386 Prof. Adeney and Mr. Becker : Determination of Rate of 



up through the water repeatedly until saturation was 

 reached. The pressure in the bubble was measured after 

 each double passage up the tube by means of a water mano- 

 meter, and this gave data for calculating the absorption 

 which took place step by step to saturation. 



With the object of reducing the observations to unit area 

 and volume, experiments have been continued along these 

 lines, and the results are given in this communication. The 

 apparatus employed for these later experiments has been 

 modified in a manner which experience showed was neces- 

 sary ; and the determinations have been extended to include 

 oxygen and nitrogen as pure gases. 



II. Temperature Control. 



In the experiments previously recorded the temperature 

 of the apparatus was maintained constant by providing 

 a large reservoir of water, and allowing the water to run 

 through the water-jacket of the apparatus while the observa- 

 tions were being made. This method only allowed of the 

 maintenance of a steady temperature for a few hours, and 

 experiments could not be repeated at the same temperature 

 at will, nor could higher temperatures than that of the 

 room be obtained. 



In order to bring the temperature under control, it was 

 decided to use a thermostat, and circulate the water from it 

 through the water-jacket of the apparatus. To provide the 

 circulation of water a small centrifugal pump was designed, 

 patterns were made and castings obtained from the Engi- 

 neering Department of the College, while the machining 

 was completed in the workshop attached to the Chemical 

 Department. 



This pump maintained a rapid stream of water through 

 the water-jacket at a constant rate ; and no difficulty was 

 experienced in keeping the temperature constant to within 

 o, l C. A farther advantage was that any desired tempera- 

 ture within fairly wide limits could be attained, and 

 experiments could be repeated as often as desired at the 

 same temperature on different days. 



III. Experiments to determine the Effect of the Area 

 of the Bubble on the Rate of Solution. 



(a) Measurements of the lengths of different bubbles in motion. 



Bubbles of five different volumes were measured at 25° C. 

 while in motion up the tube. Arrangements were made for 



