TELL-TALE MARINER’S COMPASS.

Kumara Times, Issue 1017, 5 January 1880, Page 4

TELL-TALE MARINER’S COMPASS.

From the Times we extract the following definition of an instrument invented by Mr Henry A. Severen, a gentleman well-known as a scientific lecturer. It is “ a mariner’s compass which enables the captain or officer In charge to hear, by the ringing of a bell, when the vessel is out of the ordered course. In the construction of this compass Mr Severn has availed himself of the constant position of the card and the ever varing position of the ship for the purpose of making and breaking metallic contact, which causes an electric bell to be sounded, and thus to announce the fact that the vessel is off her course. The whole of the apparatus is contained in a small box, which is easily carried about, and is intended as a rule, to be placed in the captain’s cabin. Over the card are two index hands, which can be adjusted to any angle, allowing of greater or less deviation in steering to either the port or starboard side Assuming the captain, on quitting the deck, to have given instructions to steer the ship on a certain course. Instead of having to be constantly watching the compass as at present, to see that his orders are carried out, the captain leaves the instrument to tell him by its silence if they are, and by its sounds if they are not obeyed. Should the ship be steered off her course on either side, an electric alarm-bell rings instantaneously, and, moreover continues ringing until the right course is resumed. The index hands can be raised away from the card, when the bell becomes disconnected and the compass can be used like an ordinary one. The means whereby this useful result is obtained may be thus briefly stated. The metal point on which the card is hung is insulated from the compass bowl, and to it is attached a wire from one pole of a small battery. About an inch above the card, placed parallel to its surface, and attached to its metal centre (which is insulated from the needle) is. an arm of metal reaching nearly to the edge of the card. This arm is, in metallic communication with the wire from the battery already referred to. The glass lid of the compass has a short brass rod working within a tube passing through it. These are severally attached to two brass milled heads above the glgsa lid and to the two moveable index-hands beneath the glass. These are in metallic contact with the brass-work of the compass, and this with the other pole of the battery. Beneath the outer extremities of the index-hands are suspended two pieces of platinum wire about three-quarters of an inch long. These hands can by means of the two milled-heads, be moved round to any position over any point of the card. Hence they admit of being placed on either side and equally distant or otherwise from the end of the metal arm on the card. It will thus be seen that whenever the platinum wires come into contact with the metal arm on the card the circuit is completed. The electric bell being placed in the circuit, sounds whenever such contact takes place. The bell is disconnected by simply raising the milled head up half an inch through a sliding tube, and the compass then becomes in all respects an ordinary one. Two bells of different tone can be used and thus the intrument will indicate to the captain whether the deviation in steering is to port or starboard. The arrangement is simple and compact, and the invention promises to subserve a very useful purpose in navigation. By its use the captain will be saved much anxiety, and, the knowledge that there is a cheek upon them will serve to render officers more vigilant, and steersmen more careful. Headlands and rocks may thus be guarded against with much greater security, while in the case of vessels riding at anchor in a port or road this compass will at once give intimation of swinging—a matter of importahce, especially at night, when many vessels are together. In abort, the dangers of navigation generally will be considerably lessened by its use.” The compass, we are informed, has been patented by the inventor in America, France, Germany, and England ; and three, large English firms have purchased the right to manufacture it.