If experimental plants are grown in ster1lized soil, these swellings do not appear, and the plant can then use no atmospheric nitrogen.
It is customary to speak of the disastrous effect, of cold winds, snow, hail and frost, lightning, &c., under the heading of atmospheric influences, which only shows once more how impossible it is to separate causes individually.
Lovejoy at Niagara Falls, who passed atmospheric air, or air enriched with oxygen, about a high tension arc made as long as possible; but the company (the Atmospheric Products Company) was a failure.
Lord Rayleigh in 1894 found that the density of atmospheric nitrogen was about 2% higher than that of chemically prepared nitrogen, a discovery which led to the isolation of the rare gases of the atmosphere.
It is, however, requisite to make provision for the effect of changes in atmospheric temperature.