Energy and Ether. 1013 



rophyl, which are the mouths by which the tree eats. Its proper 

 food is pure carbon. Its only supply is in the atmosphere where the 

 carbon is mixed with oxygen in the shape of carbonic acid gas. The 

 plant of itself cannot separate the carbon from the oxygen, but the agi- 

 tation of the sunlight upon the gas loosens the hold of the carbon and 

 oxj'gen upon each other, and then the carbon molecules are absorbed by 

 the leaf and carried into the sap of the plant. Trees, grass, and 

 weeds formed in this way ages ago, and washed into lakes, or growing 

 up and falling down in marshes, thus became formed into beds, and 

 being buried under vast deposits of rock and earth, have finally become 

 coal. The heat made by burning this coal under a boiler is energ} 7 that 

 the sun projected upon this earth 80, 000, 000 of 3 r ears ago, and has 

 been locked up in that coal all that time. The heat and light which are 

 now given off are simply a continuation of the energy of these ancient 

 solar radiations waked from its long nap and resuming its activity. 

 The force exerted by the man who shovels this coal into the furnace is 

 likewise a continuation of the energy of sunlight. The muscles and 

 brains of the man have been built up from materials taken from the 

 bread and beef he has eaten, and these have been formed from the 

 wheat and grass, which have grown by help of the sun's rays in the 

 same way as the coal plants did 80.000,000 years ago. Thus all muscu- 

 lar and mental energ} r of man and beast is onl} r a continuation of solar 

 radiation in new forms. Then there is wind power and water power, and 

 these too are products of the sun's rays. (See page 322.) We also 

 have electricity produced by the action of the sun (page 338), and 

 when it is produced artificially, it is still derived from the sun through 

 coal or wood fuel, or by means of water power. Thus all the motion 

 on earth, except that resulting from the attraction of gravitation, is only 

 the motion of the sun's radiation, arrested and deflected into new forms 

 and modes. All except gravitation. The sun gives a boy the power 

 to throw a ball up into the air, but it comes down again by the force of 

 gravity which appears to be an affection of every particle of matter in 

 the universe, and is independent of the sun. The sun has it in common 

 with all other bodies, and it is this power by which all the suns are able 

 to hold their tributary planets to their allegiance and to establish the 

 compromise orbits in which they travel. The force of gravitj r depends 

 on the distance apart of the attracting bodies, decreasing according to 

 Newton's law, in proportion to the square of the distance. 



Thus a wagon load of sand weighing 2,916 pounds at the earth's sur- 

 face will weigh only 729 pounds at a distance of 4, 000 miles, and at 

 216,000 miles, it would weigh just a pound. At 240,000 miles, which 

 is the distance of the moon, it would be attracted by the earth with the 

 force of 0.81 of a pound. At 93,000,000 of miles (the distance of 



