The age of electricity; from amber-soul to telephone

Front matter

FIRST GLIMPSE OF THE ELECTRIC LIGHT.

THE

AGE OF ELECTRICITY

Contents

CHAPTEB PAOE

I. The Myth of the Amber Soul . . . . 1 II. The Discoveries of the Early Experimenters 7

III. The Caging of the Lightning .... 15

Chapter I. The Myth Of The Amber Soul

Some years ago, there was found in a tomb in Egypt an alabaster vase, the sole contents of which were a few dry, hard, and blackened seeds. These the discoverer brought to England, and planted them in the rich loam of his garden, more from curiosity than from any belief that they actually would germinate. To his surprise, in due time fresh young sprouts appeared which grew and flourished ; and finally, in the harvest season, ears of wheat, as many as fifteen or twenty from a single stalk, were gathered. So it was proved that despite their having been sealed in the ancient tomb for nearly three thousand years, the seeds, to all appearances as lifeless as the huge stones which surrounded them^ had retained all their vitality : and we might imagine, that if, during these many centuries, wheat had disappeared from among the earth's products, it would have been possible in time from these few grains to cause all the lands again to teem with golden harvest.

A suggestive parallel exists between the history of the wheat kernel shut up in the Egyptian tomb, and that of a mere atom of human knowledge which for nearly as long a period remained as unfruitful and buried in the minds of men. Indeed, among all the wonders of that strangest manifestation of the energy which pervades all nature, and which we call electricity, there is nothing more remarkable and more impressive than the growth of the single, simple, and uncoordinated fact, — namely, that amber, when rubbed, behaves in a curious way, — into the great science which underlies the telegraph, the electric light, and the telephone.

How rapid this growth has been, is within the remembrance of most of us. Of the vastness of its extent, we have on all sides ocular proof. What farther progress may be made, no one can predict. Conjecture too often outstrips reason : impossibilities and impracticabilities become confounded ; and each new advance only reveals a new horizon, beyond which who knows what fields may lie?

There is a familiar old Greek legend, which tells how Phaethon, son of the Sun, once rashly undertook to drive his father's chariot through the heavens. As the story goes, the horses despised their driver, and refused to be guided by him, so that the blazing chariot approached too near the earth, and living things thereon were burned. Then Jupiter, very wroth, hurled his thunderbolt, and killed the charioteer. When his body, which fell to the earth, was found by his sisters, the Heliades, they mourned long and bitterly, until at last the Father of Gods, pitying them, changed them into ever-sighing poplars, and their tears into translucent amber.

And so, perhaps because of this legend, the Greeks looked upon amber with superstitious reverence, and even thought that it had a soul. For when it was rubbed, it seemed to live, and to exercise an attraction upon other

THE MYTH OF THE AMBER SOUL. 8

things distant from it. They likened it to the magnet ; and yet knew it to be different from the loadstone, for in the latter the property of drawing other things to itself was inherent, whereas amber could only be brought into life and activity. It was easier to conceive how a natural body might have its own peculiar properties, however incomprehensible, — just as a tree might grow, — than to imagine how this strange substance, at one time inert, could be brought to life by the same process which would restore vitality to a limb benumbed by cold. Thus they speculated upon an amber life, and an amber soul as its essence.

In the light of our modern knowledge we might perhaps trace farther the chain of ancient speculation. Jupiter's thunderbolt was but another name for the lightning-stroke, and the sequence of events following the tragedy resulted in amber. From amber we can reproduce the lightning in miniature ; so that by some stretch of the imagination we might suppose that the Greeks had a crude conception of electrical storage, and traced the manifestations derived from amber to imprisoned lightning. It is quite certain, however, that those who were initiated in the mystic rites of the ancients clearly understood many of the principles of electricity and magnetism which have been re-discovered within recent years. Professor Schweigger considers that the Vestal fire was electrical, and points out that the ' ' twin fires from the electrical spark are sketched in a very natural manner in the representations of Castor and Pollux on ancient coins." So also it is believed that the ancients knew of the therapeutic effects of electrical currents, and the polarity of electricity and magnetism.

