SCIENCE SITTINGS

New Zealand Tablet, 20 June 1918, Page 46

SCIENCE SITTINGS

By “Volt.’*

The Sperry Compass. Two points of special interest are dealt with in the first article published in the Morning Post by its special correspondent with the French fleet. One relates to the Sperry compass, an appliance which has been found to be invaluable in view of the impossibility'* of compensating the ordinary compass for use in submarines. “The Sperry compass was known in battleships before the war, but it is since the war that it has been adapted to the submarine. It is a weird invention, and it requires a knowledge of the higher mathematics really to understand the theory on which it is based. What can be said of it is that it depends fundamentally on the gyroscope. No matter what happens, when it has been running for a short time the compass points persistently to the north, quite independently of the magnetic influences of the vessel. There is nothing, I was assured, that has done more to make the submarine a weapon of precision that the adaptation to it of this compass, which makes it possible for the submarine commander to obtain absolutely accurate bearings.” Most Powerful Wireless Station in the World. The French navy has just entered the international contest for the honor of building and possessing the most powerful wireless station of the world, writes Mr. Henry Wood, special American correspondent with the French armies. In support of its claim that its newly-constructed station exceeds all others now in operation, the French navy has just demonstrated its ability to send messages as far as Australia. The stations there which registered the messages from the French new naval station wei e not powerful enough to acknowledge by wireless their leceipt, but had the courtesy to reply by ordinary cable that the French wireless communication had been received. ihe moment America made its formal declaration of war against the enemies of France the French navy decided to erect immediately a powerful wireless station that would put France* into constant and sure touch with America. It was planned also as a very effective safeguard against the submarines for the earn of troopships and munition convoys which it was realised would soon be headed for France. A site was accordingly chosen on the French coast where it was most likely that one of the American naval bases would be established, and from where it would be able to pick up with the greatest degree of certainty distress messages from an American boat which might encounter a submarine.

The metallic pylons of the French station are over 600 ft high. Perfected electrical equipment makes it possible to send out waves that will be received at any distance at which they can be picked up. The electrical apparatus furnishing the current for these waves is capable of producing 600 horse-power. What the French navy is particularly proud of, however, is that it finished the plant in six months, in time to protect from the very first, convoys of American troops and war material.