146 THE MICROSCOPE. Nov. 
a distance from the short arm equal to one-fifth the length 
of the long arm. The blade is so secured in its socket 
that its edge is parallel to a line joining the points of the 
screws on the short arm, f and g. 
The sliding-piece moves along the glass plate carry- 
ing the knife over the specimen to be cut. By rotating 
re a 
\ 20 
2 | 
== Will) 
NTT 
uli 
—— an 
= “q iy ay il 
mu 
\\ \\ 
e 
NMI 
cull 
i 
wu 
3 = 56 Se ait Ns 
SS = 
aan ee \ 
— j : : + 
CER Ih Cae 
AM: 
N hil nm 
the micrometer screw after the sliding piece has been re- 
turned to its original position, the long arm of the latter, 
and with it, the knife are lowered; when the knife is 
again carried across tbe specimen a section is cut, the 
thickness of which is measured as follows: a complete rev- 
olution of the micrometer-screw lowers the end fig. 1, e, 
