ELECTRICITY AND PLANT-GROWING. 65 



$3.50. This gain of ten clays in maturity is remarlvable when we 

 consider tliat the light never ran later than eleven o'clock at night ; 

 that nearly half of the nights had no light, and that the experi- 

 ment was made late in the season, when the strong sunlight tends 

 to obscure any effect of the artificial illumination. These results 

 were uniform throughout a house 20 X 30 feet in extent, in both 

 instances. All subsequent experiments strongly confirm these 

 results ; and nothing can be more definitely stated concerning the 

 effects of electric arc light upon vegetation than that a 2,000- 

 candle-power lamp, run half the night or even less, exerts a most 

 marked beneficial influence upon lettuce throughout a house sixty 

 feet square. In fact, I consider this point so well established that 

 we have discontinued experiments in the general forcing of lettuce 

 by the electric light. 



The influence of this naked light upon productiveness and color 

 of flowers was found to vary with the different species, and differ- 

 ent colors within the same species. Several named varieties of 

 tulips gave interesting results. When these came into full flower, 

 it was found that in every case the colors were deeper and richer 

 in the light house ; but the colors lost their intensity after four or 

 five days, and were then indistinguishable from those in the dark 

 house. The plants in the light compartment had longer stems and 

 larger leaves than the others ; and there was a greater number of 

 floriferous plants in the light. These tulips were grown at 

 distances of ten and twelve feet from the lamp. Petunias were 

 much affected by the light. The plants were much taller and 

 slenderer in the light, even at the farthest corners of the house 

 twenty and thirty feet from the lamp, and they bloomed earlier 

 and more profusely. When the specimens were in full bloom, it 

 was found that the height of plants in the dark house was to the 

 height of those in the light house as five is to six. White petunias 

 were not changed in color by the light, but purple ones quickly 

 became l)lue, especially near the lamp. 



Other fiowers behaved differently, each according to its kind ; 

 but all those, of whatever species, which stood within five or six 

 feet of the naked arc were injured. Flowers opening near the 

 light were of short duration, but those ten or twelve and more feet 

 away did not appear to be modified in this regard. But it was 

 apparent that, in general, the light hastened blooming and caused 

 the production of longer stems, but this effect was much obscured 

 5 



