. Carnegie Institution of Washington publication. aken from a fourth tree at 2 30 p. m. The two readingsmarked III4 and IV4 were taken about 4 meters from the tips, where tlie barkis brown and not green as in the other samples. In the sawing great cafewas taken to get branches widely separated on the tree, in order that thewounds might cause as little disturbance as possible. The evaporation ratewas measured by exposing atmometer No. 11-1 in an open sunny place. * Dixon and Joly, On the ascent of sap, Proc. Roy. Soc. Lond., vol. 57 B. 46 TRANSPIRATION IN A DESERT PERENNIAL. Table 20.—Water con
. Carnegie Institution of Washington publication. aken from a fourth tree at 2 30 p. m. The two readingsmarked III4 and IV4 were taken about 4 meters from the tips, where tlie barkis brown and not green as in the other samples. In the sawing great cafewas taken to get branches widely separated on the tree, in order that thewounds might cause as little disturbance as possible. The evaporation ratewas measured by exposing atmometer No. 11-1 in an open sunny place. * Dixon and Joly, On the ascent of sap, Proc. Roy. Soc. Lond., vol. 57 B. 46 TRANSPIRATION IN A DESERT PERENNIAL. Table 20.—Water content of stems and branches of adult trees. Experiinnil X VIII. Date, Augusts, 1011. Time. I, l2 l3 III II2 II3 IIIi Hi- III3 III4 IV, IV2 IV, IV» Eii-i 4 30 87 68 58 I 73 62 97 es 64 50 8 30 85 66 68 I 87 68 61 93 60 61 , 10 30 77 58 61 1 . .. 67 67 97 63 61 .037 12 30 73 63 68 1 70 70 78 72 60 .046 2 30 77 64 63 : 93 70 93 59 62 97 81 61 60 .061 5 00 85 66 62 77 73 61 63 .055 9 30 66 59 100 1 68 64 90 62 60. Fig. 22.—Graphs of water content measurements taken simultaneously from two adulttrees at three different distances from the ends. Graph for relative transpiration of aleafless branch repeated at top of figure. Exp. XVIII. Experiment XIX. Subject, the tree from which branches/, g, and h were taken. (See experi-ments XI to XIII.) End twigs about 3 to 5 cm. long were cut off, theleaves quickly severed, and the leaves and twigs placed in separate air-tightshallow weighing-bottles. The Ijottles with their contents were weighed ongood chemical balances to gm., and the contents were then transferredto glass beakers and protected from dust, etc., by filter-paper covers. Thebeakers and their contents were then dried to constant weight in an electricoven at 72° to 75° C. By the use of the above precautions it was possibleto obtain the water-content, of the small amount of material which it wasnecessary to use, accurately to per ce
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