, with bar magnets, with floating magnets, etc., etc., thus giving a practical knowledge of the subject; and it is all done in such an interesting way that one can't help remembering it. Every experiment clinches some fact and every fact is important.

Amusing Experiments.—Something for Nervous People to Try.—The Jersey Mosquito.—The Stampede.—The Runaway.—The Dog-fight.—The Whirligig.—The Naval Battle.—A String of Fish.—A Magnetic Gun.—A Top Upside down.—A Magnetic Windmill.—A Compass Upside down.—The Magnetic Acrobat.—The Busy Ant-hill.—The Magnetic Bridge.—The Merry-go-Round.—The Tight-rope Walker.—A Magnetic Motor Using Attractions and Repulsions.—And 43 Others.

The author of this Fun with Science series has spent a great deal of time and money in experimenting to devise apparatus that will do the proper work and be, at the same time, simple and cheap, and in no outfit has he succeeded better than in Fun with Electricity. When you think of an outfit retailing for 50c. and covering the whole subject of "Static Electricity," giving 60 scientific experiments upon its production, conduction and induction, with a 55–page book of instructions with 38 drawings, and a complete set of apparatus of 20 articles for performing these 60 experiments, you will understand why the sales of this outfit have been enormous. As the subject is presented in a fascinating way—and not as mere dry science—every one likes to do the experiments. No wonder these sets are highly praised by parents and educators in every part of the country!

There is Fun in these Experiments: Chain Lightning.—An Electric Whirligig.—The Baby Thunderstorm.—A Race with Electricity.—An Electric Frog Pond.—An Electric Ding-Dong.—The Magic Finger.—Daddy Long-Legs.—Jumping Sally.—An Electric Kite.—Very Shocking.—Condensed Lightning.—An Electric Fly-Trap.—The Merry Pendulum.—An Electric Ferry-Boat.—A Funny Piece of Paper.—A Joke on the Family Cat.—Electricity Plays Leap-Frog.—Lightning Goes Over a Bridge.—Electricity Carries a Lantern.—And 40 Others.

There isn't an outfit anywhere at any price that gives better value for the money. An ideal present for a boy.

Here is an outfit that every boy and girl should have, for it is amusing, instructive and educational. It is real fun to do puzzles and to puzzle your friends, and this book contains some real brain-teasers that will make you think. The book contains 15 chapters, 80 pages, and 128 illustrations, and measures 5×7½ inches. If you can't do any particular puzzle you will find its solution in the "key," which is bound with the book. If you want to win prizes by doing the puzzles in the magazines, you will find this book of four hundred puzzles a regular school of puzzles that will give you a thorough training for this kind of work. The book alone is well worth the price, to say nothing of the outfit of numbers, counters, pictures, etc.

Contents of Book: Chapter (1) Secret Writing. (2) Magic Triangles, Squares, Rectangles, Hexagons, Crosses, Circles, etc. (3) Dropped Letter and Dropped Word Puzzles. (4) Mixed Proverbs, Prose and Rhyme. (5) Word Diamonds, Squares, Triangles, and Rhomboids. (6) Numerical Enigmas. (7) Jumbled Writing and Magic Proverbs. (8) Dissected Puzzles. (9) Hidden and Concealed Words. (10) Divided Cakes, Pies, Gardens, Farms, etc. (11) Bicycle and Boat Puzzles. (12) Various Word and Letter Puzzles. (13) Puzzles with Counters. (14) Combination Puzzles. (15) Mazes and Labyrinths.

Secret Writing is explained in this book, and it shows how you can write letters to your friends and be sure that no one can read them unless they are also in the secret. This one thing alone will give you a great deal of enjoyment. Get this outfit and have some fun.

Fancy Bubbles and Films are not easily blown without special apparatus, and even with the proper outfit one must "know how." That's why we furnish a 16–page book with every set to show just how to do it. With the aid of the 21 illustrations and the directions you can produce remarkable results that will surprise and entertain your friends. A child can do it as well as a grown person.

Soap-Bubble Parties using these outfits create real sensations. Why not be the first in your town to give a "Fun with Soap-Bubbles Party?" Just write and ask about the price for any special number of them—say six or a dozen.

