144 SCIENTIFIC APPARATUS. 



Refraction, 



Double Refraction, 



Polarization, 



Circular Polarization, &c. [Melloni, Forbes, &c.] 



Apparatus for experimental proofs of the equality (under all 

 circumstances) of Radiation and Absorption for any particular 

 ray. [Stokes, Foucault, Stewart, Kirchhoff, &c.] 



Apparatus for experimental proof of Kirchhoff's fundamental 

 proposition that the hotter a body is the more it gives of the 

 lower radiations, in addition to new and higher radiations. [Akin 

 and Griffith, Tyndall, &c.] 



(c) CONVECTION. 



Processes of Hope and Joule for determination of the maximum 

 density point of water. 



Joule's Convection Thermometer for the Moon's heat. 

 Apparatus and Processes for Ventilation, &c. 



VI. TRANSFORMATIONS OF HEAT. 



(a) Into Work Heat engines of all kinds. 



Air engines, 



Steam engines, 



Ether or Chloroform engines, 



Gas engines, &c. 



(b) Into Visible Motion and Sound 



Trevelyan Rockers, &c. 



(c) Into Electric Currents 



Thermo-electric Batteries, &c. 



(d) Apparatus for determining various points of the theory of 

 heat and of heat-engines 



Calorific effects of the passage of gases under pressure through 



porous plugs. 



Determination of the efficiency of a perfect engine. 

 Determination of absolute zero of temperature. 



