Of the performance of his instruments Reis speaks modestly and carefully, nothing extenuating of his failures, nothing exaggerating of his successes. I shall not attempt to be wiser than he; nor seek to make out his instrument to have been either more perfect or more reliable than he himself knew it to be. The membrane tympanum of his transmitter was liable to become relaxed by the moisture of the breath rendering the instrument--as Graham Bell found fifteen years later with his membrane magneto-transmitters--uncertain in its action. Moreover, in some earlier forms of Reis’s transmitter, notably those with a vertical tympanum, the adjustment of the contact-points that controlled the current was a matter of delicacy requiring experience and practice, so that casual experimenters failed to obtain the results which Reis himself obtained;[11] they obtaining only a noisy snarl where he obtained intelligible speech. Lastly, the very delicacy of the essential parts, the conducting strips of metal which lay lightly in contact against one another, militated against a uniformity of success when tried with different voices, some of which were too low to produce any effect, others so loud as to rattle the delicate contact-pieces in a manner fatal to the attainment of the desired result. In spite of all these drawbacks, which were not inherent in the principle of the instrument, there is plenty of evidence that _Reis’s Telephone did transmit speech_. Reis himself records this fact: (1.) In 1861, in his memoir ‘On Telephony’ (see p. 58), “_The consonants are for the most part tolerably distinctly reproduced, but the vowels not yet in an equal degree._” (2.) In his ‘Prospectus’ (p. 86) Reis says that the tones of organ-pipes and of the piano can be reproduced as well as the tones of the human voice, “_according to my experience_.” (3.) The fact is attested by Inspector Wilhelm von Legat, in his Report in the ‘Zeitschrift’ (p. 77), 1862. After alluding to the indistinctness of the vowels, he says: “_Single words, uttered as in reading, speaking, and the like, were perceptible indistinctly, nevertheless, here also the inflexions of the voice, the modulations of interrogation, exclamation, wonder, command, etc., attained distinct expression._” (4.) Professor Quincke, of Heidelberg, testifies (see p. 113) that he heard and understood words spoken through a Reis Telephone in 1864. (5.) Professor Böttger, editor of the ‘Polytechnisches Notizblatt,’ in 1863 says (see p. 90): “The experimenters could even communicate words to one another, though certainly indeed, only such as had often been heard by them.” (6.) Dr. Rudolph Messel, an old pupil of Reis, and an eye-witness of his early experiments, has written[12]: “There is not a shadow of a doubt about Reis having actually achieved imperfect articulation. _I personally recollect this very distinctly_, and could find you plenty more people who witnessed the same.”