What is "u-tubes"

Usage examples of "u-tubes".

So the U-tubes produce a set of binary digits that is like a picture of the standing wave--a graph of the harmonics that make up the musical note that is being played on the speaker.

The crescents of mercury in all those U-tubes are shifting up and down, opening and closing the contacts, but systematically: it is not turbulent sloshing around, but a coherent progression of discrete controlled shiftings, informed by some program.

So the U-tubes produce a set of binary digits that is like a picture of the standing wave—a graph of the harmonics that make up the musical note that is being played on the speaker.