How Two Boys Made Their Own Electrical Apparatus Part 21

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 STRAP KEY protects the batteries and closes the circuit.

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 compa.s.s 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 ill.u.s.trations 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.

No. 2226X--Complete Motor Outfit, as above (P. weight, 3 lbs.) $3.75

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 ill.u.s.trations and diagrams, and you can not afford to be without it.

No. R57P--"Study of Motors," bound in paper, postpaid $0.35

No. R57C--"Study of Motors," bound in cloth, postpaid $0.60

Fun With Telegraphy (PATENTED)

TWO GREAT OUTFITS FOR STUDENTS

[Ill.u.s.tration]

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 6-1/23-3/4 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: Ill.u.s.trated Book of Instructions, called "Fun with Telegraphy"; Telegraph "Key"; Telegraph "Sounder"; Nickel-Plated "Binding-Posts"; Insulated Wires for Connections.

No. R8--"Fun with Telegraphy," without battery, postpaid $0.50

No. R8, R8B--"Fun with Telegraphy," with one dry battery, postpaid, .65

"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-fas.h.i.+oned 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: Ill.u.s.trated 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.

No. 2307--"Improved Telegraphy Number Two" (no batteries), postpaid, $1.00

No. 2307B--Same as No. 2307, but with two dry batteries, postpaid, 1.35

The Codegraph (PATENTED)

NOTE--Continental Code sent unless otherwise ordered.

[Ill.u.s.tration]

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 bra.s.s plate measures about 68 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 tr.i.m.m.i.n.gs, 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.

No. 2350--"Codegraph Plate and Pen," with Book of Instructions $1.00 If sent by mail, postage extra .12 No. 2351--"Duplex Codegraph Key and Sounder" (no batteries) 1.00 If sent by mail, postage extra .10 No. 1102--Two Dry Batteries, as shown .25 If sent by mail, postage extra .10 Special--Complete Codegraph Outfit, as in cut, postpaid 2.50