230 



FORCE. 



three miles an hour. In the same metropolis, a 

 couple of Irish chairmen continue, at the pace of 

 lour miles an hour, under a load of 300 Ibs. These 

 exertions are greatly inferior, however, to the labour 

 performed by porters in Turkey, the Levant, and 

 generally on the shores of the Mediterranean. At 

 Constantinople, an Albanian porter will carry 800 or 

 000 Ibs. on his back, stooping forward, and assisting 

 his steps by a sort of staff. At Marseilles, four por- 

 ters commonly carry the immense load of nearly two 

 tons, by means of soft hods passing over their heads, 

 and resting on their shoulders, with the ends of 

 poles, from which the goods are suspended. Accord- 

 ing to some experiments of the late Mr Buchanan, 

 the exertions of a man in working a pump, in turning 

 a winch, in ringing a bell, and in rowing a boat, 

 are as the numbers 100, 167, 227, and 248. But 

 those efforts appear to have been continued for no 

 great length of time. The Greek seamen, in the 

 Dardanelles, are esteemed more skilful and vigor- 

 ous in the act of rowing, than those of any other 

 nation. The Chinese, applying both their hands and 

 their feet, are said to surpass all people in giving 

 impulsion to boats by sculling. The several races 

 of men differ materially in strength, but still greater 

 diversity results from the constitution and habits of 

 the individual. The European and his American 

 descendants are, on the whole, more powerful than 

 the other inhabitants of the globe ; and man, reared 

 in civilized society, is a robuster and more vigorous 

 animal tiian the savage. In the temperate climates, 

 likewise, men are capable of much harder labour 

 than under the influence of a burning sun. Coulomb 

 remarks, that the French soldiers, employed on the 

 fortifications of the Isle of Martinique, became soon 

 exhausted, and were unable to perform half the work 

 executed by them at home. The most violent and 

 toilsome exertion of human labour is performed in 

 Peru by the carriers, or cargueros, who traverse the 

 loftiest mountains, and clamber along the sides of 

 the most tremendous precipices, with travellers 

 seated in chairs strapped to their backs. In this 

 manner they convey loads of twelve, fourteen, or 

 even eighteen stone ; and possess such strength and 

 action, as to be able to pursue their painful task 

 eight or nine hours for several successive days. 

 These men are a vagabond race, consisting mostly 

 of mulattoes, with a mixture of whites, who prefer 

 a life of 'hardship and vicissitude to that of a constant 

 though moderate labour. When a man stands, he 

 pulls with the greatest effect ; but his power of 

 traction is much enfeebled by the labour of travel- 

 ling. If v denote the number of miles which a per- 

 son walks in an hour, the force which he exerts in 

 dragging forward a load will be expressed nearly by 

 t (12-- 20)*. Thus, when at rest, he pulls with a 

 force of about twenty-nine Ibs. avoirdupois ; but if 

 he walks at the rate of two miles an hour, his 

 power of traction is reduced to fourteen Ibs. ; and if 

 he quicken his pace to four miles an hour, he can 

 draw only three Ibs. There is, consequently, a cer- 

 tain velocity which procures the greatest effect, or 

 when the product of the traction by the velocity 

 becomes a maximum. This takes place when he 

 proceeds at the rate of two miles an hour. The ut- 

 most exertion which a man, walking, might continue 

 to make, in drawing up a weight by means of a pul- 

 ley, would amount, therefore, in a minute, only to 

 2430 ; but if he applied his entire strength, without 

 moving from the spot, he could produce an effect of 

 3675. 



The labour of a horse in a day is commonly reck- 

 oned equal to that of five men ; but then he works 

 only eight hours, while a man easily continues his 

 exertions for ten hours. Horses, likewise, display 



much greater force in carrying than in pulling ; and 

 yet an active walker will beat them on a long jour- 

 ney. Their power of traction seldom exceeds 144 

 pounds, but they are capable of carrying more tlian 

 six times as much weight. The packhorses in the 

 M r est Riding of Yorkshire are accustomed to tran- 

 sport loads of 420 Ibs. over a hilly country. But, 

 in many parts of England, the mill-horses will carry 

 the enormous burden of 910 Ibs. to a short distance. 

 With regard, however, to the ordinary power of 

 draught, the formula (12 v)*, where v denotes the 

 velocity in miles an hour, will perhaps be found suf- 

 ficiently near the truth. Thus a horse, beginning 

 his pull with the force of 144 Ibs., would draw 100 

 Ibs. at a walk of two miles an hour, but only 64 Ibs. 

 when advancing at double that rate, and not more 

 than 36 Ibs. if he quickened his pace to six miles an 

 hour. His greatest performance would hence be 

 made with the velocity of four miles an hour. The 

 accumulated effort in a minute will then amount to 

 22,528. The measure generally adopted for com- 

 puting the power of steam engines is much higher, 

 the labour of a horse being reckoned sufficient to 

 raise, every minute, to the elevation of one foot, the 

 weight of 33,000 Ibs. But this estimate is not only 

 greatly exaggerated, but should be viewed as merely 

 an arbitrary and conventional standard. Wheel car- 

 riages enable horses, on level roads, to draw, at an 

 average, loads about fifteen times greater than the 

 power "exerted. The carriers between Glasgow and 

 Edinburgh transport, in a single horse cart, weigh- 

 ing about seven cwt., the load of a ton, and travel 

 at the rate of twenty-two miles a day. At Paris, 

 one horse, in a small cart, conveys along the streets 

 half a cord of wood, weighing two tons ; but three 

 horses yoked in a line, are able to drag 105 cwt. 5 

 Ibs., or that of a heavy cart loaded with building 

 stones. The Normandy carriers travel from fourteen 

 to twenty-two miles a day, with two-wheeled carts, 

 weighing each eleven cwt., and loaded with seventy- 

 nine cwt., or nearly four tons, of goods, drawn by a 

 team of four horses. The French draught horses, 

 thus harnessed to light carriages, are more efficient, 

 perhaps, than the finer breeds of England. They per- 

 form very nearly as much work as those in the single 

 horse carts used at Glasgow, and far greater than 

 those heavy animals which drag the lumpish and 

 towering English wagons. The London dray- 

 horses, in the mere act of ascending from the 

 wharfs, display a powerful effort, but they afterwards 

 make little exertion, their force being mostly ex- 

 pended in transporting their own ponderous mass 

 along. Oxen, on account of their steady puH, are 

 in many countries preferred for draught. They 

 were formerly employed universally in the various 

 labours of husbandry. The tenderness of their hoofs, 

 unless shod, however, makes them unfit for pulling 

 on paved roads, and they can work only with advan- 

 tage in soft grounds. But they want all the pliancy 

 and animation which are the favourite qualities of 

 the horse. The patient drudgery of the ass renders 

 him a serviceable companion of the poor. Much in- 

 ferior in strength to the horse, he is maintained at 

 far less cost. In the United States of America, an 

 ass will carry about two hundred weight of coals or 

 limestone twenty- two miles a day. But, in the 

 warmer climates, he becomes a larger and finer ani- 

 mal, and trots or ambles briskly under a load of 150 

 pounds. The mule is still more powerful and 

 hardy, being fitted equally for burden and draught. 

 In the hotter parts of Asia and Africa, the ponderous 

 strength of the elephant has been long turned to the 

 purposes of war. He is reckoned more powerful 

 than six horses, but his consumption of food is pro- 

 portionally great. The elephant carries a load of 



