By a happy accident in 1790, Galvani, of Bologna, Italy, while experimenting upon a frog, discovered that he could produce alternate motion between its nerves and muscles through the agency of a fluid generated by certain dissimilar metals when brought close together. Though this mysterious fluid came to be known as the galvanic fluid, and though galvanism was made to perpetuate his name, it was not until 1800 that Volta, another Italian, showed to the scientific world that really a new electricity had been found. [Illustration: FRANKLIN INSTITUTE, PHILADELPHIA. (From photo furnished by Institute.)] Volta constructed what became known as the galvanic pile, but more largely since as the voltaic pile, which he found would generate electricity strongly and continuously. He used in its construction the dissimilar metals silver and zinc, cut into disks, and piled alternately one upon the other, but separated by pieces of cloth moistened with salt water. This simple generator of electricity was the forerunner of the more powerful batteries of the present day, and which are still popularly known as voltaic cells or batteries. But the importance of Volta’s discovery did not lay more in the construction of his electrical generator than in the great scientific fact that chemistry now became linked indissolubly with electricity and electrical effects. The two novel and charming sciences, hitherto separate, were henceforth to coöperate in those majestic revelations and magnificent possibilities which so signally distinguish the nineteenth century. By means of greatly improved voltaic cells or batteries, that is, by jars containing acid in which were suspended dissimilar metals, electricity could be produced readily and in somewhat continuous current. By increasing the number of these cells or jars or batteries, and connecting them with conductors, the current could be made stronger and more effective. In contradistinction to the old frictional or static electricity, the new became known as chemical or current electricity.