83 
1911-12.] A Method of Measuring Mental Processes. 
began. In fact, I had practically no evidence in my results in normal 
persons even of its existence. 
The average normal mental work curves of A and B (G and H) in the 
second five minutes are most instructive. A (G in tables) showed still a 
high initial spurt and a tendency to maintain it for three minutes ; then, 
Mr B. — First Five Days’ Test. 
Showing percentage variation from minute to minute on the third day. 
The dotted line shows the percentage variation from minute to minute on the 
total of the five days. 
no -no 
Mr B.’s Second Five Days’ Test (called “Mr H.” in Tables and Text). 
120 120 
85 85 
as the effort proved too great, there was a gradual fall in the fourth and 
fifth minutes ; then ensued an interval of five minutes in which the rate 
from minute to minute was almost unswervingly maintained ; during the 
first eight minutes the attention never varied ; apparently, the greatness 
of the effort precluded the possibility of spurting ; A was working at the 
absolute maximum of his mental capacity, and the curve shows a plateau : 
