174 



THE IRRIGATION AGE. 



LETTUCE BENEFITED. 



Lettuce, however, was greatly benefited by the 

 electric light. It was found that under the protected 

 light, running all night, lettuce had made a better 

 growth than in normal conditions, but when the light 

 was burned only the first half of the night it showed 

 still greater difference. Three weeks after trans- 

 planting lettuce of equal age upon the benches of the 

 light and dark houses the plants in the light house 

 were fully 50 per cent, in advance of those in the dark 

 house in size, and the color and other character of the 

 plants were fully as good. The plants had received 

 at this time 70% hours of electric light. Just a month 

 later the first heads were sold from the light house, 

 but it was six weeks later when the first heads were 

 sold from the dark house. In other words, the elec- 

 tric light plants were two weeks ahead of the others. 

 The gain had been purchased by 161% hours of 

 electric light, worth, at current prices of street light- 

 ing, about $7. 



This experiment was repeated by reversing the 

 houses for the purpose of eliminating errors, and the 

 results were essentially the same. Seeds were sown 

 in plots on February 24, 1891. Until March 17 they 

 were grown under ordinary conditions, at which time 

 they were set in their permanent positions in the two 

 compartments. We began to pick lettuce from the 

 light house on April 30, but the first of equal size 

 from, the dark house was obtained on May 10. The 

 electric light plants were therefore upon the benches 

 forty-four days before the first heads were sold. 

 During this time there were twenty nights in which 

 the light did not run, and there had been but eighty- 

 four hours of electric light, worth about $3.50. This 

 gain of ten days in maturity is remarkable when we 

 consider that the light never ran later than 11 o'clock 

 at night, that nearly half of the nights had no light, 

 and that the experiment was made late in the season, 

 when the strong sunlight would tend 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 elec- 

 tric arc light upon vegetation than that a 2,000 can- 

 dle power lamp, run half the night, or even less, 

 exerts a most marked beneficial influence upon let- 

 tuce throughout a house 60 feet square. In fact, 

 I consider this point so well determined that we have 

 discontinued experiments in the general forcing of 

 lettuce by the electric light. 



EFFECT UPON FLOWERS. 



The influence of this naked light upon the pro- 

 ductiveness and color of flowers was found to vary 

 with the different species and different 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 a distance of 10 or 

 12 feet from the lamp. Petunias were much 

 affected by the light. The plants were much taller 

 and more slender in the light, even at the farthest 

 corners of the house, 20 and 30 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 to six. White 

 petunias were not changed in color by the light, but 

 purple ones quickly became blue, especially near the 

 lamp. Other flowers behaved differently, each 

 according to its kind ; but all those, of whatever 

 species, which stood within 5 or 6 feet of the naked 

 arc, were injured. Flowers opening near the light 

 were of short duration, but those 10 or 12 or more feet 

 away did not appear to be modified in this regard. 



HASTENED BLOOMING. 



But it was apparent that in general the light 

 hastened blooming, and caused the production of 

 longer stems, but this effect was much obscured by 

 the injuries resulting from the unscreened arc. Sub- 

 sequently we found that the use of a globe or pane of 

 glass will avert the injuries to flowers as well as to 

 foliage ; and the long stems and open inflorescence, 

 together with some increase in earliness in some 

 cases, may be obtained without fear of injury. Yet 

 we are not ready to recommend the electric arc lamp 

 for the growing of flowers. If the noxious effects of 

 the electric light can be overcome by the interposi- 

 tion of glass, it remains to determine whether the 

 light cannot be hung above the house to advantage, 

 the glass roof acting as the screen. A lamp, sur- 

 rounded by a globe, was hung six feet above the 

 middle of the glass roof, and lettuce, endive, beets, 

 radishes and spinach, and other plants, were grown 

 beneath. The lamp was so arranged that half the 

 house had no electric light, while the other half 

 received the full glare of the arc. The lettuce, as 

 usual, was a week to ten days earlier in the lighted 

 compartment, and the effect was marked in the 

 remotest corner of the house, 40 feet from the lamp. 

 Endive, which had been injured in other experi- 

 ments, now showed no bad results, although it did not 

 appear to be benefited; but radishes, which had been 

 among the plants most seriously injured in all our 

 experiments, now showed for the first time a decided 

 gain in the light compartment. 



