PROCEEDINGS. 
433 
vol. xxiv, pp. 93, 157, and 255 (1899) ; collected, 86 pp., 7 plates, 
1903.] 
Mr. C. G. Abbot then spoke on Radiation and terrestrial tem¬ 
perature, pointing out the excessive complexity of the problem, 
theoretically and experimentally. The maximum value of the 
solar constant cannot be above 3.88 calories, even if the earth 
were a perfect radiator and if it reflected as much as 44 per cent, 
of the incident solar radiation; if the constant were 1.9, under the 
same conditions the mean temperature of the earth would be above 
— 33° C.; accordingly we owe not over 58° rise of temperature to 
the imperfect radiation of the earth. But in the absence of 
clouds the mean temperature would certainly exceed 0° C. If 
the temperature of the oceans could be raised 25° the increased 
cloudiness would make glaciation probable. Arrhenius’s carbonic 
acid theory is mathematically and physically unsound. [Not 
published.] 
The papers were discussed from the geologist’s standpoint by 
Messrs. Willis, Gilbert, and Spencer, all of whom objected to 
Mr. Manson's theory as failing to account for important facts. 
Mr. Manson made a rejoinder. 
591st Meeting. ^ November 26, 1904. 
President Marvin in the chair. 
Seventeen persons present. 
Mr. E. Buckingham read a portion of a paper on The aeration 
of soils, describing his apparatus, the character of materials in¬ 
vestigated, the attempts to distinguish between the effects of dif¬ 
fusion and transpiration, and obtain the rates for each, and to 
find the amount and composition of the gas normally in the soil. 
[Published as Bulletin No. 25 of the Bureau of Soils, U. S. Dept. 
Agr., 1904.] 
The paper was discussed by Messrs. Guthe, Hayford, and 
Bauer. 
Mr. W. P. White then spoke, by invitation, on Methods of 
measuring the intensity and damping of Hertzian waves. The 
receiving instrument was a fine platinum wire bolometer in 
vacuo, with a periodic galvanometer; a null method was used, 
