THE OBSERVATIONS OF AIR AND SEA MOTIONS. 



II 



These numbers can now be introduced on the charts instead of the arrows. 

 The chart will then contain a representation of the wind-observations by use of two 

 sets of numbers, one set representing the wind-directions and another representing 

 the wind-intensities. It will be found convenient to use ciphers of different type 

 or of different color for the two different sets. The heavy numbers on plates 

 XXXVI and LIU represent wind-directions. 



S-wincL 



15 k 



SW-wind 



40 

 NE-wind *t 



55 NW-urind 



a 



& '*7 4g 49 50 



N-wind 



Fig. 32. Representation of directions by numbers. 



Charts of this description, which contain a representation of the observed 

 motions either by arrows and numbers or by two sets of numbers, will form the 

 starting-point for the whole subsequent work of kinematic diagnosis. 



99. Observations of Air-Motion in the Free Atmosphere. Until lately the drift 

 of the clouds gave the only information on air-motion in the higher strata. Quali- 

 tative results were obtained by observing the cloud-form and the direction of the 

 drift, and quantitative results in the first approximation by also measuring the 



