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30 chapters
INTRODUCTION.
INTRODUCTION.
For the benefit of the readers of Vol. III, who have not read the general Introduction found in Vol. I, a word as to the scope and object of this volume will not be amiss. It will be plain to any one on seeing the size of the little book that it cannot be an exhaustive treatise on a subject so large as that of Electricity. This volume, like the others, is intended for popular reading, and technical terms are avoided as far as possible, or when used clearly explained. The subject is treated histo
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CHAPTER I.
CHAPTER I.
The writer has spent much of his time for thirty-five years in the study of electricity and in inventing appliances for purposes of transmitting intelligence electrically between distant points, and is perhaps more familiar with the phenomena of electricity than with those of any other branch of physics; yet he finds it still the most difficult of all the natural sciences to explain. To give any satisfactory theory as to its place with and relation to other forms of energy is a perplexing proble
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CHAPTER II.
CHAPTER II.
Electricity as a well-developed science is not old. Those of us who have lived fifty years have seen nearly all its development so far as it has been applied to useful purposes, and those who have lived over twenty-five years have seen the major portion of its development. Thales of Miletus, 600 B.C. , discovered, or at least described, the properties of amber when rubbed, showing that it had the power to attract and repel light substances, such as straws, dry leaves, etc. And from the Greek wor
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CHAPTER III.
CHAPTER III.
It is said that the word magnetism is derived from the name of a Greek shepherd, called Magnes, who once observed on Mount Ida the attractive properties of loadstone when applied to his iron shepherd's crook. It is more likely that the name came from Magnesia, a country in Lydia, where it was first discovered. It was also called Lapis Heracleus. Heraclea was the capital of Magnesia. Loadstone is a magnetic ore or oxide of iron found in the natural state, and has at some time by natural processes
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CHAPTER IV.
CHAPTER IV.
Iron and steel have a peculiar property called magnetism. It is an attraction in many ways unlike the attraction of cohesion or the attraction of gravitation. It is very certain that magnetism is an inherent property of the molecules of iron and steel, and, to a small degree, other forms of matter. That is to say, the molecules are little natural magnets of themselves. It is as unnecessary to inquire why they are magnets as it is to inquire why the molecules of all ordinary substances possess th
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CHAPTER V.
CHAPTER V.
In the series of chapters on Heat (Vol. II) and in the chapter on Magnetism the word molecule was frequently used synonymously with atom. In chemistry a distinction is made, and as we can better explain the theory, at least, of electricity by keeping this distinction in mind we will refer to it here. It has been stated that there are between sixty and seventy elementary substances. An elementary substance cannot be destroyed as such. It can be united with other elements and form chemical compoun
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CHAPTER VI.
CHAPTER VI.
The simplest form of an electric machine is one in which the operator is a prominent part of the operation. Electricity, like magnetism, operates in a closed circuit, even when it is static—so-called. Take a stick of sealing-wax, say, in your left hand, and rub it with a piece of fur or silk with your right hand, and you have the simplest form of electric machine—the one that was known to the ancients, and the one from which the science, great as it is to-day, had its beginnings. The stick of se
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CHAPTER VII.
CHAPTER VII.
Of the sources of electricity we have mentioned two: Friction, and Galvanism or chemical action. There are hundreds of forms of the latter species of apparatus for generating electrical energy, so we will mention only a few of the more prominent ones. It is not our intention to go into the chemistry of batteries. There are too many exhaustive works on this subject lying on the shelves of libraries that are accessible to all. All galvanic batteries act on one general principle—the generation of e
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CHAPTER VIII.
CHAPTER VIII.
Nature has another mode of generating electricity, called atmospheric. The normal conditions of potential between the earth and the upper atmosphere seem to be that the atmosphere is positively electrified and the earth negatively. These conditions change, apparently from local causes, for short periods during storms. In some way the sun's rays have the power directly or indirectly to give the globules of moisture in the air a potential different from that of the earth. In clear weather we find
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CHAPTER IX.
CHAPTER IX.
Having given a short account of some of the sources of electricity, let us now proceed to describe some of the practical uses to which it is put, and at the same time describe the operation of the appliances used. Before proceeding further, however, we ought to tell how electricity is measured. We have pounds for weight, feet and inches for lineal measure, and pints, quarts, gallons, pecks and bushels for liquid and dry measure, and we also have ohms, volts, ampères and ampère-hours for electric
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CHAPTER X.
