Scientific Notes and News [article]

1903 Science  
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more » ... out Early Journal Content at http://about.jstor.org/participate--jstor/individuals/early-journal--content. JSTOR is a digital library of academic journals, books, and primary source objects. JSTOR helps people discover, use, and build upon a wide range of content through a powerful research and teaching platform, and preserves this content for future generations. JSTOR is part of ITHAKA, a not--for--profit organization that also includes Ithaka S+R and Portico. For more information about JSTOR, please contact support@jstor.org. 606 SCIENCE. SCIENCE. frangibility produce greater decoloring effect than those of high refrangibility, but from the results obtained here it would seem that decoloration is in no way directly or inversely proportioned to refrangibility. It will be seen that the blue and the red are close together here, while in the solar spectrum they are far apart. In the accompanying Fig. 2 , I is given the curve of decoloration of an alcoholic solution of chlorophyll with the screens already described. The vertical lines represent relative quantity of effect-d, darkness; r, red; y, yellow; g, green; v, violet; w, weak diffused light. In Fig. 2 , II is given the curve for relative phototropism. In both cases no attempt is made to represent the actual difference between any two as compared with any other two, e. g., in Fig. 2 , II, blue is three units above green simply because it happens to be stronger (in effect) than diffused light, which is stronger than violet, which is stronger than green; nor is it intended that the ' colors' indicated shall be in the exact position of the spectrum, though so far as the 'colors' are concerned they are in that order. In nearly all the experiments the apparatus was indoors, and the light exposure chiefly north. Some light came from the east and about an equal amount of exposure toward the west. The first experiments were made in the greenhouse, but it was found that too much heat was produced, resulting in the wilting and even in the'death of the plants. However, so far as carried on, the results were identical with those under diffused light. The plants which proved most susceptible to phototropic influences were barley, wheat and tobacco seedlings. The best, most positive and the quickest results were obtained with wheat and with barley seedlings from five to forty mm. high. Other seedlings used were Catalpa, Datura, bean, pea, corn, sunflower and pumpkin. No attempt is here made to deduce a physiological or a physical law from these phenomena because it is thought that sufficient data are not yet at hand; nor is there any quantitative effect estimated as existing between any two of the screens used. It is quite
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