INDUSTRIAL LABOUR 409 



ponding to an ordinate of 1 centimetre are 20, 17, 10 and 11 kg. 

 respectively, for the four graphs, reading from top to bottom. 



It should be noted that the effort exerted by the arms of the 

 workman is variable. Hence the ordinates represent the maxi- 

 mum efforts which maximum is very rapidly reached. 



Before and after each experiment the block of metal is weighed 

 on a balance reading to 1 milligramme. Hence the weight of 

 metal removed can be very accurately measured. 



312. Experiments and Calculations, The two regular subjects 

 of the experiments were : 



A.C. A journeyman fitter of 20 years' experience and good 

 physique. His age was 38 years. His weight 74 kg. His 

 height 1-72 metres. 



XP. An apprentice, aged 16, agile but not strong, weight 

 55 kg. Height 1-65 metres. He had served two years of his 

 apprenticeship. 



Fifty-seven series of experiments, extending over a period of 

 eight months, were carried out on these two subjects. 



Various other persons (J.A., L.M.., H.R., E.A., C.C.), of various 

 professions and trades, but all of them unfamiliar with the use of 

 the file, were from time to time utilised as subjects. 



In 'all the experiments the subject worked at a comfortable 

 rate in an atmosphere maintained at a temperature of, approxi- 

 mately," 17C. The air breathed was brought from the outside 

 of the room through a large pipe. 



The following results were obtained with A.C. as subject. 

 (Experiment No. IX.) 



(a) The subject at rest, seated. 



Air expired in 3J minutes ........................ 30-25 litres 



Respirations per minute ........................ 18 



Temperature ....................................... 17-5C 



Barometric pressure .............................. 758 mm. 



An analysis of the air expired gave : 



C0 2 3-15% 

 2 17-4% 



This is an absorption of 21 174 = 3-6% 

 The " respiratory quotient " 



2 O-D 



The volume of gas (reduced to OC and 760 mm. barometric 

 pressure) was 28-41 litres. 



The consumption of oxygen in 3J minutes (reduced to OG 

 and 760 mm.) was therefore : 



