WIND. 3 



The form of diagram represented in Fig. 1 shows, fairly well, 

 the direction and relative frequency of prevailing winds at 

 different periods of the year ; but it lacks one most essential 

 feature, inasmuch as it gives no indication of the force of the 

 wind. Thus, it may show that, say, southerly winds are the 

 most prevalent in any given locality, while it altogether fails 



BEAUFORT SCALE 

 FOR FORCE OF 

 WIND (see p. n). 



Light airs. 



breeze, 

 Gentle 

 J| Moderate., 

 WU, Fresh 



JED Moderate Gale. 

 m Kresh 



OBSERVATIONS TAKEN DAILY 



AT 9 A.M. 



Each line thus represents 



one observation* Its length 

 indicates the force of the wind, 

 a scale for the measurement of 

 ivhich is given opposite. 



Fio. 2. Wind diagram for Peterhead, year 1888. Each zone embraces observations for three months. 

 Zone A, January, February. March; Zone B, April, May, June: Zone C, July, August, 

 September ; Zone D, October, November, December. 



to show that those possibly from the south-east, although less 

 frequent, blow with the greatest violence. This is an all-impor- 

 tant point for the harbour engineer to be correctly informed 

 upon, and, with the view of supplying this deficiency, I, many 

 years ago, designed the form of diagram shown in Fig. 2, which 

 explains itself. 



Such diagrams may be amplified by showing the limits of 



