610 



Sir Napier Shaw 



[:\rarch 10, 



Fig. 2.— Trajectories showing the paths of air over the surface in 

 the travelling depression of March 24 -25, 1902.* 



Figs. 2 and 3 are to illustrate the progress of air over the surface, and the 

 changes in the velocity, pressure and temperature of the air in its motion 

 durmg the passage of a well-formed cyclonic depression on March 24-25, 1902. 

 From Fig. 2 we see that only one path, that marked C, led actuallv to the 

 centre; and from Fig. 3 we note that in eight hours the wind velocity increases 

 from ten miles an hour to twenty-seven miles an hour with diminishing 

 pressure; in four hours more of still falling pressure the velocity falls to 

 fourteen miles an hour, then in six hours it rises with rising pressure ta 

 thirty-six miles per hour and then slackens to thirty-one. 



