510 ANNtTAI, EEST IS UNIVERSAL. 



writes Aug. de St, Hilaire, is in a state of constant activity. The ■winter 

 is only distinguished from the summer by a changed green of the leaves, 

 and if some trees lose their leaves it is only to be immediately replaced 

 with new ones. In some districts, however, the trees become leafless 

 every year. This happens when the rains, which endure for six months, 

 suddenly cease, which takes place in February, and the heat increases 

 gradually till June. In this latter month the trees are almost leafless, 

 but in August again, before the rain commences, the buds have again 

 expanded, and the trees are covered with leaves. The cause of this 

 fall of the leaf is no doubt owing to the dryness of the soU, but it can 

 only occur in some exposed districts of the primitive forests, as in most 

 cases the trees are found on the borders of great rivers and on naturally 

 damp soUs, where the earth into which they strike their roots is never 

 dry. — Treviranus. 



In other parts of the tropics the seasons of growth and rest 

 are equally marked. In Ava, during the rainy season, which 

 lasts from May to October, the mean temperature varies from 

 78° to 91.5°; while, in the dry season, from November to 

 April, it falls to from 63° to 80°. At Calcutta, in the growing 

 season, from AprU to October, fifty-eight inches of rain com- 

 monly fall, with a mean temperature of 79° to 86°; while 

 during the season of rest, from November to March, there is not 

 perhaps an inch of rain, and the thermometer sinks to from 66° 

 to 80°. At this time vegetation is said, in such countries, to 

 " labour under a deadly languor ; but one night's rain converts 

 an arid plain into a verdant meadow." 



In most of the West India Islands situated under the tropic 

 of Cancer, there is said not to be much difference in the 

 climate, so that accurate observations made on any one of 

 them may be applied with little variation to them all. Malte 

 Brun gives the following sketch of their seasons. "The spring 

 begins about the month of May; the savannas then change 

 their russet hue, and the trees are adorned with a verdant 

 foliage. The periodical rains from the south may at this time 

 be expected ; they fall generally about noon, and occasion a 

 rapid and luxuriant vegetation. The thermometer varies con- 

 siderably; it falls sometimes six or eight degrees after the 

 diurnal rains, but its medium height may be stated at 78° 

 Fahrenheit. After these showers have continued for a short 

 period, the tropical summer appears in all its splendour. 



