“The apparatus A, a square box of wood, the cover of which shows the membrane (c) on the outside, under glass. In the middle of the latter is fixed a small platina plate to which a flattened copper wire is soldered on purpose to conduct the galvanic current. Within the cercle you will further remark two screws. One of them is terminated by a little pit in which you put a little drop of quiksilver; the other is pointed. The angle, which you find lying on the membrane, is to be placed according to the letters, with the little whole [hole] (a) on the point (a) the little platina foot (b) into the quicksilver screw, the other platina foot will then come on the platina plate in the middle of the membrane.
“The galvanic current coming from the battery (which I compose generally of three or four good elements) is introduced at the conducting screw near (b) wherefrom it proceeds to the quicksilver, the movable angle, the platina plate and the complementary telegraph to[29] the conducting screw (s). From here it goes through the conducter to the other station B and from there returns to the battery.
“The apparatus B, a sonorous box on the cover of which is placed the wire-spiral with the steel axis, wich will be magnetic when the current goes through the spiral. A second little box is fixed on the first one, and laid down on the steel axis to increase the intensity of the reproduced sounds. On the small side of the lower box you will find the correspondent part of the complementary telegraph.
“If a person sing at the station A, in the tube (x) the vibrations of air will pass into the box and move the membrane above; thereby the platina foot (c) of the movable angle will be lifted up and will thus open the stream at every condensation of air in the box. The stream will be re-established at every rarefaction. For this manner the steel axis at station B will be magnetic once for every full vibration; and as magnetism never enters nor leaves a metal without disturbing the equilibrium of the atoms, the steel-axis at station B must repeat the vibrations at station A and thus reproduce the sounds which caused them.
“Any[30] sound will be reproduced, if strong enough to set the membrane in motion.
“The little telegraph, which you will find on the side of the apparatus is very usefull and agreable for to give signals between both of the correspondents. At every opening of the stream and next following shutting the station A will hear a little clap produced by the attraction of the steel spring. Another little clap will be heard at station (B) in the wire-spiral. By multiplying the claps and producing them in different measures you will be able as well as I am to get understood by your correspondent.
“I am to end, Sir, and I hope, that what I said will be sufficient to have a first try; afterward you will get on quite alone.
“I am, Sir,
“Your most obediant Servant,
“Ph. Reis.“Friedrichsdorf, 13/7, 63.”
[The following “Prospectus” of instructions was drawn up by Reis to accompany the Telephones which were sold by Herr Wilh. Albert of Frankfort. The author of this book is in possession of original copies, of which a number are extant. The “Prospectus” was also reprinted in its entirety at page 241 of Professor Pisko’s book ‘Die neueren Apparate der Akustik,’ published at Vienna in 1865.]
Each apparatus consists, as is seen from the above illustration, of two parts: the Telephone proper, A, and the Reproduction apparatus [Receiver], C. These two parts are placed at such a distance from each other, that singing, or the tones of a musical instrument, can be heard from one station to the other in no way except through the apparatus itself.
Both parts are connected with each other, and with the battery, B, like ordinary telegraphs. The battery must be capable of effecting the attraction of the armature of the electromagnet placed at the side of station A (3-4 six-inch Bunsen’s elements suffice for several hundred feet distance).
The galvanic current goes then from B to the screw, d, thence through the copper strip to the little platinum plate at the middle of the membrane, then through the foot, c, of the angular piece to the screw, b, in whose little concavity a drop of quicksilver is put. From here the current then goes through the little telegraph apparatus, e-f, then to the key of station C, and through the spiral past i back to B.
If now sufficiently strong tones are produced before the sound-aperture, S, the membrane and the angle-shaped little hammer lying upon it are set in motion by the vibrations; the circuit will be once opened and again closed for each full vibration, and thereby there will be produced in the iron wire of the spiral at station C the same number of vibrations which there are perceived as a tone or combination of tones (chord). By imposing the little upper case (Oberkästchen) firmly upon the axis of the spiral the tones at C are greatly strengthened.
Besides the human voice (according to my experience) there also can be reproduced the tones of good organ-pipes from F—c' and those of a piano. For the latter purpose A is placed upon the sounding-board of the piano. (Of thirteen triads (Dreiklänge) a skilled experimentor could with all exactness recognise ten).
