With this plan of separating the answer, as it were, from items of secondary importance, and making it short and simple, its content is more forcibly impressed upon the mind of the reader.
In a text book, it is necessary to illustrate and explain the various species of commercial apparatus met with in practice, and in this connection the Publishers desire to call attention to the manner in which the author has treated what may be classed as the “descriptive matter.” Contrary to the usual custom of giving descriptions of commercial machines in the main text, where they would occupy considerable space, to the exclusion of the more important matter, all such descriptions are placed in small type directly under the illustrations, leaving space for an adequate presentation of the underlying principles, theories, and for the large amount of practical information that is essential to obtain a general knowledge of Electricity and its numerous applications.
Credit is largely due to Frank D. Graham, B.S., M.S. (Princeton University), and M.E. (Stevens Institute), practical engineer, for the authorship of the Guides, and for original sketches illustrating electrical principles and construction.
TABLE OF CONTENTS GUIDE NO. 1.
| INTRODUCTORY CHAPTER | |
| SIGNS AND SYMBOLS | |
| ELECTRICITY | [1] to 4 |
| Nature and source—kinds of electricity: static, current, dynamic, radiated, positive, negative, atmospheric, frictional, resinous, vitreous. | |
| STATIC ELECTRICITY | [5] to 26 |
| Electrical attraction and repulsion—the charge—distribution of the charge—free and bound electricity—conductors and insulators—electroscopes—gold leaf electroscope—electric screens—electrification by induction—nature of the induced charge—the electrophorus—condensers; Leyden jar—electric machines—action of Toepler-Holtz machine—Wimshurst machines. | |
| THE ELECTRIC CURRENT | [27] to 34 |
| Volt—ampere—ohm—Ohm’s law—production of the electric current—current strength—voltage drop in an electric current. | |
| PRIMARY CELLS | [35] to 67 |
| The word “battery”—action of cell—chemical changes; polarization—effects of polarization—methods of depolarization—depolarizers—depolarizer bag—Volta’s contact law—contact series of metals—laws of chemical action in cell—requirements of a good cell—single and two fluid cells—the Leclanche cell—Fuller bichromate cell—the Edison cell—Grenet bichromate cell—Daniell cell—directions for making a Daniell cell—gravity cells—Daniell gravity cell—so-called “dry” cells—points relating to dry cells—care of cells—cleanliness—separating the elements—creeping—amalgamated zinc—battery connections. | |
| CONDUCTORS AND INSULATORS | [68] to 74 |
| The so-called “non-conductors”—table of conductors and insulators—mode of transmission—effect of heat—heating effect of the current—insulators—impregnating compounds—water as a conductor. | |
| RESISTANCE AND CONDUCTIVITY | [75] to 82 |
| Standard of resistance—conductivity of metals and liquids—effect of heat—laws of electrical resistance—conductivity—specific conductivity—divided circuits. | |
| ELECTRICAL AND MECHANICAL ENERGY | [83] to 92 |
| Definitions: energy, matter, molecule, work, foot-pound, volt-coulomb, ampere-hour, power, horse power, watt, kilowatt, watt-hour—mechanical equivalent of heat—British thermal unit—electrical horse power—the farad. | |
| EFFECTS OF THE CURRENT | [93] to 104 |
| Thermal effect—use of heat from the current—magnetic effect—chemical effect—electrolysis—electro-chemical series—electric osmose—electric distillation—muscular contractions—electroplating—electrotyping. | |
| MAGNETISM | [105] to 124 |
| Two kinds of magnetism—nature of each—poles—magnetic field—magnetic force—magnetic circuit—magnetic flux—the Maxwell—the Gauss—magnetic effect of the current—corkscrew rule—solenoids—permeability—magnetic saturation—magnetomotive force—reluctance—analogy between electric and magnetic circuits—hystereses—residual magnetism. | |
| ELECTROMAGNETIC INDUCTION | [125] to 136 |
| Faraday’s discovery—Faraday’s machine—Faraday’s principle—line of force—induction of current—laws of electromagnetic induction—rules for direction of induced current—Fleming’s rule—Ampere’s rule—the palm rule—self-induction. | |
| INDUCTION COILS | [137] to 154 |
| Self-induction—mutual induction—primary induction coils—secondary induction coils—plain secondary induction coils—secondary induction coils with vibrator and condenser; cycle of action—magnetic vibrators—vibrator adjustment—table of induction coil dimensions—table of sparking distances in air—points relating to induction coils—wiring diagram. | |
| THE DYNAMO | [155] to 160 |
| Operation—essential parts—field magnets—armature—construction of dynamos—parts; bed plate, field magnets, armature, commutator, brushes. | |
| THE DYNAMO: BASIC PRINCIPLES | [161] to 170 |
| Definitions—essential parts—elementary alternator—operation—direction of induced current—application of Fleming’s rule—cycle of operation—the sine curve; its construction and application. | |
| THE DYNAMO: CURRENT COMMUTATION | [171] to 180 |
| How the current is produced—how direct current is obtained—the commutator—inductors—“continuous current”—action of four coil elementary dynamo—conditions for steadiness of the current. | |
| CLASSES OF DYNAMO | [181] to 198 |
| Classification—bipolar and multi-polar dynamos—difference between dynamo and magneto—self-exciting dynamo—the series dynamo—regulation of series dynamo; difficulties experienced—the shunt dynamo—adaptation—operation—characteristic—regulation—the compound dynamo—service intended for—regulation—over compounding—usual degree of over compounding—short shunt—long shunt—voltage of short and long shunt machines—separately excited dynamos—Dobrowolski three wire dynamo. | |
| FIELD MAGNETS | [199] to 220 |
| Object—essential parts—classes of field magnet—multi-polar field magnets—construction—choice of materials—design—pole pieces—eddy current—laminated fields—construction to reduce reluctance of the magnetic circuit—magnetizing coils—methods of winding—coil ends—insulation—attachment of coils—coil connections—heating—ventilation. |
INTRODUCTORY CHAPTER
The subject matter of this work relates to one of the secrets of creation which appears to have been intended at the very beginning to be “sought out.” This idea is expressed in a certain saying copied three or four thousand years ago by the men of Hezekiah, King of Judah: from Solomon’s proverbs: “It is the glory of God to conceal a thing: But the glory of Kings (i.e., wise men), to search out a matter.”
In all that may be said hereafter through the work, it is admitted that the results recorded are the determinations of experiments performed by an incredible number of searchers extending through many ages. These inquiries have been pursued with a generous rivalry which has permitted discovery to be added to discovery, until the sum total has been wrought into such exactness that it has been thoughtlessly stated that there is nothing more, save its application.