Contents of Book: Twenty-one Illustrations.—Introduction.—The Colors of Soap-Bubbles.—The Outfit.—Soap Mixture.—Useful Hints.—Bubbles Blown with Pipes.—Bubbles Blown with Straws.—Bubbles Blown with the Horn.—Floating Bubbles.—Baby Bubbles.—Smoke Bubbles.—Bombshell Bubbles.—Dancing Bubbles.—Bubble Games.—Supported Bubbles.—Bubble Cluster.—Suspended Bubbles.—Bubble Lamp Chimney.—Bubble Lenses.—Bubble Basket.—Bubble Bellows.—To Draw a Bubble Through a Ring.—Bubble Acorn.—Bubble Bottle.—A Bubble Within a Bubble.—Another Way.—Bubble Shade.—Bubble Hammock.—Wrestling Bubbles.—A Smoking Bubble.—Soap Films.—The Tennis Racket Film.—Fish-net Film.—Pan-shaped Film.—Bow and Arrow Film.—Bubble Dome.—Double Bubble Dome.—Pyramid Bubbles.—Turtle-back Bubbles.—Soap-Bubbles and Frictional Electricity.

"There is nothing more beautiful than the airy-fairy soap-bubble with its everchanging colors." This outfit gives the best possible amusement for old and young.

No wonder shadow-making has been popular for several centuries! What could give keener delight than comical shadow-pictures, pantomimes, entertainments, etc.? Professional shadowists use wires, forms, and various devices to aid them, and that is why they get such wonderful results on the stage. Do you want to do the same thing right in your own home and entertain your friends with all kinds of fancy shadows? You can do it with this outfit, for the book contains 100 illustrations and diagrams with directions for using the numerous articles included in the box. You will be surprised to see how easily you can make these funny shadows with the aid of the outfit. Better get one now and make shadows like a professional.

The Outfit contains everything necessary for all ordinary shadow pictures, shadow entertainments, shadow plays, etc. The following articles are included: One book of Instructions called "Fun with Shadows"; 1 Shadow Screen; 2 Sheets of Tracing Paper; 1 Coil of Wire for Movable Figures; 1 Cardboard Frame for Circular Screen; 1 Cardboard House for Stage Scenery; 1 Jointed Wire Fish-pole and Line; 2 Bent Wire Scenery Holders; 4 Clamps for Screen; 1 Wire Figure Support; 1 Wire for Oar; 2 Spring Wire Table Clamps; 1 Wire Candlestick Holder; 5 Cardboard Plates containing the following printed figures that should be cut out with shears; 12 Character Hats; 1 Boat; 1 Oar-blade; 1 Fish; 1 Candlestick; 1 Cardboard Plate containing printed parts for making movable figures.

Popular Pastimes are numerous, but to many there is nothing more fascinating than photography. The magic of sunshine, the wonders of nature, and the beauties of art are tools in the hands of the amateur photographer. If you want to get a start in this up-to-date hobby, this outfit will help you. You will enjoy the work and be delighted with the beautiful pictures you can make.

The Outfit contains everything necessary for making prints—together with other articles to be used in various ways. The following things are included: One Illustrated Book of Instructions, called "Fun With Photography"; 1 Package of Sensitized Paper; 1 Printing Frame, including Glass, Back, and Spring; 1 Set of Masks for Printing Frame; 1 Set of Patterns for Fancy Shapes; 1 Book of Negatives (Patented) Ready for Use; 6 Sheets of Blank Negative Paper; 1 Alphabet Sheet; 1 Package of Card Mounts; 1 Package of Folding Mounts; 1 Package of "Fixo."

Contents of Book: Chapter I. Introduction.—Photography.—Magic Sunshine.—The Outfit.—II. General Instructions.—The Sensitized Paper.—How the Effects are Produced.—Negatives.—Prints.—Printing Frames.—Our Printing Frame.—Putting Negatives in Printing Frame.—Printing.—Developing.—Fixing.—Drying—- Trimming.—Fancy Shapes.—Mounting.—III. Negatives and How to Make Them.—The Paper.—Making Transparent Paper.—Making the Negatives.—Printed Negatives.—Perforated Negatives.—Negatives Made from Magazine Pictures.—Ground Glass Negatives.—IV. Nature Photography.—Aids to Nature Study.—Ferns and Leaves.—Photographing Leaves.—Perforating Leaves.—Drying Leaves, Ferns, etc., for Negatives.—Flowers.—V. Miscellaneous Photographs.—Magnetic Photographs.—Combination Pictures.—Initial Pictures.—Name Plates.—Christmas, Easter and Birthday Cards.

