996 General Notes, [ September, : 
generally have to be adjusted so as to bring the whole length of — 
its blade into action. Very hard specimens are frequently cut 
with less difficulty by placing the knife more obliquely in regard — 
to the long diameter of the instrument. 
The inclination of the oblique plane upon which the carrier b i 
slides is 1:20, and consequently the section will be 1-20th™ 
thick if the carrier is moved 1™ on the oblique plane. A scale 
in millimeters with a vernier allows the operations to be exactly 
regulated. The vernier will be found sufficient for sections of 
0.015%" Sections of greater delicacy should always be made by 
using the micrometer-screw (c, Fig. 1), which was designed to 
obtain the utmost exactitude in the management of the carrier b. 
Fig. 3 shows it on a larger scale. : 
The carrier c’ slides on the same oblique plane as the carrier > a 
The periphery A 
the drum, ¢, which is firmly attached to the screw, sra ee ie 
vi 
i i j jons a 
thickness of section equivalent to 0.001™: The finest sections ; 
axes, and admits, therefore, of a very easy 
object in regard to the knife. It was devised to m 
for occasionally turning the object between two succ 
of sections, ‘ Between 
The two metal plates, %%, form the jaws of the amp and tbe 
them is placed the cork which carries the ine grees 
latter is fixed by turning the screws, gg. The three axes al s 
