Economy of Machinery and Manufactures. Ill 



pound fit for the manufacturer,* while the same individual, by the aid 

 of the cotton gin, can clean one thousand pounds in the same space 

 of time — language is scarcely adequate to convey a full idea of its 

 value. Mr. Whitney says in his application to Congress in 1812, 

 that his cotton gin " as a labor saving machine would enable one man 

 to perform the work of a thousand men" 



" Accumulating power." — Under this head, the author describes 

 the fly wheel and the sledge hammer. The fly wheel, constructed 

 with a heavy rim, has the weight near the circumference ; and when 

 moving with considerable velocity, produces powerful effects. It is 

 usefully employed in increasing the force for rolling iron, perforating 

 iron plates, &c. &c. • 



The power of the hammer consists in raising a weight and letting 

 it fall, and increases in the ratio of its weight and the distance, through 

 which it falls. 



Regulating power. — "Uniformity and steadiness, in the rate at 

 which machinery works, are essential to its effect and duration." 

 The contrivance which governs the steam engine, controlling its fearful 

 rapidity, producing uniformity and steadiness in its movements, is a 

 beautiful example o{ the regulating power. 



It is on the same principle, that the water power is regulated, 

 which drives the spinning-jenny, raises timber at the dock-yard, and 

 supplies fuel in particular furnaces. 



"Advantage of velocity ." — "Whenever work is light, it becomes 

 necessary, in order to save time, to increase velocity. The propor- 

 tion between the velocity 3 with which men and animals move, is of 

 considerable importance. It is also of great importance for the econ- 

 omy of labor, to adjust the weight of that part of the animal's body, 

 which is moved, to the weight of the tool it urges, and the frequency 

 of repetition of these efforts so as to produce the greatest effect." 



Twisting the fibres of wool by the fingers would be a most tedious 

 operation. In the common spinning wheel, velocity is increased by 

 a simple contrivance, which is common to a multitude of machines, 

 such, for example, as the machine for winding cotton balls, ribbons, 

 &c. &c. But the economy resulting from the increase of velocity, 

 is more striking in the larger and more important machines. f 



* Vide Memoir of Mr. Whitney, by Prof. D. Olmsted, p. 208, 



\ Economy, &c. p. 26. 



