THE FATHERS OF ELECTRICITY
It may startle some reader to be told that the foundations of modern electrical science were definitely established in the Elizabethan Age.The England of Elizabeth, of Shakespeare, of Drake and the sea-dogs, is seldom thought of as the cradle of the science of electricity.Nevertheless, it was; just as surely as it was the birthplace of the Shakespearian drama, of the Authorized Version of the Bible, or of that maritime adventure and colonial enterprise which finally grew and blossomed into the United States of America.
The accredited father of the science of electricity and magnetism is William Gilbert, who was a physician and man of learning at the court of Elizabeth.Prior to him, all that was known of these phenomena was what the ancients knew, that the lodestone possessed magnetic properties and that amber and jet, when rubbed, would attract bits of paper or other substances of small specific gravity.Gilbert's great treatise "On the Magnet", printed in Latin in 1600, containing the fruits of his researches and experiments for many years, indeed provided the basis for a new science.
On foundations well and truly laid by Gilbert several Europeans, like Otto von Guericke of Germany, Du Fay of France, and Stephen Gray of England, worked before Benjamin Franklin and added to the structure of electrical knowledge.The Leyden jar, in which the mysterious force could be stored, was invented in Holland in 1745and in Germany almost simultaneously.
Franklin's important discoveries are outlined in the first chapter of this book.He found out, as we have seen, that electricity and lightning are one and the same, and in the lightning rod he made the first practical application of electricity.Afterwards Cavendish of England, Coulomb of France, Galvani of Italy, all brought new bricks to the pile.Following them came a group of master builders, among whom may be mentioned: Volta of Italy, Oersted of Denmark, Ampere of France, Ohm of Germany, Faraday of England, and Joseph Henry of America.
Among these men, who were, it should be noted, theoretical investigators, rather than practical inventors like Morse, or Bell, or Edison, the American Joseph Henry ranks high.Henry was born at Albany in 1799 and was educated at the Albany Academy.
Intending to practice medicine, he studied the natural sciences.
He was poor and earned his daily bread by private tutoring.He was an industrious and brilliant student and soon gave evidence of being endowed with a powerful mind.He was appointed in 1824an assistant engineer for the survey of a route for a State road, three hundred miles long, between the Hudson River and Lake Erie.
The experience he gained in this work changed the course of his career; he decided to follow civil and mechanical engineering instead of medicine.Then in 1826 he became teacher of mathematics and natural philosophy in the Albany Academy.
It was in the Albany Academy that he began that wide series of experiments and investigations which touched so many phases of the great problem of electricity.His first discovery was that a magnet could be immensely strengthened by winding it with insulated wire.He was the first to employ insulated wire wound as on a spool and was able finally to make a magnet which would lift thirty-five hundred pounds.He first showed the difference between "quantity" magnets composed of short lengths of wire connected in parallel, excited by a few large cells, and "intensity" magnets wound with a single long wire and excited by a battery composed of cells in series.This was an original discovery, greatly increasing both the immediate usefulness of the magnet and its possibilities for future experiments.
The learned men of Europe, Faraday, Sturgeon, and the rest, were quick to recognize the value of the discoveries of the young Albany schoolmaster.Sturgeon magnanimously said: "Professor Henry has been enabled to produce a magnetic force which totally eclipses every other in the whole annals of magnetism; and no parallel is to be found since the miraculous suspension of the celebrated Oriental imposter in his iron coffin."** Philosophical Magazine, vol.XI, p.199 (March, 1832).
Henry also discovered the phenomena of self induction and mutual induction.A current sent through a wire in the second story of the building induced currents through a similar wire in the cellar two floors below.In this discovery Henry anticipated Faraday though his results as to mutual induction were not published until he had heard rumors of Faraday's discovery, which he thought to be something different.
