242 CASWELL GRAVE AND OTTO C. GLASER. 



TEST OF COOLER. 

 Room temperature 3iC. . . .87.8F 



Contents of Tray. Distance below 



Mouth of Shoot. 



Crushed ice 6cm. 24.5 76.1 



Crushed ice +NaCI 6 ' 23 73.4 



Crushed ice 3' 18 64.4 



Crushed ice+NaCl 3 " 17 62.6 



Several coolers, varying somewhat in size, but all modeled af- 

 ter our original one at Johns Hopkins University, are now in use in 

 different laboratories. The measurements given in connection 

 with Fig. i, are those of the cooler at the University of Michigan. 

 This particular one does not have the advantage of a removable 

 ice-pan. In general, size is of little consequence unless it in- 

 volves too great a reduction in the capacity of the ice-tray, or is 

 conducive to too much absorption of heat by the sides of the 

 pyramid. This latter difficulty is easily overcome by lining the 

 shoot with asbestos paper. 



JOHNS HOPKINS UNIVERSITY, 

 UNIVERSITY OF MICHIGAN. 



July 15, 1910. 



