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



The maximum heat at both stations is a little higher on the 3rd 

 than on the 1st ; the hours of the maximum are 2 p. m. on the hill 

 and 3 p. m. at Calcutta. 



The mean temperature from all observations of the 24 hours at 

 Calcutta is for the 1st 30°.l, and for the 3rd 30°.4. With these the 



values derived by the combination — - — ' : — '■ — '-*-?. 



J 4 



which gives very good means for many parts of India, closely agree ; 

 they are 30°.3 for the 1st, and 30°.5 for the 3rd April. In employing 

 this combination for the hill, where the observations extend over 

 only a part of the 24 hours, the temperatures for 10 p. m. on the 

 1st and for 6 a. m. on the 3rd, had to be estimated by analogy. 

 This is certainly a very imperfect method, but it may be admitted 

 in the present case, as the general state of the atmosphere was 

 the same on both days ; and the limits are so well defined, that the 

 error can hardly amount to more than about half a degree, which 

 divided by 4 becomes still more diminished. The estimated tem- 

 peratures are put down opposite these hours in the table. The 

 daily means derived in this manner for the hill are on the 1st 24°.4 

 and on the 3rd 25°.4. 



The hour in the morning of which the temperature approaches 

 nearest to the mean of the whole day falls between 9 and 10 a. m. 

 at Calcutta, and at 10 A. M. on the hill. 



The differences between the hourly temperatures at Calcutta and 

 the hill on the 1st and 3rd (Cols. III.) are smallest in the morning 

 and evening and increase towards 4 in the afternoon, when they 

 reach their maximum on both days : 8°. 8 on the 1st and 7° on the 

 3rd. The variation during the night has not been observed. On both 

 these days the variation progresses with great regularity towards 

 the maximum, but on the 4th it begins less regular, owing, doubt- 

 less to the formation of clouds on that day.* 



Column IV. in the table gives the hourly means, computed from 

 the observations at both stations ; their curve is represented in fig. 



* I have reason to suspect that the temperature observed on the hill at 9 on 

 the 4th is too high. It was taken after the thermometer had been removed from 

 the sheltered spot described above, previous to its being packed up for leaving 

 the hill. 



