252 FLOODS OF THE ARDECHE. 



low water, but the stream was again f ordable on tlie evening pf 

 tlie same daj. The inundation of 1827 was, in this respect, 

 exceptional, for it continued three days, during which period 

 the Ardeche poured into the Rhone 1,305,000,000 cubic yards of 

 water. 



The IS'ile deHvers into the sea 101,000 cubic feet or 3,74=1 

 cubic yards per second, on an average of the whole year.* This 

 is equal to 323,222,400 cubic yards per day. In a single day of 

 flood, then, the Ardeche, a river too insignificant to be known 

 except in the local topography of France, contributed to the 

 Rhone once and a haK, and for three consecutive days once and 

 one-third, as much as the average delivery of the Nile during the 

 same periods, though the basin of the latter river probably con- 

 tains 1,000,000 square miles of surface, or more than one thou- 

 sand times as much as that of the former. 



The average annual precipitation in the basin of the Ardeche 

 is not greater than in many other parts of Europe, but excessive 

 quantities of rain frequently fall in that valley in the autumn. 

 On the 9th of October, 1827, there fell at Joyeuse, on the 

 Beaume, no less than thirty-one inches between three o'clock in 

 the morning and midnight. Such facts as this explain the ex- 

 traordinary suddenness and violence of the floods of the Ardeche, 

 and the basins of many other tributaries of the Rhone exhibit 

 meteorological phenomena not less remarkable.f The Rhone, 



*Sir John F. W. Herschel, citing Talabot as his authority, Physical 

 Geography (24). 



In an elaborate paper on "Irrigation," printed in the United States Patent 

 Report for 1860, p. 169, it is stated that the volume of water poured into the 

 Mediterranean by the Nile in twenty-four hours, at low water, is 150,566,393,- 

 368 cubic metres ; at high water, 705,514,667,440 cubic metres. Taking the 

 mean of these two numbers, the average daily delivery of the Nile would be 

 428,081,059,808 cubic metres, or more than 550,000,000,000 cubic yards. 

 There is some enormous mistake, probably a typographical error, in this 

 statement, which makes the delivery of the Nile seventeen hundred times as 

 great as computed by Talabot, and more than physical geographers have 

 estimated the quantity supplied by all the rivers on the face of the globe. 



The estimates of physical geographers vary widely as to the total delivery 

 of water by the rivers of the earth to the sea. Metcalfe calculated it at 

 135,000,000,000 cubic metres per day ; Keith Johnson at 175,000,000,000, and 

 Elisee Reclus at 85,000,000,000.— Reclus, La Terre, 1., 516. 



f The Drac, a torrent emptying into the Isfere a little below Grenoble, has 

 discharged 5,200, the Is^re, which receives it, 7,800 cubic yards, and the 



