290 PLEASANT WAYS IN SCIENCE. 



part of the diaphragm should suffice to show that such and 

 such words had been uttered, is one thing ; but that these 

 movements should of themselves suffice, if artificially repro- 

 duced, to cause the diaphragm to reproduce these words, 

 is another and a very different one. I venture to express 

 my conviction that at the beginning of his researches Pro- 

 fessor Bell can have had very little hope that any such 

 result would be obtained, notwithstanding some remarkable 

 experiments respecting the transmission of sound which we 

 can now very clearly perceive to point in that direction. 



When, however, he had invented the telephone, this 

 point was in effect demonstrated ; for in that instrument, as 

 we have seen, the movements of the minute piece of metal 

 attached (at least in the earlier forms of the instrument) to 

 the centre of the receiving membrane, suffice, when precisely 

 copied by the similar central piece of metal in the trans- 

 mitting membrane, to cause the words which produced the 

 motions of the receiving or hearing membrane to be uttered 

 (or seem to be uttered) by the transmitting or speaking 

 membrane. 



It was reserved, however, for Edison (of New Jersey, 

 U.S.A., Electrical Adviser to the Western Union Telegraph 

 Company) to show how advantage might be taken of this 

 discovery to make a diaphragm speak, not directly through 

 the action of the movements of a diaphragm affected by 

 spoken words or other sounds, and therefore either simul- 

 taneously with these or in such quick succession after them 

 as corresponds with the transmission of their effects along 

 some line of electrical or other communication, but by 

 the mechanical reproduction of similar movements at any 

 subsequent time (within certain limits at present, but pro- 

 bably hereafter wkh practically unlimited extension as to 

 time). 



The following is slightly modified from Edison's own 

 description of the phonograph : 



The instrument is composed of three parts mainly; 

 namely, a receiving, a recording, and a transmitting appa- 



