TERRESTRIAL MECHANICS PRECEDES CELESTIAL. 139 



precedes the geometrical part of celestial physics ; see- 

 ing that geometry gained its first ideas from surrounding 

 objects. Until men had learnt geometrical relations from 

 bodies on the earth, it was impossible for them to under- 

 stand the geometrical relations of bodies in the heavens. 



So, too, with celestial mechanics, which had terrestrial 

 mechanics for its parent. The very conception of force., 

 which underlies the whole of mechanical astronomy, is bor- 

 rowed from our earthly experiences ; and the leading laws 

 of mechanical action as exhibited in scales, levers, projec- 

 tiles, &c., had to be ascertained before the dynamics of the 

 solar system could be entered upon. What were the laws 

 made use of by Newton in working out his grand discovery? 

 The law of falling bodies disclosed by Galileo ; that of the 

 composition of forces also disclosed by Galileo ; and that 

 of centrifugal force found out by Huyghens — all of them 

 generalizations of terrestrial physics. Yet, with facts like 

 these before him, M. Comte places astronomy before phy- 

 sics in order of evolution ! He does not compare the geo- 

 metrical parts of the two together, and the mechanical 

 parts of the two together ; for this would by no means 

 suit his hypothesis. But he compares the geometrical part 

 of the one with the mechanical part of the other, and so 

 gives a semblance of truth to his position. He is led away 

 by a verbal delusion. Had he confined his attention to the 

 things and disregarded the words, he would have seen that 

 before mankind scientifically co-ordinated any one class of 

 phenomena displayed in the heavens, they had previously 

 co-ordinated a parallel class of phenomena displayed upon 

 the surface of the earth. 



Were it needful we could fill a score pages w^ith the in- 

 congruities of M. Comte's scheme. But the foregoing sam- 

 ples wall suflace. So far is his law of evolution of the 

 sciences from being tenable, that, by following his exam* 

 pie, and arbitrarily ignoring one class of facts, it would be 