As regards the telegraph apparatus placed at the side, it is clearly unnecessary for the reproduction of tones, but it forms a very agreeable addition for convenient experimenting. By means of the same, it is possible to make oneself understood right well and certainly by the other party. This takes place somewhat in the following manner: After the apparatus has been completely arranged, one convinces oneself of the completeness of the connexion and the strength of the battery by opening and closing the circuit, whereby at A the stroke of the armature is heard, and at C a very distinct ticking.
By rapid alternate opening and closing at A it is asked at C whether one is ready for experimenting, whereupon C answers in the same manner.
Simple signals can by agreement be given from both stations by opening and closing the circuit one, two, three, or four times; for example:—
1 beat = Sing.
2 beats = Speak, &c.
I telegraph the words thus—that I number the letters of the alphabet and then transmit their numbers—
1 beat = a.
2 beats = b.
3 " = c.
4 " = d.
5 " = e, &c.
z would accordingly be designated by twenty-five beats.
This number of beats would, however, appear wasteful of time, and would be uncertain in counting, wherefore I employ for every five beats a dactyl-beat (Dactylusschlag), and there results
—~ ~ for e.
—~ ~ and one beat for f, &c.
z, = —~ ~,—~ ~,—~ ~,—~ ~,—~ ~ which is more quickly and easily executed and easier to understand.
It is still better if the letters are represented by numbers which are in inverse proportion to the frequency of their occurrence.
Phil. Reis,
Teacher at L. F. Garnier’s Institute for boys.
Friedrichsdorf, near Homburg-by-the-Height,
August 1863.
[The foregoing “Prospectus” was accompanied by a further document printed as a postscript by Reis, at the top of which the figure of the instrument was repeated, and which ran as follows:—]
“P. P.,
“Since two years ago I succeeded in effecting the possibility of the reproduction of tones by the galvanic current, and in setting up a convenient apparatus therefor, the circumstance has found such a recognition from the most celebrated men of science, and so many calls to action have come to me, that I have since striven to improve my originally very incomplete apparatus, so that the experiments might thereby become accessible to others.
“I am now in the position to offer an apparatus which fulfils my expectations, and with which each physicist may succeed in repeating the interesting experiments concerning reproduction of tones at distant stations.
“I believe I shall fulfil the wish of many if I undertake to bring these improved instruments into the possession of the [physical] cabinets. Since the preparation of the same requires a complete acquaintance with the leading principles and a tolerable experience in this matter, I have decided myself to prepare the most important parts of the same, and to leave the fashioning of the accessory parts, as also of the external adornments, to the mechanician.
“The distribution of the same I have made over to Herr J. Wilh. Albert, mechanician, in Frankfort-on-the-Main, and have placed him in the position to deliver these instruments in two qualities, differing only in external adornment, at the prices of 21 florins and 14 florins (12 thalers and 8 thalers current), inclusive of packing. Moreover, the instruments can also be obtained direct from me at the same prices, upon a cash remittance of the amount.
“Each apparatus will be tested by me before sending off, and will then be furnished with my name, an order-number, and with the year of manufacture.
“Friedrichsdorf, near Homburg-by-the-Height,
“in August 1863.“Phil. Reis,
“Teacher at L. F. Garnier’s Institute for Boys.”
[In September of the same year the telephone was shown by Prof. R Böttger at the meeting of the German Naturalists’ Association (Naturforscher), which met on that occasion at Stettin. Little or nothing is known of what took place at this exhibition, but Professor von Feilitzsch, of the neighbouring University of Greifswald, has informed the author of this work that the Telephone there shown was of the form figured in Reis’s Prospectus (p. 86), and that Reis claimed at that time to be able to transmit words by his instruments. In the same autumn the following notice appeared in Böttger’s ‘Notizblatt,’ and was copied thence into Dingler’s ‘Journal,’ and other scientific papers.]
[Translated from the original notice which appeared in Böttger’s ‘Polytechnisches Notizblatt,’ 1863, No. 15, p. 225, and in Dingler’s ‘Polytechnisches Journal,’ 1863, vol. clxix. p. 399.]
