The height of the ozone has been estimated at from 10 to 40 miles above the earth's surface. Although the total quantity of ozone above ground level is obviously of practical importance, one might conclude that its distribution as to height would be only an academic question. However, even this problem has its practical value. The earth's surface temperature is controlled by the balancing of radiation received from the sun and radiation reomitted into space. The earth's temperature, however, is thousands of degrees lower than that of the sun, and its radiation is in consequence confined to the infra-red regions of the spectrum and thus invisible to us.
It can be shown that this terrestrial radiation is most intense in a region of the infra-red at a wavelength about twenty times greater than that of visible light. Now, in addition to the great ultra-violet absorption band of ozone already mentioned, done has several other absorption bands, including an important one in the infra-red, not far from the maximum emission of the earth to space. Ozone thus absorbs a substantial fraction of the sun's ultra-violet radiation to the earth, and of the earth's infra-red radiation to space,
Text read from the printed page and cleaned; old type leaves the occasional error.