(Library of Congress)

The device now known as the telephone was independently invented by two men — Alexander Graham Bell, and inventor Elisha Grey, who both rushed to the patent office within hours of one another. Bell beat Grey to the punch.

Bell submitted to the patent office in 1876 the above hand drawing, which was made available by the Library of Congress.

The middle sketch best represents his invention, showing a person on the left speaking into the wide end of a cone, the sound vibrating through a circuit — indicated by Bell’s wavy up-and-down lines across a straight line — and a listener at the other, narrower end hearing a reproduction of the original sound.

The first person to hear that reproduction was Bell’s assistant Thomas A. Watson, who was in the next room when Bell uttered this famous line through the instrument: “Mr. Watson — come here — I want to see you.”

Bell later gave the drawing, which he did in 1876, to his cousin, telling her, “These are the first drawings made of my telephone — or “instrument for the transmission of vocal utterances by telegraph.”

Alexis Madrigal of the Atlantic wrote about the drawings in March, saying they should be appreciated for how delightfully weird they are. “Bell’s drawings are expressive in ways that few technical sketches are. Little flourishes and annotations make paging through his drawings a delight,” he writes.

See more of Bell’s drawings, and photographs of Bell and the first telephone, below:

Alexander Graham Bell's 1876 laboratory notebook, in which he recorded on March 10, 1876, the first successful demonstration of the telephone: "'Mr Watson — Come here — I want to see you.' To my delight he came and declared that he had heard and understood what I said." (No credit)

These drawings indicate the apparatus used in Bell's photophone, when used for talking with reflected sunlight. Bell also perfected the method for use with an arc lamp, and later still made conscious use of infra-red rays. (Received at Washington Post Library on March 4, 1947. Reproduction from the original.)

Another sketch from Bell’s 1876 laboratory notebook. (No credit)

This is an undated photograph of the first telephone, patented in 1876 by Bell. The first telephonic transmission occured on June 5, 1875, with a message from Bell to his assistant Thomas Watson. (AP)

Alexander Graham Bell, center, reunites with E. McIntyre, left, and Thomas Brooks in 1906 in Brantford, Ontario. Bell and these men strung a telephone line between the Bell home in Brantford and Paris, Ont., creating the world's first long distance telephone line. (AP)