PLATE 17 
Fig. 8. Interior of constant-temperature box as seen from behind 
after removal of the back. At the ends of the box the outer wooden 
and inner glass walls remain, while a part of the innér wooden is re- 
moved with the wooden back and glass top behind the microscopes. The 
two thermometers as in plate 16. The regulator, shown in figure F (p. 115), 
is at the left. The slide on the microscope stage is partly obscured by 
the mechanical stage, but the glass and rubber tubing, as shown in figure 
K, can be seen passing to one of the bottles at the right and to the 
waste bottle at the left. The exhaust rubber tube is withdrawn from the 
hole in the back of the box and is seen hanging over the glass roof and 
down in front. 
