June 23, 1899.1 



SCIENCE. 



863 : 



number of scholars a certain test which 

 would measure their ability (in a certain 

 direction, at least) to do mental work, 

 early in the school session, and then to give 

 this same test to a different lot of children 

 of approximately equal general maturity 

 and ability late in the session. The influ- 

 ence of practice is thus entirely obviated, as 

 the scholars do not have the same sort of 

 work twice. In order to save the results 

 from being vitiated by differences in the 

 general ability of the students, four difler- 

 erent tests were used, and the pupils who 

 had two of these tests early had the other 

 two late, while those who had the first two 

 late had the other two early. The influ- 

 ence of possible differences in the average 

 ability of the two sets of students can thus 

 be estimated. In order to make sure that 

 the willingness and interest of the jjupils 

 was a constant except in so far as due to 

 causes outside our control, all the tests were 

 given by myself. 



The work given was : (1) a set of multi- 

 plication examples to be done in a given 

 time ; (2) a page of printed matter full of 

 mis-spelled words which were to be marked 

 in a given time ; (3) two sets of nonsense 

 syllables to be written from memory after a 

 ten seconds' look at them, and (4) two sets 

 of figures and one set of simple forms {e. g., 

 square, triangle) to be written from mem- 

 ory in the same way. 



About 150 children (four classes) were 

 given 1 and 3 early and 2 and 4 late. An 

 equal number of children in the same school 

 grade were given 2 and 4 early in the school 

 day, the other half late. In order to elim- 

 inate the influence on the work which ex- 

 citement at my first visit, or being used to 

 me or being tired of me at my second visit, 

 might cause, I made my first visit coincide 

 with an early test in half the classes and 

 with a late test in the other half. The early 

 tests were all given between 10 minutes and 

 40 minutes after the opening of school in 



the morning, while the late tests were given 

 between 40 minutes and 10 minutes before 

 the close of school, half of them at the close 

 of the morning and half at the close of the 

 afternoon session. 



Thus any general decrease in the amount 

 or accuracy of the late work will be due to 

 mental fatigue, or to some aversion to work 

 caused by the school day and quite apart 

 from the aversion to conventional routine 

 work or to some factors yet to be demon- 

 strated. And if there is no difference we 

 can say with assurance that the day's work 

 has not decreased the child's ability to 

 work, that though he may in school do less 

 in the latter part of the day it is not in any 

 wise due to real exhaustion, to a lowering 

 of his mental energj'. 



As a fact what difference there was be- 

 tween the early and late work was in favor 

 of the latter. The multiplication test was 

 given to 152 scholars early and 144 late. 

 After reducing the amount done and mis- 

 takes made by the 152 to what would have 

 been done by 144, and comparing the re- 

 sults obtained with the work of the 144 

 who had the test late, we find that the lat- 

 ter did nearly 14% more work and made 

 less than 5% more mistakes. 



The spelling work was given to 152 

 pupils early and 14(5 late. After estimating 

 the work of 146 early pupils on the basis of 

 what the 152 did and comparing with the 

 146 late, we find that the latter worked 

 through 99 1^0^% as many lines, marked 

 about 2fo more words and marked 2^-^% 

 more words which should have been left 

 unmarked. 



The nonsense syllables were used with 

 152 pupils early and 148 pupils late. When 

 reduced to an equality in numbers the 

 late pupils did 97^'^% as well as the early. 



The figures to be remembered were given 

 to 152 pupils early and 145 late. When 

 reduced to an equality in numbers the late 

 pupils did 89 % as well as the early. 



