INTERNAL TEMPERATURE OF LEAVES. 289 



The following figures, taken from Wright's paper, show the 

 average mean monthly relative humidity for Kandy (three 

 miles from Peradeniya) : — 



It is therefore quite likely that only in the drier period is 

 there a transpiration active enough to bring up to the growing 

 periphery of the tree a supply of salts sufficient to meet the 

 demand of the large amount of new material manufactured. 

 At least it may be said that the species growing at this drier 

 period are doing so under more favourable conditions for the 

 promotion of the new growth. 



The experience of tea planters in the wetter regions of Ceylon, 

 where during the south-west monsoon the monthly rainfall 

 reaches 40-50 inches, and the days are continuously cloudy 

 with high humidity, is confirmatory of these observations. 

 During the wet humid months the growth of the tea as measured 

 by the amount of leaf plucked falls off considerably. It has 

 been possible, by the kindness of the Superintendent of the 

 Abergeldie estate belonging to the Scotti-sh Ceylon Tea Com- 

 pany, to give a curve showing the number of pounds of green 

 leaf plucked from one of the fields of that estate during 1905. 

 The rainfall is also given for each month. The figures are 

 given in average number of pounds of tea grown per day, and 

 are obtained by dividing the total number of pounds obtained 

 at each plucking by the number of days from the end of the 

 previous plucking to the end of the one in question. This 

 average number is placed in the curve at a date corresponding 

 to the middle of the period from one plucking to the next. 

 Thus the record supplied to me gives June 15-20 2,673 lb. 

 plucked, June 21-30, 1,477 lb. plucked. Thus 1,477 lb. has 

 grown between June 20 and June 30, i.e., in 10 days. This 

 gives an average growth per day of 148 lb., and this has been 

 placed in the curve on the date June 25. This procedure 

 has been necessary on account of the irregularity of the periods 

 of plucking. I have selected for representation in the curve 



