REGISTERING THE SPEED OF A VESSEL BY ELECTRICITY.

New Zealand Herald, Volume XVIII, Issue 6261, 10 December 1881, Page 3

REGISTERING THE SPEED OF A VESSEL BY ELECTRICITY.

Bay 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 arc adapting its powers to useful purposes. Among the more recent applications of its peculiar characteristics to valuable use is that of attaching an electrical apparatus to ;i 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 invontor has ath'xed 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 vertical partition, through which passes a horizontal lever or rod, insulated from the body of the apparatus, and turning upon afixed 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 the ship acting through the electric cable by which the log is towed. The index dial may be placed in the captain's cabin, or on deck, or, indeed, in any part of the ship. In trials lately made near Portsmouth every quarter knot indicated by the dial was checked by actual measurement, and found to be absolutely correct,