Box Epsilon (lever or push down) was 12 by 9 by 5 inches. At the right side of its front was a hole ½ inch broad by 1½ inches up and down. Across this hole on the inside of the box was a strip of brass, the end of one bar of a lever. If this strip was depressed ⅛ of an inch, the door at the extreme left would be opened by a spring. Box Zeta (side plug) was 12 by 11 by 10 inches. Its door was held by a round bar of wood put through a hoop of steel at the left side of the box. This bar was loose and could easily be pulled out, allowing the door to be opened. Box Theta was the same as KK except that the door could be opened as soon as the bolt alone was pulled or pushed up. Box Eta was like Alpha save that the object at the back of the box to be pulled was a brass ring. Apparatus QQ (chute) consisted of a lever mechanism so arranged that by pushing in a bar of wood ¼ to ½ an inch, a piece of banana would be thrown down a chute into the cage. The apparatus was placed outside the cage in such a way that it could be easily reached by the monkey’s arm through the wire netting. QQ (a) was of the same general plan. By turning a handle through 270° food could be obtained. QQ (b) was like QQ (a) except that 2½ full revolutions of the handle in one direction were necessary to cause the food to drop down. QQ (c) was a chute apparatus so arranged as to work when a nail was pulled out of a hole. QQ (d) was arranged to work at a sharp pull upon a brass ring hanging to it. QQ (e) was arranged to work when a hook was unhooked. QQ (f) was arranged to work when a loop at the end of a string was pulled off from a nail. QQ (ff) was QQ (f) with a stiff wire loop instead of a loop of string. EXPERIMENTS ON THE ABILITIES OF THE MONKEYS TO LEARN WITHOUT TUITION I will describe a few of the experiments with No. 1 as samples and then present the rest in the form of a table. No. 1 was tried first in BB (O at back) on January 17, 1900, being _put inside_. He opened the box by pulling up the string just above the bolt. His times were .05, 1.38, 6.00, 1.00, .10, .05, .05. He was not easily handled at this time, so I changed the experiment to the form adopted in future experiments. I put the food inside and left the animal to open the door from the outside. He pulled the string up within 10 seconds each time out of 10 trials. I then tried him in MM (bolt). He failed in 15. I then (January 18th) tried him in CC (single bar outside). He got in in 36.00 minutes; he did not succeed a second time that night, but in the morning the box was open. His times thenceforth were 20, 10, 16, 25 and on January 19th, 40, 5, 12, 8, 5, 5, 5 seconds.