CHAPTER X.
In the year 1617 Strada, an Italian Jesuit, proposed to telegraph news without wires by means of two sympathetic needles made of loadstone so balanced that when one was turned the other would turn with it. Each needle was to have a dial with the letters on it. This would have been very nice if it had only worked, but it was not based on any known law of nature. Many attempts at telegraphing with electricity were made by different people during the eighteenth century. About 1748 Franklin succeede
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CHAPTER XI.
CHAPTER XI.
With but few exceptions the Morse code is the one almost universally used the world over. As it is used in Europe, it is slightly changed from our American code, but they all depend upon dots, dashes, and spaces, related in different combinations, for the different letters. Notwithstanding its universal use it is not free from serious difficulties in transmission unless it is repeated back to the sender for correction; and then in some cases it is impossible to be sure, owing to difficulties of
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CHAPTER XII.
CHAPTER XII.
"It never rains but it pours." Almost simultaneously with the demonstration of the Morse telegraph other types were devised. There were the needle systems of Cooke and Wheatstone, the chemical telegraph of Alexander Bain, and soon the printing telegraph of House, and later that of Hughes. The latter is in use on the continent of Europe, and a modification of it has a very limited use on some American lines. The Bain telegraph used a key and battery the same as the Morse system, but it did not de
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CHAPTER XIII.
CHAPTER XIII.
Although the printing and automatic systems of telegraphing are used in America to some extent, the larger part is done by the Morse system of sound-reading and copying from it, either by pen or the typewriter. In the early days only one message could be sent over one wire at the same time, but now from four to six or even more messages may be sent over the same wire simultaneously without one message interfering with the other. Like most other inventions, many inventors have contributed to the
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CHAPTER XIV.
CHAPTER XIV.
A novel form of double transmission was invented by the writer soon after the completion of the harmonic system, and was an outgrowth of it. It is still in use on some of the railroad-lines. An ordinary railroad telegraph-line has an instrument in circuit in every office along the road, chiefly for purposes of train-dispatching. As we have heretofore explained, whenever any one office is sending, the dispatch is heard in all of the offices. The "Way duplex" system permits of the use of the line
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CHAPTER XV.
CHAPTER XV.
In the foregoing chapters I have described the method of transmitting musical tones telegraphically and its applications to multiple telegraphy, as well as to a mode of communicating with a moving railroad-train. As I stated in a former chapter, after discovering a method of transmitting harmony as well as melody, I had in mind two lines of development, one in the direction of multiple telegraphy, and the other that of the transmission of articulate speech. I will not attempt to give the names o
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CHAPTER XVI.
CHAPTER XVI.
Everybody knows what the telephone is because it is in almost every man's house. But while everybody knows what it is, there are very few (comparatively speaking) that know how it works. If you remember what has been said about sound and electromagnetism it will not be hard to understand. When any one utters a spoken word the air is thrown into shivers or vibrations of a peculiar form, and every different sound has a different form. Therefore, every articulate word differs from every other word,
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CHAPTER XVII.
CHAPTER XVII.
The first attempts at transmitting messages through wires laid in water were made about 1839. These early experiments were not very successful, because the art of wire-insulation had not attained any degree of perfection at that time. It was not until gutta-percha began to be used as an insulator for submarine lines that any substantial progress was made. The first line, so history states, that was successfully laid and operated was across the Hudson River in 1848. This line was constructed for
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CHAPTER XVIII.
CHAPTER XVIII.
Early in the history of the telegraph short lines began to be used for private purposes, and as the Morse code was familiar only to those who had studied it and were expert operators on commercial lines, some system had to be devised that any one with an ordinary English education could use; as the expense of employing two Morse operators would be too great for all ordinary business enterprises. These short lines are called private lines, and the instruments used upon them were called private-li
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CHAPTER XIX.
CHAPTER XIX.
So far we have described several methods of electrical communication at a distance, including the reading of letters and symbols at sight (as by the dial-telegraph and the Morse code embossed on a strip of paper); printed messages and messages received by means of arbitrary sounds, and culminating in the most wonderful of all, the electrical transmission of articulate speech. None of these systems, however, are able to transmit a message that completely identifies the sender without confirmation
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CHAPTER XX.
CHAPTER XX.
