38 Common Science 



you rush to the switchboard and turn on the capillary 

 attraction again. 



You can understand this force of capillary attraction 

 better if you perform the following experiments : 



Experiment 13. Fill a glass with water and color it with 

 a little blueing or red ink. Into the glass put two or three 

 glass tubes, open at both ends, and with bores of different 

 sizes. (One of these tubes should be so-called thermometer 

 tubing, with about 1 mm. bore.) Watch the colored water 

 and see in which of the tubes it is pulled highest. 



Experiment 14. Put a clean washed lamp wick into the 

 glass of colored water and watch to see if the water is pulled 

 up the wick. Now let the upper end of the wick hang over 

 the side of the glass all night. Put an empty glass under the 

 end that is hanging out. The next morning see what has 

 happened. 



FIG. 19. Will the water be drawn up higher in the fine glass tube or in a tube 

 with a larger opening? 



