Zero, Absolute.
From several considerations it is believed that at a certain temperature
the molecules of all bodies would touch each other, their kinetic motion
would cease, and there would be no heat. This temperature is the
absolute zero. It is put at -273° C. (-459° F.)
[Transcriber's note; The modern value is 0° Kelvin, -273.15° C, or
-459.67° F. The lowest reported temperature observed is 1E-10° K.]
Zero, Potential.
Conventionally, the potential of the earth. True zero potential could
only exist in the surface of a body infinitely distant from other
electrified bodies.
Zero, Thermometric.
There are three thermometric zeros. In the Réaumur and centigrade
scales, it is at the temperature of melting ice; in the Fahrenheit
scale, it is 32° F. below that temperature, or corresponds to -17.78° C.