Our attention had been especially arrested by the electric indicator or tremolan. It contained a complete chart of the electric variations of every point of the island throughout every day in the year. This had been compiled and drawn up from the observations of several centuries, and marked the differences between periodical and temporary, regional and narrowly local, terrestrial and planetary variations. Every day the instrument was set like a clock to all the electric changes which they expected to occur periodically on that day. Each of these, indicated at every point of the map, represented an electrically uniform locality of the island with which it was connected. The superintendent of the tremolan for any section of the day specially studied all the unclassified variations which had occurred at the corresponding hour of the same day and period of time. He knew every change in the position of the earth or in the movements of the stars that might affect the electricity of the atmosphere at any moment during his watch. Along with him there was a sky-watcher, who used one of their marvellous reducers of distance and magnifiers to scan the sky and the whole horizon, and reported every new appearance which broke the uniformity of the sky-line. In an adjoining chamber with transparent partitions a third observer was stationed with his ear at a makro-mikrakoust or vamolan, that gathered in the slightest sounds at the distance of even hundreds of miles and magnified them for the listening sense applied to it; it also indicated approximately the distance of the source of the sound by an automatic calculator. This was a kind of eavesdropper that could pick up whispers on the orb of the earth, just as their astronomical instruments could catch the faintest gleam in space myriads of miles beyond the scope of the eye. In another crystal-walled apartment stood a fourth watcher, who used an instrument that was to his electric sense what the telescope is to the eye and their vamolan was to their ear. With this idrolan he swept the sky for new and unclassified electric impulses; and the faintest and most distant indication, quite unrecognisable by his unaided sense, was magnified ten thousand-fold; at the same time the distance of the source was roughly measured and indicated.