THE RAINFALL OF JAMAICA. / 



Here we see that the north-eastern division has the largest rainfall ; then 

 comes the west-central ; then the northern ; and lastly the southern. 



But between the two decennial periods there was a curious shifting of the 

 rainfall from the north-east and northern divisions to the west-central and 

 southern divisions. In the second decennial period both the north-eastern and 

 northern lost six inches, while the west-central gained five, and the southern gained 

 four ; so that the whole island lost somewhat less than one inch. 



Such variations are due to the flood-rains chiefly falling in different localities. 



The rainfall divisions were not arbitrarily made ; the north-eastern and 

 northern divisions of the Island have winter rains in November, December, and 

 January ; the north-eastern and west-central divisions have summer rains ; and 

 the southern division is dry, having rains for the most part only during the 

 May and October seasons. 



Now it so happens that when Dr. Hans Sloane * was in Jamaica, as physician 

 to the Duke of Albemarle, Governor of Jamaica in the year 1687, he noticed 

 the May and October rains ; the winter rains on the north side, the summer rains 

 on the central hills, and the small rainfall on the southern plains. Consequently 

 the chief characteristics of the Jamaica rainfall have not altered for two hundred 

 years. 



It is not our present object, however, to consider the details of these rainfall 

 divisions which are so useful for statistical purposes ; we have rather to explain 

 the Rainfall Maps, which are coloured so as to represent the rainfall over different 

 areas for each month of the year, and for the year itself. 



JANUARY. Over the north-eastern part of the Island there are heavy winter 

 rains of ten to fourteen inches, which diminish westwards and southwards, no 

 doubt more gradually than is shown by the colouring ; but an abrupt scale 

 of colouring, such as that adopted, is necessary for the correct printing of the 

 Maps and their subsequent use. 



FEBRUARY. The winter rains have nearly disappeared ; the gauge at the 

 Blue Mountain Peak alone showing heavy rainfall. And clearly this is the driest 

 month of the year, although the effects, such as want of grass and water, are not, 

 as a rule, felt until March. 



MARCH. Refreshing showers now sweep the central parts of the Island, 

 leaving the northern and southern parts still very dry. 



APRIL. There are curious patches of colour in the east, and also in the 

 west, where the west-central division now makes its appearance ; and it will be 

 noticed that the sources of the Black River (and perhaps those of the Great River) 

 are replenished very distinctly. 



MAY. Very heavy rains fall in the parish of Portland ; heavy rains fall over 

 the central parts of the Island from east to west ; and moderate rains fall on 

 the northern and southern parts, with the exception of a very few places near 

 the seashore. These rains are accompanied by thunder-storms, which continue to 

 the end of September. 



JUNE. The rainfall this month exhibits strangely curved figures, and shows 

 the necessity of Maps, however roughly drawn. More stations are required in the 

 central parts of the Island in order to trace these outlines correctly. 



* Afterwards Sir Hans Sloane, the founder of the British Museum. See his 'Natural History 

 of Jamaica.' 



