HYDROKINETICS. 145 



44. What would a cubic foot of coal (sp. gr. = 2.4) weigh in a 

 solution of potash (sp. gr. = 1.2) ? 



45. A platinum ball (sp. gr. = 22) weighing 300 g. in air will 

 weigh how much in mercury (sp. gr. = 13.6) ? 



46. 500 cu. cm. of iron, specific gravity 7.8, floats on mercury ; 

 with what force is it buoyed up ? 



47. An areometer weighing 600 grs. sinks in water displacing a 

 volume = v ; in a certain acid, displacing a volume = T 9 <r v ; find 

 the specific gravity of the acid. 



Recapitulation. In this section we have considered 

 the Definition of Specific Gravity ; the Stan- 

 dards agreed upon ; the Two Elements in specific 

 gravity problems; the Rule for finding the sp.gr. of 

 Solids heavier than Water ; the same for Solids 

 lighter than "Water ; the same for Liquids ; the 

 same for Gases ; the construction and methods of 

 using Hydrometers ; Tables of specific gravities, 

 and some of the uses that may be made of them. 



ECTiON IV. 



HYDROKI NETICS. 



254. Velocity of Spouting Liquids. If a 



vessel having apertures in the side, similar to the one 

 represented in Fig. 86, be filled with water, the liquid will 

 escape from each of the apertures, but with different veloc- 

 ities. Were it not for the resistance of the air, friction, 

 and the effect of the falling particles, the water issuing at 

 V would ascend to the level of the water in the vessel ; 

 i. e., the initial velocity of the water at V would carry it 

 through the vertical distance V7i. But when equal verti- 

 7 



