620 Scientific Proceedings, Royal Dublin Society. 



into the pipette to allow of its transfer to the pump for the determination 

 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 with Nitrogen. 



The nitrogen used was prepared according to a method recommended by 

 Knorre, 1 and said to give no oxides of nitrogen. 



A mixture of 30 grams sodium nitrite, 30 grams potassium 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 b, 

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

 case is plotted against temperature in fig. 6. 



1 Chem. Oentr. 1903 (i), 125. 



