CATALOGUE.— PHILOSOPHY ANB ARTS, PUACTICAL MECHANICS. \65 



Aiiiontonson moving powers. A. P. 1703. H. 

 * Camus Traite des forces mouvantes. 8. Par. 



1722. ]\I. B. 

 Instances of Inimaa strength. Desag. Lect. 



I. '289. 

 Deparcieux on the draught of horses. A. P. 



1760. 263. H. 151. 

 Emerson's mechanics. 

 Ferguson's mechanics. 

 Lambert on human strength and its appiica- 



catiou. A. Berl. 1776. 19. 

 Cazaucl on sugar mills. Ph. tr. 1780. SIS. 

 Horses. E. M. A. I. Art. Chevaux. 

 Schulze on the strength of men and horses. 



A. Berl. 1783. 3S3. 

 Rennel on the rate of travelling of camels. 



Ph. tr. 1791- 1'29. 



About ll miles an hour. 



Kegnier's dynamometer. Journ. Polyt. II. v. 



160. Gilb. li. 91. Ph. M. I. 399. 

 Coulomb on the daily labour of men. B. Soc. 

 ■ Phil. n. 16. M.Inst. II. 380. Nich. III. 



416. 

 Buchanan on human hibour. Repert. XV. 



319. 



The comparative force exerted in the action of pumping 

 was ]74i, by a winch 2856, in ringing 3 s 83, in rowing 

 4095. 



On the powers of horses and steam engines. 

 Nich. IX. 214. 



According to Schulze's experiments, the force which a 

 man or a horse can exert with the velocity v, is n: / 



( 1 Y ,/ being the force in equilibrium, and a the ve- 

 locity without resistance. This is a formula of Euler : ano- 

 ther of his expressions// 1 \ does not agree so well 



with Schulze's experiments. But Euler's theory is founded 

 on assumptions wholly arbitrary. According to the first 

 formula, the greatest mechanical effect would be wlien jizi 

 ^a ; according to the second, when D=:v' I". 



In order to compare the different estimates of the force of 

 moving powers, it will be convenient to take a unit which 

 may be considered as the mean effect of the labour of an 



active man, working to the greatest possible advantage, and 

 without impediment ; this will be found, upon a moderate 

 estimation, sufficient to raise 10 pounds 10 feet in a second, 

 for 1 hours in a day : or to raise 1 oo pounds, which is the 

 weight of 12 wine gallons of water, 1 foot in a second, or 

 scooofcetinaday; or afiooooo pounds, or 432 000 gallons, 

 1 foot in a day. This we may call a force of 1. continued 

 36000". 



Immediate Force of men, without deductioii 

 for friction. 



Force. Continu- Days 



ation. work. 

 A man weighing 133 pounds Fr. 



ascended 62 feet Fr. by steps, in 



34", but was completely exhausted. 



Amontons. 2.8 3-t" 



A sawyer made 200 strokes of 

 18 inches Fr. each in 14 5", with a 

 force of 25 pounds Kr. He could 

 not have gone on above 3 minutes. 

 Amontons. .6 145" 



A man can raise 00 pounds Fr. 1 

 foot Fr. in 1", for 8 hours a day. 

 Bernoulli. .69 sh. .a-i 



A man of ordinary strength can 

 turn a winch, with a force of 30 

 pounds, and with a velocity of 3^ 

 feet in l", for lO hours a day. 

 Desaguliers. i.Oj loh. 1.05 



Two men working at a windlass, 

 with handles at right angles, can 

 raise 70 pounds more easily than 

 one can raise 30. Desaguliers. 1.22 1.22 



.A man can exert a force of 40 

 pounds for a whole day, with the 

 assistance of a fly, " when the 

 motion is pretty quick, as about 4 

 or 5 feet in a second." Desaguliers, 

 Lect. 4. But from the annotation 

 it appears to be doub'.ful whether 

 the force is 40 pounds or 20. 2. 2. 



For a siiort time, a man may 

 exert a force of 80 pounds, with 

 a fly, " when the motion is pretty 

 quick." Desaguliers. 3. 1' 



A man going up stairs ascends 

 14 metres in 1'. Coulomb. 1.182 l' 



A man going up stairs for a day 

 raises 205 chiliogramme* to the 



