322 



ZONES AND REGIONS 



[Pt. Ill, Sect. I 



daily loss of water was the same in both cases, namely on the average o-6 gram 

 per hour, but even in this case transpiration during the hot midday hours appears to 

 have been much stronger in Buitenzorg than in Holland. 



Experiments made by G. Haberlandt at Buitenzorg in Januar}', which 

 i.s the middle of the rainy season, and at Gratz during the hot days of 

 August, showed that transpiration in the shade in a moist tropical climate 

 is much weaker than in Central Europe : — 



The humidity of the air fluctuated at the time when Haberlandt made his experi- 

 ments (December, January), between 70-97 %. ' The minimum (70-80 %) occurred at 

 about midday, but frequently not till i p.m. Then the humidity increased rapidly 

 as the rain began, and even by 3 or 4 p.m. attained 90-95 %. Omitting slight 

 fluctuations, which seldom exceeded 5%, the curve in its tj'pical course remained 

 from the evening till about 7 a.m. at 93-97 %, and then gradually sank again tilll 

 noon ^.' The temperature during the period of observation showed a diurnal variation! 

 of 6-8° C. 



'The diurnal curve of temperature, as a rule, showed the following course:— 

 Between 6 and 7 a.m. the temperature was lowest. The minimum varied, omitting' 

 extreme cases, between 2 r and 23° C. During the forenoon the temperature at first 

 rose rapidly, then somewhat more slowly up to 29-30-5° C. This maximum was 

 rarely attained by midday, usually not till between i and 2 p.m. Then the tempera- 

 ture fell to 23-25°, sometimes more rapidly, at others more slowly, according to the 

 cloudiness, or amount and duration of the rainfall in the afternoon.' 



AMOUNT OF TRANSPIR.A.TION OF LEAVES IN 

 AND IN GRATZ (after G. Haberlandt 2). 



BUITENZORG 



(In grams per diem and over one square decimeter of surface.' 

 I. Buitenzorg. 



Conocephalus ovatus . 

 Musa Ensete 

 Gonocaryum pyriforme 

 Daemonorops oblongus 

 Xanthophyllum vitellinum 

 Carica Papaya 

 Pterocarpus saxatilis 

 Cocos nucifera 

 Grammatophyllum speciosum 

 Bactris speciosa . 

 Theobroma Cacao 

 Albizzia moluccana 

 Ficus elastica 

 Sanchezia nobilis . 

 Loranthus pentandrus . 

 Phoeni.x sp. . 

 Acalypha tricolor 



^ Haberlandt, I, p. 6. 



0-29 

 0-4S 

 0-45 

 0.47 

 0-58 

 0-62 

 071 

 0-89 

 0-89 

 I -00 

 I -06 

 1-19 



1-52 



1.56 

 1-86 



2-6o 



II, p. 807. 



