_Question 37._ “If a Reis Telephone, made in accordance with the descriptions published before the earliest dates of your invention, would in use transmit and receive articulate speech as perfectly as the instruments did which were used by you on June 25, 1876, at the Centennial, would it be proof to you that such Reis’s Telephones operated by the use of undulatory movements of electricity in substantially the same way as your instruments did upon the occasion referred to?” _Answer by Bell._ “The supposition contained in the question cannot be supposed. Were the question put that if I were to hear an instrument give forth articulate speech transmitted electrically as perfectly as my instruments did on the occasion referred to in the question, I would hold this as proof that the instrument had been operated by undulatory movements of electricity, I would unhesitatingly answer, Yes.” Surely no better authority is needed to support the proposition that if Reis made his Telephone speak, as he said he did, he employed undulatory currents. ADDITIONAL PREFERENCES CONCERNING REIS’S TELEPHONE. Schenk’s _Philipp Reis, der Erfinder des Telephons_, 1878. Sack’s _Die Entwickelung der elektrischen Telephonie_, 1878. Ferguson’s _Electricity_ (Ed. 1867), p. 257. Wiedemann’s _Galvanismus_ (1874), Vol. ii. p. 598. _Gartenlaube, die_; for 1863, No. 51, p. 807-809. _Aus der Natur_; for 1862, xxi. p. 470-474. _Cosmos_, Vol. xxiv. p. 349 (1864). _Proc. Lit. Phil. Soc. Manchester_ (1865), Nov. 10, 1864. _Rep. Brit. Assoc_. (1863), p. 19. _Die Geschichte und Entwickelung des elektrischen Fernsprechwesens_, 1880. (Officially issued from the Imperial German Post-Office, Berlin.) LONDON: PRINTED BY WILLIAM CLOWES AND SONS, LIMITED, STAMFORD STREET AND CHARING CROSS. Plate 1. [Illustration: REPRODUCTION OF TONES IN THE ELECTRO-GALVANIC WAY.] THO^s. KELL & SON. LITH 40, KING S^t. COVENT GARDEN #/ REPRODUCTION OF TONES IN THE ELECTRO-GALVANIC WAY. [Illustration] THO^s. KELL & SON. LITH 40, KING S^t. COVENT GARDEN #/ BOOKS RELATING TO =APPLIED SCIENCE= PUBLISHED BY =E. & F. N. SPON,= LONDON: 16, CHARING CROSS. NEW YORK: 44, MURRAY STREET. _A Pocket-Book for Chemists, Chemical Manufacturers, Metallurgists, Dyers, Distillers, Brewers, Sugar Refiners, Photographers, Students, etc., etc._ By Thomas Bayley, Assoc. R.C. Sc. Ireland, Analytical and Consulting Chemist and Assayer. Second edition, with additions, 437 pp., royal 32mo, roan, gilt edges, 5_s_. SYNOPSIS OF CONTENTS: