AND PRESSURE OF VAPOUR. 305 



APRIL TO SEPTEMBER. 



APRIL TO SEPTEMBER. 



^1 = + ^0021 -f- -0182 sin (0 + 135° 13') + ^0048 sm (2 0+ 193° 10') 

 + ^0034 sin (3 0+ 10° 18') 



OCTOBER TO MARCH. 



•5^2 = — '00'7'7+ -0317 sin (9+ 149° 4') + -0030 sin (2 0+ 156° 2') 

 + •0016 sin (3 + 21*7° 29') 



THE YEAR. 



^3 = — -0021 + -0237 sin (0 + 144° 46') + ^0040 sin (2 0+ 174° 17') 

 + ^0026 sin (3 + 15° 39') 



PRESSURE OE VAPOUR. 

 The average changes in the pressure of vapour in two hours that 

 accompany winds frona the eight principal points, and the formulEe for 

 finding the most probable change, -with the wind blowing from any 

 intermediate point, are given below : 



APRIL TO SEPTEMBER. 



N. N.E. E. S.E. S. S.W. W. N.W. 



— •0057 —•0034 +^0020 +"0035 +'0042 +-0001 -•0073 —-0069 



OCTOBER TO MARCH. 



N. N.E. E. S.E. S. S.W. W. N.W. 



— •0025 +-0009 +^0037 +-0031 +^0017 — •OOIS —-0032 —^0039 



THE YEAR. 



N. N.E. E. S.E. S. S.W. W. N.W. 



—•0041 -^0012 +-0025 +'0034 ^-•0034 -^0007 —•0046 —^0054 

 APRIL TO SEPTEMBER. 



■*-i = — •00169 + •00607 sin (0 + 305° 49') + -00096 sin (2 0+ 88° 48') 

 + -00110 sin (3 0+ 181° 2') 



OCTOBER TO MARCH. 



■^^ — — • 00018 + •00385 sin (0 + 330° 26') + • 00034 sin (2 0+ 287° 6') 

 + • 00022 sin (3 0+ 243° 26') 



THE YEAR. 



■^3 — — -00084 + • 00479 sin (0 + 312° 43') + • 00035 sin (2 0+ 86° 44') 

 + • 00037 sin (3 + 216° 15') 



If in the nine foregoing formulaa, the variable angle (<9) be made 

 equal in succession to 0, 11° 15' (11° 15') X 2, (11° 15')x3, &c. 

 &c (11° 15')X31, the changes of pressure will be found whieb 



