POWER OF SUNSHINE IN LIFTING WATER. 151 



beds of torrents, and forming strata in the hill- 

 sides and plains, were sculptured by sunshine. 



The power of sunshine is shown in the raising 

 of waters from the briny seas, to form inland seas 

 of fresh water, high above the level of the oceans. 

 In order to appreciate the extent of the hydrau- 

 lic operations in the mechanics of Nature, we 

 must attempt to estimate them. 1 



By concentrating the direct sunshine by lenses 

 or reflectors on a little boiler, sufficient power may 

 be obtained to operate a small steam-engine. It 

 is narrated in history that Archimedes had recourse 

 to reflecting mirrors for setting fire to a hostile 

 fleet in the harbor of Syracuse. 



By means of steam-engines, man utilizes the sun- 



1 During a summer excursion to Niagara, in the year 1841, after 

 viewing the Falls, the writer became interested to learn the amount of 

 water-power there developed. 



After personally making the attempt to sound the depths of the rap- 

 ids across the river, and realizing the difficulty and danger by losing an 

 anchor, recourse was had to the professional services of an engineer in 

 that vicinity. An accurate survey was then accomplished of the quantity 

 of water daily flowing in the river. An account and map of this survey 

 was published in Silliman's "Journal of Science," in April, 1844; being 

 the first systematic measurement, if not the only one, made of the volume 

 of water and force of that mighty cataract. By this survey it was found 

 that 701,000 tons of water per minute are continually pouring over the 

 precipice of rocks at Niagara, with a nearly perpendicular descent of 

 1 60 feet, and with a mechanical force of 6,800,000 horse-power. 



The whole descent from the level of Lake Erie to the sea being about 

 563 feet, the force of this stream is 24,000,000 horse-power. To this 

 is to be added numerous great tributary rivers in its course, and the 

 descent of the water-fall from lofty clouds in rain-drops. To maintain 

 the flow of this single river there is employed unceasingly nearly three 

 hundred millions horse-power, estimated in foot-pounds. This example 

 affords a faint idea of the extent of solar power constantly exerted in 

 raising water to irrigate our earth. 



