ON THE PHONOGRAPH. 767 



II. The Use of Mr Alfred Graham's Apparatus along with Large Resonators.* 



6. If we suspend Mr Graham's variable resistance apparatus over the phonograph 

 and connect it with the receiver, in front of which a large resonator is placed, and if an 

 electric circuit is established, the volume of tone is much increased. I usually employ 

 a dry cell battery composed of three Obach's cells. Each cell = 2 volts, and with 

 the resistance of the variable resistance and of the receiver gives a current of about ^ 

 of an ampere. It must be admitted, however, that the quality of tone is altered, some- 

 times apparently for the better, but at other times for the worse. Thus band records 

 giving complex sounds are often harsh, and the human voice often loses in distinctness 

 of articulation. On the other hand, simpler sounds, such as those of the cornet, 

 bass-tuba, saxophone, and bassoon, are sometimes richer and fuller and more like the 

 tone of the real instrument than when the sounds are strengthened by resonance alone. 

 I have observed that by the electrical method a gain beyond a certain limit of loudness 

 is at the expense of clearness and quality. If one is satisfied with the loudness obtained 

 by using one cell instead of three or four, good quality and distinctness are obtained. 

 This is a point of considerable interest, as it shows that the most complex sound waves 

 can be transmuted by the variable resistance apparatus into electrical waves which, 

 in turn, in the receiving apparatus, cause the ferrotype plate of the latter so to 

 vibrate as to give out tones closely resembling those that originally fell on the glass 

 disk of the phonograph. 



III. The Use of a Parabolic Reflector. 



7. Reflexion of waves of sound from parabolic surfaces is a well-known phenomenon. 

 Rays of sound diverging from the focus and falling on a paraboloid formed by the 

 revolution of a parabola about its axis will be reflected in directions parallel to the axis. 

 I had a paraboloid constructed of zinc, 40 inches in diameter at the open end, and having 

 its focus 5 inches from the vertex. When the wide end of the brass resonator No. 4 in 

 table is placed in the focus, and the narrow end is connected with the tube leading to 

 the phonograph disk, the sound is reflected with a pleasing effect, owing to the friction 

 noises of the phonograph becoming much less audible than when they escape from the 

 wide end of the resonators Nos. 1 and 2. 



IV. The taking of Records. 



8. Considerable experience has convinced me that the phonograph will record and 

 faithfully reproduce all manner of sounds, provided these are of sufficient intensity to 

 cause the glass disk to vibrate. When I have failed in obtaining a record, investigation 



* I have described this apparatus in Proceedings Royal Society, Edinburgh, 1896, p. 47. 



