Men Who Found Electricity - Part Three

The Wonderful Things Sir William Watson did with Two Leyden Jars

The Leyden jar, though first made in Holland, was made perfect in England by Sir William Watson, another genius of those early days. Watson was a poor tradesman's son, and was born in London, in 1715. Apprenticed to a chemist, he loved science, and when he had made enough money to live on he gave himself wholly to science. He improved the Leyden jar by covering it inside and out with tinfoil. This had important results. He used wires for carrying the current from one Leyden jar to another Leyden jar. Sending the current along the wire, he found that it gave a shock to the person holding the far end of the wire, two miles away, practically at the very instant at which it was released from the Leyden jar.

This proved that the action of electricity is instantaneous - a most important thing, as it afterwards proved in telegraphy.

More wonders Sir William did with the mysterious force. He electrified a piece of ice, and with that set fire to spirits. He did the same with a drop of water which had been electrified. He fired the gunpowder in a gun with an electric spark, and showed many pwoers of electricity which had never before been suspected.

By this time the world was getting to know a great many things that electricity could be made to do, but they still knew nothing of its nature.

Benjamin Franklin, Who Helped to Free America and to Find Electric Power

There was living in America one of the greatest men the world has seen, Benjamin Franklin, the man who first captured fire from the sky and brought it to the ground. He was born at Boston, Massachusetts, in 1706, and began his career, with very little schooling, in a small printing office of one of his brothers. He was very poor, but he had a splendid brain, and never troubled about being short of money. He educated himself entirely by his own efforts. He was first a printer, going to London to learn what he could there, then setting up in business for himself in Philadelphia.

So famous did he become that he was chosen by his countrymen to go to England as their representative. War was about to break out between Great Britain and the American colonies, and he did all that he could to prevent it. Seeing that his efforts were hopeless, he returned to America, where he found that the war had already broken out. He became a leading member of the Government which helped to give America her freedom from British control, and then was sent to France as Ambassador to gain the support of that country against England. After all, he had the delight of opening the arrangements which led to peace between England and America.

The last thing he did in public life was to make a prayer to the American Government against slavery in the United States. That prayer of his was not to be answered until many a year after he had been in the grave.

So much for his public life. The more important thing for us here, however, is what he did with electricity.

How Benjamin Franklin Sent Up a Kite to Bring the Lightning Down

In the midst of all his work he had time to study and make experiments, so that he was honoured all over the world for his knowledge about the tides and the weather, about colours, and, most of all, about electricity. He was one of the men who suspected that lightning and electricity are one and the same thing. But Franklin was not content to remain guessing; he put his belief to the proof. He made a kite of silk, and on the top of it he fixed a thin wire.

He tied a string to the kite, but near his hand he attached a silk ribbon to the string, and where the string and ribbon joined he fixed a metal key. Then one day, when a thunderstorm broke over his home, he sent up his kite into a thundercloud, and waited in a doorway to watch the result.

He had printed a statement expressing the belief that everything that had been done with electricity was no more than was to observed in lightning. Now had come the hour when he was to make his reputation as a scientist secure, or be laughed at by the whole world. He was very anxious as he stood and waited in the doorway with his son.

The first thundercloud passed without any sign at all, and Franklin feared. A second came over the kite, and he now saw that little loose strands of the string stood out stiff and bristling. He put his finger towards them, and they were attracted towards it. He placed his finger on the key, and instantly he felt a shock and saw an electric spark. Rain fell now and wetted the string of the kite, and electricity ran down the moistened string, and was so abundant that he was able to fill his Leyden jar from the key.

He had proved that lightning is electricity. He made other trials, and found that some clouds are charged with positive electricity and some with negative electricity, exactly in the same way as in the electricity produced by different bodies on earth. No sooner had he made sure of his facts than he set to work and built lightning conductors.

If lightning could be drawn from the skies, as his kite had shown that it could, then surely, he thought, it should be possible to guide into the ground the lightning, which, if left to strike freely, might destroy the house. It was in 1752 that Franklin made his great discovery. He lived for thirty-eight years afterwards, and when he died, in 1790, not only the whole of America, but the whole of France went into public mourning for him.

Discovery was now well on the way to practical success, and every year added surprises. John Canton, who was born at Stroud, in 1718, became a schoolmaster, and invented valuable electrical instruments. He was the first man to manufacture powerful artificial magnets, and discovered that the air of a room can be electrified just like so many other things.

Baccaria, a celebrated Italian, found that the air surrounding an electrified body itself becomes electrified. Then Robert Symmer made the amusing discover that silk stockings and worsted stockings, when warmed and rubbed together, become so electrified that a Leyden jar can be filled with the current from them.

More important was the work of Henry Cavendish, the grandson of the second Duke of Devonshire, born at Nice, in 1731.

He was very rich, and very strange in his manner. He lived the life of a hermit in a beautiful London house. He hated the sight of strangers - not because he was an unkind man, but because he was so shy and modest. His female servants were never allowed to see him. If he had any orders for them he would write them down and leave a note on the hall table.

Science was the great joy of his life. The chief thing that he did for electricity was to show that iron wire conducts electricity 400,000,000 times as well as water does. By the aid of electricity he exploded oxygen and hydrogen, and got pure water as the result.

Cavendish lived until 1810, and in his time two men arose who quite changed the method of producing electricity. One was Luigi Galvani, who was born at Bologna, Italy, in 1737, and died there in 1798. The other and greater was Alessandro Volta, born in 1745, at Como, where he died in 1827.

Galvani, when experimenting with an electric machine, found that the legs of a dead frog were set to work by an electric shock. He determined to see if lightning would have the same effect; but while he was fixing the frog by a copper skewer to the iron railing of his balcony, he saw the twitching renewed the moment the copper touched the iron.

Galvani declared that the electricity existed in the tissues of the frog. When Volta heard of this, he set to work to prove that the body of the frog did not contain the electricity. He argued that it was produced by the contact of two different metals, and he proved that he was right.

He placed a disc of copper on his table, and on top of that he placed a piece of cloth which had been soaked in sulphuric acid and water.

On top of that he placed a disc of zinc. Next he added copper, cloth, and zinc again, and so on, in that order, until he had built up a pile. It was a pile of pairs of zinc and copper discs, each pair having a moist piece of cloth between. Then he fastened a wire to the zinc disc at the top of the pile, and a second wire to the copper disc at the bottom of the pile.

Alessandro Volta, the Man Who Made the Electric Bell Ring

Volta put the free ends of the two wires together, then separated them. As they were drawn apart, the electric current which had been set up in the pile caused a spark at the ends of the wires. Here, then, was the first instance of the manufacture of electricity by chemical action.

It was easy soon to improve on the Voltaic pile. Instead of placing the discs and cloth on the table, for the moisture quickly to dry up, he put the pile into a jar, or cell, filled with the water and acid. That was the Voltaic cell, which to this day is used for producing electricity by chemical action. This invention belongs to the year 1800, but more than a century afterward we still sometimes use the Voltaic cell as the battery for our electric bells, and all manner of other things.

This invention caused much excitement, and set men still harder to work. They found now that they could produce electricity in this way as they liked, and cause it to flow in a steady current over wires, not letting it fly away immediately after it was created as it did from amber and other things. They found, among other things, that the current would heat wires, and this led at once to Sir Humphry Davy's discovery of the electric flame from which we get electric light, as we read on page 657.