Although these mysteries were jealously guarded from public comprehension, and hence all knowledge of them died with its possessors, Ennemoser in his History of Magic says that "it was not forbidden to make known every thing : some things were explained to the uninitiated. For instance, the uninitiated were made acquainted with amber, and with its property when rubbed." We can conjecture that the uninitiated were thus favored because in any event they would be reasonably certain to find out the phenomenon for themselves. Amber was constantly worn as an amulet and in jewellery ; and the friction of garments would produce sufficient excitation to cause it to attract lint or other fine particles which would dim its lustre, and so draw the wearer's attention. And of course, inasmuch as explanations naturally would be sought, it perhaps suited the policy of the magi to attribute the fact to the supernatural qualities of the substance. It is remarkable, however, to note that the knowledge of the electrical properties of amber survived for centuries, doubtless, because the whole world had it, while the great mass of facts which the priests and magi collected fell into utter oblivion ; and that this is exactly the reverse of the conditions under which the great bulk of learning which was handed down from antiquity through the dark ages maintained its existence. The mediaeval monks and scholars treasured their knowledge of natural science while dwelling amid rude and barbarous peoples, in order that it might be handed down to posterity. The Greek and Egyptian priests, on the other hand, in the midst of the most cultivated peoples that had ever lived, surrounded their discoveries with every sort of misleading myth, until finally they faded into oblivion.

As the world grew older, here and there in the writings of the philosophers reference to this strange property of amber appears. Thales (600 B.C.) mentions it, and, being the earliest writer who has been found to do so, is

THE MYTH OF THE AMBER SOUL. 5

too often credited with the discovery. Some three hundred years later Theophrastus notes that another body, called lyncurium, — supposed to be either tourmaline, or the hyacinth, which looks like amber, — acts in like manner ; and Pliny (B.C. 70) refers to the same.

Then there is a great gap of sixteen centuries, with hardly a published word to show that all had not been forgotten. Beckmann quotes from an edition of John Serapion, " Lib. de simplicibus medicinis," published in 1531, a reference to a red stone, " Hager Albuzedi," found in the East, " which when strongly rubbed against the hair of the head attracts chaff as the magnet does iron ; " and perhaps other references exist. The. fact however, remained, and was supposed to be peculiar to amber. No one attempted to explain it. The superstition of the amber soul faded and was forgotten. The phenomena which Pliny called the "awful mysteries of nature" puzzled men's souls ; yet to inquire into them suggested only impiety. "A star," says Seneca, "settled on the lance of Gylippus as he was sailing to Syracuse ; and spears have seemed to be on fire in the Roman camp." "About that time." Caesar records, " there was a very extraordinary appearance in the army of Caesar. In the month of February, about the second watch of the night, there suddenly arose a thick cloud, followed by a shower of stones ; and the same night, the points of the spears belonging to the fifth legion seemed to take fire." Aristotle, Pliny, Oppian, and Claudius were fully acquainted with the shocks produced by the torpedo. Eustathius, who lived in the fourth century of the Christian era, says that a freedman of Tiberius was cured of the gout by a shock from this fish ; the first-known instance of the application of electricity to medical purposes, and if authentic much more successful than its application in modern times. The same authority asserts that Wolimer, king of the Goths, was able to emit sparks from his body. But all these were wonders beyond human ken and control. The whole science lay in the knowledge of the single fact, that excited amber attracted certain light bodies.

DISCOVERIES OF EARLY EXPERIMENTERS.

Chapter II. The Discoveries Of The Early Experimenters

In the year 1600 Dr. William Gilbert of London,, a surgeon to Queen Elizabeth, published his famous work " De Magnete," and then made known that the attractive property of amber, when rubbed, was not inherent to that substance, but existed in some twenty other bodies, such as* the precious stones, glass, sealing-wax, sulphur, and resin. Inasmuch as these all acted like amber, Gilbert called them electrics; and he described the peculiar phenomenon itself as electricity, deriving the term from the Greek word for amber, elektron. It has recently been pointed out, that the Elektra of the Homeric legends possesses certain qualities that would tend to suggest that she is the personification of lightning, and that the resemblance between the names Elektra and elektron cannot be accidental. Whether, however, Gilbert was thus anticipated or not, is immaterial. The publication of his work marks the true beginning of the progress of the science ; and its immediate effect was to incite philosophers everywhere to efforts to extend his list of electrics.

