ANIMAL MECHANICS. 



51 



Example, No. 2. — The most effective mode in which the 

 labour of man can be employed is in lifting his own weight 

 through a height for a number of consecutive hours. Captain 

 Coignet, a French officer of engineers, invented (1835) a 

 hoist or box-lift, applied to the lifting of barrows of earth 

 from an excavation of about forty feet deep, which was in- 

 tended to be used in the formation of earthworks for fortifica- 

 tions. This box-lift consists of a strong rope passing over a 

 large pulley, and having suspended at each end a cage, or en- 

 closed platform. The barrow load of earth is brought by an 

 assistant to the foot of the hoist, and placed in the cage, which 

 is supposed to have just descended to the lower level. At 

 the same moment, the labourer, with an empty barrow, steps 



because the skin of the boat is smoother than the skin of iron steam-boats, and he 

 has found that the friction in iron pipes is diminished to about five-sixths, by 

 lining them with smooth pitch. This would reduce the result of my calculation 

 from 81.36 to 67.80 lbs. 



In consequence of my publication of the foregoing results, Mr. J. Scott Russell 

 published in " The Practical Mechanic's Journal," November, 1866, an addi- 

 tional calculation of the resistance of the Oxford eight- oar, the result of which 

 is 74. 23 lbs. 



The preceding calculations and observations give — 



Haughton, 81.36 lbs. 



Rankine, 67.80 „ 



Scott Russell . . . . 74.23 ,, 

 Maclaren, 73*2! >> 



Mean, . . . 74.15 lbs. 



From the preceding results, we may obtain the following rates per ounce 

 per minute of the muscles engaged : — 



Rate per ounce per Minute of Muscle employed in rowing a Boat-race. 

 Footpounds per ounce per minute. 



15.169 Haughton. 



12.640 Rankine. 



13.840 Scott Russell. 



13.650 Maclaren. 



Mean, . . 13.825 



E 2 



