278 



Messrs. Langley and Very on the 



Diagram 4. 



Pour Curves of Equal Areas, showing one unit of heat displayed 

 successively in heat spectrum of Gas, Electric Arc, Sun and 

 Fire-Ply. 



Abscissae. — Wave Lengths. 

 Ordinates. — Energy as Heat. 



ENERGY CURVE. 



G-as Flame Spectrum. 

 MAXIMUM AT 1?6. 

 Fig. 1. 



500— 

 400- 

 300— 

 200— 

 100— 

 0- 



ENERGY CURVE. 



Electric Arc Spectrum. 

 MAXIMUM AT 1^16. 



Fig". 2. 



400- 

 300— 

 200- 



ioo — j 



8 2.0 2.2 2.4. 2.6 2.8 3.0 



ENERGY CURVE. 



Solar Spectrum. 



MAXIMUM AT 0^62 



Pig-. 3. 



0.6 03 1.0 1.2 1.4 1.6 13 &0 ZS 2,4 2,6 28 3.U 



LIMITS ! 



OF ! 



VISIBLE j 



SPECTRUM] 



0.6 



Ll.0. 



1.2 



ENERGY CURVE. 



Fire-Fly Spectrum. 

 MAXIMUM AT 0^57. 



Fig-. 4. 



26 