Until within recent years it was never supposed that a sunbeam would ever laugh except in poetry. But the modern scientist has taken it out of the realm of poetry and put it into the prosy play of every-day life. The Radiophone, invented by A. G. Bell, is an instrument by which articulate or other sounds are transmitted through the medium of a ray of light. It has as yet no practical application and has never gone beyond the experimental stage, but as a bit of scientific information it is very i
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CHAPTER XXI.
CHAPTER XXI.
Broadly speaking, "Wireless Telegraphy" is any method of transmitting intelligible signals to a distance without wires; and this includes the old Semaphore systems of visual signals, such as flags and long arms of wood by day, and lights by night; also the Heliograph (an apparatus for flashing sunlight), and Sound Signals, made either through the air or water. Electrical conduction, either through rarefied air or the earth, also comes under this heading. The name "Wireless Telegraphy," however,
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CHAPTER XXII.
CHAPTER XXII.
As our readers know, Niagara Falls is situated upon the Niagara River, which is the connecting-link between Lake Erie and Lake Ontario. The surface of Lake Erie lies 330 feet above that of Lake Ontario. The high level upon which Lake Erie is situated abruptly terminates at Queenstown, which is near the point where the Niagara River empties into Lake Ontario. From Lake Erie to the falls the level of the river is gradually lowered a little less than 100 feet, and most of this (making "the rapids")
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CHAPTER XXIII.
CHAPTER XXIII.
Some years ago a company was formed for the purpose of utilizing, to some extent, this greatest of all water-powers. A tunnel of large capacity was run from a point a short distance below the falls on a level a little above the river at that point. The general direction of this tunnel is up the river; it is about a mile and one-half in length, terminating at a point near the bank of the river a mile or more above the falls. Above the end of this tunnel an upright pit comes to the surface, where
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CHAPTER XXIV.
CHAPTER XXIV.
In the last chapter I described some of the appliances used in connection with the power-house. There are many things that are commonplace as electrical appliances when used with currents of low voltage and small quantity, that become extremely interesting when constructed for the purpose of handling such currents as are developed by the dynamos used at Niagara. For instance, it is a very commonplace and simple thing to break and close a circuit carrying such a current as is used for ordinary te
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CHAPTER XXV.
CHAPTER XXV.
The production of electricity in such enormous quantities as are generated at Niagara Falls has led to many discoveries and will lead to many more. Products that at one time existed only in the chemical laboratory for experimental purposes, have been so cheapened by utilizing electrical energy in their manufacture, as to bring them into the play of every-day life. Still other products have only been discovered since the advent of heavy electrical currents. A substance called carborundum, which w
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CHAPTER XXVI.
CHAPTER XXVI.
Another industry that has assumed large proportions at Niagara Falls, owing to the vast quantity of electricity produced there, is the manufacture of a commercial product called bleaching-powder, or chloride of lime. Every one knows that chloride of sodium is simply common salt, so extensively used wherever people and animals exist. Simple and harmless as it is, while it exists as a compound of the original elements, when separated into those elements they are each very unpleasant and even dange
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CHAPTER XXVII
CHAPTER XXVII
Another comparatively new article of manufacture now produced in large quantities at Niagara Falls is aluminum. Until within the last few years this metal was not used to any extent by manufacturers, because of the great expense attending its production. Now, however, it is produced in such quantities as to make it about as cheap as brass, bulk for bulk. Aluminum is a very light metal, with a color somewhat lighter than silver; its specific gravity being about one-third that of iron. Aluminum is
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CHAPTER XXVIII.
CHAPTER XXVIII.
Another important use to which electricity is put at Niagara Falls is the manufacture of a new product, called calcium carbide. Like carborundum and aluminum, this product could not have been produced in commercial quantities in advance of a means for producing electricity in enormous volume. Calcium carbide is a compound of calcium and carbon. Calcium is a white metal not found in the natural state, but exists chiefly as a carbonate of lime, which is ordinary limestone, including the various fo
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CHAPTER XXIX.
CHAPTER XXIX.
When we consider the number of new products for whose existence we are indebted to electricity, and the number of old products that have heretofore existed experimentally, in the laboratory of the chemist only, that have now been brought into play as useful agents in the various arts and industries, we begin to realize that this is truly an electrical age and the dawning of a new era. How many, many things there are, familiar to the children of to-day, that were not even imagined by the children
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