

I allow it to descend, it would necessarily floiomd and 

 produce thin displace in. 



roaJl spaces, which 



.Id came (he point* of the - 

 descrilf in tl. forces, which respec 



at tl,. l.-t /. ; 'alkl 



H which iched to the pullirs .1. //, t' t ... h IB 



spaces a, A 7, ... are those bv whic 1 



pull'. ,at the string 



.'*e pullie.s will thus be diminished by DJ, qQ, r- : 



equence <>t' tin- i: of the n 1 



.t II' \\ through the spsce t>a-f ^ 



r that the system of force- 

 equilibrium, wo mu*t have 



..^ 

 and , since P~pW, Q~qW 



equation is the analytical expression of the principle of 

 locities. 



ustead of being zero, 

 were nei ppcar that t would be 



ce it is impossible tha 

 ascend. But we must remember, that 

 may be the connexion of the parts of the svstem t 

 . iiich consequently hold between the indefinitely 

 mtities a, 0, 7, ... can only be expressed by diflcren- 

 . are therefore itaear as to these 

 quantities; so that tin TV will be necessarily one or m 



'main iiuietcnninate and may be taken with a 

 Dative sign; thus the values of these quai 

 will ! always such that they can simultaneously change 



Il'iuv, it follows that i certain displacement 



, the quantity A-f Q&+ L'y+ ... is negmtive, it 

 wouhl income positive by changing the signs of a, p, -, 

 opposite displace: equally possible, an . 



1 make the weight descend and destroy the equilibrium. 



