REGISTERING THE SPEED OF A VESSEL BY ELECTRICITY.

Daily Telegraph (Napier), Issue 3266, 20 December 1881, Page 4

REGISTERING THE SPEED OF A VESSEL BY ELECTRICITY.

Day by day persevering students and experimenters are deducing and; revealing new facts in connection with the subtle and wondrous force known as electricity, whilst more practical men are adapting its powers to useful purposes. Among the more recent applications of its peculiar characteristics to valuable uae is that of attaching an electrical apparatus to a ship's log, and making it register with extreme accuracy the speed at ■which the ship is moving through the water. This ingenious arrangement owes its existence to the inventive genius and skill of Mr Kelway, of Portsmouth. The inventor has affixed to the lower part of the box containing an ordinary service log another box which encloses his own electrical apparatus. Into this last named box the mile spindle of the log is continued, and this is fitted with a cam wheel. The box is also divided into two parts by a vortical partition, through, which passes a horizontal lever, or rod, insulated from tho body of the apparatus, and turning upon a fixed centre. As the cam wheel revolves in passing through the water, its projections press down the lever whereby the electrical current is completed, and the distance travelled is recorded by means of a battery on board tho ship acting through the electric cable, by which the log is towed. Tho index dial may be placed in the captain's cabin, on deck, or, indeed, in any part of the ship. In trials lately made near Portsmouth every quarter of a knot indicated by the dial was checked by actual measurement, and found to be absolutely correct.