﻿30 EQUIPMENT AND WORK OF AN AERO-PHYSICAL OBSERVATORY. 



circulation by whirl action — i. e., by the mixing which a whirl with its 

 relatively large surface can accomplish. Again, his study of wave-action 

 at the common boundary of two fluids or of a fluid and a gas has a prac- 

 tical application in the measurement of air billows. We may som.e day 

 correlate the wave frequency and character with the force and direction 

 of the wind. Oberbeck's papers on the " Motions of the atmosphere,'^ 

 Hertz's " Graphic method of showing the adiabatic changes in moist air,'^ 

 and V. Bezold's " Thermodynamics of the atmosphere " are all excellent 

 illustrations of valuable research work along the lines we advocate. The 

 two last named are of particular value to the forecaster, and v. Bezold's 

 work gives an insight into the physical processes brought into action as 

 a given mixture of air and vapor passes through various levels and envi- 

 ronments. He treats of just such conditions as the forecaster is likely to 

 meet. We want to be able to forecast with certainty the formation and 

 dissolution of fog and cloud, and we must therefore know the air mixture^ 

 the quantity of heat, the cycles of cooling by contact and radiation, and 

 the adiabatic expansions and compressions for various levels. When 

 such data are accessible, the forecasting of weather will move from its 

 present resting place of empiricism. We have further tried to point out 

 the value of determinations of the total moisture in any given stratum of 

 atmosphere. Although the problem is far from being an easy one and 

 far more involved than appears at first glance, we believe that it is within 

 our power from systematic study of the absorption lines due to water 

 vapor to ascertain the vapor distribution. The infra-red portion of the 

 spectrum, being rich in these lines, should be explored with this end in 

 view. 



In another direction, that of atmospheric electricity, we urge experi- 

 mentation, for we believe that therein may lie possibilities of great exten- 

 sion of our knowledge of atmospheric phenomena. We know almost 

 nothing of the electrification of the atmosphere ; how the air acquires its 

 charge we do not know, and of the distribution of the potential and the 

 significance of its variations we have only fragmentary and scant knowl- 

 edge. In 1752 an experiment, simple enough in its details, demonstrated 

 the nature of the lightning flash. In 1895 the aurora, the origin of the 

 electricity of thunder-clouds, and similar questions are as the nature of 

 the lightning was one hundred and forty-three years ago. In what direc- 

 tion have we a more promising field for the increase and diffusion of 

 " knowledge of the nature and properties of atmospheric air in connection 

 with the welfare of man ? " 



