Like many of his contemporaries, Galvani was drawn by the fascinating behaviour of the new force of nature to carry on electrical experiments as a hobby alongside his professional work, anatomical research. For his experiments he used the room where his anatomical specimens were set out. So it happened that his electrical machine stood near some frogs’ legs, prepared for dissection. By a further coincidence his assistant, while playing with the machine, released a few sparks just when some of the specimens were in such contact with the surface beneath them that they were bound to react to the sudden alteration of the electric field round the machine caused by its discharge. At each spark the frogs’ legs twitched. What Galvani saw with his own eyes seemed to be no less than the union of two phenomena, one observed by Franklin in the heights of the atmosphere, the other by Walsh in the depths of the sea.