a 64 FHA GMENTS OF SCIENCE. 



question intrudes itself with resistless might, Whence 

 comes the sequence? What is it that bjnds the consequent 

 to its antecedent in nature? The truly scientific intellect 

 never can attain rest until it reaches the forces by which 

 the observed succession is produced. It was thus with 

 Torricelli; it was thus with Newton; it is thus pre-emi- 

 nently with the scientific man of to-day. In common with 

 the most ignorant, he shares the belief that spring will 

 succeed winter, that summer will succeed spring, that 

 autumn will succeed summer, and that winter will succeed 

 :autumn. But he knows still further and this knowledge 

 is essential to his intellectual repose that this succession, 

 besides being permanent, is, under the circumstances, 

 necessary; that the gravitating force exerted 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 relation between forces and 

 phenomena has been established, is the law of reason ren- 

 dered 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 perma- 

 nent the phenomena are necessary, whether they resemble 

 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 New- 

 ton, from Newton to our own time, eager eyes have been 

 scanning the heavens, and clear heads have been ponder- 

 ing the phenomena of the solar system. The same eyes 

 and minds have been also observing, 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 moment 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 oper- 

 ation, in the time of Galileo, the competent mathematician 

 of that day could predict what is now occurring in our 

 own. We calculate eclipses in advance, and find our cal- 



