24 . CARNOT. 



day, beyond the limits of science), the movement effected 

 would be hardly the breadth of a liair. 



If the ideal machine, the machine endowed with all 

 imaginable perfections, adds nothing to the force which 

 puts it in action, at any rate it takes nothing away from 

 it ; it transforms the effects by rigorous equivalents. It 

 is not thus with a real machine ; in this case the power 

 and the resistance communicate with one another by 

 means of pieces which we had supposed inflexible, and 

 which are not so ; by means of chains and cords whose 

 roughness cannot but be injurious ; the movable parts, 

 moreover, turn in collars or sockets where great friction 

 takes place ; all these causes united absorb in pure loss 

 a very noticeable part of the motive force ; so that the 

 effect of a machine must always be inferior to that which 

 would have been engendered by the power acting directly 

 on the i-esistance. 



These results of theory, which are, moreover, com- 

 pletely confirmed by experience, yet allow that, under 

 certain points of view, some particular machine may be 

 recommended without paradox ; that it may be useful 

 and often even indispensable. For instance, considerations 

 of solidity or ornament necessitate the carrying to the sum- 

 mit of certain edifices blocks of stone or marble whose 

 weight is beyond the strength of the most vigorous work- 

 man ; suppress the windlass and analogous machines, 

 and one man will no longer be able to execute the work 

 which the architect has conceived ; it will be necessary 

 to unite the strength of thousands of arms at the same 

 point ; the narrowness of space will prevent that ; the 

 character of grandeur will disappear from all the monu- 

 ments of architecture ; the triumphal arch, the palace, 

 will only be constructed, like the humble cottage, of 

 little rough stones. 



