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relative movements, be as follows. We take the 

 left upper and right lower counter-actions. 



(a) Accompanying the formation of the kft tipper 

 winding line, the left side of the head hall, acting as a 

 point of appHcation, revolves outward and backward. 

 This extends to its cross-line end, and then forms 

 the secondary section of the anterior winding line. 



{a') Accompanying the movement of the upper 

 end of the cross-line, the pressure of the head-ball 

 turns in its course, passing forward and to the left, a 

 movement which, when constrained by the action 

 of the right posterior line, is made directly forward. 

 This moves the cross-line ends and draws tight the 

 primary section of the upper winding line. 



(b) The tractions of the right lower Tvdnding line 

 cannot work at the head, and those of the left 

 upper line be maintained, unless by moving the 

 socket. The draioing of the right loiver loinding 

 line luould rotate the right side of the socket outward 

 and backward. This extends to its cross-line end, 

 and then forms the secondary section of the lower 

 winding Hne. Its action at the anterior end of 

 the socket resembles that of the condyle at its 

 posterior end. 



(p') The action of the lower end of the cross-line 



