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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FIG. 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 (O 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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