;{|H SMITH : \rri.H \TKtN OF THE THEORY OF 



occurred on June Kit hand 14th at Peradeniya, the temperature 

 of the bamboo remains lower than the temperature of the air 

 until noon. Should rain occur, accompanied as it usually is by 



;i rather sudden lowering of air temperature, we find that the 

 bamboo temperature falls much more slowly, so that after 

 ram the internal temperature of the bamboo is higher than 

 the surrounding air temperature. Again, when the air cools 

 rather rapidly towards evening, Say 4-6 p.m.. the bamboo lags 

 behind and is invariably higher than the air temperature at 

 this period. If this were the only effect however we should 

 find the bamboo on the average with the same temperature 

 as the surrounding air, but exhibiting a lag all through the 

 observations. This simple result is usually complicated by 

 the effect of bright sunlight or very bright diffuse light. If a 

 culm is exposed to sunlight its internal temperature rises 

 rapidly and often, as in the case of the one at Kandy (Table I.), 

 leaches a temperature higher than the maximum reached by 

 the surrounding air. Having been thus heated up the culm 

 lakes a long time tocooldown. and in these eases is higher in 

 temperature than the surrounding air all through the night. 

 This is very well seen in the case of the culm at Kandy (Table 

 I.), which shows a higher temperature on the average than the 

 surrounding air, and is only in fact lower for a short period in 



• ally morning before it receives the rays of the sun. The 

 culm at Anuradhapura (Table II.) was not exposed so freely 

 io tin direct sun. and here we do not get an internal tempera- 

 ture very much exceeding the temperature of the air. The 

 effeel of the very bright diffuse light however seems to be seen 

 in the fact that the teni perat lire for the greater part of the L' 1 

 hoin- is slightly (from I to 2° C) ftbove the temperature of the 

 -in-rounding air. 



(Hwervations taken morning and evening on different culms 



shotted Uial at the morning reading the internal temperature 

 usually louei than thai of the surrounding air by a small 

 amount . 



