52 



anterior end of tlie cross-libe is drawn around ta 

 the right, the ribs on the right of the first C and 

 on the left of the second (here being the two con- 

 vexes of the S), will be in appui, and those on the 

 concaves will be raised. The ribs along the pos- 

 terior parts of the convexes being already on their 

 outer bevels, the further traction from the left 

 anterior point of application, when it begins to 

 move the front cross-line end will increase this 

 bearing on the outer bevels. 



§ 55. The effect of continued hehcal traction of 

 the left anterior winding line throughout the con- 

 vexes, that is to say, in both the posterior and 

 anterior convex, is finally to turn all the ribs artic- 

 ulated along them outward. Even those in the 

 front portions (faced to the rear) will be thus 

 affected, so soon as, with the straightening of the 

 line, the upper cross-hne end permanently moves, 

 and they come under its direct influence. 



The posterior part of the secondary section of 

 the line (§ 23) is first affected ; then the upper 

 end of the cross-hne, being somewhat moved, 

 affects the posterior part of the primary section, 

 and so on until the secondary section, having 

 reached its hmit, the upper Cross-line end is more 

 absolutely subject to the traction. 



