762 



POPULAR SCIENCE MONTHLY. 



equal one of fifteen years not so trained. Four of tlie teachers 

 place the gain at from forty to fifty per cent in study power. 

 One teacher (class position 44) puts the gain at one hundred per 



100/0 



95% 



85% 

 75% 



50% 



35% 

 25% 



0% 



10 



12 U 



YEARS 



16 



18 



20 



Explanation of Marks on Voluntary Attention Chart. 



21,600 measurements of 2,700 individuals. 



The error to two inclies may be read in tenths of an inch at right-hand end of horizontal line, 



at tlie left end read up the lines are five per cent apart ; i>er cent arbitrarily placed at 



eighth year ; vertical hnes divide year spaces fourth tb twenty-first. 

 Line No. 1 (at thirty inches and eighty-five per cent). ^Externally sustained attention. All 



those reputed by coworkers to be superior are at or above this line by test No. 2. 

 Line No. 2. Voluntary attention. Average line of centers of groups trained in the schools 



of many States in the Union as well as Europe. 

 Line No. 3 is the high limit of the above and ends in A. x marks the individuals through 



which the line is drawn. From fourth year to fourteenth all are females. From fifteenth 



year up all are males. ? Marks the rather doubtful lower limit of groups. 

 Marks center of composite drawing, average age eleven. ^ High and low limit marks. 

 Kl Marks the center of three hundred and seventy pupils trained by free-hand drawing as a 



science study. 

 Marks known positions. 

 ^^ Movement between measured centers. 



' Supposed movement. 



oA Figure painters measured in the order' named : E. A. Bell, Clark Crum, C, C. Curran, 



Kenyon Cox, Joseph Boston, Arthur B. Davies, Henry Prellwitz. 

 oE Fitty-three teachers. ^ High and low limit marks. 



cent in geometry, claiming to have covered certain ground satis- 

 factorily in half the time usually needed for a class without the 

 special training. 



By imagining line No. 3 (the high limit of group) prolonged 

 downward and to the left, three years, and line No. 2 treated in 

 the same way to the same age (one year), it will be seen that at 

 the age of twelve months children are almost infinitely separated 



