61 



When a horse does road work it is evident that a large animal must 

 expend more energy than a small one for the motion of forward pro- 

 gression. Lavalard "' made weighings in experiments with some 30,000 

 horses belonging to the Paris cab companies and to the French arm^^ 

 He gives the average weight of horses of different kinds and of mules 



as follows: 



Table 6. — Average weight of horses. 



Heavy draft horses 



Light draft horses - - ;••,---,•.■■•■ 



Fancy horses, reserve cavalry horses, and horses of the line . 



Carriage horses and liglit cavalry horses 



Artillery and train horses 



Mules 



Weight. 



Kilograms. Pounds, 



700-800 

 500-600 

 450-.510 

 ?80-400 

 480-495 

 430 



1,540-1,760 



1,100-1,320 



990-1,120 



83.5-880 



1,055-1,090 



945 



Taking into account the average amount of muscular work expressed 

 in foot-pounds, the speed at which work is performed, the duration of 

 the work, and the amount of work done at a walk and trotting, the 

 total work done per day by army horses carrying a rider weighing SO 

 kilograms (175 pounds) without a pack, and 120 kilograms (265 pounds) 

 with a pack, and 90 kilograms (200 pounds) with accouterment for 

 maneuvers, was calculated to be as follows: 



Table 7. — Work performed by army horses per day. 



Work per day. 



OBDINARY WORK (RIDER WITHOUT PACK). 



Walking. 

 Trotting . 



Total 



KOAD WORK (RIDER WITH PACK). 



Walking. 

 Trotting . 



Weight 

 carried. 



Pounds. 

 176 

 176 



265 

 265 



Total 



MILITARY MANEUVERS (RIDER WITH LIGHT 

 PACK). 



Walking 



Trotting 



198 

 198 



Velocity Work per 

 second. «««o°*i- 



Feet. I Foot-lbs. 

 5. 446 958. 5 



9.022 1 1,587.9 



5.446 

 9.022 



1,443.2 

 2,390.8 



Total 



5.446 

 9.022 



1,078.3 

 1,786.4 



Duration 



of dally 



work. 



Hrs. Min. 

 2 30 

 1 30 



30 

 30 



2 00 



3 00 



Amount 



of work at 



different 



gaits. 



Foot-lhs. 

 8, 626, .500 

 8, 574, 660 



17,201,160 



7, 793, 280 

 12, 910, 320 



20, 703, 600 



7, 762, 760 

 19, 293, 120 



27, 055, 880 



According to the calculation of an English army officer, Maj. F. 

 Smith,^ the mean ratio of carrying power to body weight is 1 : 5.757; 

 that is to say, it takes, roughly speaking, 5.75 pounds of body weight 

 to carry 1 pound on the back during severe exertion (racing excepted). 

 The rule he gives for ascertaining the carrying power of a horse is to 



a Loc. cit. 



?* Queensland Agr. Jour., 4 (1899), p. 493. 



