Gnats are fascinated by a powerful electric lamp, and dance about it as they do in a beam of evening sunshine. Light has an attraction for many animals besides insects. Flying-fish spring out of the sea when sailors hang a lantern by the ship’s side; and in California now it is the custom to submerge a cluster of Edison lamps from the bows of a boat with a net expanded below. When the fish gather round the light the net is closed on them, and after being hauled out of the water they are put into water-tanks, and sent alive on special cars by overland rail to New York and the Eastern States. The French _chasseur_ also makes a bag sometimes by employing an electric light to attract his feathered game; pigeons especially being lured by it. Owing to its power, the arc-light is very well suited for signalling purposes; and hence it is now used with the heliograph to signal the approach of cyclones between the British island of Mauritius and Reunion in the Indian Ocean. It has also been proposed to signal by transparent balloons lit by incandescence lamps. The balloon is raised to a good height by a rope which also carries the wires conveying the current to the lamps; and flashes according to an understood code of signals are made by working a key to interrupt the current, as in the act of telegraphing. Diving operations under the sea are greatly facilitated by the electric light; and a trial was recently made of a powerful lamp at Marseilles in lighting up the hull of a sunken ship. The amber hunters of the Baltic are also using the light for seeking the fossil gum on the sea-bed, instead of waiting until the waves cast it on the shore. Sea-water is remarkably clear, and the rocks of the seashore are often beautifully covered with weeds and shells. It is no wonder, then, that a submarine balloon has been devised by one Signor Toselli at Nice, for going under water to examine them. This observatory holds eight people, and has a glass bottom and an electric light for illuminating the sea-caves.