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her sister, who had always represented her, but she also died soon after, in August, 1896; whereupon the present Queen Modjadje began to reign. She is about 30 years of age, and has a son. former power and influence this tribe had has entirely disappeared, since they have been forbidden to murder promiscuously.

Out of this tribe I now have a congregation of about 1,300 members, eight out-stations with schools; on the main station are two white missionaries, a registered school of 230 children, with two white and four coloured teachers. A large cruciform church is filled on feast-days by over 1000 attendants. A brass band introduces the Sunday, and a church choir assists at divine service. All the buildings, which are substantial and comely, were erected by the Christian natives themselves without any extra pay from the Missionary Society. The whole of the station is situated between beautiful green plantations, so that it relieves eye and heart.

I have the best hopes for the Low Country in the future, for it is rich in natural deposits, both on and under the surface, rich in water and wood, and populous.

BY COLONEL H. E. RAWSON, C.B., R.E., F.R.MET. Soc., &c. Fellow of the Physical Society.

Experiments to ascertain whether there is any special growth at sunrise are lacking, and such a book as Osterhout's Experiments with Plants, 1905, does not suggest making any, either in connection with temperature or light effects upon plants. The following were carried. out during February, March, and April, 1906, in a garden in Pretoria, Lat. 25° 45 S and Long. 28° 14 E, at a height of 4450 feet above the sea, and 270 miles from it. The mean temperature varied from 70° F in February to 62° F in April; the mean maxima were 82° F and 79° F for the same months respectively, and the mean minima 59° F and 47° F. The rainfall was 4.27ins. during February, 3.05ins. during March, and 0.52in. on 2 days during April. Cloudy days were few, and during the important tests, from March 23rd to April 23rd, the sky was overcast at sunrise on only two, and on one of these there were occasional gleams of sun. On 21 days the sky was cloudless as regards these experiments, on 5 it was overcast some time during the day, and on 6 there were detached clouds. A Rambler Rose grew 33 inches in 3 weeks and 19 inches in the two following weeks during the period of the experiments.

That some connection would be found between sunrise rays and growth was suggested by a wonderful cloud-phenomenon, which was seen at that hour on March 12th, 1905, from the deck of S.S. Gaika, when in Lat. 8° S and Long. 3° W, close to the Magnetic Equator. As the sun rose out of the water due E at 6 a.m., the sky was suddenly covered with myriads of cirrus threads as fine as those of a cobweb, and each one stretching continuously from true north to true south parallel to one another, and without break or irregularity of any kind. By the sun's action each particle of frozen moisture in the cirrus levels had been symmetrically brought into lines, so as to form a series of arches at right angles to the rays of light. At a higher level than the cirrus lines there were a few flecks of cirrus cloud drifting from north to south, but the lines had a movement of their own. As measurements with instruments proved, they swung slowly round as if endeavouring to keep themselves perpendicular to the sun. At noon the lines had thickened considerably, and half-an-hour before sunset there was a double set of them, one perpendicular, and the other parallel, to the incident rays. They were watched during the process of forming, and appeared to be evolved out of minute globules of cirrus haze. By no possibility could this have been the effect of wind, and it was the opinion of those who were taking the measurements that the arrangement of the globules into lines was directly due to the sun's rays.

This wonderful phenomenon was repeated on two consecutive days and was carefully studied in all its details, to see if it would throw any light on analogous cases in which a symmetrical arrangement of particles of matter takes place under the action of incident rays. In botany we have such a disposition of chlorophyllgranules on cell-walls which are perpendicular or parallel to the rays.

and it is thoroughly recognised that the intensity of the illumination controls the arrangement of the granules. How it does so is still a question, but it is more or less an accepted theory that living protoplasm has a directive property owing to which it can distribute. the granules in the way which is most beneficial for the growth of the plant. Protoplasm cannot live without water, and in the absence of a sufficient supply it loses much of its power. Moreover, the arrangement of the granules during darkness is not the same as during diffuse or direct sunlight. Further, there is the alteration in the shape of the granules under varied illumination which has to be explained, and which so far has not been traced to any action of protoplasm. Flat, angular, polygonal tablets, as in the leaflets of Funaria hygrometrica, become hemi-spherical or spherical bodies, when direct sunlight succeeds diffused light. Are we straining the analogy too far in tracing a connection between the change of shape in chlorophyll-granules by sunslight, and a similar change in the cirrus particles, owing to which the lines became perceptibly thicker about noon?

We already have the hypothesis advanced that the vital force of the sun regulates the processes of synthesis going on in the cells where chlorophyll-granules are at work. To the vibratory energy of the blue and violet rays the decomposition and transformation of the carbohydrates are ascribed, while the less refrangible rays assist their formation from the raw materials. Protoplasm is unable to accomplish this without the aid of the chlorophyll-granules, and it is in them that the processes are carried on. They retain or extinguish those rays which might hinder the formation of carbohydrates, transform rays with short wave-lengths into those of longer wave-length, that sugar and starch may be more effectually manufactured; and, finally, effect the conversion of light into heat, and ultimately into latent heat. * It would only be a step further in the theory of synthesis under the action of sun's energy to ascribe to the same energy a directive influence upon chlorophyll-granules, similar to that which was seen at sunrise on March 12th controlling the distribution of the cirrus particles.

