34 FRAGMENTS OF SCIENCE 



this succession, besides being permanent, is, under the 

 circumstances, necessary; that the gravitating force ex- 

 erted between the sun and a revolving sphere with an 

 axis inclined to the plane of its orbit, must produce the 

 observed succession of the seasons. Not until this rela- 

 tion between forces and phenomena has been established 

 is the law of reason rendered concentric with the law of 

 nature; and not until this is effected does the mind of 

 the scientific philosopher rest in peace. 



The expectation of likeness, then, in the procession 

 of phenomena, is not that on which the scientific mind 

 founds its belief in the order of nature. If the force be 

 permanent the phenomena are necessary, whether they"*^ 

 semble or do not resemble anything that has gone before. 

 Hence, in judging of the order of nature, our inquiries 

 eventually relate to the permanence of force. From 

 Galileo to Newton, from Newton to our own time, 

 eager eyes have been scanning the heavens, and clear 

 heads have been pondering the phenomena of the solar 

 system. The same eyes and minds have been also ob- 

 serving, experimenting, and reflecting on the action of 

 gravity at the surface of the earth. Nothing has occurred 

 to indicate that the operation of the law has for a mo- 

 ment been suspended; nothing has ever intimated that 

 nature has been crossed by spontaneous action, or that 

 a state of things at any time existed which could not be 

 rigorously deduced from the preceding state. 



Given the distribution -of matter, and the forces in 

 operation, in the time of Galileo, the competent mathe- 

 matician of that day could predict what is now occur- 

 ring in our own. "We calculate eclipses in advance, and 

 jfind our calculations true to the second. We determine 



