Being less volatile than nitrogen, argon accumulates relatively as liquid air evaporates.
Steinmetz's formula applies only for very weak inductions when the alloys are at the ordinary temperature, but at the temperature of liquid air it becomes applicable through a wide range of inductions.
Moissan (Comp. rend., 1903, 1 37, p. 363) condenses the gas by means of liquid air and fractionates the product.
Now that liquid air is available in many laboratories, it forms an advantageous starting-point in the preparation of argon.
They are non-magnetic or very feebly magnetic. But the critical points of such nickel steel though thus depressed, are not destroyed; and if it is cooled in liquid air below its Ar, it passes to the a state and becomes magnetic.
In the absence of liquid air the helium must be purified by the methods employed for argon (q.v.).
The first immersion into liquid air generally produced a permanent decrease of magnetic moment, and there was sometimes a further decrease when the metal was warmed up again; but after a few alternations of temperature the changes of moment.
By cooling it with liquid air Sir W.
Wailer (Ann., 1857, 104, p. 94), is formed by heating crystallized silicon in hydrochloric acid gas at a temperature below red heat, or by the action of hydrochloric acid gas on copper silicide, the products being condensed by liquid air and afterwards fractionated (0.