INDUSTRIAL LABOUR 399 



The friction of the wheel increases the resistant work. Gener- 

 ally the speed depends on the point of application of the power. 

 Navier found a speed of OT5m. for a duration of 8 hours, the 

 man working at the level of the axis. Then his weight of 60 

 kilogrammes takes its full effect. 



Navier calculated that : 



T - 0-15 X 60 X 3,600 X 8 = 259,200 kilogrammetres. 



The speed was 0-70 m. when the man worked at a point of the 

 wheel at 24 from the base. His effort is then only 12 kilo- 

 grammes, which is a total of work done for 8 hours of : 



T = 0-70 X 3,600 X 8 x 12 = 241,920 kilogrammetres. 



Thus, according to Navier, a man can perform 250,000 kilo- 

 grammetres per day in climbing a treadmill. 



The following results, which were obtained from official sources, 

 show the work done by the treadmill in various English jails : 



LOCALITIES WORK DONE. 



Northampton 143,643 kilogrammetres 



Nottingham 174,360 . ,, 



Devonshire 195,625 



Middlesex 212,946 



Cambridge 259,690 



Boston 281,104 



Warwick 205,517 



274,022 



342,529 



General Average 231,000 



305. (b). Actions of the Arms. The use of the winch and cap- 

 stan. In both of these machines the work is done by the exercise 

 of the arms. Navier estimated that the efforts of a man working 

 a capstan at a speed of -6 metres per second, was about 12 kg. 

 This would mean a quantity of work done in 8 hours of 12 X -6 X 

 3,600 X 8 = 207,400 kilogrammetres approximately. 



The work done per second is -6 X 12 = 7-2 kgm. Schultze 

 and Langsdorf investigated the work done in turning the crank 

 handle of a winch and obtained results varying from 10 to 11 

 kilogrammetres per second. The corresponding efforts and speeds 

 were : 



WORK PER SECOND EFFORT IN KILO- SPEED 



KILOGRAMMETRES. GRAMMES. METRES PER SECOND. 



10 13-7 -76 



11 13-3 -757 



