3o6 THE POPULAR SCIENCE MONTHLY 



tant part of its output. We can at least feel what we are paying for, 

 if we can not see it. But the electric lights far outrun the gas lights 

 in efficiency. An ordinary carbon incandescent lamp yields about six 

 per cent, of light to ninety-four per cent, of heat, the arc lamp about 

 ten per cent, of light, while the mercury arc has climbed to the enormous 

 efficiency of almost half light to half heat. This indeed is prodigious 

 compared with the means of illumination of a few years ago. 



But what have the organisms to teach us in this respect? Many 

 animals and plants are luminous. The simple one-celled animals, jelly 

 fishes, worms, clams, insects and common fishes all have luminous 

 representatives. But who ever heard of the sea being appreciably 

 warmed by its phosphorescence or of a child who burned his finger with 

 a firefly? Animal light is produced without heat, it is immensely the 

 most economical form of light. Bepeated and recent study of the 

 firefly light has shown that all of its energy lies within the visible 

 spectrum, that it contains not a measurable vestige of heat. Its effi- 

 ciency is complete and could we discover, as we shall some day, the 

 secret of the firefly light, the only occupation that would be left for 

 our municipal illuminating plants would be that of heat generators. 



By this time you must surely have caught the drift of my idea. 

 For ages past animals and plants have been slowly evolving processes 

 on some of which we have come to be absolutely dependent. Biology 

 has now advanced to that stage where the study of these processes is 

 beginning to be seriously undertaken. In my opinion the operations of 

 plants and animals will serve as models on which to build up industry 

 on a scale that human endeavor has never dreamed of before. Our 

 modern industrial world supplies man's wants by means of what I may 

 call inorganic devices. The future industrial world will draw more and 

 more from organic models. In my opinion we are on the verge of an 

 enormous expansion in applied biology. A century from to-day and our 

 work will look as small and insignificant in comparison with the biology 

 of that period as Franklin's electrical experiments do when brought 

 face to face with the enormous electrical expansion of modern times. 

 He saw in nature a few manifestations of a gigantic power which the 

 modern man of science has brought under control. It is vouchsafed us 

 in this early day to see dimly and indistinctly the powerful forces of 

 organic nature and to receive the conviction that in the not distant 

 future, these too are to be bridled and led by man. Such to my mind 

 is the forecast of biology. 



