CAPILLAR Y A TTRA CTION. 



45 



I have here a simple arrangement of apparatus 

 (Figs. 29 and 30) by which, with proper optical 

 aids, such as a cathetometer and a microscope, we 

 can make the necessary measurements on real 



FIG. 29. 



drops of water or other liquid, for the purpose of 

 determining the values of the capillary constants. 

 For stability the drop hanging from the open tube 

 should be just less than a hemisphere, but for 



