12 



Dr. W. S. Day on a Comparison of 

 Fig. 3.— Zero-Tank. 



should reach from the side of the tank to the part of the stein 

 where the zero point actually was. A device was therefore 

 made use of which is represented in fig. 3. The ice was 

 contained in a cylindrical tin-lined copper tank 33*5 centim. 



