‎"POULSEN, VALDEMAR. - THE INVENTION OF THE SOUND RECORDER.‎
‎Das Telegraphon.‎

‎(Berlin, J.A. Barth, 1900). No wrappers. In ""Annalen der Physik"", Vierte Folge. Band 3, No 12. Pp. 545-766. (Entire issue offered, No. 12). Poulsen's paper: pp. 754-760, textillustrations. Clean and fine, but punched in inner margins after cords, no loss of text.‎

Reference : 43651

‎First printing of this paper in which Poulsen describes his invention of the ""TELEGRAPHON"", THE FIRST magnetic sound recorder. The Telegraphone was shown, but not operated at the Paris Exposition in 1900 and obtained a Grand Prix.""The magnetic recording was demonstrated in principle as early as 1898 by Valdemar Poulsen in his telegraphone. Magnetic wire recording, and its successor, magnetic tape recording, involve the use of a magnetizable medium which moves past a recording head. An electrical signal, which is analogous to the sound that is to be recorded, is fed to the recording head, inducing a pattern of magnetization similar to the signal. A playback head (which may be the same as the recording head) can then pick up the changes in the magnetic field from the tape and convert them into an electrical signal.""(Wikepedia).The issue contains further Max Planck's paper ""Kritik zweier Sätze des Hrn. W. Wien"", pp. 764-766, and Ångstrøm ""Ueber die Bedeutung des Wasserdampfes und der Kohlensäure bei Absorption der Erdatmosphäre."", pp. 720-732.Shiers ""Early Television"" no 289.‎