Telegraphy without Wires, and the Guarding of Coast Lines by Electric Cable

Abstract

IT appears from an article in Commerce, December 16, that Mr. W. H. Preece, in a lecture on “Telegraphy without Wires,” at Toynbee Hall, said, that from experiments at the Goodwin Lightship it had been found impossible to get a message on board, and “that the intervening sea-water performed much the same function as an iron plate,” I would like to call the attention of the readers of NATURE to my paper laid before the Royal Society of Edinburgh in January 1893, when it was shown that neither salt nor fresh water had any appreciable effect on the transmission of these electrical waves. Take this case—an iron steamer afloat above a cable lying on the sea-bottom. If the steamer have on board suitable apparatus, messages sent along the cable from a single Leclanche cell can be and have been read on board ship by ordinary sailors. If it is possible to so convey messages to a vessel not moored by an anchor, it is surely possible to do the same to a moored ship such as a lightship. Mr. Preece's failure at the “Goodwin” is not due to the action of salt water, for, if electric vibrations work through salt water in the Firth of Forth, they will equally do so at the “Goodwin.”