INFLUENCE OF THE ELECTRIC LIGHT ON VEGETATION.

Inangahua Times, Volume II, Issue II, 26 May 1880, Page 2

INFLUENCE OF THE ELECTRIC LIGHT ON VEGETATION.

: ♦ 1 (Times, sth March.) At the mating of the Boyal Society hest evening, Dr 0. W. Siemens, F.E.S., gave a detailed description of some experiments upon the above suljeet, which have <een conducted daring the last two 1 months at his boose at Sherwood, and exhibited specimens. The method purs sued was to plnnt quick-growing seeds and plants, such as mustard, carrots, f swedes, beans, cucumbers, and melons in pots, and these pots were divided into ! four groups, one of which was kept en- ! entirely in the dark, one was exposed to ' ; the influence of the eteofric light only, 1 one to the influence of daylight only, and one to daylight and electric light in suc» ; cession, The electric light was applied for s'x hours each evening, from 5 to 11, and the plants were then left in darkness i daring the remainder of the night. The [" ' e^ral result was that the plants kept • ' entirely in the dark soon died j those exposed to the electric light only or to ! daylight only, throve about equally ; and 1 those exposed to both day and electric light throve far better than either, the of mustard and of carrots ex* 'fhibited to the Society showing this differ" ' ; ence in a very remarkable way. Dr ' ■ Siemens only considers himself as yet on ' '•■ the threshold of the investigation, but thinks the experiments already made are sufficient to justify the following eonclus 1 sions :— 1. That electic light is efficacious in producing chlorophyl in the leaves of plants, and in promatingr gpwth. 2. That jaikeleatrfc centre of light eq.ua! to 1400 -raidles placed at a distance of two metres ;frnm growing plants apppared to be equal in effect to average daylight at this spf« son of the year ; but that more economical effpc's can be obtained by more powerful light centres. 3. That the car* ».»bfcßic acid and nitrogenous compounds generated in diminutive quantities in the electric arc produce no sen«ible deleter* inus effects upon plants enclosed in the same space. 4. That plant* do, not appear to required a period of rest during the twenty-four hours of the day, but mnke increased and vigorous progress if subjected during daytime to sunlight, and during the night to electric light. 5. That the radiation of heat from powerful elecr rtic arcs can be made available to countervail the effect of night frost, and is likely to promote the setting and ripening of fruit in the nppn air. 6. That while under the influence of electric light plants can sustain increased stove heat without collapsing, a ciroumstrnce fa* vouiable to forcing by electric light. 7. That the expense of electro horticulture depends mainly upon the cost of mechanical energy, and is very moderate where natural sources of such energy, such as waterfalls, can be made available. The paper pave rise to a highly interesting discussion, in which it was pointed out that the evidence afforded of the practical identity, as regards vegetation, of % solar and electric l'ght, besides the pteo--s>a^lity that it would be turned to ims mediate account by horticulturists, would afford great facilities for the scientific in* vestigation of the influence exerted by light, as compared with other agencies, in promoting the formation of the active principles or most yaluab'e constituents of plants, such as the quinine of tl>e cinchona bark, the gluten of wheat, and so forth. Before, concluding his observa vations, Dr Siemens placed a pot of bud* ding tulips in the full brightness of an electric lamp in the meeting-room, and in about 40 minutes the buds had expanded into full bloom.