Sect. IV.] Motion and Moving Forces. 4.5 



iiished wood; the contrivances, by means of 2i flexi- 

 ble rod, and other apparatus, to make the pendu- 

 lum move in the curve of a c^jcloid; to say notliini^ 

 of many other ingenious inventions to regulate the 

 motions and to extend the application of this im- 

 portant instrument. 



In that part of philosophy which relates to the 

 structure and motion of machines, manv great 

 minds have been employed, in the course of the 

 kist age, and not without making some advances 

 in this department of science. — M. Amontons, of 

 the Royal Academy of Sciences at Paris, about the 

 beginning of the century, very successfully deve- 

 loped some of tlie general laws of machinery. 

 After him Mr. Emerson, of Great Britain, a dis- 

 tinguished mathematician, investigated and svs- 

 tematised this subject, with still more practical 

 care and accuracy. In 1735 the celebrated Euler 

 undertook to give a general and systematic \\e\v 

 of machines, in order to found a complete theory, 

 immediately conducive to the improvement of me- 

 chanics. In 1743 he published tlie first part of 

 his theory, containing many new dynamical theo- 

 rems of great importance''^. He afterwards prose- 

 cuted the subject further I, and with so nmch suc- 

 cess, as to excite deep regret that he had not 

 continued his useful labours. Since the experi- 

 ments and publications of Euler, many philoso- 

 phers of inferior name have turned their attention 

 to the same inquiry ; but without laying the scien- 

 tific world under the same obligations, by exhibit- 



* Comment. Pdropolituni. torn. i. 



t Conimeni. Petrop. lom. iii^ aud yiar.. Acad. Berlin, ];''i7 ai:^ 

 1752. 



