HOT SPRINGS, ARKANSAS. 



15 



by applying a wet towel two or three times, the flask A must again be heated and 

 cooled in the manner just described. The operation is ended when the hot liquid 

 flows back and completely fills A. a The rubber tube g is then connected with a small 

 piece of thermometer tube which is filled with water, and the gas standing over the 

 hot liquid in C is driven over into a modified Winkler gas burette by blowing into 

 the tube X and opening the pinchcock g. 



The gases in the burette were allowed to cool for about ten minutes, 

 and then passed into a simple absorption pipette filled with potassium- 

 hydrate solution (one part KO H to two parts of water). The pipette 

 was shaken two or three times to absorb the carbon dioxide, and the 

 residual gases passed back into the burette. The burette was allowed 



Fig. 1. 



to stand for a few minutes and the volume of the gas read off. This 

 gave the volume of oxygen+the volume of nitrogen. The gas was 

 then passed into a double-absorption pipette filled with potassium 

 pyrogallate, prepared by mixing 5 grams pyrogallic acid and 15 cc 

 of water with 120 grams of potassium hydroxide and 80 cc of water. 



It has been observed in waters rich in bicarbonates that it is nearly impossible to 

 drive off all the C0 2 by this means, but the O and N and part of the C0 2 are driven 

 off in the course of a half.hour's boiling. Therefore the author did not continue 

 boiling A, even though a small bubble of gas were present, more than one-half an 

 hour. 



