RELATION OF CONDITIONS TO HABITAT DISTINCTION^. 



47 



higher than that for the corresponding week at Cinchona, and that for 

 the latter week being only one-twelfth that for Cinchona. 



The Ravine station was located at the spot shown in plate 1, in the 

 dense shade of tree ferns, above which were growing Solatium and 

 Gilibertia. The sun was rarety able to strike the atmometer, which 

 was situated on the ground. The evaporation rate in the Ravine was 

 constantly low, fluctuating only between 8.8 c.c. and 2.7 c.c. per week, 

 or 1.2 c.c. and 0.4 c.c. per day respectively. 



Table 10. Rates of evaporation in the Cinchona region, July io Xovemher, 1909. 



The addition of the weekly totals of evaporation for all of the weeks 

 in which simultaneous readings were secured at Cinchona and in the 

 Ravine gives 715.6 c.c. and 52.7 c.c. respectively. Reducing the rate 

 of loss in the Ravine to unity gives a value of 13.5 for Cinchona, the 

 average difference between the evaporation in the two localities being 

 slightly greater than the maximum fluctuation of weekly rate at 

 Cinchona (1:9.8). The addition of the weekly totals for the period 

 in which atmometers were running at all three stations simultaneously 

 gives amounts as follows: Cinchona 319.3 c.c, Ridge 120. 1 c.c, Ravine 

 21.8 c.c. Reducing these amounts to terms of the Ravine as unity 

 gives the following relative values: Cinchona 14.5, Ridge 5.7, Ravine 

 1.0. A value in this series for the Windward Slopes would probably 

 fall between 3.0 and 4.0, which would mean that the total evaporation 

 of the Leeward Slopes at Cinchona is from four to five times as gr 

 as that of the Windward Slopes in the vicinity of Morce's Gap. 



