144 THOMSON ON CARNOT'S 



lowing corrected specification for the third opera- 

 tion : Let the piston be pushed down, till it readies 

 a position E^F^ , determined so as to fulfil the con- 

 dition, that at the end of the fourth operation the 

 primitive temperature S shall be reached :*] 



[During this operation the temperature of the contents 

 of the cylinder is retained constantly at T, and all the 

 latent heat of the vapor which is condensed into water at 

 the same temperature is given out to JB.] 



(4) The cylinder being removed from B, and 

 placed on the impermeable stand, let the piston be 

 pushed down from E^F^ to its original position EF. 



[During this operation, the impermeable stand prevent- 

 ing any loss of heat, the temperature of the water and air 

 must rise continually, till (since the quantity of heat 

 evolved during the third operation was precisely equal to 



* [Note of Nov. 5, 1881. Maxwell has simplified the 

 correction by beginning the cycle with Carnot's second 

 operation, and completing it through his third, fourth, 

 and first operations, with his third operation nearly as fol- 

 lows : 



let the piston be pushed down to any position E 3 F 3 ; 

 then Carnot's fourth operation altered to the following': 



let the piston be pushed down from E 3 F 3 until the tem- 

 perature reaches its primitive value 8 ; 

 and lastly, Carnot's first operation altered to the follow- 

 ing : 



let the piston rise to its primitive position.] 



