122 



THE ROYAL SOCIETY OF CANADA 



12 

 II 

 10 

 9 



a 



7 

 6 

 5 

 4 

 5 

 2 



5 10 /5 20 25 30 3S 40 45 



I/O LUMES FER 3ECO/VÛ (CC PER JSEC) 

 F/G. 2 



that for liquids and gases this critical velocity is about 



IOOO77 



50 



pa 



cms. per second, 



where p is the density of the fîuid (liquid or air) and the other letters 

 have the meanings given above, all being expressed in C.G.S. units. 

 For tube (.4) this velocity is for air about 



1000 X. 00018 



. 00125 X. 078 



