8 Meteorological Observations on Parisnath Hill. [No. 1. 



VIII. a + IV. p. + I. p. + II. p., ... . . n , ., 

 ^r ! — which gives, lor Calcutta, a 



tolerably good approximation to the mean.* 



Mean daily pressure. 1st. 2d. 3d. 4th. 



Calcutta, 29.830 29.789 29.758 29.759 



Hill, 25.979 25.909 



Difference, 3.851 3.849 



The rate of falling was about the same at both stations. This 

 diminution of the pressure was doubtless connected with the 

 change in the wind during the same period, the current from the 

 South or South-west displacing the North-westerly breeze. 



It is seen from the table or the figures that the turning points of 

 both curves during the day fall within admissible small limits, upon 

 the same hours, and we may infer from the direction of the curve 

 on the hill, in such places, where it is interrupted, that the maxima 

 and minima during the night would have shown the same coinci- 

 dence, had they been observed. The curve of the hill differs in so 

 far from the Calcutta curve, as it is flatter, the extent of its daily 

 variation being smaller. In the figure, the parts of the curve 

 between the hours at which the observations had been interrupted, 

 have been filled up with dotted lines for no other purpose, than 

 better to define the position of such parts as had been observed. The 

 readings substituted for the unobserved hours and also the manner 

 in which they have been obtained, are given in the appendix. 



The great regularity of the barometrical curves and the coinci- 

 dence of their turning points, promising an equal regularity in all 

 other atmospheric changes during the same period, has encouraged 

 me to make the attempt to complete such data as were wanting 

 in the small number of observations at my disposal, with a view of 

 obtaining a complete picture of the atmospheric processes on the 1st 

 and 3rd of April. Obliged as I have been in doing so, to have 

 recourse once or twice to more or less conjectural estimations, the 



* The means derived by this combination are generally about 0.006 inches too 

 low. For the month of April, 1856, it differs — 0.004. 



The means of the four days from the 1st to 4th April, derived by the combina- 

 tion for Calcutta, are 



Mean daily pressure. 1st. 2nd. 3rd. 4th. 



Calcutta, 29.830 29.793 29.759 29.751 



Difference, from real daily mean, 0.000 +0.004 +0.001 —0.008 



