Part 3

An old and charming story runs, that Aladdin, son of a widow of Bagdad, became owner of a magic lamp, by means of whose remarkable powers he could bring to his instant aid the services of an all-helpful genie. When Aladdin wished for aid of any kind, he had but to rub the lamp. At once the genie appeared to gratify his desires. By means of the lamp Aladdin could hear the faintest whisper thousands of miles away. He could annihilate both time and space, and in a twinkling could transfer himself to the tops of the highest mountains. How the charm of this ancient story is lost in the presence of that marvelous realism which marks the achievements of modern electrical science!

The earliest known observations on that subtle mystery which pervades all nature, that silent energy whose phenomena and possibilities are limitless, and before which even the wisest must stand in awe, are attributed to Thales, a scholar of Miletus, in Greece, some 600 years B. C. On rubbing a piece of amber against his clothing, he observed that it gained the strange property of at first attracting and then repelling light objects brought near to it. His observations led to nothing practical, and no historic mention of electrical phenomena is found till the time of Theophrastus (B. C. 341), who wrote that amber, when rubbed, attracted “straws, small sticks, and even thin pieces of copper and iron.” Both Aristotle and Pliny speak of the electric eel as having power to benumb animals with which it comes in contact.

Thus far these simple phenomena only had been mentioned. There was no study of electric force, no recognition of it as such, or as we know it and turn it to practical account to-day. This seems quite strange when we consider the culture and power to investigate of the Egyptians, Phœnicians, Greeks, and Romans. True, a few fairy-like stories of how certain persons emitted sparks from their bodies, or were cured of diseases by shocks from electric eels, are found scattered through their literatures, but they failed to follow the way to electrical science pointed out to them by Thales. Even in the Middle Ages, when a few scientists and writers saw fit to speak of electrical phenomena as observed by the ancients, and even ventured to speculate upon them in their crude way, there were no practical additions made to the science, and the ground laid as fallow as it had done since the creation.

[Illustration: OLD FRANKLIN ELECTRICAL MACHINE.

(By permission of Franklin Institute.)]

After a lapse of more than two thousand years from the experiment of Thales, Dr. Gilbert, physician to Queen Elizabeth (A. D. 1533–1603), took up the study of amber and various other substances which, when subjected to friction, acquired the property of first, attracting and then repelling light bodies brought near them. He published his observations in a little book called “De Magnete,” in the year A. D. 1600, and thus became the first author of a work upon electricity. In this unique and initial work upon simple electrical effects, the author added greatly to the number of substances that could be electrified by friction, and succeeded in establishing the different degrees of force with which they could be made to attract or repel light bodies brought near them.

Fortunately for electrical science, and for that matter all sciences, about this time the influence of Lord Bacon’s Inductive Philosophy began to be felt by investigators and scientific men. Before that, the causes of natural phenomena had not been backed up by repeated experiments amounting to practical proofs, but had been accounted for, if at all, by sheer guesses or whimsical reasons. Bacon’s method introduced hard, cold, constant experiment as the only sure means of finding out exactly the causes of natural phenomena; and not only this, but the necessity of series upon series of experiments, each based upon the results of the former, and so continuing, link by link, till, from a comparison of the whole, some general principle or truth could be drawn that applied to all. This _inductive_ method of scientific research gave great impetus to the study of every branch of science, and especially to the unfolding of infallible and practical laws governing the phenomena of nature.

For very many years electrical experiments followed the lines laid down by Dr. Gilbert; that is, the finding of substances that could be excited or electrified by friction. By and by such substances came to be called _electrics_, and it became a part of the crude electrical science of the time to compute the force with which these electrics, when excited, attracted or repelled other substances near them. Among the ablest of these investigators were Robert Boyle, author of “Experiments on the Origin of Electricity,” Sir Isaac Newton, Otto von Guericke, and Francis Hawksbee, the last of whom communicated his experiments to the English Royal Society in 1705. Otto von Guericke used a hard roll of sulphur as an electric. He caused it to revolve rapidly while he rubbed or excited it with his hand. Newton and Hawksbee used a revolving glass globe in the same way, and thus became the parents of the modern and better equipped electrical machine used for school purposes.

The next step in electrical discovery, and one which marks an epoch in the history of the science, was made by Stephen Gray, of England, in 1729. To him is due the credit of finding out that electricity from an excited glass cylinder could be conducted away from it to objects at a remote distance. Though he used only a packthread as a conductor, he thus carried electricity to a distance of several hundred feet, and his novel discovery opened up what, for the time, was a brilliant series of experiments in England and throughout France and Germany. Out of these experiments came the knowledge that some substances were natural conductors of electricity, while others were non-conductors; and that the non-conductors were the very substances—glass, resin, sulphur, etc.—which were then in popular use as electrics. Here was laid the foundation of those after-discoveries which led to the selection of copper, iron, and other metals as the natural and therefore best conductors of electricity, and glass, etc., as the best insulators or non-conductors.

