.: AXtt. 



ll^-ii Mr*, farcm maintain a My in 



it', in '.}. mm pi "". 



trnijjht : tions of two 



of tin- t-'iv. < .m.l not paralh-l : -ree, and uk 



; therefore the equation /, ~ o 



require* : 1 have n.. u, t,,. ,.t round 



; that n. th. 'rev must 



pa** through the axis of x. Since then any straight line, 



i in. : - ctions of two of the forces, and it not 



para 1 1 third, meets that direction, the 



three forces n u one pi 



. 58, we see 



ree forces V y in equilibr . mutt all 



i no and most meet at a point or be parallel* 



86. .vordinatet be oblioue, toppose /, , 



-ines of the angles betneeu uic aiet of y and s, 



lien we may shew, i 

 iiat an J s; 



>ng the axes of x, y t 9 re; 



iiree couples ree co-ordinate planes, having 



moments cquul : //., where, as before, 



Also Ibrium, we must have, as bet" 



r-o t s^r-o; 



X-0, Jf-0, .Y-o. 



That the forces may admit of a single resultant w most have, 

 as before, 



\ + M:L) =-0, 



an- 



not all vanishing. 



ns arc connected with the subject 



