Edison's "strip" design, first attempted in July 1877, as illustrated in Scientific American magazine, August 24, 1878. Scientific American

A PROTOTYPE PHONOGRAPH—

When making different sized telephone diaphragms it was a very common usage to mount them in a frame with a mouthpiece, hold them up, and talk to them in a loud or low voice; at the same time putting a finger close to the centre to feel how much vibration was communicated to them.



One night, after supper (which was prepared for us at midnight) and at which all the principal workers sat down together; Mr. Edison who had been trying different diaphragms in this manner suddenly remarked "Do you know Batch I believe if we put a point on the centre of that diaphragm and talked to it whilst we pulled some of that waxed paper under it so that it could indent it, It would give us back talking when we pulled the paper through the second time’—The brilliancy of the suggestion did not at first strike any of us—It was so obvious that it would do so that everyone said `Why of course it must!!’



I said We’ll try it mighty quick! and we went to work—Mr. Kruesi the Chief Mechanician took the diaphragm to solder on to it at the middle a needle point about ¼” long; he also took one of the automatic telegraph wheels and stands to fasten the diaphragm to so that we could draw the paper through easily—



I cut and got ready some strips of paper of different thicknesses of parafin coating— It was a matter of an hour or so when we all got together again to make a trial— We fixed the instrument on to a table and I put in a strip of paper and adjusted the needle point down until it just pressed lightly on the paper— Mr. Edison sat down and putting his mouth to the mouthpiece delivered one of our favorite stereotyped sentences used in experimenting on the telephone "Mary had a little lamb" whilst I pulled the paper through—



We looked at the strip and noticed the irregular marks, then we put it in again and I pulled it through as nearly at the same speed as I had pulled it in the first place and we got "ary ad elll am" something that was not fine talking, but the shape of it was there, and so like the talking that we all let out a yell of satisfaction and a "Golly it’s there"!! and shook hands all round— We tried it many times and in many different ways continually improving the apparatus during the early morning— During the time that some of these changes were being made Edison & I would talk about the possibilities of such an invention and it was then that we fully realized the brilliancy of the suggestion and the magnitude of its possible applications—Before breakfast the next morning we had reproduced almost perfect articulation from a strip of the waxed paper which I had embossed as it were with a ridge in the middle running the whole length, the needle point in this case was ground chisel shaped.

[Transcribed from: Charles Batchelor Journal, November 4, 1905 to June 19, 1908, NPS catalog # EDIS 1339.]

In this first-person account, Charles Batchelor recalled how a device like the one shown proved that sound could be stored and retrieved at will. Arguably the first working phonograph, it remained just a prototype in the lab. No example survives.