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deficient in the orange rays. The use of an orange- 

 colored globe makes it more nearly like sunlight, 

 and favors its action upon vegetation. The naked 

 arc-light, if too near some plants, exerts a detri- 

 mental action upon them, and one must carefully 

 study the susceptibility of the individual plant in 

 order to regulate the distance between it and the 

 light. The length of time the lamp is kept burn- 

 ing and the color of the shade through which the 

 light is permitted to pass are also matters of im- 

 portance. 



The value of interposing glass between the light 

 and the plants has been demonstrated frequently: 

 for instance, Dr. Bailey, of Cornell, whose work in 

 electro-horticulture has been of the highest order, 

 found that radishes under the naked light lost from 

 forty-five per cent, to sixty-five per cent. ; under a 

 light covered by an opal globe the loss was but 

 slight, while when the light was strained through 

 the opal globe and the glass roof of the greenhouse 

 there was an increase in both tubers and tops. He 

 obtained similar results with beets and spinach. 

 Cauliflowers were so influenced by the light as to 

 grow tall and extend their leaves in a vertical 

 direction, but they did not head so well as those 

 grown without the light. Tulips and petunias 

 grew taller and more slender, had richer hues, and 

 bloomed earlier and more freely. Lettuce was 

 from ten to twelve days earlier, and felt the influ- 

 ence of the light all over the greenhouse, which 

 extended forty feet from the lamp. Another ex- 

 perimenter tells us that a 2Ooo-candle-power arc- 



