The Mental Life of the Monkeys 177 
of arrangements which could be set up beside a cage, and 
which would, when some simple mechanism was set in 
action, throw a bit of food into the cage. Figure 26 
shows one of these. See description of QQ (ff) on page 182. 
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Fic. 26. A, loop; BB, lever, pivoted at M. A bit of food put in front of C 
would be thrown down the chute DDD when A was released. 
APPARATUS 
The different mechanisms which I used were the follow- 
ing : — 
Box BB (0 at back) was about 20 by 14 by 12 inches with 
a door in the front which was held by a bolt to which was 
tied a string. This string ran up the front of the box out- 
side, over a pulley, across the top, and over another pulley 
down into the box, where it ended in a loop of wire. 
Box MM (bolt) was the same as BB but with no string 
and loop attachment to the bolt. , 
Box CC (single bar) was a box of the same size as BB. 
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