49 



the rate only of 6 miles an hour ; and if 10 hours, only at 

 the rate of 4. 6 m. When loaded, one half of that distance 

 is to be taken ; wherefore if a loaded horse is made to go six 

 hours a day, his limit is 3 miles an hour ; if 10 hours, his 

 limit is 2 miles and a fraction an hour. 



It appears from a range of experiments, that the distance 

 limited bv natural exertion, is 20 miles a day for every day, 

 for beneficial effect: this may be performed in ten hours, or 

 any other period not less than two hours. It is stated by that 

 scientific and practical writer, Wood, that heavy horses with 

 a load, fall into the rate of two miles an hour as their natural 

 pace, and that lighter horses, under the same circumstances, 

 increase that rate. This would seem to point to the conclu- 

 sion that the respective rate of horses is as their own weights. 

 It consists with observation that heavy horses find it conven- 

 ient to move at a slow pace : on the other hand, some lighter 

 animals of a keen spirit, are with difficulty brought to a mod- 

 erate pace, when their load is not more than a just one. — 

 Whilst it is admitted that 20 miles a day for every day, may 

 be considered the average distance fot beneficial effect ; the 

 longest period of continued action, or ten hours at two miles 

 an hour, is thought to have a wearying and stupifving effect 

 on many animals of a keen temper ; a speed equal to four 

 miles an hour for five hours cverv day, is thought to produce 

 premature stiffness of the joints. Tredgold, a writer of much 

 investigation, thinks the average distance of 20 miles for every 

 dav, is h»-M divided into six hours ; working three hours, and 

 then, after an interval of rest, working three hours more.— 

 This would furnish a rule of three and one third miles an 



hour - , ' . 



As the object of this paper is to awaken attention to Ae abu- 



llid the demonstration will be clearer if we examine the 

 ure of motion on rail roads. 

 The great velocity of mo 

 a pi; 



)aratively small 



"quired to produce similar effects on ordinary roads, 



M » - ™,psp r, t 



ntion of other materials, such 



is familiar to all men. These principles being cons! 

 application through 

 as wood and iron, has uu 

 duce the same etiects upon artificial roads. Ihe beat adapta- 

 tion of them is found to be upon the smooth surface which iron 

 affords. On an iron road properly constructed, it is found that 

 the moving power, whether animal or mechanical, has little 



