ZOOLOGY AND BOTANY, MICKOSOOPY, ETC. 



1085 



plate H is seen (fig. 242) to be perforated by holes, tbe larger of 

 which are intended for fixing the knife in different positions. The 

 rods J J are for the purpose of supporting extra weights, to be 

 attached when additional weight is required for the carrier, and the 

 holes J' in the plate (fig. 242) are for altering the position of the rods 

 in case they interfere with the knife. 



The apparatus for the object-carrier and its motor is somewhat 



Fig. 241. 



complicated. The section-holder a £ y (fig. 242) consists of a clamp 

 with two jaws a £, the serrations of which point to the left, in order 

 to oppose the course of the knife. The bars (3 are fitted with spiral 

 springs, and their action is opposed by the screw rj working against 

 the plate e, which in its turn presses against £. The clamp is fitted 

 within a quadrilateral frame 0, and the latter swings between the 

 upper arms of an H-shaped piece li through the intervention 

 of the screws t (fig. 242). The lower arms of li are fitted to the 

 front ends of a similar shaped piece v, the hinder ends of which fit 

 into a rectangular excavation of the middle plate D. Both these 

 hinder arms are perforated by screws, the ends of which work against 

 the sides of the excavation in D. The front ends of v are screwed to 

 the lower ends of \l. The C-shaped piece x is fixed to the upper 

 arms of /x by screws at £, while through its prolongations posteriorly 

 the screws A work against the sides of the excavation in D. 



