Dimensions of a Body on its Thermal Emission. 273 



Fiar. 1. 



Thermal Emissivities of Wires at Different Temperatures. 



Ordinates represent Emissivities. 

 Abscissae represent Radii of Wires. 



Messrs. Ayrton and Kilgour's Experimental Values indicated thus: 



Points on their Empirical Curves indicated thus : 



Curves represented by formulae given in this paper indicated thus: 



— e~ 



•005 



•0L0 



•015 



•020 cm. radius. 



