58 MASSACHUSETTS HORTICULTURAL SOCIETY. 



follow continuous light throughout the twenty-four hours, that 

 electric light often deepens the green of leaves and the tints of 

 flowers and sometimes intensifies flavors, and that it aids to 

 produce good seeds ; and he thought that the addition of the 

 electric light enabled plants to bear a higher temperature in the 

 greenhouses than they otherwise could bear. But whatever may 

 be the value of the electric light to horticulture, the scientific value 

 of Siemens's experiments is still great. They have furnished data 

 in regard to several obscure relations of light to vegetation. 

 "Nature" made the following comments upon this feature of the 

 application of the electric light by Dr. Siemens: ''But the scien- 

 tific interest of its present application nmst rest mainly on the fact 

 that the cycle of transformation of energy engaged in plant life is 

 now complete, and that, starting from the energy stored up in 

 vegetable fuel, we can run through the changes from heat to 

 electricity, and thence to light, which we now know we can store 

 up in vegetable fuel again." While the experiments were designed 

 for practical purposes, and while the economic results seemed to be 

 important, the most valuable conclusions of these signal investiga- 

 tions are such as concern the purely scientific questions of the 

 interrelations of plants and electrical illumination. 



Whilst Siemens was concluding his experiments in England, 

 Deh^rain was conducting similar ones in Paris ; but while Siemens 

 had attempted only to supplement daylight by electric light for a 

 part or all of the night, the other endeavored to grow plants by 

 the continuous electric light alone, with practically no aid from the 

 sun. He found at once that the naked arc injures plants, even 

 though it promotes assimilation more rapidly than the screened 

 light. Barley in head and flax in flower were brought into the 

 lighted compartment; also chrysanthemums, pelargoniums, roses, 

 and a variety of ornamental plants. After seven days of contin- 

 uous electric lighting most of the plants were seriously injured. 

 All the pelargoniums lost their leaves, cannas were discolored, 

 four o'clocks were tarnished, and bamboos were blackened. 

 "But tlie most curious effect was produced upon the lilacs; all 

 tlie parts of the leaves that had received the direct rays from the 

 lamp were lilackened, while those protected l)y the upper leaves 

 preserved theii- beautiful green color, and tlie impi'cssion i)r()(lu('ed 

 upon tlie epidermis by tlie electric rays had the clearness of a 

 photographic plate." Similar effects were produced upon azaleas, 



