OF GIBRALTAR. 21 



gallons. On Europa-flat is a well of moorish con- 

 struction, which is said to be capable of holding one 

 hundred thousand gallons of water. So long as we 

 hold possession of a part of the isthmus which connects 

 Gibraltar with the mainland, and there falls the 

 average quantity of rain, there is little or no chance 

 of the garrison suffering from a complete drought. 

 The wells on the neutral ground, although only a 

 few feet deep, afford abundance of fresh water, and 

 they have not been known to fail even in the driest 

 seasons. The source of this abundant flow of fresh 

 water in almost a sandy desert, and so near the sea, 

 is a subject of some interesting speculations. The 

 only way I can account for it is, by attributing its 

 source to the mountains of Spain on the principle of 

 Artesian springs, or as some suppose, there may be at 

 no considerable depth below the sands, a layer of im- 

 penetrable rock which prevents the rain-water from 

 percolating to unfathomable depths, and thereby 

 makes the neutral ground a reservoir for water. 



The quantity of rain which falls during different 

 seasons varies considerably, as the following formula 

 will show : 



Rainy season of 1837 and 1838, there fell 50'53 inches 

 1840 and 1841 2MO 



1841 and 1842 22'20 



1843 and 1844 17'60 



1844 and 1845 45 13 



I may safely say, that on an average, Gibraltar is 