Chemistry is universally considered to be an interesting subject, even in school, and it is certainly an important one in these days of scientific progress. This outfit starts you at the right place and presents the elements of the subject in a most interesting fashion. The experiments are so enjoyable that you will take pleasure in doing them over and over again, and you will want to do them for your friends. You can have a lot of fun with this set, and even if you have taken advanced courses in the subject you will find something new in these experiments. The more you know about chemistry the more you will enjoy it, for then you can more easily appreciate what a splendid outfit this is for the money.

The Outfit contains over 20 different articles, including chemicals, test-tubes, adjustable ring-stand, litmus paper, filter paper, glass tubing, etc.; in fact, everything needed for the forty-one experiments. The Book of Instructions is fully illustrated, and measures 5×7½ inches.

Fun Found Here: From White to Black, or the Phantom Ship.—Yellow Tears.—Smoke Pearls.—An Ocean of Smoke.—A Tiny Whirlwind.—A Smoke Cascade.—An Explosion in a Teacup.—A Gas Factory in a Test-Tube.—Making Charcoal.—Flame Goes Over a Bridge.—A Smoke Toboggan-Slide.—Fountains of Flame.—Making an Acid.—Making an Alkali.—A Chemical Fight.—Through Walls of Flame.—An Artificial Gas Well.—A Lampblack Factory.—Steam from a Flame.—The Flame that Committed Suicide.—Chemical Soup.—A Baby Skating-Rink.—A Magic Milk-Shake.—The Wizard's Breath.—A Chemical Curtain.—Scrambled Chemicals.—And Many Other Experiments.

Shooting Animals by electricity is certainly a most original game, and it will furnish a vast amount of amusement to all. The game is patented and copyrighted—because it is really a brand-new idea in games—and it brings into use that most mysterious something called electricity. While the electricity is perfectly harmless, there being no batteries, acids or liquids, it is very active and you will have plenty to laugh at. It is so simple that the smallest child can play it and so fascinating that grandpa will want to try it.

The "game-preserve" is neatly printed in colors, and the birds and wild animals are well worth hunting. Each has a fixed value—and some of them must not be shot at all—so there is ample chance for skill. Tissue-paper bullets are actually shot from the "electric gun" by electricity, and it is truly a weird sight to see them shoot through the air impelled by this unseen force.

The Outfit contains the "Game-Preserve," the "Electric Gun," the "Shooting-Box," and the "Electric Bullets," together with complete illustrated directions, all placed in a neat box.

Splendid game for two, three, or four players; great improvement upon the good old game; fascinating game instantly learned; nothing better for children's parties and progressive birthday parties; box with game-board, 12 men, directions; discount for party orders.

By THOMAS M. ST. JOHN. Met. E.

This book contains 140 pages and over one hundred
original drawings, diagrams, and full-page plates.

It measures 5×7½ in., and is bound in cloth.

SECOND EDITION Price, postpaid, $1.00

CONTENTS: Chapter I. Toys Operated by Permanent Magnets.—II. Toys Operated by Static Electricity.—III. Making Electromagnets for Toys.—IV. Electric Batteries.—V. Circuits and Connections.—VI. Toys Operated by Electromagnets. VII. Making Solenoids for Toys.—VIII. Toys Operated by Solenoids.—IX. Electric Motors.—X. Power, Speed, and Gearing.—XI. Shafting and Bearings.—XII. Pulleys and Winding-Drums.—XIII. Belts and Cables.—XIV. Toys Operated by Electric Motors.—XV. Miscellaneous Electric Toys.—XVI. Tools.—XVII. Materials.—XVIII. Various Aids to Construction.

While planning this book, Mr. St. John definitely decided that he would not fill it with descriptions of complicated, machine-made instruments and apparatus, under the name of "Toy-Making," for it is just as impossible for most boys to get the parts for such things as it is for them to do the required machine work even after they have the raw materials.

Great care has been taken in designing the toys which are described in this book, in order to make them so simple that any boy of average ability can construct them out of ordinary materials. The author can personally guarantee the designs, for there is no guesswork about them. Every toy was made, changed, and experimented with until it was as simple as possible; the drawings were then made from the perfected models.

