There remains, lastly, a peculiar property of loess which is perhaps more important than all other features when measured by its man-serving efficiency. This is the manner in which it brings forth crops without the aid of manure. From a period more than 2,000 years before Christ, to the present day, the province of Shansí has borne the name of Grainery of the Empire, while its fertile soil, hwang-tu, or ‘yellow earth,’ is the origin of the imperial color. Spite of this productiveness, which, in the fourteenth century, caused the Friar Odoric to class it as the second country in the world, its present capacity for raising crops seems to be as great as ever. In the nature of this substance lies the reason for this apparently inexhaustible fecundity. Its remarkably porous structure must indeed cause it to absorb the gases necessary to plant life to a much greater degree than other soils, but the stable production of those mineral substances needful to the yearly succession of crops is in the ground itself. The salts contained more or less in solution at the water level of the region are freed by the capillary action of the loess when rain-water sinks through the spongy mass from above. Surface moisture following the downward direction of the tiny loess tubes establishes a connection with the waters compressed below, when, owing to the law of diffusion, the ingredients, being released, mix with the moisture of the little canals, and are taken from the lowest to the topmost levels, permeating the ground and furnishing nourishment to the plant roots at the surface. It is on account of this curious action of loess that a copious rain-fall is more necessary in North China than elsewhere, for with a dearth of rain the capillary communication from above, below, and vice versa, is interrupted, and vegetation loses both its manure and moisture. Drought and famine are consequently synonymous terms here.
RICHTHOFEN’S THEORY OF ITS ORIGIN.
As to the formation and origin of loess, Richthofen’s theory is substantially as follows:[170] The uniform composition of this material over extended areas, coupled with the absence of stratification and of marine or fresh-water organic remains, renders impossible the hypothesis that it is a water deposit. On the other hand, it contains vast quantities of land-shells and the vestiges of animals (mammalia) at every level, both in remarkably perfect condition. Concluding, also, that from the conformation of the neighboring mountain chains and their peculiar weathering, the glacial theory is inadmissible, he advances the supposition that loess is a sub-aërial deposit, and that its fields are the drained analogues of the steppe-basins of Central Asia. They date from a geological era of great dryness, before the existence of the Yellow and other rivers of the northern provinces. As the rocks and hills of the highlands disintegrated, the sand was removed, not by water-courses seaward, but by the high winds ranging over a treeless desert landward, until the dust settled in the grass-covered districts of what is at present China Proper. New vegetation was at once nourished, while its roots were raised by the constantly arriving deposit; the decay of old roots produced the lime-lined canals which impart to this material its peculiar characteristics. Any one who has observed the terrible dust-storms of North China, when the air is filled with an impalpable yellow powder, which leaves its coating upon everything, and often extends, in a fog-like cloud, hundreds of miles to sea, will understand the power of this action during many thousand years. This deposition received the shells and bones of innumerable animals, while the dissolved solutions contained in its bulk stayed therein, or saturated the water of small lakes. By the sinking of mountain chains in the south, rain-clouds emptied themselves over this region with much greater frequency, and gradually the system became drained, the erosion working backward from the coast, slowly cutting into one basin after another. With the sinking of its salts to lower levels, unexampled richness was added to the wonderful topography of this peculiar formation.[171]
Pumpelly, while accepting this ingenious theory in place of his own (that of a fresh-water lake deposit), adds that the supply of loess might have been materially increased by the vast mers-de-glace of High Asia and the Tien shan, whose streams have for ages transported the products of glacial attrition into Central Asia and Northwest China. Again, he insists that Richthofen has not given importance enough to the parting planes, wrongly considered by his predecessors as planes of stratification. “These,” he says, “account for the marginal layers of débris brought down from the mountains. And the continuous and more abundant growth of grasses at one plane would produce a modification of the soil structurally and chemically, which superincumbent accumulations could never efface. It should seem probable that we have herein, also, the explanation of the calcareous concretions which abound along these planes; for the greater amount of carbonic acid generated by the slow decay of this vegetation would, by forming a bicarbonate, give to the lime the mobility necessary to produce the concretions.”
METHODS OF WORKING COAL.
The metallic and mineral productions used in the arts comprise nearly everything found in other countries, and the common ones are furnished in such abundance, and at such rates, as conclusively prove them to be plenty and easily worked. The careful digest of observations published by Pumpelly through the Smithsonian Institution, carries out this remark, and indicates the vast field still to be explored. Coal exists in every province in China, and Pumpelly enumerates seventy-four localities which have been ascertained. Marco Polo’s well-known notice of its use shows that the people had long employed it: “It is a fact that all over the country of Cathay there is a kind of black stone existing in beds in the mountains, which they dig out and burn like firewood. It is true that they have plenty of wood also, but they do not burn it, because those stones burn better and cost less.”[172] This mineral seems to have been unknown in Europe till after the return of the Venetian to his native land, while it was employed before the Christian era in China, and probably in very ancient times, if the accessible deposits in Shensí then cropped out in its eroded gorges, as represented by Richthofen. The few fossil plants hitherto examined indicate that the mass of these deposits are of the Mesozoic age. The mode of working the coal mines is described by Pumpelly,[173] and was probably no worse two thousand five hundred years ago. Want of machinery for draining them prevents the miners from going much below the water-level, and a rain-storm will sometimes flood and ruin a shaft. An inclined plane seldom takes the workmen more than a hundred feet below the level of the mouth, and then a horizontal gallery conducts him to the end of the mine. Some water is bailed out by buckets handed from one level up to another at the top, and the coal is carried out in baskets on the miners’ backs, or dragged in sleds over smooth, round sticks along passages too low for the coolies to do better than crawl as they work. Mr. Pumpelly found the gallery of one mine near Peking so low that he had to crawl the whole distance (six thousand feet) to see its construction, and when he emerged into daylight, with his knees nearly skinned, ascertained that the workmen padded theirs. The timbering is very expensive, yet, with all drawbacks, the coal sells, at the pit’s mouth, for $2.00 down to 50 cents a ton. The mines, lying on the slopes of the plateau reaching from near Corea to the Yellow River, supply the plain with cheap and excellent fuel.
Blakiston gives an account of the manner in which coal is worked on the Upper Yangtsz’, near the town of Süchau: “Having to be got out at a great height up in the cliff, very thick hawsers, made of plaited bamboo, are tightly stretched from the mouth, or near the mouth, of the working gallery, to a space near the water where the coal can be deposited. These ropes are in pairs, and large pannier-shaped baskets are made to traverse on them, a rope passing from one over a large wheel at the upper landing, and down again to the other, so that the full basket going down pulls the empty one up, the velocity being regulated by a kind of brake on the wheel at the top. At some places the height at which the coal is worked is so great that two or more of these contrivances are used, one taking to a landing half way down, and another from thence to the river. The hawsers are kept taut by a windlass for that purpose at the bottom.”[174] This useful mineral appears to be abundant throughout Sz’chuen Province, and is used here much less sparingly than in the east. With such inexpensive methods of getting coal to the water-courses, foreign machinery can hardly be expected to reduce its price very materially.
COAL GORGE ON THE YANGTSZ’. (FROM BLAKISTON.)