At the meeting of the Physical Society of Frankfort-on-the-Main, on the 4th of July, a member of this Society, Herr Ph. Reis, of Friedrichsdorf, near Homburg-vor-der-Höhe, exhibited some of his improved Telephones (means for the reproduction of tones at any desired distance by the galvanic current). It is now two years since Herr Reis first gave publicity to his apparatus,[31] and though even already at that time the performances of the same in their simple artless form were capable of exciting astonishment, yet they had then the great defect that experimenting with them was only possible to the inventor himself. The instruments exhibited in the above-named meeting scarcely reminded one of the earlier ones. Herr Reis has also striven to give them a form pleasing to the eye, so that they may now occupy a worthy place in every Physical Cabinet. These new apparatus may now also be handled by every one with facility, and work with great certainty. Melodies gently sung at a distance of about 300 feet were repeated by the instrument which was set up, much more distinctly than previously. The scale was reproduced especially sharply. The experimenters could even communicate words to one another, though certainly indeed only such as had often been heard by them. In order moreover that others who are less accustomed [to experimenting] may be able to understand one another through the apparatus, the inventor has placed on the side of the same a little arrangement,[32] which according to his explanation is completely sufficient, the speed of communication of which is indeed not so great as that of modern Telegraphs, but which works quite certainly, and requires no special skill on the part of the one experimenting with it.
We would bring to the notice of gentlemen who are professional physicists that the inventor of these interesting pieces of apparatus now has them prepared for sale under his oversight (the important parts he makes himself), and the same can be procured from him direct, or through the mechanician, Mr. Wilhelm Albert, of Frankfort-on-the-Main, at 14 and at 21 florins, in two qualities, differing only in external adornment.
[A review, written by Dr. Röber of Berlin, of this and other articles relating to the Telephone appeared subsequently in the ‘Fortschritte der Physik,’ 1863, p. 96.]
[Another consequence of the publicity thus given to the Telephone was the appearance of an article on that instrument, under the title of “Der Musiktelegraph,” in a popular illustrated weekly family paper, ‘Die Gartenlaube,’ published at Leipzig. This article, from the pen, it is believed, of Dr. Oppel of Frankfort, is made up chiefly of slightly altered extracts from the previously quoted documents. The form of the instrument described is identical with that described in Reis’s ‘Prospectus,’ and the figure given in the ‘Gartenlaube,’ No. 51, p. 809, is a reprint, apparently from the same wood-block of the figure which heads Reis’s Prospectus, and which is reproduced on p. 86 of this work. The only passage of further interest is a brief sentence relating to the exhibition of the Telephone at the German Naturalists’ Assembly at Stettin in 1863, and is as follows:—]
“Now in order also to give to a still wider circle, especially to technologists (Fachmännern), the opportunity of witnessing with their own eyesight the efficiency of this apparatus,—lately, in fact essentially improved,—Professor Böttger of Frankfort-on-the-Main exhibited several experiments therewith at the meeting of the German Naturalists (Naturforscher) and Physicians recently held at Stettin, in the Section for Physics; which [experiments] would certainly have been crowned with still greater success if the place of meeting had been in a less noisy neighbourhood, and had been filled with a somewhat less numerous audience.”
[The next extract is a brief record from the Report of a scientific society meeting in Giessen, which during the Austro-Prussian war of 1866 had become disorganised, and which in 1867 published a condensed account of its proceedings for the preceding years. Amongst those proceedings was a lecture by the late Professor Buff, at which Reis’s Telephone was shown, and at which Reis himself is believed to have been present.]
P. 155. Report on the doings and condition of the Association from the 1st of July, 1863, to the 1st of July, 1865, by Herr Gymnasiallehrer Dr. W. Diehl.
... On the 13th of February [1864], ‘On the Tones of the Magnet, with Application to the Telephone, with experiments,’ by Professor Buff.
Exhibition of the Telephone to the Naturalists’ Association of Germany. (Deutsche Naturforscher Versammlung.)
