466 PREPARATION, MOUNTING. AND COLLECTION OF OBJECTS 



Fig. 395 presents an object-holder intended to analyse It // 

 section objects which are wedged or fan-shaped in form on a fixed 

 axis, but may be applied to other purposes. 



B is a prism-shaped, semicircularly bent bar, moving in the slot 

 F F 1 ; at 1> and b l the jaws occupy the position common to those of 

 the ordinary form. 



3 



FIG. 395. Object-holder for analysis by diversified section. 



( hi tlic circumference of B a spiral is cut. which become.- slightK 

 visible at (j ; into this spiral a screw passes at H. which is turned by 

 the milled head S, which can alter the position of the arc to the 

 horizontal to the extent of 1 mm. ; and the amount of the change of 

 position can be read off on the graduated circle K. 



In a fixed position the middle of this section-holder is the plane 

 of action of the knife. If an object be fixed in the jaws so that the 



PIG. ::'.H>. Cylinder for use with jaws. 



fixed axis of it lies in this plane, it will only be required that the 

 screw S be lii-onght into action to obtain wedge-shaped sections of 

 whatever thickness is required, which will all be made in this axis. 



The set of cylinders which may be used with these and other 

 jaw- i> represented in tig. :! ( .)(j : by is the cylinder, CJ the compressing 

 screw for it. the block W being held in the jaws. 



Tin- olji'd */;//, ii-i(li //.s- n-micr may be sliddeu up the incline by 



