IMPROVED MARINER’S COMPASS.

New Zealand Times, Volume XXXIII, Issue 5384, 29 June 1878, Page 1 (Supplement)

IMPROVED MARINER’S COMPASS.

There is now to bo Been on board the mail steamer Zealaudia (says tha Melbourne Aryns) a new description of compass, the invention of Sir William Thompson. Captain Chevalier states that the invention is a most valuable one, and from his own experiments with it he can testily that it fulfils admirably the purpose for which it was designed. In size and outward appearance it much resembles the ordinary ship’s compass, but the patent cord is constructed on an entirely new principle. It consists of a central aluminium boss, and au puter rim of the same metal connected together by fine silk cords from tho rim, and thin paper marked with the points of the compass and degrees is attached to the rim, and partially supported by tho silk cords between tho rim and tho boss. Thus tho principal part of the weight is removed from tho centre on which tho card moves, and it thereby gains a very free oscillation. Tho card with the needles is extremely light, and the fractional error is re-

duced to a minimum. The quadrautol error cau be most accurately corrected in any latitude by a couple of iron globes fixed on tho two sides of the binnacle. The semi-circular eri\)r is adjusted by two magnetic correctors, one for neutralising the thwartship component, and the other for the fore-and-aft component of the vessel’s magnetism. What is known as the heeling error is corrected by a magnet beneath tho compass. For taking bearing, whether of celestial or terrestial objects, there is provided what is called the azimuth mirror, which will throw the image of a star upon the compass card, by which, even when a ship is tumbling about in a seaway, the position of the object can be accurately judged. Neither is the compass affected by the rolling to anything like the extent the standard compass is, and for taking cross-bear-ings its immunity from deviation is especially valuable.