OZONE IN THE UPPER ATMOSPHERE 465 



be retained in the vessel when turned in any position. A free 

 circulation of air through the vessel took place when this was 

 placed horizontally and exposed to a wind, and similarly, when 

 drawn in a vertical position through the air, as when attached 

 to a balloon. The glass funnels (C C) were extended by means 

 of paper (D D), and the whole enclosed in a cage of hard spring- 

 wire (B B) for protection. The glass vessel was blackened on 

 the outside to protect the reagent from light. By placing a 

 fuming liquid in the vessel and exposing to a wind, the air in 

 passing through was seen to assume a rapid rotatory motion 

 inside. The efficiency of the absorption of ozone during this 

 passage was tested by taking a vessel of the above form, placing 

 the potassium iodide reagent inside, and then joining the vessel 

 in series with a wash bottle containing the same reagent. On 

 passing ozonised air from a gasometer through the two vessels 

 in succession, and varying the speed of circulation, it was found 

 that even at higher velocities than those subsequently given by 

 the atmosphere, more than four-fifths of the ozone was in every 

 case absorbed by the first vessel. 



An approximate calibration of the volume of air circulated 

 was made by means of the assumption that this amount is 

 arithmetically proportional to the velocity of the wind. A 

 measurement was then made by placing some pure benzene 

 in the vessel, and after exposing for definite intervals to a wind 

 of known velocity, noticing the loss in weight. Knowing the 

 vapour pressure of benzene at the prevailing temperature, it 

 was possible to calculate the volume of air passed by assuming 

 that evaporation of the benzene would take place to the saturation 

 point. The average of a number of these determinations showed 

 that when the apparatus was exposed to a wind for an interval, 

 during which a horizontal flow of air of one mile occurred, 

 the volume circulated through the vessel corresponded to 

 5'i2 litres. 



Estimations of ozone, extending over several days, were 

 made in Switzerland, first at a point near Scheidegg (Wengern 

 Alps), at an altitude of 6,970 feet, and then at a point near the 

 Jungfraujoch, of 11,690 feet altitude. 



During these measurements, tests were made for hydrogen 

 peroxide by exposing titanic acid solution in an apparatus 

 similar to that used for the ozone estimation. The colour of 

 this reagent remained quite unchanged after exposing for two 



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