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Topography of the Province of Si'chuen.
JUNE,
In this way these small pits or shafts are made perpendicular, and smooth as glass. Sometimes they come to the bottom without meeting with rock, passing through layers of earti, coal, &c. The operation then becoines more difficult, and is sometimes fruitless; for as these substances do not present an equal resistance, it is found that the shafts lose their perpendicularity. But such cases are rare. Sometimes it happens that the thick iron ring to which the rummer is suspended is broken, and it then requires five or six months to succeed with other rammers in breaking the first, and reducing it to powder. When the rock is tolerably favorable for working, two feet are dug through in twenty-four hours, and at least three years are consumed in exca- vating a single pit.
For drawing out the water, a tube of bamboo twenty-four feet in length is passed down into the pit, at the bottom of which there is a valve. When it comes to the bottom of the pit, a strong man who is seated by the cord, gives it a jerk, each shake causes the valve to open and the water to ascend. When the bainboo is full, a great cylinder, fully fifty feet in circumference, upon which the cord is wound, is turned around by two, three or four buffaloes or oxen, and the tube of water is thus raised. This cord is also made of rattan. The poor animals are not able to endure this labor, and many of them die in consequence of it. If the Chinese could avail themselves of our steain-engines they would be at much less expense; but some thousands of laboring people would then be thrown out of employment. The water is very brackish. On being evaporated, it yields a fifth or more, sometimes a fourth, of its weight of salt. This salt is very pungent, and contains a large portion of nitre. People who do not smoke (men and women, rich and poor, all smoke), lose their teeth. There are here many blind and deaf persons, which circumstance I attribute to the use of this salt. Sometimes it affects the throat so as to produce ailments, in which case they make use of salt brought from Canton or Tungking made from sea-water.
The air which issues from these pits is very inflammable; if a torch be presented at the mouth of a pit when the tube happens to be nearly filled with water, it will send out a great fanie from twenty to thirty feet in height, and illumine the boilery with a suddenness and explosion like that of thunder. This happens sometimes by the imprudence or the malice of a workman who wishes to commit suicide in company. From some of these pits they are not able to obtain salt, only fire coines from thein; and they are called pits of fire. A small bamboo tube closes the mouth of the pit, and con- ducts the inflammable air wherever it is wished. They light it with a can- dle and it burns incessantly. The flame is bluish, three or four inches high, and an inch in diameter. Here this flame is too feeble to evaporate the salt. For evaporating the water and getting the salt, they make use of a sort of large boiler of cast metal, which is five feet in diameter, and only four inches in depth. The Chinese have learned that by presenting a larger surface to the fire, the evaporation is more rapid, and that there is also a saving of coal. The basin is at the least an inch in thickness. There are several other caldrons of greater depth placed about it, containing water which boils at the same fire, and serves to replenish the great boiler. The whole process is completed in such a manner, that the salt, when the water is evaporated. entirely fills the vessel and assumes its formi.-This block of salt, of two hundred pounds weight or more, is as hard as stone; it is broken up into three or four pieces in order to its being transported as an article of commerce. The fire is made so hot that the great boiler becomes absolutely red, and the water bubbles up in the centre nine or ten inches. When the fire is made from the pit gos, the water is thrown up still more, and the boilers are calcin- ed in a very little time, although those which are exposed to this fire are at least three inches in thickness.