The Age of Invention by Holland Thompson (best ebook reader for surface pro .txt) 📖
- Author: Holland Thompson
- Performer: -
Book online «The Age of Invention by Holland Thompson (best ebook reader for surface pro .txt) 📖». Author Holland Thompson
machines. A demand sprang up in Europe for Blanchard copying lathes and a hundred other American tools, and from this time on the manufacture of tools and appliances for other manufacturers, both at home and abroad, became an increasingly important industry of New England.
* Henry Barnard, “Armsmear”, p. 371.
The system which the gunmakers worked out and developed to meet their own requirements was capable of indefinite expansion. It was easily adapted to other kinds of manufacture. So it was that as new inventions came in the manufacturers of these found many of the needed tools ready for them, and any special modifications could be quickly made. A manufacturer, of machine tools will produce on demand a device to perform any operation, however difficult or intricate. Some of the machines are so versatile that specially designed sets of cutting edges will adapt them to almost any work.
Standardization, due to the machine tool, is one of the chief glories of American manufacturing. Accurate watches and clocks, bicycles and motor cars, innumerable devices to save labor in the home, the office, the shop, or on the farm, are within the reach of all, because the machine tool, tended by labor comparatively unskilled, does the greater part of the work of production. In the crisis of the World War, American manufacturers, turning from the arts of peace, promptly adapted their plants to the manufacture of the most complicated engines of destruction, which were produced in Europe only by skilled machinists of the highest class.
CHAPTER IX. 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 1745
and 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 1824
an 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.
The attempt to send signals by electricity had been made many times before Henry became interested in the problem. On the invention of Sturgeon’s magnet there had been hopes in England of a successful solution, but in the experiments that followed the current became so weak after a few hundred feet that the idea was pronounced impracticable. Henry strung a mile of fine wire in the Academy, placed an “intensity” battery at one end, and made the armature strike a bell at the other. Thus he discovered the essential principle of the electric telegraph. This discovery was made in 1831, the year before the idea of a working electric telegraph flashed on the mind of Morse. There was no occasion for the controversy which took place later as to who invented the telegraph. That was Morse’s achievement, but the discovery of the great fact, which startled Morse into activity, was Henry’s achievement. In Henry’s own words: “This was the first discovery of the fact that a galvanic current could be transmitted to a great distance with so little a diminution of force as to produce mechanical effects, and of the means by which the transmission could be accomplished. I saw that the electric telegraph was now practicable.” He says further, however: “I had not in mind any particular form of telegraph, but referred only to the general fact that it was now demonstrated that a galvanic current could be transmitted to great distances, with sufficient power to produce mechanical effects adequate to the desired object.”*
* Deposition of Joseph Henry, September 7, 1849, printed in Morse, “The Electra-Magnetic Telegraph”, p. 91.
Henry next turned to the possibility of a magnetic engine for the production of power and succeeded in making a reciprocating-bar motor, on which he installed the first automatic pole changer, or commutator, ever used with an electric battery. He did not succeed in producing direct rotary motion. His bar oscillated like the walking beam of a steamboat.
Henry was appointed in 1839. Professor of Natural Philosophy in the College of New Jersey, better known today as Princeton University. There he repeated his old experiments on a larger scale, confirmed Steinheil’s experiment of using the earth as return conductor, showed how a feeble current would be strengthened, and how a small magnet could be used as a circuit maker and breaker. Here were the principles of the telegraph relay and the dynamo.
Why, then, if the work of Henry was so important, is his name almost forgotten, except by men of science, and not given to any one of the practical applications of electricity? The answer is plain. Henry was an investigator, not an inventor. He states his position very clearly: “I never myself attempted to reduce the principles to practice, or to apply any of my discoveries to processes in the arts. My whole attention exclusive of my duties to the College, was devoted to original scientific investigations, and I left to others what I considered in a scientific view of subordinate importance—the application of my discoveries to useful purposes in the arts. Besides this I partook of the feeling common to men of science, which disinclines them to secure to themselves the advantages of their discoveries by a patent.”
Then, too, his talents were soon turned to a wider field. The bequest of James Smithson, that farsighted Englishman, who left his fortune to the United States to found “the Smithsonian Institution, for the increase and diffusion of knowledge among men,” was responsible for the diffusion of Henry’s activities.
The Smithsonian Institution was founded at Washington in 1846, and Henry was fittingly chosen its Secretary, that is, its chief executive officer. And from that time until his death in 1878, over thirty years, he devoted himself to science in general.
He studied terrestrial magnetism and building materials. He reduced meteorology to a science, collecting reports by telegraph, made the first weather map, and issued forecasts of the weather based upon definite knowledge rather than upon signs.
He became a member of the Lighthouse Board in 1852 and was the head after 1871. The excellence of marine illuminants and fog signals today is largely due to his efforts. Though he was later drawn into a controversy with Morse over the credit for the invention of the telegraph, he used his influence to procure the renewal of Morse’s patent. He listened with attention to Alexander Graham Bell, who had the idea that electric wires might be made to carry the human voice, and encouraged him to proceed with his experiments. “He said,” Bell writes, “that he thought it was the germ of a great invention and advised me to work at it without publishing. I said that I recognized the fact that there were mechanical difficulties in the way that rendered the plan impracticable at the present time. I added that I felt that I had not the electrical knowledge necessary to overcome the difficulties. His laconic answer was, ‘GET IT!’ I cannot tell you how much these two words have encouraged me.”
Henry had blazed the
Comments (0)