TELEGRAPHY WITHOUT WIRES
Letter from Sir Oliver Lodge to The Times, June 17 (year unknown)
TO THE EDITOR OF THE TIMES
Sir,-
It appears that many persons suppose that the method of signaling across space by means of Hertz waves received by a Branly tube of filings is a new discovery made by Signor Marconi, who has recently been engaged in improving some of the details. It is well known to physicists, and perhaps the public may be willing to share the information, that I myself showed what was essentially the same plan of signaling in 1894. My apparatus acted very vigorously across the college quadrangle, a distance of 60 yards, and I estimated that there would be some response up to a limit of half a mile. Some of the hearers of Mr. Preece's recent lecture at the Royal Institution seem to have understood his references to these previous trials to signify that I had asserted or prophesied that more powerful apparatus would always be limited to some such distance: whereas my statement was a scientific one, concerning the small and early apparatus which, with the help of my assistant, Mr. E. E. Robinson, I had at the time devised and constructed. My apparatus was substantially the same as that now used by Signor Marconi - there was a row of sparking spheres; the sparks were taken under oil sometimes, as suggested by M. Sarasin; there were iron and brass filings in a high vacuum and likewise in hydrogen: there was also my own coherer with a single contact, which is more sensitive, but less manageable than a filings tube; and the restoration to sensitiveness was effected by an electrically-worked hammer. Signor Marconi uses nickel and silver filings in a lower vacuum, and by employing greater power he has obtained signals over much greater distances; moreover, instructed primarily by Professor Righi, and aided in his trials by the British Post Office, he was worked hard to develop the method into a commercial success.
For all this full credit is due - I do not suppose that Signor Marconi himself claims any more - but much of the language indulged in during the past few months by writers of popular articles on the subject about "Marconi waves," "important discoveries," and "brilliant novelties" has been more than usually absurd. The only "important discovery" about the matter was made in 1888 by Hertz; and on that is based the emitter of the waves; the receiver depends on cohesion under electrical influence, which was noticed long ago by Lord Raleigh and has been re-observed in other forms by other experimenters, including the writer in 1890.
Yours faithfully,
OLIVER LODGE
University College, Liverpool, June 17.
TO THE EDITOR OF THE TIMES
Sir,-
It appears that many persons suppose that the method of signaling across space by means of Hertz waves received by a Branly tube of filings is a new discovery made by Signor Marconi, who has recently been engaged in improving some of the details. It is well known to physicists, and perhaps the public may be willing to share the information, that I myself showed what was essentially the same plan of signaling in 1894. My apparatus acted very vigorously across the college quadrangle, a distance of 60 yards, and I estimated that there would be some response up to a limit of half a mile. Some of the hearers of Mr. Preece's recent lecture at the Royal Institution seem to have understood his references to these previous trials to signify that I had asserted or prophesied that more powerful apparatus would always be limited to some such distance: whereas my statement was a scientific one, concerning the small and early apparatus which, with the help of my assistant, Mr. E. E. Robinson, I had at the time devised and constructed. My apparatus was substantially the same as that now used by Signor Marconi - there was a row of sparking spheres; the sparks were taken under oil sometimes, as suggested by M. Sarasin; there were iron and brass filings in a high vacuum and likewise in hydrogen: there was also my own coherer with a single contact, which is more sensitive, but less manageable than a filings tube; and the restoration to sensitiveness was effected by an electrically-worked hammer. Signor Marconi uses nickel and silver filings in a lower vacuum, and by employing greater power he has obtained signals over much greater distances; moreover, instructed primarily by Professor Righi, and aided in his trials by the British Post Office, he was worked hard to develop the method into a commercial success.
For all this full credit is due - I do not suppose that Signor Marconi himself claims any more - but much of the language indulged in during the past few months by writers of popular articles on the subject about "Marconi waves," "important discoveries," and "brilliant novelties" has been more than usually absurd. The only "important discovery" about the matter was made in 1888 by Hertz; and on that is based the emitter of the waves; the receiver depends on cohesion under electrical influence, which was noticed long ago by Lord Raleigh and has been re-observed in other forms by other experimenters, including the writer in 1890.
Yours faithfully,
OLIVER LODGE
University College, Liverpool, June 17.
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