754 Mil. C. T. BELLAMY ON THE [Nov. I9OO, 



(13) Catchment of Lake and Areas. 



But the chief interest will be centred in fig. 2, p. 748. On this 

 map the original watershed or catchment of the lake is defined by 

 oblique hatching, and its entire area is computed at 22 square 

 miles, say 14,080 acres. The country which now drains directly 

 into the lake is cross-hatched, and its area is about 2*4 square 

 miles, say 1,536 acres ; while the surface of the lake occupies about 

 2-1 square miles, say 1,344 acres, and its circumference is about 

 lOf miles. Of the 22 square miles comprising the catchment, the 

 surface-water from 17| square miles is collected in the catehwater 

 or intercepting channels, and carried away to sea without being 

 permitted to enter the lake. Therefore only the rain falling within 

 an area of 4^ square miles, comprising the surface of the lake and 

 that of the land within the cross-hatched area, has a direct influence 

 upon the contents of the lake. 



As to the cubical capacity of the lake, if it be assumed that 

 the mean depth throughout is 1 foot, the contents will be, say, 

 77 million cubic feet (76,980,160 cubic feet correctly), which is 

 equivalent to about 480 million gallons in round numbers. 



(14) Rainfall. 



A fall of 1 inch of rain produces 14| million gallons of water per 

 square mile, and the amount of water collecting in the lake from 

 the cross-hatched area, as well as that falling upon the surface of 

 the lake itself as the product of 1 inch of rain, would therefore be 

 G5| million gallons. In order to fill the lake to the height at which 

 it stood at the time of observation, a fall of 7*35 inches would 

 suffice. 



The rainfall returns for Larnaca, the nearest point to the salt- 

 lake at which there is a rain-gauge, show that from the end of 

 August 1899 the following quantity of rain fell : — 



Inches. 



September 0'50 



October 1-27 



November 4*52 



December 1st to 19th 1-08 



7-37 



This quantity corresponds very nearly to that sufficient to fill the 

 lake, without taking into consideration the loss by evaporation or 

 other causes. 



It may be safely assumed that the net product of an inch of 

 rain falling upon the surface of the lake would be 100 per cent., 

 and that the run-off or surface-water from the cross-hatched area, 

 allowing for infiltration or absorption, would be 50 per cent, of the 

 rainfall. 



This fall of 7*37 inches over an area of 2*1 square miles repre- 

 senting the surface of the lake would amount to 224^ million 

 gallons,, and over the cross-hatched area of 2-4 square miles would 



