[27] [This word, as the context and ending of the paragraph shows, should have been spelled _tones_. The letter, written in English by Reis himself, is wonderfully free from inaccuracies of composition; the slip here noted being a most pardonable one since the plural of the German “_ton_” is “_tönen_,” the very pronunciation of which would account for the confusion in the mind of one unaccustomed to write in English. So far as is known, this is the only piece of English composition ever attempted by Reis.--S. P. T.] [28] [Reis here sketched a figure identical in all its parts with that which a fortnight later was issued in his ‘Prospectus.’ His sketch is reproduced in facsimile in Fig. 28.] [29] [This was the little auxiliary signalling apparatus at the side of the box, placed there for the same reasons as the auxiliary call-bell attached to modern telephones.] [30] [This word is underscored in Reis’s original letter.] [31] [Compare Böttger Polyt. Notizbl. 1863, p. 81, the notice translated at p. 61 preceding.]--S. P. T. [32] [This rather obscure passage refers to the call-key or communicator fixed to the side of the instruments, and which as the inventor explains in his Prospectus (see p. 87), to be intended, like the call-bell or communicator of modern telephones, as a means of sending signals to the speaker, and which, as the Prospectus says, can also be used--as any call-bell can--for telegraphing words by a pre-arranged code of signals.]--S. P. T. [33] [Fig. 30 of this book.] [34] [References.] _Telephon von Reis_ im Jahresbericht des physikalischen Vereins zu Frankfurt-a.-M. für 1860-1861, pag. 57 bis 64. _Müller-Pouillet_, Physik, 1863, 6. Auflage, II pag. 352, Fig. 325. _Berl. Ber._ für 1861, xvii. pag. 171 bis 173. Der Musiktelegraph in der “Gartenlaube” 1863, Nr. 51, pag. 807 bis 909. Aus der Natur 1862, xxi. pag. 470 bis 484; _König’s_ Catalog, 1865, pag. 5. [35] [This part of the apparatus is in fact a “call,” serving precisely the same function as the call-bell attached to ordinary telephones, by which the subscriber can be “called up” to listen to the instrument. It is not without importance to observe that this function was perfectly well-known at the time; for it was gravely argued during a former telephone law-suit in England that the presence of this “signal-call” at the side of the Reis Transmitter was a proof that it was intended to transmit singing only _and not speech_, or “else there would not have been that little Morse-instrument at the side by which to talk”! This suggestion is, however, self-evidently absurd, because if this had been the case the little electromagnetic Morse telegraph would have been fixed, not on the side of the transmitter but on that of the receiver. Reis himself explains the use of the “call” (see p. 87) in his “Prospectus.”]--S. P. T.