80 H. Wartli — Air -temperature 8f humidity at different elevations. [April, 



9. This table will in some measure fulfil the suggestions made by 

 the Meteorological Reporter to the Government of India, pages 169 and 

 170 of Part II, Indian Meteorologist's Vademecum. 



The difference of temperature between 4 feet and 63 feet is considera- 

 ble. The minimum is, at 66 feet, 7'4° higher, the maximum, I'S** lower, and 

 the daily mean, 3"2° higher than at 4 feet. 



I have taken great trouble to find out a law according to which the 

 great difference of the minimum thermometer changes in different months. 

 Everything failed, even a comparison with the nocturnal radiation ascer- 

 tained by a minimum thermometer on grass at the Great Trigonometrical 

 Survey. 



The vapour tension illustrates minutely the theory given, page 14, para. 

 15 of the Vademecum, Part II. Near the ground where there is a supply 

 of moisture, the vapour tension rises from morning till evening considerably. 

 At 66 feet, where the vapour is only received by diffusion from below, it 

 rises very little in comparison and diminishes towards evening. 



10. I have now to communicate the results of experiments which I 

 made to ascertain the rate at which the changes of temperature progress 

 from the bottom of the scaffolding to the top. For this purpose I fixed a 

 thermometer cage to the scaffolding at 49 feet above the ground. The 

 protection was afforded by the platform of planks, to the lower side of 

 which I screwed the temporary cage. I observed for 12 days personally 

 the dry and wet minimum at all three cages, 4 feet, 49 feet and ijQ feet 

 above the ground. After this I shifted the temporary cage lower down by 

 screwing it to the boards of a lower platform. It was here 25 feet above 

 the ground. I observed again for 11 days. Thus I obtained figures to 

 compare the cage at 4 feet in standard pattern thatched shed with the 

 temporary cage at 25 feet and at 49 feet on the scaffolding and the perma- 

 nent cage 66 feet above the ground also on the scaffolding. 



The following shows the actually obtained mean temperatures and the 

 increments reduced from both experiments to one mean standard. 



\ 



♦ 



Mean reading 

 12 days in February, 



1882. 



Mean reading 

 11 days in March, 



1882. 



Reduced increment 

 one standard. 





Dry 



Mini- 

 mum. 



Wet 

 Mini- 

 mum. 



Dry 

 Mini- 

 mum. 



Wet 

 Mini- 

 mum. 



Dry 



Mini- 

 mum. 



Wet 

 Mini- 

 mum. 



4 feet 

 25 feet 

 49 feet 

 66 feet 



416 



471 



48-3 



397 



421 

 48-2 



450 

 481 



Vo-s 



43-5 

 44-9 



46 1 



0-0 

 3-4 

 5-0 

 61 



00 

 1-7 

 2-2 

 3-2 



