File:The literary digest (1890) (14762141476).jpg

Identifier: literarydigest16newy (find matches)
Title: The literary digest
Year: 1890 (1890s)
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Publisher: New York : Funk & Wagnalls (etc.)
Contributing Library: Robarts - University of Toronto
Digitizing Sponsor: University of Toronto

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glass was more succes. Vol. XVI., No. 10) THE LITERARY DIGEST. 285 ful. Red, green, blue, and white (or uncolored) glasses wereused with the result shown in the illustration. The growth wasfar greater under the red, while the development of woody fiberwas greatest under the clear glass, that is, in normal conditions.It will be seen that the blue-glass theories of twenty years agoare decidedly negatived. Says the author: In relation to these results of his investigations, Flammariondirects our attention particularly to two circumstances. First,the intensity of the light as an illuminating agent was not in allcases the same, for the clear glass has of course the highest powerin this direction and the blue glass the least. Secondly, the tem-perature is not the same throughout, for here again the clearglass lets through most heat rays and the blue the fewest. Thereis, now, for all plants a maximum temperature up to which theygrow best, and also doubtless a degree of light-intensity under
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Diffuse Light. Light Greatly Decreased. EFFECT OF THE INTENSITY OF LIGHT OX THE GROWTH AND APPEARANCE OF COLEUS LEAVES. which they flourish to the best advantage. So the chief factorsin plant growth are color, light-intensity, and temperature, whichall work together in the same direction. Later investigations, however, showed that temperature hasvery little influence, for when it was so carefully regulated as tobe the same for each color, the striking differences under thevarious colors still remained. M. Flammarions investigationsalso brought out interesting effects of light on the colors of leavesand flowers. To quote again : All plants may be divided into three principal groups: first,those in which the influence of light on the nutritive processes inthe cell causes the colors of leaf and flower; second, those inwhich the color is influenced by the direct effects of the sunlight;third, those in which the coloring of certain parts is not dependentupon light. We all know that green h

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