OBSERVATIONS ON THE FALL OF RAIN. 167 
wards the interior; the river, after passing through 
Lough Neagh, finally discharges its waters at 
Coleraine into the North Channel. 
ne hills are composed of primary and tran- 
sition strata, many parts uncovered with any kind 
of earth or vegetation, the declivities for the most 
part being excessively steep. 
Rain gauges were placed at Lough Island 
Reavy, 400 feet above the sea, and on the sum- 
mit of the Spelga Mountain 1400 feet above the 
sea. The gauge at Lough Island Reavy was 
placed within about 9 ins. or a foot of the level 
of the ground—that on Spelga, within the same 
distance of the top of a mound raised about four 
feet above the general level of the ground, with a 
trench dug round it to prevent the approach of 
sheep which fed upon the mountains. 
From October 1837 to October 1838 there 
fell at Lough Island Reavy 72 2 ins., and on 
Spelga 74 ins. of rain. 
This period was below an average in other 
places where observations were taken, as were 
also the succeeding years to 1841. It was difli- 
