TRANSACTIONS OF SECTION A. 447 
current first withdraws from North-Western India, being replaced by light, 
variable, or north-westerly land winds. These land winds increase in extension 
and volume with the continued contraction of the south-west monsoon current. 
The more important phases of the contraction and withdrawal of that circulation 
from India are of especial interest. The first phase, the retreat of the current 
from North-Western India, accompanies a rise of pressure over the Persian area 
and North- Western India, with a shift of the trough of low pressure from W.N.W. 
to N. or N.E. and corresponding change of direction of the average tracks of the 
storms of the period. This is followed after a short period of rain in North-Eastern 
India and Burma by a rise of pressure in Assam, Upper Burma, and Bengal, and 
the withdrawal of the monsoon current from those areas. The current then recurves 
over the centre of the Bay, in the same manner as during the monsoon proper 
over the north of the Bay and Bengal, and is directed or determined to the west 
or Madras coast of the Bay, which hence receives frequent rain during a short 
period of about two months—the rainy season of the eastern and southern parts of 
the peninsula south of Orissa and Ganjam. 
These rains were formerly described as accompanying the setting in of the 
north-east monsoon on the Madras coast. That, however, is a misnomer, as the 
true north-east monsoon winds are dry land winds, and the rain-giving winds of 
this period in Madras are those of the south-west monsoon in its retreat or con- 
traction down the Bay. The period during which this rainfall occurs is hence 
now usually termed the retreating south-west monsoon. 
The year in India may hence be divided into two monsoons of nearly equal 
length, viz.:— 
(a) The north-east or dry monsoon. 
(6) The south-west or wet monsoon, 
The first terms are based on the general direction of the air movement in the 
Indian seas during the periods, and the second on the most prominent feature of 
the weather in India itself. Of an average annual total rainfall of 41 inches 
(according to the most trustworthy calculation), at least 85 per cent. falls during 
the wet season, and only 16 per cent. during the dry season. 
The dry monsoon in India is subdivided into— + 
1, The cold-weather period. 
2. The hot-weather period or transitional period of preparation for the south- 
west monsoon. 
_ The wet monsoon is subdivided into— 
1, The south-west monsoon proper, or period of general rains. 
2. The period of the retreating south-west monsoon and gradual slow establish. 
ment of the dry monsoon, 
Each of these periods practically covers three months, 
One of the most noteworthy features of the meteorology of India not referred 
to in the previous statement is that the storms of each period—viz., the cold- 
weather period, the hot-weather period, and the wet monsoon—are characteristic 
and special to the period. They are all in the broadest sense of the word cyclonic 
in character; but they originate under different conditions and exhibit very 
different features in each of those periods. 
The disturbances of the cold weather are large shallow depressions which 
originate in the upper humid return current of the north-east monsoon circulation 
chiefly in the Persian plateau region, and which drift eastward with a slight 
southing across Extra-tropical India. Storms do not occur south of the Deccan 
or peninsula-dividing ranges during this period. These storms are chiefly 
remarkable for the frequent development of stationary secondary depressions 
in the Punjab, usually of much greater intensity than the primaries; a feature of 
which, I believe, there is no parallel elsewhere. They are of great importance, 
as they give the main snow supply to the Western Himalayas and the light but 
