668 



SUMMAltY OF CURRENT RESEARCHES RELATING TO 



gives full particulars of the details connected with rotation about the 

 vertical axis, rotation about the horizontal axis, and rotation about the 

 object-cylinder-axis. 



4. The movement of the lever F is connected, by means of a strongly 

 twisted cord of Chinese silk, with the rocking-lever D, but in a manner 

 differing somewhat from the ordinary mode. One end of this cord is 

 connected with a double eye (fig. 102), the larger eye engaging on one 

 of the two screws v 1 or v 2 , of the lever. The cord then runs round the 

 horizontal roller R 1? then round the vertical roller E 2 , and finally over 

 the roller R 3 inserted in the back part of the rocking-lever D. The cord, 

 finally, is attached by its other end to the sliding-sleeve E, which is 

 clamped on to D by the screw w. German-silver springs, only partly 

 visible in the figure, prevent the cord from slipping out of place. The 



* % 



Gulp* 1 



application and action of these three rollers distinguishes this microtome 

 from the ordinary form, which introduces only two. The advantage is 

 that the range-movement of the object can be varied by attaching the 

 cord either to v 1 or to v 2 . In the last case the range is one-and-a-half times 

 as great as in the first ; this would be convenient in the case of cutting a 

 very high object. Fig. 102 shows the working-lever in three positions : 

 F is the rest position ; F 2 the extreme position, and F x the position at 

 which the forward removal of the object begins, the instrument being 

 adjusted as RMi (fig. 99) and arranged for sections 10 /* thick. It will 

 be easily seen from fig. 102 that the cord at F 2 is longer than at F x . 

 This means that the removal of the object is carried out only on the 

 small final part of the object-track. With this same arrangement for 

 section thickness, an object 23 mm. high can be dealt with if the cord 

 is hooked on at v x , or 35 mm. high if the cord is attached to v 2 . With 

 adjustment RMii (fig. 99), these figures are respectively 20 and 31 mm. 



