MOTION, MECHANICS, ETC. 



143 



quantity of air will escape through the water, the water 

 displacing the air, not penetrating it. Price, $1.00. 



Tubes for Capillary Attraction. (Fig. 148, as below.) 

 These consist of a number of small glass tubes of different 

 sized bore, attached to a piece of wood, which may be 

 placed in a glass vessel, allowing all the tubes to be immers- 

 ed at one end. The liquid will rise to different heights in 

 the several tubes, and highest in the tubes having the small- 

 est bore. Price, $1.00. 



Fig. 149. 



Fig. 148. 



Glass Plates for Capillary Attraction. Fig. 149, as 

 above, consists of two plates of glass about five inches 

 square, joined at two of their edges, and separated at the 

 other a small space, forming an angle of about two degrees. 

 When immersed about an inch in water, the water will rise 

 between the plates, and will rise higher as the space is 

 smaller, forming a curve called a hyperbole. The effect is 

 shown best if the liquid is colored. 



Price, $1.00 and $2.00. 



Collision Balls for Action 

 and Reaction. (Fig. 150). 

 This apparatus consists of a 

 number of ivory balls, sus- 

 pended contiguous to each 

 other by strings of equal 

 length, sometimes mounted 

 on a frame, having a gradu- 

 ated arch over which the 

 balls may oscillate freely. 



Fig. 150. 



