November 21, 1877

Phonograph

Edison demonstrates the tinfoil phonograph at Scientific American's office

The hand-cranked machine Edison set down on the editors' desk asked how they liked the phonograph, then bid them good night.

About 7 December 1877: the machine that answered back

On the best-supported reconstruction the date is 7 December 1877, and Edison carried a hand-cranked tinfoil phonograph into the New York offices of Scientific American. He put the small machine on a desk and turned the crank. It asked after the staff's health, asked how they liked the phonograph, and bid them good night.

The apparatus recorded speech as indentations pressed into foil wrapped around a rotating cylinder, and played it back through a second diaphragm-and-needle unit. John Kruesi, Edison's machinist, had built it during the first week of December from a design Edison settled near the end of November; the Library of Congress cites diary evidence for construction on 4–6 December, the Edison Papers chronology for 1–6 December.

The day itself is a reconstruction rather than a record. ASME gives 7 December; Britannica places the first demonstration only in early December. No consulted chronology supports 21 November, the date this entry lists.

The precursor: a paper-tape machine described in print

A month earlier the idea had already gone public without a working machine behind it. With Edison's permission, Edward H. Johnson sent Scientific American a description of a proposed apparatus for recording and reproducing speech. The issue carried a 17 November date, but the Edison Papers establish that it was printed and available by 6 November 1877.

What Johnson described was not what Edison later carried to New York: it recorded voice vibrations as indentations in a moving strip of paper. The New York Sun reprinted the report on 6 November, and the New York World and the New York Times answered on 7 November with a mixture of scepticism and jokes. Edison then abandoned paper tape for a tinfoil cylinder, and dated his surviving cylinder-phonograph drawing 29 November.

What the demonstration set off

Scientific American printed its detailed account of the visit on 22 December 1877, and New York and other papers followed. Within weeks the Edison Speaking Phonograph Company was formed to exhibit the machine, on reported terms of $10,000 and twenty per cent of profits. The patent, U.S. 200,521, was granted on 19 February 1878.

What Edison had was not yet a product. The foil was difficult to work, a recording survived only a few playings, and early sales were poor. Earlier researchers, Édouard-Léon Scott de Martinville among them, had traced sound waves visually; the combination Edison brought to the desk that afternoon was recording plus audible playback.

For the machine that first gave back a human voice, the day it spoke outside the laboratory can be dated no more closely than about 7 December.

Sources

Researched 23 Aug 2026 6 sources 2 audit passes, 3 issues open Date disputed

How this was checked

Researched from the web into a fact sheet, rewritten from that sheet, then audited against it by a different model. How the pipeline works →

Date disputed. Sources disagree; the research places it at ~1877-12-07.

What the sources leave uncertain

No consulted primary or scholarly Edison chronology supports November 21 as the announcement date.
The initial Scientific American account has two relevant dates: its issue was dated November 17, but the Edison Papers establish that it was printed, available, and reprinted by November 6.
November 29 is the date on Edison's surviving cylinder-phonograph drawing, not the first demonstration.
The first internal successful test occurred when Kruesi completed the machine by December 6; the first securely dated demonstration outside the laboratory was at Scientific American on December 7.