524 POPULAR SCIENCE MONTHLY. 



The time of this trip was sixteen minutes. The times of some of 

 the other trials were as follows: 



10th trip 4 minutes. 



15th « 



20th 

 25th 

 30th 

 35th 

 40th 

 45th 

 50th 



The route for the thirtieth trip was, as Fig. 6 indicates, almost 

 direct. 



The times of these experiments are generally longer than those of 

 the first series because the inclines consumed considerable time. 



During the formation of the habit of crawling up incline 3 and 

 sliding down incline 4 a very interesting modification of the action 

 occurred, namely, the shortening of the path to the sand-box by 

 crawling over the edge of incline 4. At first the animal, after 

 climbing up 3, would slide all the way to the bottom of 4 and 

 would then turn toward the nest. Soon, however, it began making 

 the turn toward the nest before reaching the bottom, thus throwing 

 itself over the edge of 4. The turn was made earlier and earlier on 4, 

 until finally it got to crawling over as soon as it reached the top of 3, 

 or M. It always turned itself over the edge carefully, and landed, after 

 a fall of four inches, usually on its head or back. By this process the 

 path was shortened eight or ten inches. This action is a splendid illus- 

 tration of the way in which an advantageous habit may grow by accre- 

 tion, as it were, until it seems as if it must have been the result of 

 reasoning. Some would, no doubt, hold that in this case the turtle 

 chose the direct path because of inferences from judgments. Although 

 this may be true, there is surely a sufficient explanation of the habit, 

 as we have come to know it, in the profiting by chance ex- 

 perience. No one would say that the nest was at first found by 

 inferences. It was reached because of the animal's impulse to move 

 about, to seek escape or hiding. Had the turtle stopped to judge and 

 draw inferences as to the way to escape, instead of persistently moving 

 from place to place, it would probably be in the pen yet. No; the 

 wandering impulse led by chance to the finding of satisfaction, turtle 

 pleasure, in the nest. Because of this satisfaction, the action was im- 

 pressed on the vital mechanism, so that there was a tendency (the 

 beginning of a habit) toward repetition of it. Had the action failed to 

 give satisfaction, the probability of its being repeated would have been 



