LOCOMOTION 



377 



Let us take, as an example of the application of the above 

 table, the transportation of a load of 43 kg. 



The maximum economy will be attained with a rate of produc- 

 tion equal to 4,000 metre-kilogrammes per minute. The cor- 

 responding speed is quite slow, namely : 



^r- -T^- x 60 = 2-124 kilometres per hour. 

 /U + 4o 



To obtain the maximum power, at a rate of production equal 

 to 10,000 metre-kilogrammes per minute, a load of 33 kg. will 

 be. chosen and the speed will be : 

 i n noo 

 70 4- 33 x ^O = 5 '825 kilometres per hour. 



With a rate of production of 11,000 metre-kilogrammes per 

 minute the heavy load of 53 kg. will be chosen, and the speed will 

 be:- 



11 000 

 m\~ r~Ko X 60 = 5-366 kilometres per hour. 



/U + Oo 



We see, from the above figures, that the development of great 

 power is attained by walking heavily loaded (with a load of 53 

 kg. at 5-4 kilometres per hour approximately). We also see that 

 a reduction of the load to 33 kg. is compensated for by an in- 

 crease of speed to 5-8 kilometres per hour. We have, however, 

 to consider the nature of the workman and the difficulty which 

 will be experienced in carrying the heavier load, even with fre- 

 quent intervals of rest. 



290. The above experimental results have one defect, namely, 

 that the expenditure of energy was measured for a very short 

 time only, generally from two to three minutes. They will 