Singularly enough, this remarkable treatise was severely condemned by Bacon in the " Novum Organum." Not content with singling it out for citation as a peculiarly striking instance of inconclusive reasoning, and of truth distorted by " preconceived fancies," he elsewhere alludes to the " electric energy concerning which Gilbert has told so many fables." A century and a half later, as we shall see, these " fables " assumed the form of realities. The sweeping censure of so high an authority seems to have produced its natural effect, and may have had much to do in materially retarding the development of the infant science.

To Gilbert's category, Cabseus, an Italian Jesuit, added the gums, white wax, and gypsum. Then Robert Boyle got the first glimpse (it was no more) of the electric light, by noting that a diamond when rubbed became luminous in the dark. Then Otto von Guericke, burgomaster of Magdeburg, and inventor of the air-pump, discovered that electricity was manifested by repulsion as well as by attraction, and that a globe of sulphur after attracting a feather repelled the same until the feather had again been placed in contact with some other substance.

Guericke contrived an apparatus for rotating his sulphur globe, and succeeded in obtaining sparks therefrom ; and that was the real genesis of the electric light. By this time the attention of the scientific world was aroused, and other philosophers joined in the investigation of the curious phenomena. Boyle, then contemporary with von Guericke, proved that a suspended piece of rubbed amber, which attracted other bodies to itself, was in turn attracted by a body brought near it ; and he even went so far as to maintain that an electrified body threw out an invisible glutinous substance which laid hold of light bodies, and, returning to the source from which it emanated, carried them along with it. Sir Isaac Newton, by rubbing a flat glass, caused light bodies to jump between it and the table, and noticed that electric attraction was thus transmitted through the glass. A sea-captain named Grofton exc;ted the dismay of mariners by asserting that

DISCOVERIES OF EARLY EXPERIMENTERS. 9

a violent thunder-storm had reversed the polarity of the compass-needles aboard his vessel. Dr. Wall, in 1708, made experiments with large pieces of amber rubbed by wool, and found that " a prodigious number of little cracklings" was produced, each accompanied by a flash of light. "This light and crackling," says Dr. Wall, "seem in some degree to represent thunder and lightning."

Probably every one has observed the peculiar crackling which follows combing of the hair during dry, cold weather, and the tendency of the " knotted and combined locks to part" under the electrical excitement following the rubbing of the comb.

Robert Boyle appears to have discovered this ; and he wrote in 1675 this amusing description — intended to be perfectly serious and scientific — of his original experiment on ' • Locks (false) worn by two very Fair Ladies that you know:" "For at some times I observed that they could not keep their Locks from flying to their Cheeks and (though neither of them made any use or had any need of Painting) from sticking there. When one of these Beauties first shew'd me this Experiment, I turn'd it into a Complemental Raillery, as suspecting there might be some trick in it, though I after saw the same thing happen to others Locks too. But as she is no ordinary Virtuoso,, she very ingeniously remov'd my suspicions and (as I requested) gave me leave to satisfie myself further by desiring her to hold her warm hand at a convenient distance from one of these Locks taken off and held in the air. For as soon as she did this, the lower end of the Lock which was free applied itself presently to her hand : which seemed the most strange because so great a multitude of Haii would not have been easily attracted by an ordinary Electrical Body."

In this way, for more than a hundred and twenty years after the publication of Gilbert's work, and at long inter vals, isolated phenomena were observed, and a fact here and there gathered. A variety of curious theories had been formulated. Cabseus, in the quaint language of Robert Boyle, "thinks the drawing of light bodies by Jet, Amber, etc., may be accounted for by supposing that the steams that issue, or if I may so speak, sally, out of Amber when heated by rubbing, discuss and expell the neighbouring air ; " and that these " Electrical Steams . . . shrinking back swiftly enough to the Amber do in their returns bring along with them such light bodies as they meet with in their way." Then there was the hypothesis ' ; proposed by that Ingenious Gentleman Sir Kenelm Digby, and embraced by the very Learned Dr. Browne," that " Rayes or Files of unctuous steams " were emitted, which became cooled and condensed, and so "shrinking" back, carried light bodies with them. Newton supposed that the excited body emitted an elastic fluid which penetrated glass ; and Gravesande and other writers maintained that electricity was fire, which, being inherent to all bodies, became manifest by friction.

