Vol. 3 No. 8 



TORREYA «5* 



N6* 



^N\C* L 



August, 1903 GA*° b 



AN APPARATUS FOR DETERMINING GAS INTER- 

 CHANGE IN A SMALL SPACE 



By H. M. Richards 



In investigating the question of the C0 2 -0 2 coefficient in 

 dealing with small objects, one is confronted with several difficul- 

 ties. There have been devised a number of different forms of 

 apparatus which are indeed applicable to this purpose, but they 

 require large masses of the material under investigation. It is 

 often exceedingly tedious, especially for an experiment which 

 must be repeated several times, and at times indeed impossible, 

 to get together enough material. With the idea in view of ob- 

 viating this trouble, the writer constructed the herein described 

 piece of apparatus for some work being carried on in his labora- 

 tory, which unfortunately could not be completed by the investi- 

 gator who was undertaking it. 



The essential feature of the apparatus is a glass bulb, say an 

 inch to an inch and a half long, by about three fourths of an 

 inch in diameter, one end of which is drawn to a tube of one 

 fourth inch internal bore, and the other end joined to a longer 

 piece of capillary tubing bent in a double L. This will be 

 readily understood by reference to the figure (Fig. 1). This 

 tube in fact constitutes the respiration chamber and of course can 

 be made of any desired size ; in the case in question it was de- 

 sirable to keep it as small as possible. The material is intro- 

 duced through the larger aperture and then a sufficiently tight 

 and thick-walled rubber tube is brought over the end, by which 

 another capillary tube, also bent in an L, is affixed. This 

 tube leads down under a mercury-bath, and a pinchcock is 



[Vol. 3, No. 7, ofToRREYA, comprising pages 97-112, was issued July 25, 1903.] 



113 



