22 Mr G. R. Blackwell on the 



circumstance of its issuing from Lake Erie, in an average 

 equalised current throughout the various seasons of the year, 

 unaffected by the droughts of summer and the floods of win- 

 ter. In order to ascertain the average volume of water dis- 

 charged by most other rivers of the earth, it becomes neces- 

 sary to multiply a great number of observations during the 

 several seasons of the year. But the flow of the Niagara 

 River remains always nearly the same, varying only from the 

 action of winds on the surface of Lake Erie, and from a pe- 

 riodical succession of several rainy or dry years in the broad 

 regions ot the upper lakes.* 



The results of the admeasurements of the volume of water 



* It appears from the best inforaiation I was enabled to obtain, that a 

 strong breeze or gale on Lake Erie^ in the direction of the outlet of this 

 lake, will cause the waters to become heaped up at that end, so as to pro- 

 duce a rise of the level of about two feet, and a corresponding rise of 

 the Niagara River. A subsidence of the level of the surface to an equal 

 extent occurs^ whenever a gale takes placed in an opposite direction, 

 making a total variation of about four feet in the rise and fall of the 

 level of the river, from the simple action of the wind on the surface of 

 the lake. These changes of level have sometimes taken place in the 

 course of a few hours. A nearly equal, but more gradual change of level 

 is produced, as before stated, by the alternations of a period of several 

 rainy years followed by a period of successive years of comparative 

 drought. The descent of the waters of Niagara River^ from the outlet 

 of Lake Erie, is at first so considerable, as to cause the flow of the cur- 

 rent to become accelerated to a velocity of about eight miles per hour. 

 By means of an embankment^ constructed parallel with the shore, along 

 the margin of the river, the level of the surface of Lake Erie is main- 

 tained or upheld, through a distance of several miles, above the level of 

 the descending stream. This embankment serves to form a portion of 

 the Erie Canal, and also to convey a supply of water to several large 

 flour-mills at Black Rock ; thus afibrding an efiicient fall of about five 

 feet. 



From the general levelness of the low banks of the river between 

 Black Rock and Lewiston, it appears probable that water-power, to any 

 extent that ever will be required, may be obtained by diverting the 

 water of the Niagara River over the table land adjacent to its bed ; and 

 that mills might there be erected sufiicient to grind all the wheat pro- 

 duced on the broad regions of country whose tributary waters swell 

 the great lakes, and the Niagara affording unrivalled facilities for trans- 

 porting the wheat to these mills. 



