22 CARNOT. 



pieces, by the aid of which forces of all sorts ordinarily 

 produce effects which their direct action could not bring 

 about. Take, for instance, the stone-mason with his 

 hand on the handle of a very simple machine, the winch 

 of the lifting-jack or the roller ; he turns about enormous 

 blocks, or inclines them to suit his convenience, or raises 

 them to the summit of the highest buildings, when, with- 

 out the machine, he could not stir them a hair's breadth. 



At sight of these effects, the ignorant make great out- 

 cry at the marvel ; they persuade themselves that ma- 

 chines multiply force, and this false idea, radically false, 

 leads them into fantastic and generally very complicated 

 conceptions, which take away an immense quantity of 

 capital every year, in pure loss, from agriculture, and 

 manufacturing industry, and commerce. 



With a force of any nature whatsoever, that which 

 must be valued in money, that which the fabricator buys 

 from the engineer, may be easily referred to a very sim- 

 ple effect, of which every one has a clear idea. Let the 

 force be supposed directly applied to the raising of a 

 weight ; the height to which the force raises the weight 

 in a certain time is observed, and these two data from 

 experiment, the weight and the height, multiplied together 

 form a product which is the exact value of the force em- 

 ployed. This product, indeed, for a given time^and the 

 same height, cannot be augmented or diminished with- 

 out the force augmenting or diminishing in the same 

 proportion ; so that, for example, if it becomes double, 

 triple, or decuple, it is the result of the force being mul- 

 tiplied by two, three, or ten. 



The product, which gives the direct measure of a 

 force, serves equally to measure it when it exercises its 

 action against a resisting body by an intermediate ma- 



