THE QUESTION OF FATIGUE FROM THE ECONOMIC STANDPOINT. 313 



potent than a state like practice, that is removing pressure from the 

 nervous centres. 



Now, if this explanation of the agreements and disagreements in 

 the ascertained time-distribution of accidents and output respectively be 

 con-ect, the following would be the psycho-physical diagnosis of a 

 spell of factory work considered chronologically. 



First hour: Fingers, arms, body and mind after their rest are 

 working slow, but sure. To increase the pace and even perhaps to 

 concentrate attention is uphill work and a fight against subjective 

 feelings of sloth. In an emergency, however, muscles could be per- 

 fectly controlled. 



Second hour: Body and mind, getting into their stride again, are 

 working very fast, but not perhaps so exactly. Feelings of sloth are 

 conquered, but there is a terrible long prospect of work ahead. How- 

 ever, as work is running easily, the mind may think of pleasanter 

 things : attention scatters. 



Third or third and fourth hours : Body and mind running on, but 

 attention lost. If any sudden danger threatens or emergency arises, 

 it may not be quick enough perceived, and when perceived, muscles 

 may not be quick enough to prevent an accident; they can continue 

 rhythmically and automatically at the same work, but for any 

 change of movements that may be suddenly called, there is insufficient 

 control. 



Last hour (fourth or fifth) : Body no longer running automatically 

 with the same ease, an effort of the will required (spurt) to keep speed 

 up; but the end is ahead, with food and rest; the attention awakes 

 and control over the muscles is braced up — danger is better perceived 

 and more quickly avoided. At the very end, however, even this new 

 attention and control may tire, as indeed the whole body is tired, and 

 only a rest can bring recovery. 



B. Particular. 



The agreement within the accident and output ' time-distributions 

 or curves ' was sufficient to justify the use of the term ' normal distri- 

 bution ' for industry in general and the discussion of its causation. 

 Now, however, we may examine each time-distribution or curve given 

 in the tables more closely, so as to describe any differences between them 

 and to correlate such differences in the output or accident curves with 

 differences in the conditions of each (see Section I.). The main con- 

 ditions whose results our tables thus enable us to seek are : 



1. Conditions affecting the factoiy hygiene and particularly tem- 



perature. 



2. The nature of the worker : sex and age. 



3. The nature of the work. 



4. Factory organisation, 



1. How far differences between the individual output and accident 

 curves are attributable to differences in atmospheric conditions 

 influencing the hygienic state of the factory may be gauged from 

 Table XVII., where the accidents occurring at Hans Renolds' are 

 analysed into summer and winter accidents. 



