THE SOURCES OF THE NITROGEN OF VEGETATION, ETC. 559 
May 22.—A pipette-ful of the sulphuric-acid solution added. 
May 29.—Hight plants, 4 to 6 inches high; each with four leaves, the two lower 
yellow, the two upper green and healthy. A drop of water appears on the tip of the 
upper leaves in the morning, but it disappears before midday, as the air is passed 
through the shade. <A pipette-ful of the phosphate-solution added. 
June T.—A pipette-ful of the phosphate-solution, and a pipette-ful of the sulphuric- 
acid solution added. 
June 19.—Plants 5 to 7 inches high; two lowest leaves on each dried up; upper 
ones yellowish green. 
June 26.—Eight plants, 6 to 7 inches high; six leaves each, three lower ones dried 
up, next two pale green, only upper central one green and healthy. Apparently at 
limit of growth without more combined nitrogen; very much as last year without 
nitrogenous manure. 
July 3.—A pipette-ful of the phosphate-solution, and a pipette-ful of the sulphuric- 
acid solution added. 
July 14.—Plants 6 to 8 inches high, with six or seven leaves each; only the two 
upper ones yellowish green; apparent stagnation of growth. 
July 29.—Much as last; two upper leaves seem to sustain life at the expense of the 
rest. 
August 17.—After long inactivity several plants show tendency to grow in stem. In 
this, somewhat more like the barley than wheat of last year. Some disposition to 
heading. 
September 7.—Still developing stem; nodes and internodes distinctly marked. Plant 
(a) 13 inches high, ten leaves, three nodes bare, slightly swelled at top as if heading ; 
new stem-leaves, only 2 to 3 inches long. Plants (6 and c) 94 inches high, nine leaves, 
two or three bare nodes; slight indication of heading. Plants (d, e, and f) 74-inches 
high, two bare nodes; stems shorter, leaves eight or nine, a little longer than above. 
Plant (g) two branches; the first short, and dried up; a new one formed from its base, 
green, but only 43 inches high, with four green leaves. Plant (A), dried up stem with 
three long leaves; but a new green shoot with two leaves, though little growth. 
General remark :—all lower and first-formed leaves dried up, the next yellowish, and 
only the two upper ones green. Drops of water collect at the tips, and axils, of the 
green leaves. The later growth obviously at the expense of the earlier. 
October 5.—Little change, except riper. Plant (a) 14 inches high, eleven leaves, 
nearly all dried up, four bare nodes, a head with indications of seeding: (b) 104 inches 
high, eleven leaves, all ripe but the uppermost, three bare nodes, and indication of 
heading: (¢) 94 inches high, nine leaves, three nodes: (d and e) 83 inches high, eleven 
leaves each: (f and g) 4 to 7 inches high, dead stems with eight to ten leaves each, 
but green shoots at the base: (4) 7 inches high and seven leaves, dead ‘ripe. 
October 24.—Weather much warmer again lately, and slight renewal of growth; 
drops of water again appear on the green top leaves. The chief growth is further deve- 
MDCCCLXI. 46 
