316 REPORTS ON THE STATE OP SCIENCE.— 1915. 



fact that the small local muscles, though easily fatiguable, are also soon 

 rested in the mid-day break and will either work better in the after- 

 noon or will tire then less easily. Abb6 (Index C8) found indeed that 

 in the Zeiss Optical Works a reduction of hours increased the output 

 per hour of the finer handwork less than of the coarser machine work. 

 And here we may refer again to Dr. Marsh's (Index D6) records 

 of girls wire-stitching magazines; after a break from 5.30 to 6 ' there 

 was a marked recovery and a maximum rate till 9.30 ' (page 36). 

 Machine-sewing also to some extent focuses work on the hands and 

 fingers, and here again (Table IV. Col. 3) we find a high afternoon 

 output after the local fatigue has been given an hour to recuperate, 

 particularly where the frequency of operation, i.e., the number of 

 buttonholes to the hour, is very high and the fingers, therefore, have 

 to be all the quicker. 



Of movements concentrating their tax on the central muscles, 

 building may be cited in particular, and also all the pursuits included 

 under mining, lumbering (forestry), and agriculture, though their hours 

 of work are somewhat irregular. A useful output distribution would 

 be impossible to collect in these industries, owing to the heterogeneous 

 work and working conditions; but, failing this, separate accident curves 

 from different sources have been collected and plotted in Diagram IV. 

 for buildmg. Diagram V. for mining, and Diagram VI. for lumbering 

 and agriculture. The astonishing feature of these ' time-distributions ' 

 is their similarity to the normal curve for the more strictly manu- 

 facturing industries (c/. Diagram I.). In building and mining, how- 

 ever, there is an earlier decrease of accident in the afternoon spell, 

 attributable, since the eight-hour day prevails here, to an earlier close 

 of work. In lumbering and agriculture the dips in the German 

 curve at 8-9 and 4-5 are probably attributable to short meal-breaks; 

 it should be noted that about half the work called lumbering is 

 performed in sawmills with quite regular working hours and meal- 

 breaks. 



Several examples of work that involves nervous concentration have 

 their output and accident time-distribution recorded. 



JiLdgments of distance and of quality, including the activities of 

 sensitivity, comparison with memorised standard, and muscular con- 

 trol, are found in machine-sev/ing, where the material must be directed 

 under the needle absolutely correctly (Table IV.) ; in tin-labelling, where 

 the label must be pasted exactly square (Table V. Col. 2 and Table VI.) ; 

 in soldering and in tin-straightening, where, as in all skilled work, a 

 definite standard of quality must be obtained (Table III. and Table V.). 

 Now, it is in all these processes that we find the output curve most 

 normal. The afternoon's output is somewhat less than the morning's, 

 but in both spells the maximum output occurs in the second, or, where 

 the first period recorded is half an hour, as at Peak, Frean's (Table V.), 

 m the first hour and a half or second hour and a half. After this there 

 is the gradual decrease of output, till the last hour's output may only 

 total about 80 per cent, of the maximum for the spell, less if it is the 

 fifth hour (as general in the morning), more if it is the fourth hour 

 (as general in the afternoon). The total of the records of output of the 



