CHAPTER II. GALVANI, VOLTA, THE BATTERY AND THE ELECTRIC CURRENT. THE world will perhaps never know with certainty to what extent it is indebted to a woman for the inauguration of the new era in electrical experiment and research. A hundred years ago, September 20, 1786, Galvani, an Italian physician, saw, in the twitching of the legs of a frog, the beginning of modern electricity. It is difficult to understand how the circumstances attending so important a discovery should in any way be involved in obscurity, but, nevertheless, such is the case. Several high authorities, including the eulogist of Galvani, M. Alibert, have given weight to the pleasant story in which it is related that the wife of the philosopher, being in a declining state of health, "employed as a restorative, according to the custom of the country, a soup made of frogs." The culinary and philosophical operations of Galvani's establishment not being completely differentiated, several of these animals, after being prepared for the former, were placed on a table on which the latter was represented by an electrical machine. While the machine was in operation, one of the frogs was accidentally touched by a knife in the hands of an assistant, and the muscles of the limb were instantly thrown into strong convulsions. This fact was observed by the lady, who communicated it to her husband on his return. The editor of Galvani's works, published in 1841 by the Academy of Sciences of the Institute of Bologna, Sylvestro Gherardi, discredits this story entirely, and indignantly labors to put a quietus upon it, although he quaintly adds in a foot-note: "In this connection we do not wish to deny that Galvani might not, on one or more occasions, have had frogs in his hands with the amiable intention of himself preparing broth for his adored spouse." Galvani's own account of the experiment is contained in the opening paragraph of his work, "De Viribus Electricitatis Artificialis in Motu Musculari," and is essentially as follows: I dissected a frog, and prepared it as in Fig. 2, Plate V., and, putting it on the table on which was the electrical machine (Fig. 1) I placed it wholly disconnected from its conductor, and separated from it by an interval not short. One of those who were assisting me in the work lightly touched by accident, with the point of the scalpel, the internal nerves D D in the legs of the frog, when all at once every muscle 7.2. I've Leirge Falvari Galvani's Fig. 2, Plate V., with autograph. of the joints was seen to be contracted, so that they seemed to have fallen into the most vehement and violent convulsious. It appears to be tolerably well established that Galvani was long engaged in the investigation of the effect of electricity upon the muscles of animals, and that he gave especial attention to its influence upon the frog, which, owing to its extreme sensitiveness to electric disturbances, was well calculated to be the means of leading him to the discovery which has forever fixed his name in the nomenclature of the science. It seems that some of these animals were sus pended on an iron railing by means of copper hooks, and that their muscles occasionally twitched when there was no apparent electrical disturbance in their vicinity. This was the observation of prime importance, and it is recorded as having been made on the date mentioned above. It did not become generally known, however, until about 1790, when it immediately attracted the attention of students of electricity in all countries. Galvani believed that the animal was itself the source of the electricity, and that the connecting pieces of metal acted only as conductors. Thus arose the term "Animal Electricity;" and by many who doubted the identity of the new and the old the word "galvanism" was used,a name which held its place so tenaciously that it has been only recently dislodged. Among those who took a deep interest in Galvani's discovery was another Italian philosopher who was destined almost to wrest from his countryman the honor of having created a new science. Although descended from an ancient and honorable family, Volta exhibited in his youth a very slow development of intellectual powers, a fact ascribed by his friends to his having been placed in the care of a foolish nurse. His earliest exhibition of talent was in making poetry, from which he easily and rap idly rose to a position of great distinction as a man of science, and he especially cultivated the science of electricity. Galvani's discovery found him in the prime of life, well trained for observation and experiment; and, indeed, he had already made some notable contributions to the knowledge of electricity then existing. In 1793 he communicated to the Royal Society of London an account of some discoveries made by M. Galvani, to which he added many curious and valuable observations of his own. He did not agree with Galvani in the view held by the latter as to the origin of the new electricity. He found that two different metals were essential to the successful performance of the experiment with the frogs' legs, and he attributed the appearance of electricity to the disturbance of the electric equilibrium brought about by the contact of the two different metals. He enunciated the general proposition, that, whenever two different metals are placed in contact, one will become positively and the other negatively charged. This was the first statement of what is known as the "contact theory" of the voltaic cell, and to this theory Volta clung persistently. Later on, when the chemical action of the voltaic current came to be studied, and especially when the chemical action going on in the |