324 KANSAS CITY REVIEW OF SCIENCE. 



I claim to be. I believe if they will resort to diagrams and mathematics, astron- 

 omers have the data for determining both of these with the utmost precision. 



On Plate II we have a representation of the moon in its revolution about 



the earth. All will admit that the moon makes its revolutions after this manner. 



May we have some analogical reasoning here? " The science of astronomy had 



its origin in the study of the moon." Were it not for the moon astronomers would 



have been left to grope in comparative darkness. It is doubtful whether even 



the law of gravitation would have been discovered. If the moon has been so 



useful in suggesting truth in other directions why not look to it for a hint on the 



anner of efecting revolutions 1 Better do this than make the moon an oddity in 



the planet family, as some are disposed to do. Surely the moon is none other 



han a satellite. It makes its revolutions very much as does the outer satellite of 



Jupiter. So it would appear if seen from Venus or Mercury. 



I must insist that the planets make their revolutions with reference to their 

 ruler, the Sun, very much as the Moon does with reference to its ruler, the Earth, 

 Then, as the Moon only seems to move around the earth, so the planets only 

 seem to move around the Sun. In their movements through space the earth and 

 moon pass and repass each other, thus giving the appearance of movement in an 

 orbit. So, in their movements through space, the earth and Sun pass and repass 

 each other, thus giving the appearance of movement in an orbit. So, I suppose, 

 in their movement through space, the Sun and Sirius pass and repass each other, 

 thus giving the appearance of movement in an orbit. So, like the old astronomers 

 in relation to the earth, we have been taking the apparent for the real. I am 

 compelled to believe that all the spheres of the system are moving in the same 

 general direction : A law of supremacy and of subordination giving to each the 

 path in which it is to move ; that in most cases, what we call the orbit is formed, 

 the one half by the faster movement of the subordinate sphere ; the other half by 

 the faster movement, relatively, of the ruling sphere. They pass and repass each 

 other, and out of that comes our revolutions. 



Some one asks, " What then beconies of Newton and Kepler? " The laws 

 that Newton discovered will take care of themselves. And they will be found 

 to apply nowhere more beautifully than in the theory of movement here presented. 

 As to the first and second of Kepler's laws, they are in a sense true. They are 

 true if you speak only of something which \% apparent. The first law is, "The 

 planets move around the Sun in elliptical orbits." In the same sense in which 

 this is true of the moon and earth, it is true of the planets and the Sun. Turn to 

 the diagram on the moon's revolution, Plate II, and there define your idea of 

 moving around^ and of orbit ; but especially of moving around. There you see in 

 what sense this is true and in what sense it is false. In the primary meaning of 

 these words it is not true. And the moving around is as ideal as the orbit. But 

 the law is true of the relative positions of the planets and the Sun during apparent 

 revolutions. In relative position we have the conditions of an ellipse, a revolu- 

 tion, an orbit. 



Kepler's second law is that "the radii vectores pass over equal spaces in 



