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



Considering the character of the data and the method of computation, 

 this close coincidence in the winter months must be regarded as in 

 some degree fortuitous. 



In order to test the hypothesis more thoroughly, I have selected 

 four stations, the data for which are more ample, and thoroughly 

 trustworthy, viz., Bombay, Calcutta, Batavia, and Melbourne ; and in 

 the case of the last three, I have compared the critical phases in 

 question for every month of the year. 



The data for Bombay are taken from Mr. C. Chambers's volume on 

 the Meteorology of the Bombay Presidency. The barometric data for 

 Calcutta are extracted from vol. 1 of the ' Indian Meteorological 

 Memoirs,' and as I have not the corresponding thermometrical data 

 at hand,* I have substituted those obtained from the measurements of 

 the Alipore photographic traces for the six years 1881-1885. These 

 latter relate, therefore, to a different and later series of years, and are 

 furnished by a different observatory, but this is hardly a matter of 

 importance. The Batavian data are taken from the first volume of 

 Dr. Bergsma's ' Magnetical and Meteorological Observations,' and 

 have been derived from the hourly readings of three years ; and the 

 Melbourne data are from Dr. Neumayer's discussion of the observa- 

 tions of the Flagstaff Observatory. They extend over five years. 

 The results are shown in the following table : — 



Bombay. 



Max. rise temp. Bar. max. Interval. 



April to September, mean 7 h. 45 m. a.m. 9 h. 43 m. a.m. 1 h. 58 m. 



October to March „ 7 h. 53 m. „ 9 h. 31 m. „ 1 h. 38 m. 



* Since the reading of the paper before the Society I have received from 

 Calcutta the mean values of the horary readings of the thermometer, corresponding 

 to those of the barometer here dealt -with. See appended note at the end of the 

 paper. 



