Bulletin, Issue 36

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U.S. Government Printing Office, 1905

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Page 311 - The visitations most marked and best defined, occur at intervals of about sixty-five years, reckoning from the middle of one period to the middle of the next period, and last from twenty to twenty-two years, making the interval from the end of one to the beginning of the next about forty-five years. 6.
Page 371 - Étude sur la Force chimique contenue dans la lumière du Soleil, la mesure de sa puissance, et la détermination des climats quelle caractérise, par Eug. Marchand. — Paris, Gauthier-Villars, in-8".
Page 160 - His results are summarized as follows : (1) Peas, alfalfa, serradella, lupine, probably clover, and apparently all leguminous plants, have the power of acquiring large quantities of nitrogen directly from the air during their growth. There is no doubt that the free nitrogen of the air is thus acquired by these plants. This acquisition has something to do with the tubercles on the roots of these plants, but the details of the process are still to be solved. The cereals, oats, etc., with which experiments...
Page 138 - ... found external to the fungus mantle, which prolonged into threads among the particles of soil. Frank concluded that the chlorophyllous tree acquires its nutriment from the soil through the agency of the fungus. Such a mode of accumulation by these green-leaved plants plainly allies them very closely to fungi themselves; but inasmuch as in the cases observed by Frank the action of the fungi was most marked in the surface layers of soil rich in humus, and since this development has not been observed...
Page 112 - ... a plant under given conditions are found at a given level, and if we change these conditions as to moisture, temperature, etc., we shall change the distance from the surface down to this level. (Wollny's Forschungen, Vol. XIV, p. 132.) TRANSPIRATION. The quantity of water transpired by trees and plants depends upon the amount of water at their disposal, as well as on the temperature and dryness of the air, the velocity of the wind, the intensity of sunlight, the stage of development of the plant,...
Page 26 - ... decidedly than do other rays; yet that is an effect perhaps more negative than positive, if the flexure proceeds, as many still believe, from what is going on on the side least exposed to the light.
Page 138 - The authors suggest (1) that somehow or other the plant is enabled tinder the condition of symbiotic life to fix free nitrogen of the atmosphere by its leaves, a supposition in favor of which there seems to be no evidence whatever; (2) that the parasite microbe utilizes and fixes free nitrogen and that the nitrogenous compounds formed by it are then taken up by the plant host. On this latter supposition the large gain of nitrogen, as made by the leguminous plant, when growing in a soil that is free...
Page 101 - ... 1 pm 2p.m. 3 pm 4 pm 5 pm 6 pm 7 pm 8 pm 9 pm 10 pm 11 pm 12t 1 amt 2a.m.
Page 3 - Hon. JAMES WILSON, Secretary of Agriculture, Washington, DC SIR: I have the honor to submit the manuscript of a first report, by Prof.
Page 20 - ... the soil until it arrives at a layer 30 to 50 feet below the earth's surface, where the gradient of temperature just in front of it is the same as that just behind it. Here the heat would accumulate and push its way still deeper were it not that by this time, in most cases, the diurnal and annual changes of temperature at the earth's surface, where this heat wave started, have brought about a deficiency just below the earth's surface; consequently the heat that had reached the depth of 30 or...

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