interest. The day on which he made the discovery that he could
break the wooden one and one-half inch horizontal bars that were
held out from his cage walls on cast iron brackets, was for him a
great day. Before his discovery was noted by the keepers he had
joyfully destroyed two bars, and with a broken piece used as a
lever was attacking a third. These bars were promptly replaced by
larger bars, of harder wood, but screwed to the same cast-iron
brackets that had carried the first series.

For a time, the heavier bars endured; but in an evil moment the
ape swung his trapeze bar, of two-inch oak, far over to one side
of his cage, and applied the bar as a lever, inside of a
horizontal bar and from above. The new force was too much for the
cast-iron brackets, and one by one they gave way. Some were broken
off, and others were torn from the wall by the breaking of the
screws that held them. Knowing that all those brackets
must be changed immediately, Dohong was left to destroy them;
which he did, promptly and joyfully. We then made heavy
brackets of flat wrought iron bars, 1/2 by 21/2 inches, unbreakable
even with a lever. These were screwed on with screws
so large and heavy that our carpenters knew they were quite
secure.

[Illustration caption: THE LEVER THAT OUR ORANG-UTAN INVENTED, AND
THE WAY HE APPLIED IT By W. A. Camadeo, in the "Scientific
American," 1907]

In due time, Dohong tested his lever upon the bars with their new
brackets, and at first they held securely. Then he engaged Polly,
his chimpanzee companion, to assist him to the limit of her