358 POPULAR SCIENCE MONTHLY. 



memory. He had no idea of my purpose but regarded the exer- 

 cise as a game, a notion which I encouraged by now and then 

 pitting myself against him. Simple as the exercise appears, it 

 afforded a clearer view of Isaiah's mind than speech could pos- 

 sibly have done. Here, at the stage of simple sensation and within 

 the psychic circle that it evolves, he was all alert and responsive. 

 It is difficult for me to convey a clear idea of his awakened activi- 

 ties ; I can only sum up what he did in dry statistics, which are 

 meaningless aside from comparison. I should add, with reference 

 to the experiments, that in the absence of apparatus for signaling 

 our expedient was as follows : 



At the word noiv from Isaiah the series presented was covered 

 and the duplicate set of cards placed before him. An assistant, 

 watch in hand, marked the time passed both in examining and 

 placing the cards. I did not caution Isaiah against the use of 

 mnemonic devices, for I judged that he knew none, his range of 

 associations being extremely limited. The experiments were 

 made from twice to three times a week for about five weeks. In 

 three instances, the same series was repeated twice in succession, 

 in every other case a series was presented but once. The sum- 

 mary of results is as follows : Simultaneous presentation, eight- 

 een series, ten colors each ; average time for learning each color, 

 five and three fourths seconds (or fifty-seven and a half seconds per 

 series) ; average time for placing each color, nine and two thirds 

 seconds, or one minute and thirty- six seconds per series ; percent- 

 age of errors, 36"6. Successive presentations of ten series, ten 

 colors each ; average time for observing each color, five and three 

 fifths seconds ; average time for placing each color, nine and three 

 fourths seconds ; percentage of errors, twenty-nine. 



I made occasional essays with aural series i. e,, reading the 

 names of the colors arranged until Isaiah was ready to replace 

 them. Of these I preserved only the following record : Four 

 aural series, ten colors each ; average time for learning each color, 

 five and five sevenths seconds; average time for placing each 

 color, six seconds ; percentage of errors, fifty. 



The experiments having proceeded thus far, I entered upon an 

 educative series. By this means the time for learning a series 

 was reduced to half a minute, and for placing the same, to forty- 

 five seconds, while the percentage of errors fell to sixteen. 



In arranging the series the boy's action was slow, and he 

 seemed able to begin indiscrimately at either end or in the 

 middle. Apparently he recalled the colors partly by name ; this, 

 however, helped him little, as he did not know the names of shades 

 and neutral tints. I tried having him count, as a means of in- 

 hibiting the names when he was examining the cards, but I 

 thought this helped rather than hindered, as the name attached 



