Prepare for your new weekly dose of history, as WDD recaps significant events that took place in the tech and engineering space.

Consider this one small step for phones, one giant leap for selfies 140 years later…

On March 10, 1876, Alexander Graham Bell made the first telephone call, summoning Thomas Watson, his assistant, who was in the other room.

A year prior, Bell had been working on an acoustic telegraphy device, capable of transmitting telegraph signals over the same wire, when he heard a “twang” after Watson had accidentally plucked one of the device’s reeds. This prompted Bell to explore whether his device could be used to transmit the sounds of the human voice.

According to the device’s patent, issued to Bell on March 7, 1876: the device incorporated a “method of…transmitting vocal or other sounds telegraphically…by causing electrical undulations, similar in form to the vibrations of the air accompanying the said vocal or other sound.”

Three days later, Bell got the device to work, using a liquid transmitter that varied the electrical resistance in the circuit.

According to his journal:

“I then shouted into M [the mouthpiece] the following sentence: “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. I asked him to repeat the words. He answered, ‘You said “Mr. Watson—come here—I want to see you.”’ We then changed places and I listened at S [the speaker] while Mr. Watson read a few passages from a book into the mouthpiece M. It was certainly the case that articulate sounds proceeded from S. The effect was loud but indistinct and muffled.”

Years later in 1915, Bell would utter the same words into his telephone in New York City, “summoning” Watson who was in San Francisco—a symbolic demonstration of the world’s first transcontinental phone call.