It was in the year 1745 that electric experiments became very popular, owing to the accidental discovery of a piece of apparatus by which the electric discharge, or spark, could be made much stronger. This discovery was made about the same time in Pomerania and in Holland. In both places people were trying to electrify water in a bottle. The electricity was conducted into the water by a long nail, which stuck out of the bottle at the neck. The bottle was held by an assistant, and when enough electricity had been conducted into the water, the assistant took the nail out of the water. In doing so he received a great shock which paralysed his arms and shoulders. In Holland, this experiment was performed at Leyden, and the jar which can be made to give such a great shock is therefore called a “Leyden jar.” The man who received the electric shock said that he would not take another for the kingdom of France. But this feeling was not shared by others, and many people tried the electric shock just to see what it was like. Professor Bose went so far as to say he wished he might die by the electric shock so that the account, of his death might furnish an article for the French Academy of Sciences. [Illustration: Fig. 49.--Discovery of the Leyden Jar.] The new apparatus became so popular that a great number of people made a living by going from place to place to exhibit it. In France especially such entertainments attracted large crowds. On one occasion an electric discharge was sent through a row of 180 soldiers. At another time several hundred monks were made to join hands in a row 900 feet long, and a strong electric spark was sent through the whole row. It made all the monks jump at the same moment. It was not long before these experiments were repeated in America, and when they did so they soon attracted the attention of a man who was able to develop them much further. That man was Benjamin Franklin, who was then engaged in the printing business. He saw the first experiment in the year 1746, and at once began to investigate the subject. He was the first to observe what a very important effect metallic points have in drawing out, or throwing off, what the French called the “electric fire.” He constructed a Leyden jar, and made many experiments with it. When the hot summer weather came he proposed to his friends to wind up his experiments with an electric dinner, for which a turkey was to be killed by an electric shock and roasted in front of a fire lighted by electricity.