Figure 4.—Patent Drawings from U. S. patent 341214, granted May 4, 1886, to Chichester Bell and C. S. Tainter.
The method of reproduction used on the machine, however, is even more interesting than the quotation. Rather than a stylus and diaphragm, a jet of air under high pressure was used.
"This evening about 7 P. M.," Tainter noted on July 7, 1881, "The apparatus being ready the valve upon the top of the air cylinder was opened slightly until a pressure of about 100 lbs. was indicated by the gage. The phonograph cylinder was then rotated, and the sounds produced by the escaping air could be heard, and the words understood a distance of at least 8 feet from the phonograph." The point of the jet is glass, and could be directed at a single groove.
Figure 5.—Experimental Graphophone photographed in 1884 at the Volta Laboratory. This is similar to one preserved at the Smithsonian Institution. (Smithsonian photo 44312-D.)
The other experimental Graphophones indicate an amazing range of experimentation. While the method of cutting a record on wax was the one later exploited commercially, everything else seems to have been tried at least once.
The following was noted on Wednesday, March 20, 1881: "A fountain pen is attached to a diaphragm so as to be vibrated in a plane parallel to the axis of a cylinder—The ink used in this pen to contain iron in a finely divided state, and the pen caused to trace a spiral line around the cylinder as it turned. The cylinder to be covered with a sheet of paper upon which the record is made.... This ink ... can be rendered magnetic by means of a permanent magnet. The sounds were to be reproduced by simply substituting a magnet for the fountain pen...."
The result of these ideas for magnetic reproduction resulted in patent 341287, granted on May 4, 1886; it deals solely with "the reproduction, through the action of magnetism, of sounds by means of records in solid substances."