224 J. HOPKINSOIf — THE CLniATE OF ST, ALBANS. 



The spring and summer half of the year is much drier than the 

 autumn and winter half, having 12 per cent, less mean relative 

 humidity. Summer is drier than spring by 6 per cent. ; autumn 

 is di-ier than winter by 2 per cent. iSpring and summer are the 

 brightest seasons ; winter is the most cloudy one ; autumn having 

 the mean amount of cloud of the year. Summer and winter have 

 fewer days of clear sky than spring and autumn ; spring and 

 autumn have nearly the same number of days of overcast sky ; 

 summer has much the fewest, and winter has much the greatest 

 number. 



The air is driest in May, June, and July, and most humid in 

 November, December, and January, the humidity decreasing each 

 month from January to May, and increasing each month from July 

 to jN"ovember. Although as a rule the colder months are the more 

 humid, the air is much drier in comparison with the temperature 

 in the spring than it is in the autumn ; thus April is much drier 

 than September although its temperature is about the same. 



Force and Direction of the Wind at 9 a.m. (Tables X-XII, p. 225). 

 — Although the force of the wind is arrived at, in the absence of 

 an anemometer, in the same way as is the amount of cloud, that 

 is by estimation, it is much easier to estimate the proportion of 

 cloud to clear sky when the whole sky is in sight, than it is to 

 estimate the projiortionate force of the wind when there is nothing 

 to compare the force with at any time but a vague recollection 

 of what it has been at other times. It is even difficult to say 

 sometimes whether the air should be considered calm or as having 

 the force 1 on Beaufort's scale. Again, as we never experience the 

 force 12 (a hurricane) in this country, it is difficult to say how 

 near this is approached in a severe gale. The greatest force, on 

 this scale, at which I have estimated the wind at 9 a.m. on any 

 occasion, is 6 : this has occurred several times in some years and 

 in others not once. The greatest estimated mean force in any 

 month is 2'8 (in March, 1891); the least in any month is 1'2 (in 

 January, 1887, November, 1892, and September, 1893). The 

 mean annual force has varied from 1-6 to 1-9. The wind is 

 strongest in spring, lightest in summer, and the mean force of the 

 year in autumn and winter, but the seasonal variation is very 

 slight. It is strongest in March and lightest in June. 



With regard to direction, S.AY. winds are much the most pre- 

 valent, and are followed in frequency by W. winds; E. and S.E. 

 winds are the least frequent. The wind has been S.W. on as many 

 as 78 days in the year, and it has been E. and S.E. on as few as IH. 

 S.W. winds prevail most in summer and least in spring, and are 

 more prevalent in autumn than in winter; N.E. winds are pre- 

 valent in spring, and W. ■winds in summer. There is no gi'eat 

 preponderance of winds from any other quarter in any season. 

 S.W. and W. winds prevail most in August; N.E. winds most in 

 April. There are very few E. winds in August and October. 

 Calms occur most often in December; much the least often in 

 March, April, and July. 