In 1720 Stephen Gray, a Charterhouse pensioner, that "most meritorious philosopher" as Tyndall calls him, began a series of investigations which terminated only when he died sixteen years later.

In 1729 Gray experimented with a glass tube stopped by a cork. When the tube was rubbed, the cork attracted light bodies. Gray states that he was "much surprised " at this, and he " concluded that there was certainly an attractive virtue communicated to the cork." " This," says Professor Tyndall, " was the starting-point of our knowledge of electric conduction ; " and the same authority gives the following account of Gray's most remarkable experiment : —

DISCOVERIES OF EARLY EXPERIMEXTERS. 11

"He suspended a long hempen line horizontally by loops of pack-thread, but failed to transmit through it the electric power. He then suspended it by loops of silk, and succeeded in sending the ' attractive virtue ' through seven hundred and sixty-five feet of thread. He at first thought that the silk was effectual because it was thin ; but on replacing a broken silk loop by a still thinner wire, he obtained no action. Finally he came to the conclusion that his loops were effectual, not because they were thin, but because they were silk. This was the starting-point of our knowledge of insulation."

Gray died in the midst of his work ; and the report of his last experiments was dictated by him from his deathbed, to the secretary of the Royal Society.

In 173o Dufay, a French physicist, while experimenting with an electrically excited body, found that a piece of gold-leaf floating in the air was repelled if the excited substance was glass, and attracted if the excited substance was resin. And hence he recognized two kinds of electricity, which were for a long time known respectively as vitreous and resinous. There is no such real distinction, because by changing the rubbing material the electricity of resin can be obtained upon glass, and vice versa. But what we now know as plus or positive electricity is that produced by rubbing glass with silk ; and negative or minus electricity, that due to the rubbing of resin with ^annel.

The electrical apparatus of 1730 was, as may readily be .magined. very crude. We reproduce from Dr. Grave- ?ande's treatise of that date, the accompanying representation of an electrical machine of the period. It consists eimply of a glass globe G, supported on tubes which are revolved by a belt from the large pulley R, which is rotated by the handle M. One of the tubes has an

THE AGE OF ELECTRICITY.

open end, and is provided with a stop-cock E. Through this tube the air can be exhausted from the interior of

Fig. 7.— Electrical Machine of 1730.

the globe. Over the globe is an arch of brass wire from which are suspended threads. The hand is used as a

DISCOVERIES OF EARLY EXPERIMENTERS. 13

rubber, and the machine as shown is intended to demonstrate the following experiment : —

u Whirl the globe, and apply the hand, and immediately the threads will be moved irregularly by the agitation of the air ; but when the glass is heated by the attrition, all the threads are directed toward the centre of the globe, as may be seen in the figure ; and, if the hand be applied a little on one side, or nearer the pole of the globe, the threads will be directed toward that point of the axis which is under the hand. If the air be drawn out of the globe, this whole effect ceases."

This machine had a very disagreeable habit of exploding by reason of the expansion of the air within the glass globe, caused by the heating of the latter b} 7 friction.

We have already stated that Otto von Guericke made his electrical machine from a globe of sulphur. For the sulphur globe, Hawksbee and Winkler substituted the glass globe represented in the engraving. The prime conductor, at first a tin tube supported by resin or suspended by silk, and nearly equal in importance to the glass insulator which is to be excited, was not invented until ten years after by Boze of Wittenberg (1741) ; and Winkler of Leipsic suggested a fixed cushion instead of the human hand as a rubber. Still later Gordon of Erfurt substituted a glass cylinder for the globe ; and in 1760 Planta introduced the circular plate of glass still used.

In the year 1745 a discovery was made, which in point of importance overshadowed every thing that had been previously accomplished. And it seems as if the time had come for some great advance. The electrical machine had reached a form in which, with little variation, it has since remained. Large pieces of electrical material had been used to produce manifestations sufficiently potent to suggest thunder and lightning ; and certain properties of the electric fluid, or aura, or whatever it might be, had been more or less perfectly recognized. Yet, after all, what practical advantage to mankind had been gained ? Curious things had beeu developed, as wonderful as any thing the conjurers could do ; but beyond gratifying the natural taste for the marvellous, and furnishing food for the speculations and material for the lecture-room experiments of a few philosophers, all that had been clone had added nothing, so far as then appeared, to that knowledge which directly contributes to human welfare.

