82 H. Warth — Air -temperature Sf humidity at different elevations. [Afeil, 



The daily means differ very little. No. 2 is only 0'1° cooler than No. 

 1. The maximum differs slightly. No. 2 maximum is 1-3° higher than 

 No. 1. On the other hand, No. 2 minimum is 0-4° lower than No. 1. The 

 radiation from the ground upon which the sun shone all round the 

 thermometer of No 2 was no doubt the cause of the higher temperature 

 during the afternoon. 



4. The elevated observatory No. 2 is situated in a portion of the 

 Forest Office compound which is planted with fruit trees about 18 feet 

 high and alongside of a solitary large fig tree, the crown of which reaches 

 as high as the observatory, about 70 feet above the ground. At the sur- 

 face of the ground the trees have some influence. When there is frost 

 outside, there is none immediately underneath the trees. The observatory 

 No. 2 itself is, however, so much elevated that the small fruit trees below 

 cannot well influence it much : it stands also quite free of the large fig 

 tree and I suppose the readings must be nearly the same as if the obser- 

 vatory stood directly over No. 1 on the grass plot. The distance between 

 the two observatories No. 1 and No. 2 is 400 feet. 



5. The readings at the two observatories were made every day twice, 

 Sundays excepted. On odd dates No. 1 was observed first and on even 

 dates No, 2 was observed first. This was done to avoid differences arising 

 from the time it took the observer to get from one observatory to the 

 other. 



6. The observations were made by Babu Annadaprasad Ray, Mathe- 

 matical Master of the Forest School. Once during October 1882, Mr. 

 Laurie observed alternatively with the Babu, and it was a source of great 

 inconvenience to have two people observing, one in the morning and one in 

 the evening. Mr. Laurie's other duties sometimes prevented his reading, 

 and at other times he did not pour water into the vessels, so that the Babu 

 found the thermometers dry the next morning. Babu Kalikant Kar 

 observed for a fortnight in February, 1883. When he was prevented, he 

 deputed once a third party to read for him. Once the Mathematical master 

 got a chaprasi to put new cloth on the thermometers of No. 2 : the 

 chaprasi did not set the pins and thus the next reading of the wet minimum 

 was lost. Once I found that the Mathematical master had deputed a 

 chaprasi to water the thermometers of No. 2 on Monday morning : the 

 chaprasi did not do what he had been told and readings were lost. 



Such were the accidents which came, off and on, to my notice. I had 

 opportunity to check the observations very often. I checked especially 

 minima and maxima by reading them sometimes before they had been 

 observed by the observer and comparing afterwards. I made also repeated- 

 ly experimental readings and observations for various other purposes, which 

 served as a check to the records. 