The following experiments were accordingly carried out to see whether any special influence was exerted upon chlorophyll-granules by sunrise rays, which could be detected during the growth of a plant. A strip of garden ground, which was practically virgin soil, was lightly manured with stable manure, and on Feb. 19th, 20th, 28th, and on March 6th, twenty-six rows, each 12ft. long, of Dwarf Stratagem peas, onions, beets, and lettuces were carefully planted. The rows ran north and south, and except for a low hedge of pomegranate and quinces 4ft. high and at a distance of not less. than 3ft. from the rows, they may be described as unsheltered from the sun till about 4 p.m. Each plant was watched from the moment its leaves appeared above ground, and its position was entered on a large chart. By March 23rd considerable differences could be traced,

* Natural History of Plants, from the German of Anton Kerner, 1894, vol. I pp. 371-9.

which might easily have been attributed to the seed or to the soil had not records been kept of the amount of sunrise rays each plant had received. It was quite certain

1o. That wherever plants had received a greater share of the earliest rays than their neighbours, even though the distance between them might be only four inches, they had grown more rapidly.

In consequence of a difference of 18 minutes between the times the south and north ends of Rows I. and II. received direct sunlight, there was a marked difference between the peas there. There were four strongly-defined lines stretching diagonally across the rows, where growth had been stimulated by early rays which came through gaps between distant trees and out-houses, or through crevices in the hedge. Though the rays passed to the adjoining plants in less than 10 minutes, the latter were inferior, and never grew to as large a size.

2o. That rays which fell on ground after 8h. 43m. did not have the same effect upon growth as those previous to that hour.

Sunrise was at 6.25 a.m. about this time. Up to March 23rd no seed had germinated at the north ends of the rows, within the shadow cast by the hedge up to 8h. 43m. There was no exception to this, and the line of shadow at that hour could be distinctly traced by the line of growth.

The first result can most easily be explained by considering it as an effect of temperature, though it is remarkable that the loss of only 10 minutes of direct sunlight at this hour of the day should have caused such a marked difference in the growth of plants which were not more than three inches out of the line of the ray. We cannot, however, leave out of account the action of light in arranging chlorophyll-granules on cell-walls according as it is diffused or direct, nor the fact that the chloroplasts are most active when illuminated by the red, orange, and yellow rays of the spectrum.

Differences of temperature, however, will not explain the second result. Here the direct sunlight from 8h. 43m. to nearly 16h. was powerless to make the end seeds in 14 rows out of 26 germinate. But when, owing to the sun's increasing northerly declination, direct light came through a gap about 7h. 15m. and fell on the same portion of these rows, the seeds put up leaves. This occurred in numerous cases after March 23rd, and there could be no mistake about the observation.

With the view of obtaining further information regarding these two results, and of determining whether plants which were deprived of the sunrise rays up to 8h. 43m. would show any etiolation, or decreased action on the part of the chloroplasts, the following experiment was made.

On March 22nd a portion of Rows I. and II., in which the peas had received the same amount of the earliest rays, and were particularly strong and even in growth, was shaded off by an iron screen 2ft. 4ins. long and 9 inches high. It was fixed in the ground 7 inches

from the nearest plants, and made to slant outwards from them till the shadow just left their roots at 8h. 43m. Those which were 6 inches further off in Row I. had their roots in shadow till 8h. 6m. The leaves of all the plants were in sunlight about 18 minutes previously.

By March 26th six of the 7 peas belonging to Row I. were in flower, but only one of the 7 in Row II. On the 27th the pea in Row I, which had not flowered (No. 10) had begun to turn yellow. Its tendrils had no coil in them, and especially those highest up the stem, were hanging limp. By the 28th the condition of the plant was so bad that it was feared that it would die. No. 11 next to it was also turning yellow, especially on the south side, which received the sunlight 2 to 3 minutes later than on the north side. Its tendrils also had lest their coil. Both 10 and 11 were measurably smaller in every way than those next them, both in the dimensions of their stems and of their leaves. None of the other peas behind the screen were as yellow as 10 and 11, but all were distinctly smaller than those at the south end of the rows, which received rays as early as 6h. 45m. As it was important that 10 and 11 should not die, in which case the decay might have been attributed to bad seed, insects, or to soil, the screen was lowered before sunrise on the 29th, so as to allow them to be in full sunlight little earlier. This was effected by sloping the screen outwards without otherwise altering its position. It is suggested that the change of colour was not an effect of temperature, but of distribution of the chlorophyll-granules on the walls of the cells under the action of light. This view is supported by the fact that No. II continued to turn yellow all through the 29th and 30th. The prejudicial action was not arrested suddenly.

The alteration of the screen allowed direct sunlight to fall on both 10 and 11 about three-quarters of an hour earlier, and as soon as the first ray touched the roots of 10 at 7h. 25m. on the 31st, the tendrils began to coil for the first time. The plant remained stunted and yellow, but from this onwards the chlorophyll began to return to the foliage, and there was never any doubt but that the plant would survive. Similarly No. 11 had become green and healthy by March 31st. It had received direct rays 4 minutes before No. 10 each morning. On March 30th there were stratus clouds at sunrise, and at 2 p.m. a heavy shower of rain fell, accompanied by some thunder.

So far, these experiments were in favour of the hypothesis that cutting off the early rays till after 8h. was prejudicial to such plants as peas, onions, lettuces, and beets; and that not only was the growth affected by variations in temperature, but that the chlorophyllgranules were being disadvantageously arranged for doing work, by the intense illumination they were subjected to during the day. It appeared as if the early rays were required to distribute the granules to the best advantage, and enable them to recover from the effects of the intense sunlight of the previous day.

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