M. Lambrigot suggests that the speaking plates might be useful in many ways: for example, they might make it easy to learn the correct pronunciation of foreign languages, since a sufficient number might be collected to make a sort of vocabulary which would give the accent of the words most in use in a given language. By this simple process M. Lambrigot has been able to obtain a strong impression, within a copper groove, of the vibrations caused by the voice, and they are so distinctly engraved that whole sentences may be heard, if they are retraced by the sharpened point of a match. It is true that the reproduction is imperfect, and that those words are only to be distinguished which were previously known; but it is possible that better results will be obtained from improvements in the system, and at any rate the distinct impression of the vibrations of the voice on a hard metal is a really interesting discovery. I have made one somewhat important observation in the working of the phonograph--namely, that if speech is registered on the instrument in a very hot room, and it is then carried to a colder room, the reproduction of speech is imperfect in proportion to the difference of temperature. This is probably owing to considerable modifications in the elasticity of the caoutchouc pad which is inserted between the tracing point and the vibrating disk: perhaps differences of expansion in the tinfoil have also some effect. FABER’S AMERICAN SPEAKING MACHINE. About two years ago the newspapers announced with some pomp that a speaking machine had reached Paris, which far surpassed Vaucanson’s duck, and which would attract general attention. Unfortunately the invention was not in the first instance brought forward with any scientific authority, and was soon relegated to take a place among the curiosities exhibited by conjurors. In a country so essentially critical and sceptical as France, there are always those who profess incredulity, and who will even resist evidence, and it was asserted that the machine only spoke because its exhibitor was an able ventriloquist. This is an old assertion which has lately been made with reference to the phonograph. Some scientific papers echoed the absurdity, and the speaking machine was so discredited that it is now unnoticed, although it is a most ingenious and interesting conception. When will our country be cured of the error of denying everything without due examination? Since we ourselves only judge of things after having seriously considered them, we think it just to vindicate the truth as to Mr. Faber’s machine, and this can only be done by an exact description of it.