[By far the most important of all the public exhibitions given by Reis of his Telephone, was that which took place on the 21st of September, 1864, at Giessen, on the occasion of the meeting of the German Naturalists’ Association (Versammlung Deutsche Naturforscher). Here were assembled all the leading scientific men of Germany, including the following distinguished names, many of whom are still living:—Prof. Buff (Giessen), Prof. Poggendorff (Berlin), Prof. Bohn (Frankfurt-a.-M., now of Aschaffenburg), Prof. Jolly (Munich), Dr. Geissler (Bonn), Prof. Weber (Göttingen), Prof. Plücker (Bonn), Prof. Quincke (Heidelberg), Prof. Dellmann (Kreutznach), Prof. Böttger (Frankfurt-a.-M. and Mainz), Prof. Kekule (Bonn), Prof. Gerlach (Erlangen), Dr. J. Frick (Carlsruhe), Dr. F. Kohlrausch (Würtzburg), Prof. Reusch (Tübingen), Prof. J. Müller (Freiburg), Prof. Helmholtz (Heidelberg), Prof. Melde (Marburg), Prof. Kopp (Marburg), Prof. A. W. Hoffmann (London, now of Berlin), Mons. Hofmann (Paris, optician), Hofrath Dr. Stein (Frankfurt-a.-M.), Dr. W. Steeg (Homburg), Mons. Hartnack (Paris, and of Pottsdam), Prof. G. Wiedemann (Basel, now of Leipzig), E. Albert (Frankfurt-a.-M., mechanician), Dr. Thudichum (London), W. Schultze (York, apothecary), Dr. J. Barnard Davis (Shelton), E. J. Chapman (London, chemist), Dr. L. Beck (London, chemist), Prof. Chas. J. Himes (U.S.A., chemist), E. W. Blake (New Haven, U.S.A., student), C. G. Wheeler (United States Consul in Nürnberg), and many others. Dr. C. Bohn (now of Aschaffenburg) was Secretary of the Association, and also Secretary of the Section of Physics. The meetings of this Section were held in the Laboratory of Professor Buff. Reis came over from Friedrichsdorf accompanied by his young brother-in-law, Philipp Schmidt. A preliminary trial on the morning of that day was not very successful, but at the afternoon sitting, when communications were made to the Section by Prof. Buff, by Reis himself, and by Prof. Poggendorff, the instrument was shown in action with great success. Reis expounded the story how he came to think of combining with the electric current interruptor a tympanum in imitation of that of the human ear, narrating his researches in an unassuming manner that won his audience completely to him; and the performance of the instrument was received with great applause. Various professors essayed to experiment with the instrument, with varying degrees of success according to whether their voices suited the instrument or not. Amongst these were Prof. Böttger and Prof. Quincke of Heidelberg, whose account of the occasion is to be found on p. 112. Dr. Bohn, the Secretary of the Section, wrote for the ‘Journal’ (Tagesblatt), issued daily, the following notice.]
“Afternoon sitting on 21st September, 1864.
“Prof. Buff speaks about the tones of iron and steel rods when magnetised, and exhibits the corresponding experiments.
“Dr. Reis demonstrates his Telephone, gives thereupon an explanation and the history of this instrument.
“Prof. Poggendorff produces tones in a metal cylinder, the slit up edges of which touch one another firmly, and which is placed loosely round an induction-bobbin through which there goes an interrupted current.”
[This occasion was the crowning point of Philipp Reis’s career, and might have proved of even greater importance but for two causes: the inventor’s precarious health, and the indifference with which the commercial world of Germany viewed this great invention. Where the keen insight of Reis contemplated the vast possibilities opened out by the invention of a new mode of inter-communication, others saw only an ingenious philosophical toy, or at best a pleasing illustration of certain known principles of acoustic and electric science. And in spite of the momentary enthusiasm which the exhibition of the Telephone had evoked, the interest in it dwindled away. A few of the public journals of that date, noticed the invention in eulogistic terms and spoke of the prospect it afforded of communication between distant friends and of simultaneous concerts being given in different towns, all transmitted telephonically from one orchestra. But the invention came too early. The public mind was not yet prepared to take it up, and the enthusiasm died away. Still in a few of the more important books on Physics, Acoustics, and Electricity, the matter continued to receive attention. In the well-known Müller-Pouillet’s ‘Textbook of Physics’ (Lehrbuch der Physik) edited by Professor J. Müller; in the ‘Technical Physics’ of Hessler, of Vienna, edited by Professor Pisko; in Pisko’s ‘Recent Apparatus of Acoustics,’ and particularly in Kuhn’s admirable ‘Handbook of Applied Electricity,’ the Telephone was accepted as a definite conquest of science, and was described and figured. From the works named we transcribe the extracts which follow, and which sufficiently explain themselves.]
