[53.] Experiments with the Telephone.
(a.) As soon as one brings the mouth to the funnel S and sings, the membrane of the transmitter, A, vibrates in a corresponding manner, and the iron rod, E E, at the second station begins to give forth a tone. Every time a spark is seen at the first station s, the rod at the other station certainly gives forth a tone. The same is true when one hears the peculiarly snarling tone which arises from the stroke of the vibrating platinum strip against the spike of angular hook resting upon it.
The appearance of these sparks or of the peculiar snarling at the transmitter A gives the sign to the observers at the station A that the rod in C is giving a tone. Tones and melodies which were sung into the sound aperture, and especially sounds in which the teeth and bones of the head also vibrated (so-called humming tones), always evoked a tone in the rod or needle E E, and indeed, as already mentioned (§ 51), without change in the pitch, but only with the reproduction of the rhythm of the respective song or words.
The pitch of the tone excited at C in the rod E E was in the apparatus at my disposal h; its strength not very great and its clang snarly, similar to that of a lightly sounding reed-whistle, somewhat like that of a child’s wooden trumpet. The cuticle lying about the heart of the smaller and even the larger mammals (from calves, &c.) makes the best membranes. Goldbeater’s-skins reproduce only the deeper tones. The cover of the sounding-box appeared in my apparatus superfluous, and indeed the tone was somewhat stronger without the cover.
1. In experiments with the telephone, one must look closely as to whether the ends of the platinum strip is still fastened to the membrane, and one must, if necessary, press upon the membrane. If the strip will no longer stick, heat a knife-blade, touch a small piece of sealing wax with it, and carry thus the melted sealing-wax to the under side of the round end of the platinum-strip, n s. Then press it immediately on the membrane, m m.
Ph. Reis showed his apparatus in very primitive form for the first time in October, 1861, to the Physical Society at Frankfort-on-the-Main; on July 4th, 1863, before the same society, he showed the form represented in [Fig. 33]. This time he experimented upon a distance of 300 feet. Professor Boettger brought the apparatus before the Naturforscher-Versammlung at Stettin (1863) in the section for Physics.
[16.] Hessler’s ‘Text-book of Technical Physics,’ vol. i. p. 648.
[Next in chronological order comes a notice of the Telephone in Hessler’s ‘Lehrbuch der technischen Physik,’ edited by Prof. Pisko, and published at Vienna in 1866. The brief account given in this work adds nothing to the accounts previously given, and is evidently written by some person ignorant of Reis’s own work, for beside omitting all mention of the transmission of speech by the instrument, or of its being constructed upon the model of the human ear, the writer appears not even to know how to spell Reis’s name,[37] and speaks of him as “Reuss.”]
[17.] Kuhn’s ‘Handbook of Applied Electricity,’
(‘Handbuch der Angewandten Elektricitätslehre,’ von Carl Kuhn), being vol. xx. of Karsten’s ‘Universal Encyclopædia of Physics’ (Karsten’s ‘Allgemeine Encyclopädie der Physik’).
[Karsten’s ‘Encyclopædia of Physics,’ which has been for many years a standard work of reference, both in Germany and in this country, consists of a number of volumes, each of which is a complete treatise, written by the very highest authorities in Germany. Thus Helmholtz contributed the volume on Physiological Optics, Lamont that on Terrestrial Magnetism, whilst the names of Dr. Brix, Professor von Feilitzsch, and others, are included amongst the authors. Carl Kuhn, who wrote vol. xx., was Professor in the Royal Lyceum of Munich, and member of the Munich Academy. Kuhn’s volume on ‘Applied Electricity,’ published in 1866, is to be found on the shelves of almost every library of any pretensions in Great Britain. The account given therein of Reis’s Telephone is interesting, because it describes two forms, both of transmitter and of receiver. In fact the descriptions and figures are taken almost directly from von Legat’s Report (p. 70), and from Reis’s Prospectus (p. 87). The extract translated below includes all the matter that is of importance.]