— no — The following count of the number of bolls per plant is typical of the results obtained : Number of bolls per plant from two observation rows : Average of 200 plants 3-1 Averages of groups of thirty-five plants counted in different squares of plot : 31, 3-5, 30, 3-2,. 30, 3-2, 3-0, 3-2, 3-1.

Furthermore, it is not intended to make any final statement until confirmation has been obtained by repeated observations extending over several years.

A few words are necessary in explanation of the methods used in the laboratory. The length of the fibres has been obtained by combing out the lint from the seed, and measuring to the extreme length of the halo by means of dividers. Strength has been estimated by a home-made machine similar to that invented by O'Neill.* This machine has never been standardised with any other, so that the figures obtained are purely comparative. It is believed, however, that they are approximately correct. " Ginning percentage " was obtained by ginning 500 grammes of seed cotton with a hand-roller gin and dividing the weight of lint obtained by five. " Weight of Seed " was calculated as the average of 250 seeds.

SECTION I.

The Influence of Climate and Soil on the Growth of the Cotton Plant.

Before discussing the effect of agricultural treatment on the crop, it will be well to review the scanty available data bearing on the influence of climate and soil on the growth of the plant.

Temperature and Growth,—During the period of most active growth, that is, from July to September, there are usually very few days when the daily maximum temperature does not exceed the optimum for healthy development.

Daily measurements of the increase in height have shown that the maximum amount of growth takes place not in the daytime, but between sunset and the early hours of the morning.

Should the night temperature remain high, growth is continuous until dawn, when inhibition soon occurs by reason of the increasing intensity of the sun's rays. This " sunshine effect " is very marked in the Sudan and is due to the excessive strain thrown on the transpiratory organs of the plant.

The alternate rise and fall in the growth rate, and the effect of direct sunshine are well brought out in Fig. 1. The growth curve was obtained by * Henry : " Determmation de la valeur commeroiale des fibres de coton," p.- 36. The very ingenious method of mounting the fibres introduced by Hughes was used throughout the work.

•j- Balls : " The Cotton Plant in Egypt,"