272 ILLINOIS STATE ACADEMY OF SCIENCE 



The production of light in chemical reactions, or chemi- 

 luminescence, is fairly common. The crystallization or 

 precipitation of certain salts may be accompanied by 

 luminescence. Slow oxidation of organic matter, such 

 as rotten wood, decayed fish and meat, and the oxidation 

 of phosphorus are luminescent. The glow of phosphorus 

 is often erroneously referred to as phosphorescence, but 

 it has been found to be due to the second stage in the ox- 

 idation of phosphorus — that of P 2 3 to P 2 5 . The bio- 

 luminescence of bacteria, the fire-fly and the glow-worm, 

 is likewise produced by oxidation. The production of 

 light by the fire-fly has been studied thoroughly by Prof. 

 Harvey of Princeton 2 . He has been able to extract two 

 substances from the fire-fly, luciferin, an oxidizable ma- 

 terial, and luciferase, an enzyme which is a catalyst for 

 its oxidation. When these substances are mixed in con- 

 tact with air or an oxidizing agent, light is produced. 

 Prof. Harvey points out that the heat of the reaction is 

 extremely small and the product of the oxidation is oxy- 

 luciferin and not carbon dioxide and water. Hence the 

 reversal of the reaction and regeneration of the luciferin 

 should be' easy. 



The light of the fire-fly is of interest principally be- 

 cause it proves that an ideal cold light is not an impossi- 

 bility. In this paper it has been endeavored to emphasize 

 the extreme inefficiency of present methods of light pro- 

 duction. A careful study of the natural phenomena out- 

 lined above may suggest means of improving luminous 

 efficiency. If we follow the advice of Louis Agassiz and 

 "study Nature, not books," some success in this direc- 

 tion will no doubt be attained. 



CHART 2— LUMINOUS EFFICIENCY. 



Source C-P/W L/W Per Cent 



Perfect 49 . 1 617 100 



Sun 6.9 86.5 14 



Mercury Arc 3.12 39 6.35 



Flaming C Arc 2.08 26 4.24 



W. in Argon (3,000° K) 1.66 20 3.4 



W. in Vacuum 8 9 1 . 45 



Nernst Rare Earth Glower .41 5 .8 



C. Filament 28 2.7 .57 



Inc. Mantle (C*H 2 ) 2 ' 2.5 .4 



