Moissan (Comp. rend., 1903, 1 37, p. 363) condenses the gas by means of liquid air and fractionates the product.
This treatise, animated and sometimes brilliant, is valuable for modern readers in that it condenses his general view of philosophy and religion.
We may also consider here cases of sublimation wherein a solid vaporizes and the vapour condenses without the occurrence of the liquid phase.
The rising air condenses so that some of the water in the whirling mass falls as rain.
This water vapor rises, condenses and forms clouds, and then returns to the planet's surface as rain or snow.