SCIENCE SIFTINGS

New Zealand Tablet, 27 November 1919, Page 46

SCIENCE SIFTINGS

(By - “Volt.”)

Butterflies as Ocean Flyers. . The most wonderful of ocean flyers are the butterflies which cross the ocean in the spring. Naturalists tell us that one of the most amazing sights in the world is to see millions of these delicate creatures, like a cloud of tiny pieces of paper, flying across the Channel, from the Continent to English shores, when the wind is favorable. Their stamina and endurance are extraordinary, and although some fall exhausted into the sea, the bulk make a successful crossing. The butterfly army of invasion generally includes many beautiful specimens, and as an -illustration of their powers of endurance it might be mentioned many butterflies have descended to rest on vessels 200 miles at sea. The farthest authenticated distance at which a moth lias been captured at sea was recorded by a well-known scientist eight years ago, 7 ho took specimens of a certain large moth 1200 miles from the nearest possible land.

Talking Along a Beam of Light. Among the latest scientific marvels of the world must be placed the searchlight telephone, an apparatus which enables one to speak along a beam of light, using 1 it as a substitute for the telephone wire. Either natural or artificial light can. be used, and clear and distinct messages can be transmitted up to a distance of eight miles in sunlight, and half a mile in artificial. The secret of the invention lies in the transmitter, which, when words are spoken into it, causes the intensity of the light to fluctuate, these fluctuations being reproduced in a telephone at the receiving end, which is so tuned that it varies according to the light falling upon it, and so conveys the message. One great advantage of this wonderful invention is that, unlike wireless messages, which are distributed broadcast, the searchlight ’phone can only be tapped by an interception of the beam of light. As the inventor. Dr. A. O. Rankine, of University College, London, points out, the invention would prove highly useful, for instance, in the case of ships coming to anchor outside a port, and anxious to get into communication with the shore authorities immediately. As a rule the laying of telegraphic or telephonic cables from the shore has resulted in much delay. But this invention would enable a ship to start verbal communication immediately with the shore, simply by focusing the sun’s rays or using the searchlight. Nothing but the destruction, or partial destruction, of the beam of light would stop the conversation. Secret verbal communications with aircraft would not be impossible, so long as the connection was maintained with the beam of light ; while the invention would entirely displace the use of the heliograph and other devices for signalling in Morse code. „ An Automatic Lightship. The efficient lighting of the waterways so that they can be safely navigated at night is an all-important matter. It is effected by the ordinary stationary lighthouse on shore, and also by manned lightships and various kinds of automatic light-buoys. The latest of these latter is an ingenious , automatic lightship, requiring no attention whatever when once set in motion, built by a British firm. It is a very ingeniously-constructed vessel, and the very latest of its kind. In its two steel tanks sufficient gas can be stored to supply the vessel for several months. Experiments have shown that the light may be depended upon to burn continuously for months at a time without any attention whatever. The approximate duration of the light can always be pre-determined, and there is no danger whatever of the light being extinguished either by wind or spray. The light is visible at a distance of eight to 12 miles. The lightship also boasts of a bell, which is made to ring automatically by means of a highly-ingenious device which utilizes the gas as it passes from the tanks to the lantern to actuate the bell clapper. The light is not interfered with in the slightest degree by the operation of the bell-striking device. It is only set in motion, however, in very foggy weather, when the light cannot be distinguished at any great distance.