Chapter III. The Caging Of The Lightning

On Oct. 11, 1745, Dean von Kleist of the cathedral of Canrin, in Germany, made an experiment which on the following 4th of November he describes in a letter to Dr. Lieberkuhn of Berlin, in the following terms : —

" When a nail or a piece of brass wire is put into a small apothecaries' phial and electrified, remarkable effects follow ; but the phial must be very dry and warm. I commonly rub it over beforehand with a finger on which I put some powdered chalk. If a little mercury or a few drops of spirits of wine be put into it, the experiment succeeds the better. As soon as this phial and nail are removed from the electrifying glass, or the prime conductor to which it hath been exposed is taken away, it throws out a pencil of flame so long that with this burning machine in my hand I have taken about sixty steps in walking about my room ; when it is electrified strongly I can take it into another room, and then fire spirits of wine with it. If while it is electrifying I put my finger or a piece of gold which I hold in my hand to the nail, I receive a shock which stuns my arms and shoulders."

This was the first announcement of the possibility of accumulating electricity.

In the following year Cunseus of Leyden made substantially the same discovery. It caused great wonder and dread, which arose chiefly from the excited imagination. Musschenbroek felt the shock, and declared in a letter to a friend, that he would not take a second one for the crown of France. Bleeding at the nose, ardent fever, a heaviness of head which endured for days, were all ascribed to the shock. Boze, on the other hand, seems to have coveted electrical martyrdom ; for he is said to have expressed a wish to die by the electric shock, " so that an account of his death might furnish an article for the Memoirs of the French Academy of Sciences."

Winkler, his coadjutor in the improvement of the electrical machine, " suffered great convulsions through his body," which " put his blood into agitation ; " and his wife, who took the shock twice, was rendered so weak by it that she could hardly walk. Nothing daunted, this adventurous lady (who shall say whether from scientific interest or feminine curiosity?) persisted in being shocked for the third time ; and then her previous ailments were augmented by the nosebleed.

After the philosophers had got through administering shocks to themselves and to their immediate relatives, and had recovered in some measure their mental as well as personal equilibrium, — and it might equally well be added, their moral balance, for as a matter of fact their reports as to the force of the shock and its attendant disastrous effects were all more or less grossly exaggerated, — they set about seeing what this extraordinary discovery really amounted to. What Von Kleist actually did was simply to insert a nail through a cork into a phial into which he poured a little mercury, spirits, or water. Why this simple contrivance should produce the observed effects, Von Kleist did not know ; but Cunaeus and the other Leyden philosophers solved the problem, and in this way Von Kleist' s apparatus came to be known as the Ley den- jar.

THE CAGING OF THE LIGHTNING.

Fig. 2. — Leyden-dar.

Subsequently the jar was constructed by Dr. Be vis in the form shown in Fig. 2, which is that which it has ever since had. In charging the jar, the outer coating, usually of tin-foil, is connected with the earth ; and the inner coating of the same material, by means of the central wire and knob, receives the sparks from an electric machine. The positive electricity from a glass electrical machine, passing to the inner coating, acts inductively across the glass upon the outer coating, and is supposed to attract only its negative electricity, while the positive electricity there resident is repelled into the earth, with which the outer coating is connected. In this way two opposite and mutually attracting electricities are separated by the glass. But if a path be provided by which these two electricities can flow to one another, they will do so, and the jar will be discharged. If the outer coating be grasped with one hand, and the knuckle of the other hand be presented to the knob of the jar, the body will then form a conducting path over which this flow can take place ; a bright spark will pass between the knob and the knuckle, with a sharp report ; and at the same moment a convulsive k, shock" will be communicated to the muscles of the wrists, elbows, and shoulders.

In Von Kleist's apparatus, the water or mercury formed the inner conducting coating, and his hand, grasping the bottle, the outer coating which was thus connected to earth through his body. When he touched the nail with his disengaged hand, he completed the path between the inner and outer coatings through his body, and thus received the shock.

