INSTRUMENTS FOR EXPERIMENTS ON SOUND. 155 



very singular that this apparatus should not only reproduce 

 pitch but also quality. When it was tried many years ago 

 at the Polytechnic, some of you may recollect a band of 

 players was placed in a lower room, each playing his own 

 instrument, and to each instrument was attached a long rod of 

 deal. These rods, after passing through the floor, were fixed 

 to harps in an upper room, and when the players played, one 

 harp, standing before you by itself, seemed to play a violin, 

 another a clarionet, another a double-bass, another a piano, 

 the sounds being conveyed through the rods of wood and 

 giving not only the pitch, but actually the musical quality of 

 the generating instrument. 



Lastly, I have to mention a perfectly new and very remark- 

 able distributor of sound in the shape of electricity. It has 

 long been known that a rod of iron when magnetized by a 

 galvanic current gives a peculiar clink ; that I propose to show 

 you first. 



I have put the clinking apparatus in the middle of the 

 room. It is a rod of iron surrounded by a long coil, and 

 here I have the means of passing a current through the 

 coil ; the current first passes through a harmonium reed, a 

 wire attached to the vibrating end of which dips into a mer- 

 cury cup, so that rapid vibrations can be produced. I can 

 transmit the vibrations of the reed up into the coil and thus 

 intermittently magnetize the bar of iron. Those who are 

 near it can hear the clinking no doubt, though it is faint. 

 That clinking rises to a musical sound when the intermissions 

 become more rapid. 



Some years ago Eeuss utilized this. His plan was to have a 

 small box, such as I have here, with the vibrating membrane 

 at the top connected with a battery. If you speak into the box 

 and the membrane vibrates, making an intermittent contact, 

 the vibration is reproduced at the other end of the circuit, as 

 you will hear when I sing into the instrument. The tone is 

 now reciprocated by the receiving instrument at the other end. 

 That is an early stage of the telephone. I am proud of being 

 able to show (through the kindness of Mr. Latimer Clark) 

 the new instrument invented by Mr. Elisha Gray, of Chicago, 

 which has come over for this Exhibition. There are four 

 springs, vibrating like tuning-forks, which are kept in motion 

 by electricity. They give the common chord. Then there 

 is an arrangement by which the vibrations that each of them 