[Published at Brunswick, Sixth ed., 1863, vol. ii. page 352, fig. 325; and Seventh ed., 1868, vol. ii. pages 386-388, figs. 348-350. The following translation is from the latter edition.]
“This tone ... has Reis used for the construction of his Telephone.
“Figure 348[33] exhibits Reis’s interrupting apparatus. In the lid of a hollow cube of wood A, a circular opening is made, which is closed by an elastic membrane (pig’s lesser intestine) strained over it. Upon the centre of this membrane is glued a little plate of platinum, which stands in conductive communication with the clamping-screw a by means of a quite thin little strip of metal f (distinctly visible in Fig. 349) [Fig. 31].
“Upon the middle of the little platinum plate, rests a short little platinum pencil, which is fastened at g to the under-side of the strip of tin-plate h g i, one end of which, h, rests upon the little metal pillar l, while a little platinum spike fastened upon its under-side at i, dips into the hollow of the little metal pillar k, containing some quicksilver. The clamping-screw b, is put into conductive communication with the little metal pillar k.
“From one pole of the battery there goes a conducting-wire to the clamping-screw a of the interrupting apparatus Fig. 348 [Fig. 30], from the other pole of the same there goes a wire to the clamping-screw d of the reproducing apparatus, Fig. 350 [Fig. 32], which is to be presently described. The clamping-screw c, of this apparatus, is connected by a wire with b, Fig. 348 [Fig. 30]. The clamping-screws c and d are connected with the ends of the wire of the small magnetising spiral M, Fig. 350 [Fig. 32]; with the connexion described above, the current of the current-generator (battery) goes, therefore, through the spiral M.
“As soon now as the sound-waves of an adequately powerful tone enter through the mouth-piece S into the hollow cube A, the elastic membrane which closes this at the top is set into vibrations. Each wave of condensation on entering lifts the little platinum plate together with the little spike which sits upon it; but if the membrane swings downwards, the tin-piece h g i, with the little spike at i, cannot follow it quick enough; there therefore occurs here, at each vibration of the membrane, an interruption of the current which lets itself be recognised by a little spark appearing at the place of interruption.
“Now in the spiral M is stuck a knitting-needle, which, as the figure shows, is fastened into a sounding-board. A lid provided with second sounding-board may be clapped over the spiral, and the tone be thereby greatly strengthened.
“If now, tones are produced before the mouth-piece S, whilst one sings into the same or whilst one blows organ-pipes, one at once hears at the reproducing apparatus a peculiar creaking noise which is independent of the pitch of the tones produced at the interrupting apparatus, but, beside this, those tones are themselves reproduced by the steel wire distinctly perceptibly, and indeed Reis found that this is the case for all tones between F and f''.
“In Reis’s experiments the interrupting apparatus was 300 feet distant from the spiral, and was indeed set up in another house with closed doors. But since the length of the conducting wire can be extended just as far as in direct telegraphy, Reis gave to his apparatus the name Telephone (Jahresbericht des physikalischen Vereins zu Frankfurt-a.-M. für 1860/61).”
[This book, ‘The more recent Apparatus of Acoustics,’ by Dr. Francis Joseph Pisko, Professor of Physics in the Gewerbeschule in Vienna, was published at Vienna in 1865. At that time the novelties in acoustics were König’s apparatus for the graphic study of sounds, König’s manometric flames, Schaffgotsch’s singing flames, Helmholtz’s ‘Researches on the Quality of Sounds,’ Duhamel’s Vibrograph, Scott and König’s Phonautograph, and Reis’s Telephone. The account given of the latter is more detailed in some respects than any other published at the time.]
Page 94.—Principle of the “Telephon” of Reis.
