24 WRITINGS OF JOSEPH HENRY. [1824- 



voirs. From the data furnished by the above table, which 

 may be considered as an approximation to truth, we find 

 that the whole amount of water is 10,500 cubic miles ; more 

 than one half of the fresh water on the surface of the globe.* 



The discharged waters of the upper lakes, in passing from 

 the middle to the lower sub-basin of the St. Lawrence, are 

 precipitated over the great falls of Niagara. This celebrated 

 cataract has been rendered so familiar to almost every person, 

 by the pen and pencil of the many travellers who have 

 visited it, that a formal description, in this sketch, would be 

 entirely unnecessary. About 20 miles below Lake Erie the 

 Niagara river narrows, and the rapids commence : these are 

 of such force and velocit}^, that their noise, agitation and 

 fury constitute an object of as much curiosity as the falls 

 themselves. On the very brink of the precipice, is situated 

 Goat island, which contains about eighty acres, and extend- 

 ing up the stream, divides the waters. At this place the 

 Niagara river, nearly half a mile wide, and flowing with im- 

 mense velocity, is j)recipitated headlong over a perpendicu- 

 lar ledge of rocks, into an almost unfathomable abyss below. 

 The height of the falls, from the surface of the water above 

 to that of the water below, is 151- feet on the Canada side, 

 and 164 feet on the American. The descent of the country 

 from Lake Erie to Ontario, is principally by a step, not at 

 the falls, but at Lewiston, several miles below. The surface 

 on each side is a level plain, through which the Niagara 

 river passes below the falls, in a deep chasm, nearly a mile 

 wide, with almost perfect mural sides. In viewing the posi- 

 tion of the falls, and the features of the country around, it 

 is impossible not to be impressed with the idea, that this 

 great natural race-way has been formed by the continued 

 action of the irresistible current of the Niagara, and that the 

 falls, beginning at Lewiston, in the course of ages have worn 

 back the rocky strata to their present site. 



The distances and descents along the Niagara river, from 

 Lake Erie to Lake Ontario, from actual survey, on the Amer- 

 ican side, are as follows : 



*See Edinburgh Encyclopaedia, Article " Phys. Geog.," page 605. 



