152 PHYSICAL GEOGRAPHY. 



On the ocean alone " the sun raises during every minute an aver- 

 age of not less than 2,000,000,000 tons of water to a height of three 

 and a half miles — the mean altitude of the clouds." In other 

 words, to raise this quantity of water to the height of three and a 

 half miles per minute, would require the continued exercise of the 

 force of 2,757,000,000,000 horses per minute. 



Here then is a power enormous beyond conception. Now such 

 engineers as Ericson, have announced the opinion that an engine 

 run by solar heat is practicable. He has even constructed an engine 

 that gives uniformly a speed of 240 revolutions per minute, and at 

 this rate uses up only a part of the steam produced by his solar 

 generator. His machine includes a concentrating apparatus by 

 means of which the feeble intensity of the sun's rays is increased to 

 the degree that will answer to produce steam at a working pressure. 

 He has also shown that such " a concentrating apparatus will 

 abstract in all latitudes between 45 North and 45 South at least 

 three and a half heat units for every square foot presented vertically 

 to the sun's rays." " With one hundred square feet of surface, 

 eight and two-tenths horse power would be developed during nine 

 hours between the above latitudes." In the latitude of Nebraska it 

 could be used for at least ten hours on each day of sunshine. 



Monchat has advanced even farther than Ericson, and exhibited 

 a solar engine at the Paris exhibition that attracted the attention of 

 engineers from all lands. It received one of the medals of the ex- 

 hibition. 



u The time will come," says Ericson, " when Europe must stop 

 her mills and factories for want of coal. Upper Egypt, then, with 

 her never-ceasing sun-power, will invite the European manufacturer 

 to remove his machinery and erect his mills on the firm ground 

 along the sides of the alluvial plain of the Nile, where sufficient 

 power can be obtained to enable him to run more spindles than a 

 hundred Manchesters." Now it is true that the coal fields of the 

 United States will not be exhausted for many thousand years, 

 but the transportation of coal is costly, and there is no reason, if solar 

 engines are possible, why the sections that are adapted to them 

 should not use them, especially if their cost is much less than those 

 run with coal. 



Now then, in Nebraska, as if it was a region specially reserved 

 for the exhibition of the adaptability of the solar engine to the uses 

 of civilization, there is a remarkable amount of sunshine. As we 



