1891.] ESSAYS. 53 



made, viz. : in the use of artificial light as well as artificial heat. 

 Sunlight is one of the most, perhaps the most important factor 

 in producing those subtle and mysterious chemical changes, 

 essential in nearly all the processes of healthy plant growth. 

 Ever since electricity was first introduced for lighting, I have 

 believed that the electric light could be utilized in growing lettuce 

 during the long winter nights. I did not suppose, however, that 

 the pecuniary advantage would be enough to pay the cost. But 

 I have often said that if I had a few thousand dollars that I could 

 aflford to throw away I would myself try the experiment for the 

 sake of establishing what I believed to be a scientific fact. My 

 reason for this belief was based upon the fact that the electric 

 light has more of the elements of sunlight than any other arti- 

 ficial light, except the light produced by burning silver and gold. 

 The light produced by the combustion of these two metals, we 

 are told by scientists, give us precisely the same elements as 

 constitute sunlight. But such a light would, of course, be alto- 

 gether too costly for practical use in this kind of horticulture — 

 at least, at the present low prices for lettuce — unless, indeed, 

 unlimited coinage should sufliciently cheapen these metals. Per- 

 haps that is what the Farmers' Alliance is driving at. But I 

 think that gas light, or even kerosene affords a sufficiently brill- 

 iant light, if well focused, to show the folly of some of their 

 financial theories. 



A few years after I began to discuss my electric light theory 

 for growing lettuce a paper was read before the French Academy 

 of Sciences describing an experiment that had been tried in 

 growing plants by electric light, and that it had proved a success. 



In 1887, while spending the winter and nearly all the summer 

 on the gulf coast at Tampa, in South Florida, an electric light 

 plant was built in that city. The electrician was a young man 

 from Chicago, whose acquaintance I made, and with whom I used 

 to spend an occasional evening in social chat and discussing elec- 

 trical questions, and in trying amusing electrical experiments, 

 some of which we used to try in the college laboratory. Outside 

 the ofiice door of that electrical light plant was suspended an arc 

 light of, perhaps, 2,000 candle power. I noticed that under that 

 light the grass and weeds grew much more rapidly and vigorously 



