On March 10, 1876, Alexander Graham Bell picked up his telephone in his rented, Boston laboratory and called his assistant Thomas A. Watson.
He said the first complete sentence transmitted by telephone: “Mr. Watson — come here — I need you.”
On this recording (the audio from a lost video produced by the Edison motion picture film studio in the Bronx) Watson recalls the invention of the instrument that transmitted these words. His account of the big event is pretty slim, but hearing him catalog it as one event in the many years of experiments and telephone models may be the most telling part of his story. This audio comes from the Prelinger archive.