51. (a.) Allied to the Membrane Phonautograph is the “Telephon” of Reis[34] (Fig. 33). Upon the little membrane, m m, in the middle, is fastened with adhesive wax the round end s of a light strip of platinum, n s, so that the platinum strip can join in with all the vibrations of the membrane. Very near to the central end, s, of the little platinum strip, n s, a platinum spike stands, in such a way that it is brought into contact, by the vibrations of the membrane, with the platinum strip that vibrates with the latter. Suppose now that the outer end, n, of the platinum strip and the platinum spike are connected with the poles of a galvanic battery, then, by the vibration of the membrane the galvanic current will, according to the phase of the vibration, be alternately established and interrupted. Inserted in this circuit, an electro-magnetic bell, or an electro-magnetic telegraph, will give signals to great distances that somebody is speaking;[35] though, obviously, it cannot inform what is being spoken.
(b.) As is known, an iron wire around which flow rapidly-interrupted powerful galvanic currents, is thereby thrown into tones which, according to circumstances, may be longitudinal or transverse or both together. Such an iron wire, lying in a multiplying wire-coil, G, Reis inserted at the second [receiving] station, C. The wire emitted sounds when the membrane was set into vibrations by singing or speaking (at S, Fig. 33) into the hollow cubical piece A. In the investigations made by me with the telephone, the rod (of iron) never altered the pitch of its tone with the most different kinds of tones and clangs, and always gave only the rhythm of the words sung or spoken into the piece A (the transmitter) at S. Usually the air of the song that was sung could be recognised by its rhythm.[36] The special researches on these points follow in paragraph 53. However, it is so far clear that there is still plenty of time yet before we have the simultaneous concerts, and the transmission of singing to different towns, as the daily newspapers have sanguinely expected. The apparatus of Reis is certainly a “Telephone” but not a “Phonic Telegraph.” The single means of transmission for song and speech—and that only for moderate distances—remains the old familiar speaking-tube. Nevertheless, the experiment of Reis must ever be reckoned amongst the most beautiful and interesting of school-experiments. And since the means for this are so simple, the apparatus of Reis will certainly find a speedy entrance into educational establishments that are only moderately endowed. It is easily proved that the tones of the wire in the telephone do not arise from acoustic conduction, for by cutting out the coil from the circuit the tones immediately cease.
1. The Telephone of Reis originally consisted of a cube of wood with a conical boring. The smaller opening was strained over with a membrane. A knitting-needle which served for a sounding wire projected about 2 inches on each side of the multiplying coil, and lay upon the two bridges of a sounding-box. The surrounding helix consisted of six layers of thin wire. Fig. 33 shows the Telephone as it is constructed at the present time by the mechanician, Albert, in Frankfort, and by the mechanician, Hauck, in Vienna, according to the directions of the inventor.
(a.) The same (Fig. 33) consists in its essentials:
(b.) The transmitter, A, is essentially a parallelepipedal body of wood. The upper part, u x, of it is cut out of one piece [of wood] with square cross-section, the side, x x, of which measures 9 centimetres, and its height, u x, 2·8 centimetres.
This part is moveable upon a hinge on the lower little box, A A. If the cover, x u, is laid back, one sees that a small circle of 3·9 centimetres diameter has been cut out in the same. Into this hole passes a brass collar with a flange 8 millimetres broad, which is furnished at one side with a groove like a pulley. Over the collar there is stretched the membrane, m m, by means of a silk thread lying in the shoulder of the same. This circular membrane is surrounded by a wider circular aperture, b b, = 8·5 centimetres. A shovel-shaped little strip of platinum, n s, lies (over it) leading to the brass binding-screw, d, with the circular part, s, falling upon the centre of the membrane.
By means of some sealing-wax this circular part is fastened to the membrane, and thereby compelled to take part in the vibrations of the same. The further transmission of the galvanic current from the centre takes place by means of a platinum or steel point resting in a cup of mercury, which is extended in a screw, which transmits the current farther. The point a serves as a support for the angular hook, a s b, which in general is supported like a tripod, in order that the point of contact, s, may remain as constant as possible. The hook, a s b, is simply struck with a hole at a upon a projecting point, and lies upon a broader under part. From b the galvanic circuit proceeds by means of an overspun wire to the brass key e (A, Fig. 33), and from there farther in the direction represented by the arrow.
The lower part A A of the transmitter is put together of thin wood and forms a parallelepiped, whose height = 6·8 cm., and whose width = 7·7 cm. An inclined mouthpiece of tin with funnel-shaped opening serves to receive the tones. The longer side of this mouthpiece measures 6·7 cm., the shorter 4·7 cm.; the longer diameter of the widening measures 7·15 cm., the shorter diameter 7·5 cm., and finally the diameter of the narrow tube 3·9 cm.
