194 EQUILIBRIUM OF FLOATING BODIES. 





This fact may be demonstrated by means of the 

 vessel with a lateral spout. The vessel is filled with 

 water, and the portion above the spout allowed to run 

 away. A body lighter than water is then weighed, 

 placed in the water in the vessel, and the portion 

 which now runs out by the spout is received in a 

 tumbler and weighed. Its weight will be equal to that 

 of the body. 



To obtain an exact result in this experiment, care must be taken 

 lest the floating body touch the sides of the vessel ; this often 

 happens if a piece of wood is used ; an apple answers very well for 

 the experiment. 



If the same body be made to float in different 

 liquids, the volumes of the immersed portions of the 

 body also differ. This may be illustrated as follows : 

 a rather large test-tube is fixed upright in the re- 

 tort-stand, and as much alcoliol is poured into it as 

 will just reach the top when a smaller test-tube is 

 placed almost completely inside it ; this smaller tube 

 is then weighted with shot or clean sand until it just 

 floats, in the manner shown in fig. 138 A. The larger 

 test-tube is next filled with water in place of alcohol ; 

 it will then be found that the small tube sinks to only 

 about four-fifths of the depth to which it sank in 

 alcohol ; and if a saturated solution of salt be used 

 instead of water it will sink still less. The reason oi 

 this is obvious. The displaced liquid must in carl) 

 case weigh as much as the floating test-tube. If the! 

 weight of the latter is 1 2^, the volume immersed ir 

 water will be 12 CC . But l cc of alcohol weighs onl\ 

 about 0^*8, while l cc of the saline solution weighs aboul 

 1^*2 hence 12^ of alcohol have a volume o! 



