46 John Eliot — On the occasional Inversion of the Temperature [No. I, 



ture at the level of the plains would probably fall to about 36° on such 

 clear nights, the minimum temperature in the plains would hence be 

 slightly below that at the hill stations 6000 feet above. 



The previous supposition gives an average case, and shews that in or- 

 dinary anti-cyclonic weather in December and January the minimum tem- 

 perature at the hill stations tends to be higher than at the plain stations. 



The following are specific examples taken from the observations of 

 the inversion of the vertical temperature relations was most marked : — 



On the 2nd the maximum temperature at Rawalpindi was 70'5°. 

 The corresponding temperature of convection at the level of Murree 

 4800 feet higher would be (70'5 — 24°) or 46"5°. The minimum tempera- 

 ture on the night of the 2nd was 49"3° or slightly greater. On the 3rd, 

 the maximum at Rawalpindi was 68'9° and the convection temperature 

 at the level of Murree 449°, which was practically identical with the 

 actual minimum at Murree 44.6°. The minimum temperatures on these 

 two nights at Rawalpindi were 37"4° and 36 9° or 11'9° and 7-7° lower 

 than at Murree. Again at Ludhiana on the 3rd the maximum was 77' 7 

 and at the level of Simla 6200 feet high the corresponding convective 

 temperature would be (77'7° — 3L°) or 46'7°. The minimum at Simla on 

 the night of the 3rd was 48'4° and 2"8° higher than at Ludhiana. At 

 Roorkee on the same day the maximum was 72'3° and the corresponding 

 convective temperature at the level of Musoorree (6000 feet higher) was 

 42*3°. The minimum at Mussooree was actually 42 - 0° and 5*7° higher 

 than at Roorkee. It is not necessary to multiply examples, as these shew 

 roughly that the minimum temperatures at the hill stations and therefore 

 the temperature during the greater part of the evening and night is prac- 

 tically that of dry air at the level of the hill station rising rapidly with 

 the maximum day temperature at the level of the plains or what may be 

 termed the convective temperatures corresponding to the maximum 

 temperature conditions of the lowest stratum. 



Hence the explanation and facts appear to establish the following: — 

 (a) — In ordinary anti-cyclonic weather when the horizontal air 

 motion by day or night is very small, the temperature at 



With these figures may be compared the following temperature observations 

 recorded at Lahore on the same days. 





Temperature of the air at 



Maximum 

 tempera- 

 ture during 

 day. 



I «a.g 



P n E? _J 



Date. 



4 hrs. 



8 hrs. 



10 hrs. 



16 hrs. 



22 hrs. 



Minim 



tempe 



ture du 



nigh 



December 9th ... 

 11th ... 



405 

 410 



475 



460 



660 

 660 



762 

 725 



5C0 

 486 



74-2 

 75'2 



389 

 394 



