CONTENTS. 



MEMOIR I. 



EXAMINATION OF THE RADIATIONS OF RED-HOT BODIES. THE PRO- 

 DUCTION OF LIGHT BY HEAT. 



Ascertainment of the temperature at which bodies become self-luminous ; 

 it is 977 Fahr. Proof that all solids begin to shine at the same de- 

 gree. The spectrum of incandescent solids has no fixed lines. The 

 reference spectrum. Colors of light emitted as the heat increases are 

 in the order of the spectrum. Frequency of vibration increases with 

 the temperature. Intensity of the light emitted. Intensity of the heat 

 radiated Page 23 



MEMOIR II. 



SPECTRUM ANALYSIS OF FLAMES. PRODUCTION OF LIGHT BY CHEM- 

 ICAL ACTION. 



Spectrum analysis of a candle flame. Examination of various other 

 flames. Spectrum analysis of the light of a burning solid. Flames 

 consist of a succession of shells. Spectrum of cyanogen. Combustion 

 of flames in oxygen. Effect of air in the interior of a flame. The 

 blowpipe cone. General result, the more energetic the chemical action 

 the higher the refrangibility of the resulting light; the vibrations 

 increase in frequency as the chemical action is more violent. Fraun- 

 hofer j s fixed lines 52 



MEMOIR III. 



ON INVISIBLE FIXED LINES IN THE SUN 5 S SPECTRUM DETECTED BY 



PHOTOGRAPHY. 



The photography of Fraunliofer* s fixed lines. The lines in the red due 

 to absorption by the earth's atmosphere. Nomenclature of the Fraun- 

 hofer lines. Discovery of the invisible fixed lines. Original map of 

 them. The new ultra spectral red lines a,/3, y. Rediscovered by Fou- 

 cault and Fizeau. M. BecquereTs discovery. Experiments in 1 834. . 74 



