236 BENJ. PIKE'S, JR., DESCRIPTIVE CATALOGUE. 



Fig. 255. 



long- 

 tube 



on a brass base ; to the sides of the brass cup are soldered 

 brass tubes, about one inch in diameter, and five inches 

 ; at the end of one there is a joint having a long glass 

 , which may be inclined to any angle ; the other tube is 

 terminated in a socket, into which tubes of various shapes 

 may be inserted, a variety of which, each attached to a cork 

 fitting the socket, accompany the instrument ; also a siphon 

 tube to illustrate intermitting springs, etc. This instrument 

 is designed to show that in tubes that have a communication, 

 whether they be equal or unequal, short or oblique, the 

 fluid always rises to the same height. Price, $7.50. 



Fig. 256. 



Hydrostatic Equilibrium. (Fig. 256, as above.) This 

 arrangement consists of a tjn box, A B, formed as repre- 

 sented in the cut, with the two raised extremities open at 

 top ; the sides are made of glass, water tight, having four 

 differently shaped tubes, cemented into caps, on the surface 

 of the oblong part. To use, fill the vessel with water to 



