Page:The Journal of Indian Botany.djvu/383

OBSERVATIONS ON THE VOLVOCAGEAE.

331 the end of ifc, when its force gets more and more spent, we in Madras get small showers (local showers) at very frequent intervals.

The effect of these small intermittent summer showers is, falling as they do on a parched up soil, merely to wet the surface soil and to fill up the various small depressions in the ground, causing numerous rain water pools all over the place. During these Summer Monsoon months the water in these pools is constantly changing its level. Thus after a fairly good rain the depressions are filled up. During the succeeding rainless days, the level of the water goes down slowly, and in the shallower depressions the water dries up completely. In the deeper pools, however, where the water does not get com- pletely dried up, a fresh rain sends the level up once more. And this process is repeated again and again.

During the N. E. or Winter Monsoon, the rains are heavy and generally continuous. And all the big tanks, streams, ponds, pools, and all low-lying tracts of land get filled up and often overflow. The numerous small rain-water pools that are merely filled up during the Summer Monsoon Season are during this season completely flooded and practically washed out.

The temperature during the S. W. Monsoon months though slightly lower than in May is still fairly high and the sky is generally cloudy and the weather very sultry, the month of September being the most sultry and trying part of the whole year. But with the advent of the N. E. or the Winter Monsoon, the temperature soon goes down and the weather, though the sky is often cloudy, is quite cool and pleasant.

The following table gives the details of the temperature, rain- fall and cloud values of the different months of 1919 at Madras : —