As the result of the enormous amount of work and experimenting which were required to originate and perfect so many new models, the author feels that this book may be truly called "Real Electric Toy-Making for Boys."

The "St J. Motor No. 1" (List No. 2201) is designed for students and others who want a small motor for experimental purposes as well as for all of the work that any small motor can do. We believe this to be the best small motor made, and we know that it can be used in more ways than any other motor of equal cost ever built. It has four binding-posts,—making it possible to energize the field or armature separately,—and so it can be used in circuits with reversers and rheostats for experiments. The speed and direction of rotation can be changed at will, thus adapting it for running toys, etc. As the binding-posts are mounted upon the frame, this motor can be taken from the base for remounting and using in many ways, and as it has a three-pole armature it will start promptly in any position. The shaft carries a pulley, and a fan can be added at any time. One cell will give a high speed, and more cells may be added, according to the work it has to do.

Motor No. 1 stands 3½ inches high. It is finished in black enamel with nickel-plated trimmings,—strong and well made. With it are furnished three nickel-plated connecting-straps, which are to be used for connecting the field and armature in "series" or "shunt." So much can be done with this motor that it is simply impossible to tell it here; in fact, it is used as the basis for a whole book of 60 experiments called "The Study of Electric Motors by Experiment," and, when used in connection with the other parts of the Motor Outfits, it will give a practical knowledge of motors that no other plan can give.

These motors and motor outfits have been highly praised by electrical experts and educators as being invaluable to students. They can do everything the big motors can do, and if used with the rheostats, reversers and other apparatus in the outfits, the student will have a whole motor laboratory.

Why not get a motor that has brains and that can do tricks and experiments? Any good motor will go when you turn on the power; but that doesn't mean much when it comes to understanding things.

These outfits have been designed for students and others who want to do real experimental work with motors, so as to get right down to the bottom of the matter and thoroughly master the foundation principles of the subject. It is simply astonishing to see how much can be learned with one of these outfits, especially if the work be done as fully detailed in "The Study of Electric Motors by Experiment." Every electrical laboratory should have one of these sets, and the more you know about motors the more you will appreciate an outfit of this kind.

Don't simply read about motors—get right down to the practical part of it and experiment for yourself. Every experiment will settle an important point in your mind.

ELECTRIC MOTOR OUTFIT No. 2226X contains everything needed for sixty interesting and profitable experiments. With the improved apparatus that we now give we feel that this is the most complete set ever sold for the money. The following articles are included, packed in a wooden box:

THE "ST. J." MOTOR, fully described on another page, is well called "A motor that can do things."

THE FIVE-POINT RHEOSTAT is used as a "starting-box" in the armature-circuit and in various other ways to regulate speed. (See cut.)

THE ELEVEN-POINT RHEOSTAT is used to regulate the "field-magnetism," as one method of speed-regulation, and for other purposes. (See cut.)

THE DOUBLE-KEY CURRENT REVERSER is, really, a key, a two-point switch, and a current-reverser combined. On this account it can be used in many ways, shown in numerous wiring-diagrams. (See cut.)

THE HANDY CURRENT-DETECTOR is used as a current-detector and as a device for studying the counter-electromotive force of motor while running.

THE TWO-POINT SWITCH is useful in quickly switching the current wherever it is needed, and for many other experiments.

THE MINIATURE ELECTRIC LAMP AND SOCKET are used in the motor-circuit to prove certain things and form an attractive addition to the outfit.

THE MAGNETIC NEEDLE in the new outfits is nickel-plated and serves as a compass for studying the magnetism of the poles, etc.

IN ADDITION to the articles mentioned above, the outfit contains a Set of Wires for Connections, a Box of Iron-Filings for studying lines of force, an Experimental Package containing Iron, Steel, etc., three Connecting-Wires, and

THE BOOK OF INSTRUCTIONS, called "The Study of Electric Motors by Experiment." This contains 10 chapters, 110 pages, and over 70 illustrations and diagrams. Bound in stiff paper.

BATTERIES are not included, unless ordered extra. Three of our No. 1101 batteries cost 36c., and extra postage for 2 lbs.

THE STUDY OF ELECTRIC MOTORS BY EXPERIMENT contains Sixty Experiments that Bear Directly upon the Construction, Operation, and Explanation of Electric Motors, together with Much Helpful Information upon the Experimental Apparatus Required. This book will be a great help to those who want to do real experimental work with motors. It contains 10 chapters, 110 pages, over 70 illustrations and diagrams, and you can not afford to be without it.

