ANIMAL MECHANICS. 61 



Dividing this result by 311, in order to reduce it to foot- 

 tons, we find 



b. Work done by porters, alternately loaded 



and unloaded, 7640 ft. tons. 



(c.) On questioning a number of pedlars who travelled, 

 always loaded with their packs, Coulomb found that they were 

 able, with a load of 44 kilos., to travel 19000 metres per day. 

 Assuming their weight at 70 kilos., as before, we find — 



Useful work = 19000 x 44 = 836000 kil. met. 

 Fatigue work= 19000 x 70 = 1330000 ,, 



Total, . . . 2,166000 kil. met. 

 Converting this, as before, into foot tons, we obtain — 



c. Work done by loaded pedlars = 6964 ft. tons. 

 Collecting together the preceding estimates, we find — 



a. Man walking without load, 7543 ft. tons. 



b. Man alternately loaded and without load, . 7640 ,, 



c. Man loaded, 6964 ,, 



Mean, .... 7382 ft. tons. 



If the horizontal transport be effected at the usual rate of 

 3 miles an hour, we must divide the preceding result by 20.65 

 (as already explained), in order to convert it into weight lifted 

 through height. Hence we obtain, as the mean of the work 

 done in the horizontal transport of weights, — 



Work done in horizontal transport ) 7^82 



, \ — > =358 ft. tons 



01 loads, • ; 20.65 



From Examples 4, 5, 6, 7, a very close approximation may 

 be made to the daily work of a good labourer. 



