172 THE SEVEN FOLLIES OF SCIENCE 



it would take him to move the earth only one inch, suppos- 

 ing his machine constructed and mathematically perfect ; 

 that is to say, without friction, without gravity, and in com- 

 plete equilibrium, and the following is the result : 



For this purpose we shall suppose that the matter of 

 which the earth is composed weighs 300 pounds per cubic 

 foot, this being about the ascertained average. If the di- 

 ameter of the earth be 7,930 miles, the whole globe will be 

 found to contain 261,107,411,765 cubic miles, which make 

 1,423,499,120,882,544,640,000 cubic yards, or 38,434,476,- 

 263,828,705,280,000 cubic feet, and allowing 300 pounds 

 to each cubic foot, we shall have 11,530,342,879,148,611,- 

 584,000,000 for the weight of the earth in pounds. 



Now, we know, by the laws of mechanics, that, whatever 

 be the construction of a machine, the space passed over by 

 the weight, is to that passed over by the moving power, in the 

 reciprocal ratio of the latter to the former. It is known 

 also, that a man can act with an effort equal only to about 

 30 pounds for eight or ten hours, without intermission, 

 and with a velocity of about 10,000 feet per hour. If 

 then we suppose the machine of Archimedes to be put in 

 motion by means of a crank, and that the force continually 

 applied to it is equal to 30 pounds, then with the velocity 

 of 10,000 feet per hour, to raise the earth one inch the 

 moving power must pass over the space of 384,344,762,- 

 638,287,052,800,000 inches; and if this space be divided 

 by 10,000 feet or 120,000 inches, we shall have for a quo- 

 tient 3,202,873,021,985,725,440, which will be the number 

 of hours required for this motion. But as a year contains 

 8,766 hours, a century will contain 876,600 ; and if we 

 divide the above number of hours by the latter, the quo- 

 tient, 3,653,745,176,803, will be the number of centuries 



