G24 



REPORT — 1898. 



will be seen that a graduated circle (the divisiona on which were f(jund by 

 calculation) is used in order to set the auxiliary pair of rollers so as to 

 give any required radius. The corresponding upper pair of rollers is 

 afterwards turned into the required position, so that the axes of the upper 

 and lower rollers are parallel. In the figure they are shown turned back 

 upon a hinge in order to insert the cardboard, after which they are 

 turned down, and a weight placed upon a projecting pin so as to insure 

 the requisite friction when in action. 



KXG. 8. 



Kk; <J. 



An examination of fig. 8 will show that not only can the auxiliary 

 pair of rollers be lifted up, but that the frame carrying the main rollers 

 can also be turned back about pivots which are shown at the end of the 

 frame. It may also be noted that the plane surface upon which the 

 cardboard moves can now be made of glass, since actual pivots for the 

 centres are no longer required. This enables the two moving pieces of 

 cardboard to slide easily, and is very much cleaner to use than a wooden 

 or metal surface. The main spindle under the glass plate through which 

 motion can be transmitted to both sheets of cardboard by turning the 

 milled heads at either end has upon it a pair of bevel wheels which gear 

 with a third bevel wheel carried upon a vertical axis. This arrangement 

 is for the purpose of drawing various forms of cycloidal curves for setting 

 out the teeth of wheels for which the two sheets of paper are required to 



