SCIE 



LEuiereU al ihe Posi-Office of New York, N.V., as Second-Class Matter.] 



A WEEKLY NEWSPAPER OF ALL THE ARTS AND SCIENCES. 



Eighth Year. 

 Vol. XV. No. 379. 



NEW YOEK, Mat 9, 1890. 



Single Copies, Ten Cents. 

 $3.50 Per Year, in Advance. 



THE MICEO-GRAPHOPHONE. 



In the construction of Tny talking-machine, which I call the 

 micro-graphophone, my object was to record articulate speech 

 and other sounds, and reproduce them more distinctly, more 

 naturally, and with greater volume, in order to obviate the ne- 

 cessity of hearing-tubes, and to be sure always of having a good 

 record made and a good reproduction. 



My experiments have shown me that to attain these ends there 



points, called " nodes," — points where the vibrations are indistinct 

 or dead. If Tyndall and other scientists are correct (which I 

 think will not be disputed;, if a knife is attached to only onepoint 

 on the diaphragm, the point selected may sometimes be dead or 

 nearly dead, and consequently the vibrations existing in the plate 

 cannot be correctly recorded. Such a diaphragm may sometimes 

 make a very good record, and sometimes an altogether unsatis- 

 factory one. 



Suppose a spider attached to a vibratory body by many legs of 



LIEUT. BETTINI'S MICRO-GRAPHOPHONE. 



must be changes made as much in the recording device as in the 

 reproducer. In my recorder, instead of attaching the recording 

 knife to one point in the centre of the diaphragm, as in other talk- 

 ing-machines, I use a device which I call a spider, to which the 

 knife is attached, and which has branches or legs of different 

 lengths attached to several points of the diaphragm. 



A diaphragm made to \ibrate by sound-waves vibrates over 

 its entire surface, but with different degrees of vibration at dif- 

 ferent points. Tyndall, and other masters of the science of sound, 

 show how a vibrating diaphragm or body is covered with dead 



different lengths, six or eight, or more (Figs. 3 and 3). Two or 

 three of the points of attachment may be dead points, and unable 

 to transmit vibrations : but by the others the knife will receive 

 all that is necessary to make a good record. 



The spider gives to my device other advantages. It gives more 

 force to the knife in making a record, as this force is concen- 

 trated from several points, whereas in other machines it has but 

 one source; further, it gives to the knife great steadiness, which 

 I consider most important; and, further yet, a great advantage is- 

 that in my device not only are all the tones recorded, but also 



