The Wind and its Direction. 



127 



•To understand this correctly we will take several examples, 

 but before doing so, it is requisite to mention that a long piece 

 of drawing paper is placed upon a roller; this passes between 

 two brass cylinders on to a glass table, at the end of which is 

 another roller with weights, a clock drives this paper across the 

 table at the rate of half an inch an hour, and the roller and 

 weights wrap it up after the records have been made. Fig. 1 

 is an exact copy of the movements of the wind on the 30th of 

 last August, the two stars showing the direction at 9*20 a.m. 

 and 7*45 p.m. The line WW is the zero of a west wind, the 

 line EE that of an east wind, and the line NN that of a north 

 wind, if the curve is concave, but south if convex. It will be 

 sufficient to say, that if the wind pencil (which writes amongst 

 these three lines) touches the line E, it must be east and so on. 

 The wind on August 30th, 1863, is an example of a stationary 

 wind, although the changes between 10 a.m and 8 p.m. were 

 most extraordinary. The wind had been blowing WNW. where 

 marked A, on reaching the star 

 (*) NW., at B it was NNW., 

 moving in one sweep from B to 

 C, at it was NNE., in which 

 quarter it remained till the point 

 J) was reached, it then veered in 

 one sweep through east (D') and 

 south (D") to nearly SSW. (E), 

 remaining in this quarter to F, 

 then sweeping through E. to NE. 

 (G) at 7.40 p.m., remaining for 

 some time in this quarter, and 

 becoming NNE. at H, so that 

 from A to G in the space of 

 twelve hours the wind moved — 



WNW. 



to NNE. 



= 90° 



NNE. 



to SSW. 



= 180' 



SSW. 



to E. 



= 1121 



E. 



to NE. 



= 45' 



427i° 



Or 427'5° without a single oscil- 

 lation. 



In Fig. 2 we have a different 

 character of wind (the example 

 being on January 25th, 1864), 

 what I have called a nodding 

 ivind, on WSW., with veerings 

 to SW. at A, B, and C, and a 

 singular change through S. to ESE. at D, and back again in 



FIG:2. 



JAN. 25. 



10.A.M.W. 



