of soot has vanished into the limbo of superseded inventions.
Science appears to show that every physical process is reciprocal, and may be reversed. With this principle in our minds, we need not be surprised that the microphone should not only act as a transmitter of sounds, but that it should also act as a receiver. Mr. James Blyth, of Edinburgh, was the first to announce that he had heard sounds and even speech given out by a microphone itself when substituted for the telephone. His transmitting microphone and his receiving one were simply jelly-cans filled with cinders from the grate. It then transpired that Professor Hughes had previously obtained the same remarkable effects from his ordinary 'pencil' microphones. The sounds were extremely feeble, however, but the transmitting microphones proved the best articulating ones. Professor Hughes at length constructed an adjustable hammer-and-anvil microphone of gas-carbon, fixed to the top of a resonating drum, which articulated fairly well, although not so perfectly as a Bell telephone. Perhaps a means of improving both the volume and distinctness of the articulation will yet be forthcoming and we may be able to speak solely by the microphone, if it is found desirable. The marvellous fact that a little piece of charcoal can, as it were, both listen and speak, that a person may talk to it so that his friend can hear him at a similar piece a hundred miles away, is a miracle of nineteenth century science which far transcends the oracles of antiquity.
The articulating telephone was the forerunner of the phonograph and microphone, and led to their discovery. They in turn will doubtless lead to other new inventions, which it is now impossible to foresee. We ask in vain for an answer to the question which is upon the lips of every one-What next? The microphone
