TRANSACTIONS OF THE SECTIONS. .'}.") 



limes per second, we obtain "galvanic music" by the vibrations which the iron bat 

 imparts to the air. The iron bar itself imparts these vibrations by its change of 

 form each time it is magnetized or demagnetized. 



De la Rive, of Geneva, in 1843, increased these musical effects by operating on 

 long stretched wires which passed through open bobbins of insulated wire. 



Philip Reiss, of Friedrichsdorf, in 1801, produced the first telephone which re- 

 produced musical sounds at a distance. lie utilized the discovery of Page by 

 causing a vibrating diaphragm to rapidly make and break a galvanic circuit. The 

 principal of his apparatus is shown in Fig. 1 annexed, in which the diagram (b) is 

 a hollow wooden box into which the operator sings through the mouthpiece (a). 



Xine 



The sound of his voice throws the diaphragm (e) into rapid vibration, so as to make 

 and break contact at the platinum points (d) at each vibration. This interrupts the 

 current flowing from the battery (c) as often as the diaphragm vibrates, and 

 therefore magnetizes and demagnetizes the electromagnet as often. Hence what- 

 ever note be sounded into the box (a) the diaphragm (e) will vibrate to the note, 

 and the electromagnet/ will similarly respond, and therefore repeat that note. 



Musical sounds vary in tone, in intensity, and in quality. The tone depends on 

 the number of vibrations per second only ; the intensity on the amplitude or extent 

 of those vibrations ; the quality on the form of the waves made by the vibrating 

 particles of air. 



It is evident that in Reiss's telephone everything at the receiving end remains the 

 same, excepting the number of vibrations, and therefore the sounds emitted by it 

 varied only in tone, and were therefore notes and nothing more. The instrument 

 remained a pretty philosophical toy, and was of no practical value. 



Cromwell Varley, in 1870, showed how sounds could be produced by rapidly 

 charging and discharging a condenser. 



Elisha Gray, of Chicago, in 1873 succeeded in producing tones from the finger 

 when rubbing a dry sonorous body, such as an ordinary tin can, while the inter- 

 mittent currents sent by a vibrating tuning-fork were passing through it ; and by 

 attaching an electromagnet to a hollow sounding-box, open at one end and closed 

 at the other, he was able to reproduce the tones of the musical notes transmitted. 

 His electromagnet had its armature rigidly fixed to one pole, and separated from 

 the other by a space of f jth of an inch. He called it a resonator. The vibrations 

 of this armature are imparted to the sounding-box, and become, therefore, magnified. 

 He constructed a keyboard, of two octaves compass, with steel reeds, each of which 

 was tuned to its proper note and maintained in vibration by electromagnets. 

 When the key corresponding to any note was depressed, its corresponding reed was 

 connected to line and the proper number of currents transmitted to the distant 

 station, where they operated the resonator and thus reproduced the note. In this 

 way tunes were played, and the instrument became an electric organ. By attaching 

 organ-pipes to his resonator he magnified the sounds, and was able to fill a large 

 hall with music played at places from 00 to 208 miles away. More than that, he 

 proved the practicability of transmitting chords and composite sounds to distant 

 places. Gray also invented a method by which the intensity of the notes as well 

 as their tones could be transmitted. Mr. Leonard Wray also introduced a capital 



