14 HISTORY OF MECHANICS. 



writes in such a manner as to show that he had 

 taken a good hold of his subject for his time, refers 

 to Pappus's solution of the problem of the Inclined 

 Plane, but makes no mention of that of Jordanus 

 and Tartalea 2 . No progress was likely to occur, 

 till the mathematicians had distinctly recovered 

 the genuine Idea of Pressure, as a Force producing 

 equilibrium, which Archimedes had possessed, and 

 which was soon to reappear in Stevinus. 



The properties of the Lever had always con- 

 tinued known to mathematicians, although, in the 

 dark period, the superiority of the proof given by 

 Archimedes had not been recognized. We are not 

 to be surprized, if reasonings like those of Jor- 

 danus were applied to demonstrate the theories 

 of the Lever with apparent success. Writers on 

 mechanics were, as we have seen, so vacillating in 

 their mode of dealing with words and propositions, 

 that their maxims could be made to prove any 

 thing which was already known to be true. 



We proceed to speak of the beginning of the 

 real progress of Mechanics in modern times. 



Sect. 2. Revival of the Scientific Idea of Pressure. 

 Stevinus. Equilibrium of Oblique Forces. 



THE doctrine of the Center of Gravity was the part 

 of the speculations of Archimedes which was most 



2 Ubaldi mentions and blames Jordanus' s way of treating the 

 lever. (See his Preface.) 



