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with a ruinous policy during many centuries of using up all available timber, so that now almost everywhere the hillsides are not only bare of trees but are literally scratched for roots each season, have so decreased the margin which the people have between a state of enough and that of utter want, that when the floods come, which they do almost annually in certain sections as a result of this ruthless deforestation, vast numbers are subject to actual famine.

The remedy is threefold: First a reduction of the birth rate as general education advances and a saner sociology prevails.

Secondly, a comprehensive system of reforestation, for from a physical point of view the primary fact about China is that she has used up her trees. Reforestation on a small scale has been begun in some parts but much more needs to be done and the need for it must be made clear and appropriate measures approved and financed.

Thirdly, improved methods of agriculture must be introduced. What is needed is more extensive farming. The Chinese farmer is altogether a gardener. He is the world's best expert in intensive farming, and we can learn from him in that line; but he seems to know little of extensive farming as we know it in the West, or of the ways of improving varieties. Modern agricultural schools are being established and some large agricultural development schemes have been formed. We may expect to see considerable progress in due time. I would commend to you the late Professor King's "Farmers of Forty Centuries," and G. W. Groff's pamphlet, "Agricultural Reciprocity between America and China."2

I believe that one of the best examples of re-forestation is given by Denmark in which in the course of twenty-five years, a considerable area has been given full-grown trees of a quick-growing variety and the rainfall has already been markedly affected. It is not likely that the same conditions exist in China so that it will be at least two or three generations before the conditions with reference to re-forestation

Either of these can be secured from the Trustees of the Canton Christian College, 156 Fifth Avenue, New York.

can be adequately altered. There must, in the meantime, be a survey of flood-subjected areas of the rivers involved so that the adequate measures of protection may be carried out. During one of my recent trips in Anwhei Province, one of the regions of chronic famine, I met the American engineer, Mr. Jameson, who had been sent by the Red Cross Society for the purpose of determining in what way such protective works might be carried out, and I have noted recently in the press that President Taft has commended Mr. Jameson's report to President Yuan Shih Kai. But this task of determining what should be done for the control of the rivers and canals is a gigantic one and needs the attention of the world's best experts.

Chief among the rivers needing such control is the Yellow River, "China's great sorrow." This is but little inferior to the Yangtsze in length, being nearly 2500 miles, running from southwest to northeast. But is is one of the most unmanageable rivers in the world and of little utility. It is a characteristic river of the loess region, with a broad shallow course which is apt to change. It owes its color and name to loess sediment. During the whole known historical period, this river has frequently changed its course for the last 350 miles. These changes have swept over a fan-shaped areas of 60 degrees in one of the most densely populated and highly cultivated regions in all China, and have, consequently caused great loss of life both directly by flood, and indirectly by consequent famine through destruction of standing crops as well as of stored food supplies.

Throughout its whole lower course, its waters run through the plain where it is most to be dreaded, because the mud and sand carried down by its stream have actually raised the bed of the river until it is several yards above the level of the surrounding country. Consequently there are few important towns on its banks. At its crossing with the Grand Canal, its bed is 16 feet above the level of the Canal.

In 1642, the city of Kai fung, 350 miles inland, was submerged 20 feet, and 200,000 persons are said to have perished. In 1854 the river flowed into the Yellow Sea in latitude 34 degrees N, but in that year it diverted near Kai fung fu, into

a northern bed it occupied 550 years before, and joining the Ta tsing ho, discharged into the Gulf of Chihli, several hundred miles further up the coast. In 1887 a terrible inundation occurred by the river bank giving in, and towns and villages were swept away.

To hinder its overflowing, embankments hem it in, some nearer, others farther, ranging one behind another at variable distances. In this manner, if one gives way, another prevents the inundation. In its present state, the work is still very inefficient, the dikes being weak, and constructed with materials that offer insufficient resistance.

The mud and sand which frequently obstruct the Yellow River, render it also very difficult of navigation. The only portion where it can be availed of, is to the north of Honan, and in the last 25 miles of its course. But even in this part, a shoal prevents junks except of very light draft from passing.

