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



admit of, that the results obtained by calculation might not have 

 agreed quite so well, or quite in the same way, with the values 

 observed, as they apparently did: but in all such cases, a deviation 

 from expected results will teach us something new. My intention 

 in discussing these observations in the manner I have done, having 

 been less to establish a law from the conclusions arrived at, than 

 to direct the attention of meteorologists to the advantage of corre- 

 sponding observations between stations similarly situated as Paris- 

 nath hill and Calcutta, particularly in India, and to invite repetition ; 

 I shall be fully satisfied, if that object be gained. 



In connexion with the latter part of the discussion, I beg permis- 

 sion to offer a few remarks regarding the action of the watery 

 vapour mixed with the atmosphere. 



I give in Fig. 6 — 8 the curves of the hourly tensions of moisture 

 on the 2nd (6), 3rd (7) and a part of the 4th (8) of April at 

 Calcutta, and in Fig. 13 a fragment of the same curve on the hill. 

 Fig. 9 is the curve of the mean hourly tensions for the whole month 

 of April, and Fig. 10 for the whole year at Calcutta; the Figs. 11 

 and 12 represent the curve for the month of April and the whole 

 year of 1850 at Bombay. The Fig. 6 a — - 13 a, give the hourly baro- 

 metrical pressures for the same dates, and 6 b — 13 b, the curves of 

 the so-called pressure of the dry air, that is, the curves which 

 remain after deducting the hourly tensions of vapour (6 — 13) from 

 the respective hourly barometric pressures (6 a — 13 a). 



The tensions of Figs. 6, 7, 8, 9 and 13 were calculated from the 

 observations, by August's formula ; those of Fig. 10 were computed 

 from the published monthly results of the Calcutta Observatory, 

 which are obtained by the so-called Greenwich constants ; the in- 

 dividual values are on an average about 0.018 inches lower than 

 those obtained by August's formula, but the general course of the 

 hourly variations remains the same. The tensions of Figs. 11 and 

 12 were taken from the Register of the Bombay Observatory, where 

 Apjohn's formula is in use.* 



* The readings of the barometer and tensions of moisture which served for the 

 construction of the curves are given in the Appendix, with the exception of those 

 of the monthly curves at Calcutta, which are published in the Society's Journal, 

 and the curves of Bombay, which are also published. 





