312 HISTORY OF MECHANICS. 



CHAPTER I. 



PRELUDE TO THE EPOCH OF GALILEO. 



Sect. I. Prelude to the Science of Statics. 



SOME steps in the science of Motion, or rather in the science ol 

 Equilibrium, had been made by the ancients, as we have seen. 

 Archimedes established satisfactorily the doctrine of the Lever, some 

 important properties of the Centre of Gravity, and the fundamental 

 proposition of Hydrostatics. But this beginning led to no permanent 

 progress. Whether the distinction between the principles of the doc- 

 trine of Equilibrium and of Motion was clearly seen by Archimedes, we 

 do not know ; but it never was caught hold of by any of the other 

 writers of antiquity, or by those of the Stationary Period. "What was 

 still worse, the point which Archimedes had won was not steadily 

 maintained. 



We have given some examples of the general ignorance of the Greek 

 philosophers on such subjects, in noticing the strange manner in which 

 Aristotle refers to mathematical properties, in order to account for the 

 equilibrium of a lever, and the attitude of a man rising from a chair. 

 And we have seen, in speaking of the indistinct ideas of the Stationary 

 Period, that the attempts which were made to extend the statical doc- 

 trine of Archimedes, failed, in such a manner as to show that his fol- 

 lowers had not clearly apprehended the idea on which his reasoning 

 altogether depended. The clouds which he had, for a moment, cloven 

 in his advance, closed after him, and the former dimness and confusion 

 settled again on the land. 



This dimness and confusion, with respect to all subjects of me- 

 chanical reasoning, prevailed still, at the period we now have to 

 consider ; namely, the period of the first promulgation of the Coper- 

 nican opinions. This is so important a point that I must illustrate it 

 further. 



Certain general notions of the connection of cause and effect in mo- 

 tion, exist in the human mind at all periods of its development, and are 

 implied in the formation of language and in the most familiar employ- 

 ments of men's thoughts. But these do not constitute a science of Me- 