It is clear that, if necessary, the platinum strip can be replaced by a strip of thin sheet-brass, the platinum or steel points by iron. Only in this case the points of contact must be oftener cleaned to a metallic polish.
(c.) The receiver (Zeichengeber) C is in general a double resonant box, whose upper part, “the cover,” is moveable upon two hinges, and can be laid back. The length of this cover is 16·4 cm., its width 9·5 cm., and its height 3·2 cm. The length of the lower box measures 22·9 cm., its width 9·6 cm., and its height 2·5 cm. The under part of the resonant box bears two wooden bridges, which stand about 7·4 cm. from each other, and which serves as supports for the 21·5 cm. long, and 0·9 cm. thick iron needle destined for reproducing the tones. The length of spiral wound over the needle, and designed for making an electro-magnet of the same, is 15 cm. The wooden covers of both parts, scraped as thin as possible, and the greatest breadth of the circular holes shown in the figure, measures 13 mm.
(d.) For a battery one can successfully use a small Smee’s consisting of four elements, or two larger Bunsen’s cells.
The conductor must be at least sufficiently long that one cannot perceive the tones that are produced. For correspondence between the two stations the inventor has employed the electro-magnetic telegraph arrangement, e v g h, seen in the mechanism, and easily understood. An agreement in reference to corresponding signs can be easily arranged, and the simplest way is to accept the signals arranged by the inventor. (See ‘Prospectus.’)
The receiver C gives, when the key e is pressed, the corresponding telegraphic signals by means of tones in the rod E E, while at the transmitter, A, the electro-magnet v gives the signals by means of the springy armature z.
(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.
[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.”]
(‘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.]
P. 1017. The researches established by Reis on the 26th of October, 1861, in Frankfurt[38] have already shown that if the current interruptions follow one another almost continuously and very rapidly, in a spiral arranged with a thin iron core, the iron wire can be set into longitudinal vibrations, whereby therefore the same is constrained to reproduce tones of different pitch.
[Here follows a reference to Petrina’s Electric Harmonica.]
From the communications made known by Legat, it follows that “the ideas concerning the reproduction of tones by means of electro-galvanism which were put forward some time since by Philipp Reis of Friedrichsdorf, before the Physical Society, and the meeting of the Free German Institute in Frankfort-on-the-Main,” relate to similar arrangements. “What has hitherto been attained in the realisation of this project,” Legat announces in his report, and we extract therefrom only that part which gives an explanation of the disposition of the telegraphic apparatus, with which it is said to be possible to produce the vibrations and the excitement of tones in any desired manner, and by which the employment of electro-galvanism is said to make it possible “to call into life at any given distance vibrations similar to the vibrations that have been produced, and in this way to reproduce at any place the tones that have been originated at another place.”
This apparatus consists of the tone-indicator (transmetteur) and the tone-receiver (récepteur). The tone-indicator (Fig. 34, p. 109) consists of a conical tube, a b, having a length of about 15 cm., a front aperture of about 10 cm., and a back aperture of about 4 cm., the choice of the material and the greater length of which is said to be indifferent, while a greater width is said to be injurious; the surface of the inner wall should be as smooth as possible. The narrow back aperture of the tube is closed by a membrane, o, of collodion, and upon the centre of the circular surface formed by this membrane rests the one end, c, of the lever, c d, the supporting-point of which, e, being held by a support, remains in connection with the metallic circuit. This lever, the arm, c e, of which must be considerably longer than c d, should be as light as possible, so that it can easily follow the movements of the membrane, because an uncertain following of the lever, c d, will produce impure tones at the receiving station. During the state of rest the contact, d g, is closed, and a weak spring, n, keeps the lever in this state of rest. Upon the metallic support, f, which is in connection with one pole of the battery, there is a spring, g, with a contact corresponding to the contact of the lever, c d, at d, the position of which is regulated by means of the screw, h. In order that the effect of the apparatus may not be weakened by the produced waves of air communicating themselves towards the back part, a disc “of about 50 (?) cm. diameter, which rests fixedly upon the exterior wall of the tube,” is to be placed above the tube, a b, at right angles with its longitudinal axis.