THE SOURCES OF THE NITROGEN OF VEGETATION, ETC. 569 
The roots tolerably distributed throughout the whole pot, though not extending much 
to the sides, but passing through all the holes at the bottom, and some at the sides, of 
the pot, and forming a dense matted mass underneath it in the pan. Those of the 
plants nearest to the watering and manuring tube have sent by far the most roots down- 
wards into the pan,—those furthest from it having their roots proportionally much more 
confined in the soil near the base of the plant, where they are much matted, with diva- 
ricate branches and short branchlets—these characters being more nearly those of the 
Cereals grown without nitrogenous manure. 
Preparation and analysis as described at pp. 543, 544. 
No. 10.—Barley (1858); four seeds; prepared soil; with nitrogenous manure. 
(See Plate XV. fig. 11.) 
April 27.—Seeds set, and the pot placed over sulphuric acid, and covered with a glass 
shade. 
May 7.—The pot removed to its shade on the stand. 
May 20.—Two plants up. 
May 22.—A pipette-ful of the sulphate-of-ammonia solution (=0-004 gramme N.) 
added to the soil. 
May 29.—Two plants; 4 to 6 inches high; five leaves on each, the lowest dead, the 
others green; improved since the addition of ammonia, more active growth and colour 
- deeper green. A pipette-ful of the phosphate-solution added. 
June 7.—Second pipette-ful of the sulphate-of-ammonia solution added; also a 
pipette-ful of the phosphate-solution. 
June 19.—Two plants; 10 to 12 inches high, forming stem well; each plant seven 
leaves; one stem has a small shoot forming at its base. 
June 21.—Third pipette-ful of the sulphate-of-ammonia solution added. 
June 26.—Fourth pipette-ful of the sulphate-of-ammonia solution added. Two plants; 
16 to 18 inches high, healthy and vigorous; eight leaves each; also each a vigorously 
growing shoot 4 to 5 inches long. 
July 3.—Fifth pipette-ful of the sulphate-of-ammonia solution added ; also a pipette-ful 
of the phosphate-solution. 
July 12.—Sixth pipette-ful of the sulphate-of-ammonia solution added. 
July 14.—Seventh pipette-ful of the sulphate-of-ammonia solution added. Two plants, 
namely,— 
No. 1. (a) Main stem, 26 inches high; lower leaves ripe or dead, and yellow, upper 
ones green and growing; beard just appearing at the head. (6) Shoot, 18 inches high ; 
three ripe or dead leaves, and three green. 
No. 2. (a) Main stem; 28 inches high; lower leaves ripe or dead, four upper ones 
green; air-roots developing. (4) Shoot, 12 to 14 inches high; one dead, and four green 
leaves. (c) Shoot, 4 to 6 inches high; one dead, and three green leaves. 
July 19.—Eighth ‘pipette-ful of the sulphate-of-ammonia solution added: 
4H2 
