The instrument before which he seated himself was very like a great window sash, on account of the fact that there were three or four hundred frosted glass squares visible. In a space at the center, not occupied by any of these glass squares, was a dark oblong area and a ledge holding a piece of chalk. And above this area was a huge brass cylinder toward which the professor directed his subsequent remarks.

(From Visaphone from 'John Jones Dollar' by Harry Stephen Keeler)
(Published in Amazing Stories in 1927)

In order to assure himself that it was time to press the button which would notify the members of the class in history to approach their local Visaphones, the professor withdrew from his vest pocket a small contrivance which he held to his ear... the professor replaced the instrument in his vest pocket and pressed a button at the side of the Visaphone.

As though in answer to the summons, the frosted glass squares began, one by one, to show the faces and shoulders of a peculiar type of young men; young men with great bulging foreheads, bald, toothless, and wearing immense horn spectacles. One square, however, still remained empty. On noticing this, a look of irritation passed over the professor’s countenance. But, upon seeing that every other glass square but this one was filled up, he commenced his talk.

“I am pleased, gentlemen, to see you all posted at your local Visaphones this afternoon...

At this point in the professor’s lecture, the frosted glass square which hitherto had shown no image, now filled up. Sternly he gazed at the head and shoulders that had just appeared.

“B262I172476Male, you are late to class again. What excuse have you to offer today?”

From the hollow cylinder emanated a shrill voice, while the lips of the picture on the glass square moved in unison with the words :