418 



Results of Makerstoun Observations, 1844. 



TABLE XVI.— Hourly Means of the Relative Humidity for each Month in 1843, 



Saturation being = 1. 



TABLE XVn.— Houi'ly Means of the Relative Humidity for each xlstrononiical Quarter, 



and for the Year 1844. 



Diurnal Variation of the Relative Humidity. — The relative liumidity is a minimum from noon to 3 p.m. in 

 the different months of the year, occurring as early as O*" 40'" p.m. in August, and as late as 3h 10'" p.m. iu 

 November and April : it is a maximum in general about sunrise, though it varies little from sunset to sunrise 

 in the winter months. The following are the epochs of maxima and minima for each of the astronomical 

 quarters and for the year 1844 : — 



Winter. Spring. Summer. Autumn. Year. 



.5'' 40"" A.M. .5'' 10'" A.M. 3'' 10" A.M. 'S^ 40>n A.M. 3'' 30"" A.M. 



Max. 

 iMin. 



Ih 45m 



\b 30m p M. 



P.M. 2'' 0"" P.M. 1'' 10'" P.M. 



The mean value of the relative humidity occurs at 8'' 40'" a.m. 

 T*" 12'" P.M. 



The interval between the periods of mean humidity =: lO^ 32™ 



1'' 35'" p.m. 