The flow of the Yellow River varies much with the season. It has been reckoned to be a little over 4000 cubic yards per second, in its middle portion, near Tsinan Fu(Shantung). The flow is three miles greater in the flood season. It is on the whole relatively small for such a great river, but this is partly accounted for by the waste of the water that filters through the embankments. The mud and sand, which it unceasingly deposits in the Gulf of Chihli, constantly lessen the depth of the latter, and form there new alluvial lands. Opposite the former mouth of the river (1851) one can see what great quantity of sediment was carried in its waters.

The last serious breach in its dykes occurred in September, 1902. The Chinese engineers showed great ingenuity in effecting its repair. The breach was near Liu-wang-chuang and was 1500 yards, through which most of the river flowed. It was repaired by building out from each side, dams in the form of a series of pakwerks of kaoliang stalks and sacks of clay, each pakwerk or buttress being joined to the previous one by ropes and piles.

Kaoliang is a kind of sorghum, probably identical with Barbados millet. The core of the stalk, except for a very thin and weak covering, is entirely pith, but it has a matted

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bunch of fairly hard and strong roots which form its chief virtue for construction work. The stalk is about 6 feet long,

inch in diameter, and the bunch of roots, 3 to 5 inches in diameter. The face of the werk including the sides is composed of the roots which mat together and make a splendid surface for keeping out water.

The final opening in this breach of 1500 yards, after pakwerks were built out from each side, was reduced to 55 feet, and this, after two disastrous attempts in which the lives of many workmen were lost, was effectively closed on March 16, 1903, by letting down a huge mattress of kaoliang stalks and sacks of clay, the mattress being anchored to the side of the river by a great many 15-inch hawsers so as to prevent canting due to impact of current. Over one hundred 8-inch ropes spaced closely together were stretched across and belayed to anchor piles. On these were than placed in alternate layers the kaoliang stalks and sacks of clay. When these materials reached the level of the sides of the dam, the ropes were manned, and at a given signal were each lowered 1 foot on each side.

The rush through the opening was reduced by the construction of a deflecting groyne on the up river side of the breach, constructed similar to the pakwerk, and projecting some 120 feet into the current. The width of the river channel abreast of the breach had been 600 feet but was reduced to 300 feet by the formation of a sand bank on the opposite side of the river.

The control of the Yellow River is today one of the most pressing of China's physical problems. Experience has shown that the diking of such rivers is insufficient and almost futile. Captain William Tyler, coast inspector of the Chinese light house service, has presented a report on the Yellow River published by the inspectorate-general of customs at Shanghai in 1906, in which he proposes to control the river's lower reaches by providing for the depositing of the silt by deliberate flooding of large areas along the river, that is, to regulate its floods.

For this as well as for other rivers subject to floods, very comprehensive surveys should be made and the history of

the streams involved secured as accurately as possible. It has been surprising to me to see how often the railway engineers have erred in China, from their inadequate attention to this factor of river history, and after costly experience have had to redetermine the level of their tracks when flanking a river or lake or to rebuild their bridges crossing a stream.

Another example of Chinese engineering skill employed in protecting the land from the "misbehavior" of rivers is the great sea wall along the north side of Hangchow Bay, of which I have elsewhere given a full account, and is, considering the difficulties under which it was built, one of the finest pieces of such engineering to be found anywhere.

The Hangchow bore is caused chiefly by the funnel-shaped character of Hangchow Bay, combined with extensive mud and sand bars that occupy its mouth so that the tide in coming up the by instead of gradually rising, banks up near the entrance. The difference in level is such that a great wall of water anywhere from 10 to 30 feet in height rushes up the bay and up the river at a speed which sometimes equals that of an ordinary express train. This occurs twice a day and always amounts to a considerable wave, although sometimes it is much larger than others. Of course, an exceedingly strong wall is required to keep out such a mass of rushing water from the surrounding country which, as a matter of fact, is in many places below the level of the river. Some 750,000 taels are spent each year for the upkeep of this wall. It is built of heavy granite blocks joined together with double iron wedges and besides the wall which is ordinarily 30 feet in height, there are two granite platforms or ledges each edged with a multiple series of long piles driven into the sand, constituting one of the strongest sea footings that could be secured to keep the wall from being undermined. At intervals of about half a mile for a good part of the wall, there are pakwerk buffers to deflect the current of the bore.

As if these two cases of the devastating forces to be overcome were not enough to develop resourcefulness and hardihood in the people compelled to face them, the coast of

Popular Science Monthly, February and March, 1908.

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