Heat and Thermodynamics

12.6 Boltzmann ′s Ether Engine

In this engine, radiation is used as the working substance. It consists of a hollow cylinder and a frictionless piston (Fig. 12.8). The walls and base of the cylinder also the piston are impervious to heat. They have vanishingly small heat capacity and are placed in perfect vacuum. In the base of the cylinder, there is a small hole through which radiation can pass into or out of the cylinder. This hole may be closed by a disc which is a perfect reflector. The source of heat is a black body at temperature T₁. The sink is another black body at a lower temperature T₂. We shall suppose the temperature T₁ to be only slightly higher than T₂; with this engine, we now perform the following cycle of operations:

 

 

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