418 Mr. H. F. Blanford. The Diurnal Barometric 



between sunset and midnight, the average hour being about 10 p.m. ; 

 and some show a second subordinate minimum about 9 or 10 a.m. 

 The cloud curves for Allahabad given by Mr. S. A. Hill on Plate 

 28, vol. 1 of the ' Indian Meteorological Memoirs,' exhibit both these 

 minima in most months of the year, that of the evening being the abso- 

 lute minimum of the twenty-four hours. On the average of the year, 

 the mean proportion, at 10 p.m., is 2*52 (on the to 10 scale), that of 

 the twenty-four hours being 3*10 : the deficiency therefore is more than 

 one-sixth. The cloud curves of Melbourne given by Dr. Neumayer also 

 show that, in every month except November, the diurnal minimum of 

 cloud is between 7 h. 30 m. p.m. and 1 h. 30 m. a.m. ; and, on the mean 

 of the whole year, it occurs at 9 h. 44 m. p.m. At this hour, the mean 

 proportion is 5*55, the general mean of the twenty-four hours being 

 6*56; so that, here also, the deficiency amounts to one-sixth of the 

 average. At Bombay, the absolute minimum, according to Mr. 

 Chambers's table, occurs at 8 and 9 p.m., and the deficiency is one-ninth 

 of the general average. The mean diurnal cloud curves of Allahabad, 

 Melbourne, and Bombay, for the average of the whole year are given 

 in figs. 1, 2, and 3. 