Up to this time an excited electric, such as a glass cylinder or wheel, had furnished the only source whence electricity had been drawn for purposes of experiment. But now another great step forward was taken by the momentous discovery that electricity, as furnished by the excited but quickly exhausted electric, could be bottled up, as it were, and so accumulated and preserved in large quantities, to be drawn upon when needed for experiment. It is not known who made this important discovery; but by common consent the storage apparatus, which was to play so conspicuous a part in after-investigations, was named the _Leyden Jar_ or _Phial_, from the city of Leyden in Holland. It consisted of a simple glass jar lined inside and out with tinfoil to within an inch or two of the top, the tinfoil of the inside being connected by a conductor passing up through the stopper of the jar to a metallic knob on top. This jar could be charged or filled with electricity from a common electric, and it had the power of retaining the charge till the knob on top was touched by the knuckle, or some unelectrified substance, when a spark ensued, and the jar was said to be discharged. By conductors attached to the knob, guns were fired off at a distance by means of the spark, and it is said that Dr. Benjamin Franklin ignited a glass of brandy at the house of a friend by means of a wire attached to a Leyden jar and stretched the full width of the Schuylkill River at Philadelphia.

[Illustration: LEYDEN JAR.]

At this stage in the history of eighteenth century electricity there enters a character whose experiments in electricity, and whose writings upon the subject, not only brought him great renown at home and abroad, but perhaps did more to systematize the science and turn it to practical account than those of any contemporary. This was the celebrated Dr. Benjamin Franklin, of Philadelphia, Pa. He showed to the world that electricity was not created by friction upon an electric, but that it was merely gathered there, when friction was applied, from surrounding nature; and in proof of his theory he invaded the clouds with a kite during a thunder-storm, and brought down electricity therefrom by means of the kite-string as a conductor. The key he hung on the string became charged with the electric fluid, and on being touched by an unelectrified body, emitted sparks and produced all the effects commonly witnessed in the discharge of the Leyden jar.

Franklin further established the difference between positive and negative electricity, and showed that the spark phenomenon on the discharge of the Leyden jar was due to the fact that the inside tinfoil was positively electrified and the outside tinfoil negatively. When the inside tinfoil was suddenly drawn upon by a conductor, the spark was simply the result of an effort upon the part of the two kinds of electricity to maintain an equilibrium. By similar reasoning he accounted for the phenomenon of lightning in the clouds, and by easy steps invented the lightning-rod, as a means of breaking the force of the descending bolt, and carrying the dangerous fluid safely to the ground. Here we have not only a practical result growing out of electrical experiments, but we witness the dawn of an era when electricity was to be turned to profitable commercial account. The lightning-rod man has been abroad in the world ever since the days of Franklin.

Thus far, then, electrical science, if science it could yet be called, had gotten on at the dawn of the nineteenth century. No electricity was really known but that produced by friction upon glass, or some other convenient electric. Hence it was called _frictional_ electricity by some, and _static_ electricity by others, because it was regarded as electricity in a state of rest. Though a thing fitted for curious experiment, and a constant invitation to scientific research, it had no use whatever in the arts. An excited electric could furnish but a trivial and temporary supply of electricity. It exhausted itself in the exhibition of a single spark.

II. THE NEW NINETEENTH CENTURY ELECTRICITY.

By a happy accident in 1790, Galvani, of Bologna, Italy, while experimenting upon a frog, discovered that he could produce alternate motion between its nerves and muscles through the agency of a fluid generated by certain dissimilar metals when brought close together. Though this mysterious fluid came to be known as the galvanic fluid, and though galvanism was made to perpetuate his name, it was not until 1800 that Volta, another Italian, showed to the scientific world that really a new electricity had been found.

[Illustration: FRANKLIN INSTITUTE, PHILADELPHIA.

(From photo furnished by Institute.)]

Volta constructed what became known as the galvanic pile, but more largely since as the voltaic pile, which he found would generate electricity strongly and continuously. He used in its construction the dissimilar metals silver and zinc, cut into disks, and piled alternately one upon the other, but separated by pieces of cloth moistened with salt water. This simple generator of electricity was the forerunner of the more powerful batteries of the present day, and which are still popularly known as voltaic cells or batteries.