These two outfits are similar in construction, although they differ in details, each being designed for its special work. The "keys," "sounders" and "binding-posts" are neatly mounted upon ebonized bases measuring 6½×3¾ in., these also serving as sounding-boards.

"Fun with Telegraphy" is the original low-price telegraph outfit for students that has sold by the thousands and given universal satisfaction. It is considered the best 50-cent outfit ever produced, and, although we have made several improvements lately, the price is the same as before. In connection with a peculiar oscillating electro-magnet and a queer anvil, the sounding-board aids in giving out a loud, clear click that is found elsewhere only in noisy railroad sounders. This outfit is best adapted for a learner's set of one instrument and a battery to be used on the table for practising, either with or without the "codegraph," and not for telegraphing over wires to other stations.

Outfit: Illustrated Book of Instructions, called "Fun with Telegraphy"; Telegraph "Key"; Telegraph "Sounder"; Nickel-Plated "Binding-Posts"; Insulated Wires for Connections.

"Improved Telegraphy No. 2."—In answer to a number of requests for an improved outfit for regular line work between two stations a few hundred feet apart, we now offer this set, which is, in general, similar in plan to our first "Telegraphy No. 2." We have replaced the single electro-magnet of the old set, as shown in the cut, with two larger ones of superior construction, thus making the instrument much more sensitive. The key has also been greatly improved, and we now have a fine set at low cost.

No expensive gravity batteries are needed with this ingenious arrangement, as it is designed to work with dry batteries which are clean and cheap. By means of a peculiar switch, either station may "call" the other at any time, even though the line is kept on "open circuit." There is absolutely no waste of current when the line is not in use—and, even then, only at the instant the dots and dashes are made. This is certainly a great advantage over the old-fashioned methods with gravity batteries which amateurs have heretofore been obliged to use. With this instrument you have a learner's set as well as one that can be used to send messages to another station. If you do not care for the superior advantages of "Semi-Wireless," this outfit will give entire satisfaction for ordinary work.

Outfit: Illustrated Book of Instructions called "Telegraphy Number Two"; Improved Telegraph "Key"; Telegraph "Sounder" with Double Electromagnets: Special "Switch" for controlling the batteries; Nickel-plated Screw "Binding-posts"; Insulated Wires for connections.

The Codegraph is a brand-new scheme for thoroughly and rapidly learning the telegraphic code, and it has been worked out with the beginner in mind. This code-learning system really adapts itself to the beginner, and it gives a personal touch to each individual student according to his needs. No other system can do so much, for the student sees, hears and feels every letter and signal.

The greatest trouble that every one has in learning by listening to regular messages is in separating the letters and words as they come in so fast. There is no time to think, and letters pile up in the mind. The codegraph avoids all confusion because every letter is under perfect control and may be repeated as many times as desired; hard things can be made easy; words and sentences can be built at will. We guarantee that any one of average ability can make rapid improvement with the codegraph.

What It Is. A complete codegraph outfit, as shown in the cut, has three main parts: (1) The "plate and pen," (2) some form of "key and sounder" and (3) two batteries. While any key and sounder can be used with the plate, we wish to call especial attention to the duplex sounder shown, as this has been designed to do double work. If you already have "Fun with Telegraphy," for example, and want to order the "Codegraph Plate and Pen," we will include, free of charge, an extra attachment for connecting up your instrument.

The Plate and Pen. When the pen is lightly drawn over the plate, the sounder responds and shows exactly how every letter and signal should sound. The student can then practise each letter until perfect. The surface of the plate is covered with a special insulating enamel, bare spots corresponding to correct dots and dashes. The polished brass plate measures about 6×8 inches and has a most elegant appearance. The book tells all about practising, etc.

Duplex Codegraph Key and Sounder, as shown, has a double action and is the latest thing in code-learning devices. By the mere turning of a switch you can have the ordinary telegraph clicks or the wireless buzzes, making two sounders in one and at the cost of one. The combination sounder and a substantial key are mounted upon a finely finished base with nickel-plated trimmings, binding-posts, switch, etc. If you want to become an operator in the shortest possible time, no matter whether you have ever tried before or not, get one of these outfits and begin at once. You will be pleased right from the start, because you will make rapid progress right from the start.