396 Prof. Adeney and Mr. Becker: Determination of Rate oj 



at the same temperature as that of the bubble, and there was 

 sufficient moisture in the reservoir to keep the gas saturated 

 with aqueous vapour at that temperature. 



When the observations were completed, the lower tap B 

 was connected to the gas pipette described in Part I. of this 

 communication, by means of a piece of rubber tubing filled 

 with mercury, and the water in the tube was run into the 

 pipette to allow of its transfer to the pump for the deter- 

 mination of its gas-content without exposure to the 

 atmosphere. 



Using this apparatus, a number of experiments were made 

 with both nitrogen and oxygen, the results of which are 

 given below. 



VI. Experiments with Pure Gases. 

 (a) Experiments ivith Nitrogen. 



The nitrogen used was prepared according to a method 

 recommended by Knorre *, and said to give no oxides of 

 nitrogen. 



A mixture of 30 grams sodium nitrite, 30 grams potas- 

 sium bichromate, and 45 grams ammonium sulphate, was 

 dissolved in about 500 c.c. water, and placed in a litre 

 retort. This was connected to three bulb tubes, the first 

 containing a mixture of 5 vols, of a saturated solution of: 

 potassium bichromate to 1 vol. strong sulphuric acid ; the 

 second, dilute potassium permanganate solution ; and the 

 third, alkaline pyrogallol. 



The whole apparatus was exhausted with a water-pump, 

 and the liquid warmed until the pressure rose to that of the 

 atmosphere, when it was again exhausted, and the process 

 repeated. In this way the air in the apparatus was very 

 completely removed. The gas was collected over water 

 which had been boiled for some time, and allowed to cool 

 out of contact with air. 



A series of experiments over a range of 35° was made 

 with this gas, and the results are given below. 



The experimental figures were treated graphically in two 

 ways. In one case the rate of solution was plotted against 

 the mean value of the gas-content, and in the other the 

 logarithms of the absorptions were plotted against the time 

 intervals. Each set of graphs gave values for a and fr, 

 which are given in Table VII., and the mean of the values 

 of b in each case is plotted against temperature in fig. 6. 

 * Chem. Centr. 1903, i. p. 125. 



