even after that date, for they gave hopes of a much more economical solution of the problem.  Among the most interesting are remembered those that S.W.  Wilkins carried on for a long time between France and England.  Like Cooke and Wheatstone, he thought of using as a receiver an apparatus which in some features resembles the present receiver of the submarine telegraph.  Later, George E. Dering, then James Bowman and Lindsay, made on the same lines trials which are worthy of being remembered.

But it is only in our own days that Sir William H. Preece at last obtained for the first time really practical results.  Sir William himself effected and caused to be executed by his associates—­he is chief consulting engineer to the General Post Office in England—­ researches conducted with much method and based on precise theoretical considerations.  He thus succeeded in establishing very easy, clear, and regular communications between various places; for example, across the Bristol Channel.  The long series of operations accomplished by so many seekers, with the object of substituting a material and natural medium for the artificial lines of metal, thus met with an undoubted success which was soon to be eclipsed by the widely-known experiments directed into a different line by Marconi.

It is right to add that Sir William Preece had himself utilised induction phenomena in his experiments, and had begun researches with the aid of electric waves.  Much is due to him for the welcome he gave to Marconi; it is certainly thanks to the advice and the material support he found in Sir William that the young scholar succeeded in effecting his sensational experiments.

Sec. 4

The starting-point of the experiments based on the properties of the luminous ether, and having for their object the transmission of signals, is very remote; and it would be a very laborious task to hunt up all the work accomplished in that direction, even if we were to confine ourselves to those in which electrical reactions play a part.  An electric reaction, an electrostatic influence, or an electromagnetic phenomenon, is transmitted at a distance through the air by the intermediary of the luminous ether.  But electric influence can hardly be used, as the distances it would allow us to traverse would be much too restricted, and electrostatic actions are often very erratic.  The phenomena of induction, which are very regular and insensible to the variations of the atmosphere, have, on the other hand, for a long time appeared serviceable for telegraphic purposes.

We might find, in a certain number of the attempts just mentioned, a partial employment of these phenomena.  Lindsay, for instance, in his project of communication across the sea, attributed to them a considerable role.  These phenomena even permitted a true telegraphy without intermediary wire between the transmitter and the receiver, at very restricted distances, it is true, but in peculiarly interesting conditions.  It is, in fact, owing to them that C. Brown, and later Edison and Gilliland, succeeded in establishing communications with trains in motion.