HOW TO USE THE MICROSCOPE 35 
The cutting surface consists of two separated but parallel glass 
benches. The object is held by a clamp and is raised by a 
micrometer screw, which, when moved through one division by 
turning the divided head, raises the specimen 0.01 mm. 
The sliding microtome has a track of 250 mm. The object 
is held by a clamp and its height regulated by hand. The disk 
regulating the micrometer screw is divided into one hundred 
parts. When this is turned through one division, the object is 
raised 0.005 mm. or 5 microns, at the same time a clock-spring 
in contact with teeth registers by a clicking sound. If the disk 
is turned through two divisions, there will be two clicks, etc. 
In this way is regulated the thickness of the sections cut. When 
the micrometer screw has been turned through the one hundred 
divisions, it must be unscrewed, the specimen raised, and the 
steps of the process repeated. The knife is movable and is 
drawn across the specimen in making sections. 
The base sledge microtome (Fig. 36) has a heavy iron base 
which supports a sliding-way on which the object-carrier moves. 
Fic. 36.—Base Sledge Microtome 
The object-carrier is mounted on a solid mass of metal, and is 
provided with a clamp for holding the object. The object is 
raised by turning a knob which, when turned once, raises the 
specimen one to twenty microns, according to how the feeding 
mechanism is set. 
