 from Tainter Papers, NMAH |
from Tainter Papers, NMAH |
 from Tainter Papers, NMAH |  from Tainter Papers, NMAH |  from Tainter Papers, NMAH |  from Tainter Papers, NMAH |
 from Tainter Papers, NMAH |
"I have had in my mind for several months past a method of obtaining a record of speech vibrations, and of reproducing the speech from the record so made. The idea occurred to me while discussing the phonograph, and the defects of that instrument with Mr. Bell, and he seemed to think very highly of it at that time. This idea together with some others upon the same subject, was noted upon a piece of paper as our note-book was not at hand at the time they occurred to us. This paper has doubtless been lost or destroyed before this, and I will note the idea here. [illustration] Fig. 1 is a plan view of my phonograph (or graphophone) and Fig. 2 is an end elevation partly in section... Attached to the end of the axle E. is a large circular disk K. upon which the speech vibrations are to be recorded. This disk can be made of some soft metal that can be easily engraved, or it can be made of some light substance, like hard rubber, ivory, celluloid, or box-wood. The axis E. and disk K. are then rotated at a uniform speed by the crank O. while speaking to the mouthpiece I. and the result will be that a spiral groove will be cut in the disk K. and all the vibrations of the diaphragm L. will be recorded in irregularities in the groove thus: [illustration on p. 5 of spiral groove] The spiral groove is formed by the motion of the slide B. across the base due to the rotation of the screw H. To reproduce the sounds recorded a slightly blunted tool is used in the place of M. and this tool is made to pass along the groove in the same manner as in cutting the goorve, but with the ear placed at the mouthpiece L. as in the ordinary phonograph of Edison. The disks K. can be reversed on the axle E. and both sides utilized or a new disk can be easily put on. These disks can be very easily manufactured and sold for a small amount and are much more convenient that the cylindrical form, as they give the maximum amount of surface with the least bulk and weight. A disk engraved with speech vibrations upon one instrument can be placed upon any other and the sounds reproduced as easily as upon the instrument by which the record was made. Or if the engraved disk is made of some substance that will stand a temperature of about 250 degrees centigrade, casts can be obtained of the groove in light metal (or plaster if it will not stand the temperature of melted light metal) and other disks made from these molds. If it is not desirable to keep the record in the disk, it can be faced off smooth and is then ready for a new record, this can be repeated until the disks are too thin for use...."
Source: Tainter Papers, Smithsonian National Museum of American History, Washington, D. C.
The photos on these pages are used with permission of the Smithsonian National Museum of American History. They may not be reproduced or distributed without written permission of the NMAH. |