But the importance of Volta’s discovery did not lay more in the construction of his electrical generator than in the great scientific fact that chemistry now became linked indissolubly with electricity and electrical effects. The two novel and charming sciences, hitherto separate, were henceforth to coöperate in those majestic revelations and magnificent possibilities which so signally distinguish the nineteenth century. By means of greatly improved voltaic cells or batteries, that is, by jars containing acid in which were suspended dissimilar metals, electricity could be produced readily and in somewhat continuous current. By increasing the number of these cells or jars or batteries, and connecting them with conductors, the current could be made stronger and more effective. In contradistinction to the old frictional or static electricity, the new became known as chemical or current electricity.

As was to have been expected, Volta’s invention and discovery excited the whole domain of electrical science to new investigation, and brought in their train a host of wonderful results, growing more and more practical each year, and pointing the way more and more clearly to the commercial value of electricity as a familiar, inexhaustible, and irresistible power. Thus, in 1801, Nicholson showed that an electric current from a voltaic pile would, when passed through salt water, decompose the water and resolve it into its two original gases, oxygen and hydrogen. In 1807, Sir Humphrey Davy, carrying electricity further into the domain of chemistry, showed, by means of the electric current, that various metallic substances embraced in the earth’s crust, and before his time supposed to be elementary, were really dissoluble and easily resolved into their component parts, whether solids, or gases, or both. Two years later, in 1809, he made the equally momentous discovery of something which was to prove a veritable _sit lux_, “Let there be light,” for the nineteenth century, and illuminate it beyond all others. Though it had been known almost from the date of the first voltaic pile that, when the ends of its two conducting wires were brought close together, a spark was seen to leap in a curved or arc line from one wire to the other, which phenomenon was known as the voltaic arc, it remained for Davy to exhibit this arc in all the beauty of a brilliant light by using two charcoal (carbon) sticks or electrodes, instead of the wires, at the point of close approach. Here was the first principle of the after-evolved arc light to be found by the end of the century in every large city, and to prove such a source of comfort and safety for their millions of inhabitants. This principle was simply that a stream of electricity pouring along a conducting wire will, when interrupted by a substance such as carbon (charcoal), which is a slow conductor, throw off a bright light at the point of interruption. The phenomenon has been very aptly likened to a running stream of water in whose bed a stone has been placed. The stone obstructs the flow of water. The water remonstrates by an angry ripple and excited roar. In Davy’s experiment with the pieces of charcoal, both became intensely hot while the electricity was making its brilliant arc leap from one to the other, and would, of course, soon be consumed. He, therefore, in showing the principle of a permanent luminant, failed to demonstrate its practical possibilities. These last were not to be attained till the nineteenth century was well along, and only after very numerous and very baffling attempts.

Between 1810 and 1830, many important laws governing electrical phenomena were discovered, which tended greatly to render the science more exact, and to give it commercial direction. Oersted, of Denmark, discovered a means of measuring the strength and direction of an electric current. Ampère, of France, discovered the identity of electricity and what had before been called galvanism. Ritchie, of England, made the first machine by which a continuous motion was produced by means of the attractions and repulsions between fixed magnets and electro-magnets. This machine was an early suggestion of the dynamo and motor of the coming years of the century. It meant that electricity was a source of power, as well as of other phenomenal things.

In speaking of the electro-magnet in connection with Ritchie’s machine, it is proper to say that the electro-magnet was probably discovered between 1825 and 1830, but precisely by whom is not known. It differs from the natural magnet, or the permanent steel horseshoe magnet, and consists simply of a round piece of soft iron, called a core, around which are wrapped several coils of fine wire. When an electric current is made to pass through this wrapping of wire, called the helix, the iron core becomes magnetized, and has all the power of a permanent magnet. But as soon as the electric current ceases, the magnetic power of the core is lost. Hence it is called an electro-magnet, or a temporary magnet, to distinguish it from a permanent magnet.

[Illustration: INDUCTION COIL.]

While the discovery of the electro-magnet was very important in the respect that it afforded great magnetic power by the use of a limited or economic galvanic force, or, in other words, by the use of smaller and fewer Voltaic batteries, it was not until Faraday began his splendid series of electrical discoveries, in 1831, that a new and exhaustless wellspring of electricity was found to lay at the door of science. Faraday’s prime discovery was that of the induction of electric currents, or, in other words, of manufacturing electricity directly from magnetism. He began his experiments with what became known as an induction coil, which, though then crude in his hands, is the same in principle to-day. It consists of an iron core wrapped with two coils of insulated wire. One coil is of very lengthy, thin wire, and is called the secondary coil. The other is of short, thick wire, and is called the primary. When a magnetic current is passed through the primary coil, with frequent makes and breaks, it induces an alternating current of very high tension in the secondary coil, thus powerfully increasing its effects. In Faraday’s further study of electric induction, he showed that when a conductor carrying a current was brought near to a second conductor it induced or set up a current in this second. So magnets were found to have a similar effect upon one another.

