Precisely a half-century ago today, the stern, square face of a moustached man emerged hazily on a little glass screen in New York. The watcher at the screen spoke into a telephone:

"How do you do, General? You're looking well . . . You screen well, General, you look more handsome over the wire."

The speaker was AT&-T president Walter S. Gifford. The face on the screen belonged to Gen: J.J. Carty, who was 220 miles away in Washington.

On this day, in the first such public demonstration in America, live TV images of people were transmitted electronically through the air. Along with company officials and Bell Laboratories scientists, Secretary of Commerce Herbert Hoover took part in the show. He spoke to Gifford from Washington as thousands of tiny dots of light flashed his image across a 2-by-2 1/2-inch neon glow lamp, or picture tube.

But, once everybody had finished saying hello, what to do next? Bell Lab had an answer: Its people at the Whippany, N.J., plant came on and described for the New York audience how the thing worked.

And then they sang some songs.

And then they put on an amateur vauderville act, the first TV variety show.

The course of American television had already been set.