Scientists everywhere now began to investigate this phenomenon. Graham caused a number of persons to lay hold of the same metal plate, which was connected with the outer coating of a charged Leyden-jar, and also to grasp a rod by which the jar was discharged. The shock divided itself equally among them. Abbe Nollet procured a detail of one hundred and eighty soldiers, stood them up in a line, and sent shocks through the whole battalion, — a significant commentary on the strength of military discipline, which could make ignorant men face manifestations which disconcerted and agitated the philosophers themselves. But the monks outdid the soldiers : seven hundred and fifty Carthusians formed a line 5,400 feet long, an iron wire extending between each two persons ; when the abb6 caused the discharge, the entire company of ecclesiastics "gave a sudden spring, and sustained the shock at the same instant." Apparatus was constructed so that large quantities of electricity could be accumulated, and results hitherto unexpected were obtained. Dr. Watson made experiments to discover through how great a distance the electric shock could be propagated, and in 1747 conveyed it across the River Thames at Westminster Bridge, and finally concluded that " the velocity of the electric matter in passing through a wire 12,276 feet in length is instantaneous." Other investigators killed small animals and birds with powerful discharges from the Leyden-jar.

In 1745 Mr. Peter Collinson of the Royal Society sent a jar to the Library Society of Philadelphia, with instructions how to use it. This fell into the hands of Benjamin Franklin, who at once began a series of electrical experiments. On March 28, 1747, Franklin began his famous letters to Collinson, regarding which Priestley says, " Nothing was ever written upon the subject of electricity which was more generally read and admired in all parts of Europe. It is not easy to say whether we are most pleased with the simplicity and perspicuity with which they are written, the modesty with which the author proposes every hypothesis of his own, or the noble frankness with which he relates his mistakes when they are corrected by subsequent experiments." In these letters he propounded the single-fluid theory of electricity, and referred all electric phenomena to its accumulation in bodies in quantities more than their natural share, or to its being withdrawn from them so as to leave them minus their proper portion. A body having more than its natural quantity, he regarded as electrified positively, or plus; and one having less, as electrified negatively or minus. On this theory he explained the action of the Ley den- jar as it has already been explained above ; and he conceived the idea of connecting together a number of Leyden-jars, the outer coating of each being connected to the outer coating of the next succeeding one, and thus produced his famous "cascade battery," in which the strength of the shock was enormously increased.

He also discovered that the connecting coatings of the Leyden-jar " served only, like the armature of the loadstone, to unite the forces of the several parts, and bring them at once to any point desired ; " and that the electricity in fact existed only upon the glass. One of Franklin's letters to Collinson is celebrated for his quaintly humorous proposition of an • ; electric feast " to be held on the banks of the Schuylkill. Whether this ever occurred, is questionable ; but Franklin's description of it is well worth quoting. " The hot weather coming on," he says, " when electrical experiments are not so agreeable, it is proposed to put an end to them for this season, somewhat humorously, in a party of pleasure on the banks of the Schuylkill. Spirits, at the same time, are to be Jlred by a spark sent from side to side through the river without any other conductor than the water ; an experiment which we some time since performed to the amazement of many. A turkey is to be killed for .our dinner by the electric shock, and roasted by the electric jack before a fire kindled by the electric bottle; when the healths of all the famous electricians of England, Holland, France, and Germany are to be drunk in electrified bumpers, under a discharge of guns from the electrical battery.'" If Franklin's proposal bordered on the absurd or grotesque, it proves how neai the ridiculous in thought may be to the sublime ; for sl{ that same period he was formulating the speculations which ultimately culminated in one of the most audacious yet most brilliantly successful experiments ever made by man. More than forty years before, Wall had compared the crackling from his rubbed amber to thunder and lightning ; Nollet in France had not long before quaintly said, " If any one should take upon him to prove from a well-connected comparison of phenomena, that thunder is in the hands of Nature what electricity is in ours, and that the wonders which we now exhibit at our pleasure are little imitations of these great effects which frighten us ; I avow that this idea, if it was well supported, would give me a great deal of pleasure." Meanwhile the facts derived from experiment were rapidly multiplying, which showed the similarity between the powerful sparks of the Leyden battery and the lightning flash. The exaggerated accounts of Musschenbroek and others who had received the shocks went to prove that increase in force or strength would cause death. Experiments upon birds and small animals did produce death as sudden as that due to the lightning stroke. Franklin himself was twice struck senseless by shocks ; and he afterwards sent the discharge of two large jars through six robust men, who fell to the ground, and got up again without knowing what had happened, neither feeling nor hearing the discharge.