36 



Meteorological Observations on Parisnath Hill. JNo. 1, 



vapour also decreased from 10 a. m. towards the time of the greatest 

 heat and remained stationary between 4 and 6 p. M., following on 

 the whole the course indicated by the mean tensions of moisture in 

 table VIII. 



The weight of the dry air, if determined on the assumption upon 

 which the so-called pressure of the dry atmosphere is founded, will 

 show a different result. If the Mass of the dry atmosphere be re- 

 presented by the height of the barometrical column after deducting 

 the tension of vapour at Calcutta, the same must be true for the 

 hill, and the differences between the pressures of the dry air above 

 and below must be equal to the weight of the dry air between the 

 stations. These differences are given in the following table. 

 Deductiug them from the observed barometrical differences, the 

 remaining quantities would represent the weight of the watery 

 vapour between the stations. 



Table XII. — The supposed weights of dry air and vapour. 



3rd April. 



Supposed Weight 



Weight of 



S. 



of dry Air. 



Vapour. 



Observed. 



9 A. M. 



3.138 4 



0.738 = 



3.876 



10* 



3.143 4 



0.730 = 



3.873 



2 P. M. 



3.207 4 



0.630 = 



3.837 



3 



3.160 4 



0.679 == 



3.839 



4 



3.078 t 



0.765 = 



3.843 



5 



2.988 4 



0.856 = 



3.844 



6 



3.020 4 



0.826 = 



3846 



According to these values, leaving the vapour altogether out of 

 the question, the weight of the dry air between the stations, or the 

 specific gravity of the air, would have increased at an enormous rate 

 towards the time of the greatest heat, and diminished still more 

 rapidly towards evening, a result which would be contrary to all 

 scientific experience. 



It is evident that the assumption upon which these results have 

 been obtained, cannot represent the true nature of the case. 



In endeavouring to reconcile these apparent contradictions be- 

 tween theory and experience, it seemed to me that the difficulty 



* 10 h. 10 m. 



