124 OUTLINES OF NATURAL PHILOSOPHY. 



prevent its motion altogether, be found by expe- 

 riment ; then if the load be reduced to - of this 



d^^**& fmw^a-.,^^^^8&^i- 9 



quantity, the effect of the machine will be the 

 greatest possible. 



?9Vll i\ V '.>..) i f y."i3*^EO ' '.'^f* *$ij '^iUC/Oi'l '*?! ' III 



194 The moving power and the resistance be- 

 ing both given, other things remaining as above, 

 if a machine be so constructed that the velocity of 

 the point to which the power is applied, be to the 

 velocity of the point to which the resistance is ap- 

 plied as 9 R to 4 P, the machine will work to the 

 greatest possible advantage. 



The velocities of the points just mentioned are capa- 

 ble of being adjusted to any given ratio, on princi- 

 ples that have already been explained. 



Under the name of the Load, we suppose the fric- 

 tion of the parts of the machine to be comprehend- 

 ed, which must therefore be determined by experi- 

 ment. 



195. Care should be taken to give to every ma- 

 chine the greatest possible regularity in its mo- 

 tion. 



The contrivance known by the name of a Fly, is one 

 of the best adapted for this purpose. When the 

 impelling power is subject to alternate intention 

 and remission, the inertia of a heavy wheel, by 



preserving 



