ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
437 
tended to 5 feet, it will be necessary to provide steps, as l thus comes up 
above the bead of the standing operator. The focusing lens can rest on 
the ground glass, or swing on a vertical pivot fastened into the frame l , 
or be carried on a rack-stand resting near h. 
“ For long focusing, when it is inconvenient to reach the fine adjust- 
ment with the hand, I use a stick, the end of which carries a piece of metal 
Fig. 36. 
Back view of white screen having universal movements; d,e,f, and h, same as in 
fig. 34 — that is: d, opaque blind ; e, 1/4 in. board, 8 in. wide, attached to d, and 
rising and falling with it ; /, 1 in. board, 8 in. wide, top of which is slotted to 
receive e ; h , the same diamond-shaped opening shown in fig. 34 ; g, top of screen ; 
i, forked wrought-iron spindle, shown black, except where it enters the post — 
the dots show its continuation ; l /, uprights imbedded in the ground and passing 
up into the building without touching it, and supporting the Microscope-camera 
above the operator’s head ; m, pillar supporting the Microscope, imbedded in the 
ground, and passing up into the building without touching it. The cords and 
pulleys are for the purpose of moving the screen from inside the building. The 
small mirror mentioned in the text is placed on the front of the screen near g. 
that fits into a slot filed in the top of the fine adjustment screw. When 
the adjustment is secured, the stick is removed. This convenient arrange- 
ment has often enabled me to take photomicrographs with great rapidity. 
“ The pillar e forms a model support for a dissecting stand, the 
tables q q being then placed at equal heights to serve as arm-rests. 
“ The light is obtained from a white screen, having universal move- 
