864 



SCIENCE. 



[N. S. Vol. IX. No. 234. 



In remembering the simple forms the 

 late pupils did 94j'\|% as well as the early. 



It seems clear that the mental work of 

 the school day does not produce any marked 

 decrease in the ability to do further work. 

 The data here given are somewhat influ- 

 enced by certain factors, though not by 

 practice. These factors will be fully dis- 

 cussed in a later report. 



The multiplication, spelling and figure 

 tests when given to about 300 children in 

 another city showed the following results : 



The multiplication test was given to 156 

 children early and to 154 later. When 

 evaluated for 153 children the results 

 show the latter to have done 86f % as 

 much work, to have made 14y„ % more 

 mistakes. Taking together the work of all 

 the children tested (594, 297 early, 297 

 late), we find that the children who did the 

 work late did 2f'g % more work, and made 

 exactly the same number of mistakes. 



The spelling test was given to 1 35 early 

 and 128 late. When evaluated for 127 

 children the results show the latter to have 

 worked through 92y^ % as many lines, to 

 have marked y\ of 1 % more words, and to 

 have marked wrongly 87 % as many words. 

 Taking together the work of all the chil- 

 dren tested, we find that those who did the 

 work late worked through 94j'-|y % as many 

 lines, marked If"^ % more words and marked 

 wrongly 93yV % as many. 



The figure test was given to 15G chil- 

 dren early and to 152 late. After reducing 

 the results of the 156 to a basis of 152 we 

 find that those who had the tests late did 

 17 % better. 



Taking together the work of all the chil- 

 dren tested, we find that those who had the 

 test late did almost 2% better than those 

 who had it early. 



Besides these three tests, which are of the 

 same sort as some of those given to the first 

 lot of children, there was given to this sec- 

 ond lot a test with letters similar to the 



figure test. This test was given to 140 

 children early and to an equal number late. 

 Those doing the work late did 97 % as well 

 as those who had it early. 



The factors mentioned as influencing the 

 work of the first set of children were largely 

 counterbalanced by factors at work in the 

 second ; one, however, should be mentioned. 

 A certain circumstance probably lessened 

 the work of one class (of 30) of the first lot 

 of children during an early spelling test. 

 So the early work in this test should prob- 

 ably be reckoned about 2 % higher. On 

 the whole these additional data render 

 more probable our previous conclusion that 

 "the mental work of the school day does 

 not produce any decrease in the ability to 

 do mental work." A glance at the follow- 

 ing table, which summarizes the more im- 

 portant data, shows this better perhaps than 

 the detailed accounts already given. 



Edward Thokndike. 

 Western Reserve University, 

 Cleveland, Ohio. 



TEE INTERNATIONAL CATALOGUE OF SCIEN- 

 TIFIC LITERATURE. 

 PHYSICS. 



The plan proposed is to issue a book 

 catalogue once in five years, arranged ac- 

 cording to both subjects and authors, and 

 to issue also, from week to week, two sets of 

 card catalogues — one according to subjects 

 and the other according to authors. Esti- 

 mates are given of the proposed cost of this ; 

 and various alternatives are proposed, such 

 as the issuing of a book catalogue by itself, 

 or a book catalogue and an author card 

 catalogue. It is estimated that each arti- 



