266 METEOROLOGY AND, ALLIED SUBJECTS. 



of air, or an excess of 0.34 volumes duriug the night. This result agrees 

 with the observations of Trouchot, Schulze and others, and is accredited 

 to the influence of vegetation which absorbs carbonic-acid gas during 

 the day time. {Z. 0. O. 3L, XVI, 1881, p. 154.) 



Schloaing has investjgated the action of the ocean water as an ab- 

 sorber and regulator of the carbonic acid gas in the atmosphere. He 

 shows that pure water in contact with the mineral carbonates, and an at- 

 mosphere containing COz dissolves a certain quantity of bicarbonate 

 which increases with the tension of the CO2 in the atmosphere accord- 

 ing to a mathematical law. The same is true of sea-water in which 

 neutral alkalies and salt are contained; but a condition of equilibrium 

 as to this chemical action is never attained, owing to the movement of 

 currents and winds — only a tendency towards such is going on. When 

 the air contains only a little of COz the sea gives up some and it de- 

 posits neutral carbonates; when the air contains too much of CO2 the 

 sea absorbs and forms bicarbonates. Thus the ocean acts as a regulator, 

 and so much the better, inasmuch as a slight calculation shows that it 

 contains about ten times as much CO2 as the entire atmosphere, which 

 latter may be said to be controlled by it. {Z. 0. G. 31., XYI, 1881, 

 p. 155.) 



Lecher and Pemter have contributed somewhat to the question of 

 the absor])tion of dark-heat rays by gases a.nd vapors. Since the first 

 investigations of Tyndall, who maintained that aqueous vapor exerted a 

 powerful absorbing influence upon rays of heat, the tendency has been 

 to diminish the estimated amount of this absorption. Thus, for in- 

 stance, the results of the observations by Violle on Mont Blanc give 

 IG per cent, as the sum total by air and moisture combined when a beam 

 of sunlight passes through 2,428 meters of air of uniform temperature 

 and pressure, or an absorption of 0.007 of 1 per cent, for a thickness of 

 one meter of air. But Tyndall's measure gave for pure dry air a greater 

 absorption than this, so that nothing could be left to be attributed to 

 the action of aqueous vapor. If, however, we assume that pure air has 

 no absorption, and that all that was observed in the atmosphere is the 

 result of aqueous vapor alone, even then the figure given by Tyndall — 

 namely, from 4 to C per cent, for a thickness of something more than 

 one meter — must be considered as extraordinarily great. The experi- 

 ments of Tyndall were made with heat rays of a temperature of 270^ C 

 The researches of Stefan and Jacques show that Tyndall's figures must 

 be multiplied by one-sixth in order to make them applicable to radia- 

 tion from the sun, for one meter of atmosphere should absorb 0.102 of 

 1 per cent. o#the heat rays studied by Tyndall, instead of the 4 or G per 

 cent, actually observed by him. The explanation of this great dilier- 

 ence as now usually accepted is that first given by Magnus — namely, 

 that condensing vapor adhered to the sides of the apparatus. The in- 

 vestigations of Lecher and Peruter entirely agree with this explanation 

 and seem to establish the fact that aqueous vapor proper has no more 



