488 



NA TURE 



[OCTOHKR 2 f , IQO9 



FURTHER EXPERIMENTS WITH THE 

 GRAMOPHONE. 



IN Natures of April 15 I described a number of 

 experiment;, with the gramophone. Since then I 

 have continued to work on this interesting subject, 

 and have at last succeeded in transcribing the vibra- 

 tions of tones or chords as these are produced by the 

 gramophone ; that is to say, during the time that the 

 sounds are given forth. The method is illustrated in 

 the figure accompanying this paper (Fig. i), and I also 

 give several illustrations of the tracing so obtained. 

 The sounds of the gramophone are carried by a tin 

 tube from the end of the arm of the instrument to 

 which the horn or trumpet-resonator is attached, to a 



physiologists; but, taking a hint from the use of 

 elasticitv in the construction of the reproducer of the 

 gramophone and improved phonograph. I arranged 

 thin india-rubber bands so as to hold the keeper of the 

 tiny electromagnet about one or two milhmetres from 

 the small soft iron cores, and so placed that the keeper 

 was kept in equilibrium between two forces, at the 

 distance I have mentioned. I found that with this 

 arrangement, when the gramophone was played, the 

 electromagnetic recorder gave forth the tune with 

 perfect accuracy, and when one touched the keeper it 

 could be felt thrilling on the finger. 



The electromagnetic recorder acted like a little tele- 

 phone. .Mter many contrivances, I found the best 

 method was to place the recorder on the well-knowr- 



FlG. I. — Arrangement ofapparaius.. Gramophone to the left. Observe the tin tube carrying the sound waves to the microphone. The operator iS on 

 the right controlling the movable stage. The upper electromagnetic marker adjusted to the cylinder (revolving drum) registers the vibrations of 

 the i/iooth per second tuning fork seen in the middle ol the table. The lower electromagnetic marker writes the vibrations of the sound waves as 

 these act on the microphone. While it is registering the lower marker gives forth the sounds played by the gramophone. 



sensitive microphone. The microphone used was made 

 by Herr Miiller-Uri, of Brunswick, and was intended 

 to be used in the experiment of the singing-arc flame 

 and also for a loud-speaking telephone. In the circuit 

 of the microphone I have five or si.\ dry cells giving a 

 current of about five volts. In the same circuit is the 

 recorder, which is a very small electromagnet having a 

 marker attached to the keeper. 



In early experiments I used a large electromagnet 

 acting on a spring that carried a marker, but such 

 an arrangement "only recorded notes or chords, as 

 regards intensity, but without showing the con- 

 stituent vibrations. It was not quick enough. 

 Accordingly I adopted a small electromagnetic ar- 

 rangement, like a " Deprez-signal," known to 



NO. 20S6, VOL. 81] 



Cambridge platform-stand, which can be moved up or 

 down by a finely cut strong screw (see Fig. i). On 

 the platform I placed a device of my own, by which 

 I could adjust the marker on the smoked paper with 

 great nicety. On the same platform, as shown in the 

 illustration] I placed an electromagnetic recortler con- 

 trolled by a 100 vib. tuning fork, so as to register on 

 the tracing 1/ tooths of a second. The drum used 

 was an old-fashioned Hawksley drum, well known to 

 physiologists, and it rotated at a speed that _ gave 

 12 inches per second. The paper was smoked in the 

 usual wav over a camphor flame, and, after the 



' tracing was taken, it was fixed by clear shellac 

 varnish. The tracings shown are from slightly en- 



, larged photographs of a portion of each tracing, and 