[Illustration: MAGNETIC FIELDS OF FORCE.]

The secret of these phenomena was found to lie in the fact that a magnet, or a conductor carrying a current, was the centre of a field of force of very considerable extent. Such a field of force can be familiarly shown by placing a piece of glass or white paper sprinkled with fine iron filings upon the poles of a magnet. The filings will be drawn into concentric circles, whose extent measures the magnet’s field of force. So also the extent of the field of force surrounding a conductor carrying a current may be familiarly shown. In these instances the filings brought within the fields of force are magnetized. So would any other conducting substance be, and would become capable of carrying away as an independent current that which had been induced in it. Here we have the essential principle of the modern dynamo-electric machine, commonly called simply dynamo. Faraday actually constructed a dynamo, which answered very well for his experiments, but failed in commercial results because the only source of energy he could draw upon in his time was that supplied by the rather costly voltaic cells.

During Faraday’s time and subsequently, electricians in Europe and the United States were active in formulating further laws relative to the nature, strength, and control of electrical currents, and each year was one of preparation for the coming leap of electrical science into the vast realm of commercial convenience and profit.

III. THE TELEGRAPH.

From the date of the discovery that electricity could be conducted to a distance, dreams were indulged that it could be made a means of communicating intelligence. In the eighteenth century, many attempts were made to carry intelligent signals over electric wires. Some of these were quite ingenious, but in the end failures, because the old-fashioned frictional electricity was the only kind then known and employed. Even after the discovery of the voltaic cell or battery, which afforded an ample supply of chemical electricity to operate a telegraphic apparatus, the time was not ripe for successful telegraphy, for up till 1830 no battery had been produced that was sufficiently constant in its operation to supply the kind of current required. For feasible telegraphy, two important steps were yet necessary. One was the discovery of the electro-magnet, 1825–30. The other was the discovery of the Daniell’s battery or cell, in 1836, by means of which a constant electric current could be sustained for a long time.

[Illustration: DANIELL’S CELLS.]

But even before these two indispensable requisites had been supplied by human genius, much had been done to develop the mechanical methods of conveying intelligence. In 1816, Ronalds, of England, constructed a telegraph by means of which he operated a system of pith-ball signals which could be understood. In 1820, Ampère suggested that the deflection of the magnetic needle by an electric current might be turned to account in imparting intelligence at a distance. In 1828, Dyar, of New York, perfected a telegraph by means of which he made tracings and spaces upon a piece of moving litmus paper, which tracings and spaces could be intelligently interpreted through a prearranged code. A little later, 1830, Baron Schilling constructed a telegraph which imparted motion to a set of needles at either end.

[Illustration: MORSE TELEGRAPH AND BATTERY.]

From this time up to 1837, which last year was a memorable one in the history of telegraphy, the genius of such distinguished men as Morse in America, Wheatstone and Cooke in England, and Steinhill in Munich, was brought to bear on the further evolution of the telegraph. While all these names have been associated with the invention of the first practical telegraph, it is impossible, with justice, to rob that of Morse of the distinguished honor. Morse conceived his invention on board the ship Surry, while on a voyage from Havre to New York, in October, 1832. It consisted, as conceived, of a single circuit of conductors fed by some generator of electricity. He devised a system of signs, which was afterwards improved into the Morse alphabet, consisting of dots or points, and spaces, to represent numerals. These were impressed upon a strip of ribbon or paper by a lever which held at one end a pen or pencil. The paper or ribbon was made to move along under the pencil or pen at a regular rate by means of clockwork. In accordance with these conceptions, Morse completed his instrument and publicly exhibited it in 1835. He gave it further publicity, in much improved form, in 1837. In this form it was entirely original in the important respects that the ribbon or paper was made to move by clockwork, while a pen or pencil gave the impressions, thus preserving a permanent record of the message conveyed.

[Illustration: SAMUEL FINLEY BREESE MORSE.]

Though under systems less original and effective than that of Morse, a first actual telegraph had been operated between Paddington and Drayton, England, a distance of 13 miles, in 1839, and one at Calcutta, India, for a distance of 21 miles, it was not until 1844 that the world’s era of practical telegraphy actually set in under the Morse system, which speedily superseded all others. In that year, amid the jeers of congressmen and the adverse predictions of the press, Morse erected the first American telegraph line in America, between Baltimore and Washington, a distance of 40 miles, and, to the confusion of all detractors, sent the first message over it on May 27 of that year. From that date the fame of Morse was established at home, and soon became world-wide. His system of telegraphy, with slight modifications, became that of all civilized countries.

[Illustration: CYRUS W. FIELD.]