bottoms are covered with sand and pebbles, bowlders of porphyry, feldspar, and granite, and huge angular fragments of trachyte, sandstone, and gypsum. In various parts of these ravines, where the rock is exposed, both on the bottoms and on the sides, are deep scratches or grooves, running in the direction of the ravine. The sides present bold precipices. On those of the quebradas which terminate at the border of the pampa, near the mountain of Chalocolo, water lines are plainly discernible; and the crevices in the rock, at an elevation of several hundred feet above the plain, are filled with the same kind of clay which covers for miles this part of the pampa.

The quebradas are generally barren; but in some parts of that of Pisagua, alfalfa is raised in considerable quantity. In the eastern parts of those of Camarones, Chisa, Písagua, and Tiliviche, are small streams which take their rise in the Andes; they are absorbed or evaporated before they reach the sea.

Beneath the surface of a part of the pampa, lies an extensive forest of large trees, all of which are more or less inclined to the southwest. They are, for the most part, of the Algarobo species. The wood is dark brown, inclining to red, and very brittle; it burns freely and with little smoke, although it contains a large portion of resin. Parts of some of the trees have the appearance of having been charred. From latitude 20° I have traced this forest for nearly sixty miles in a southeast direction. About thirty miles further north, trees have also been discovered, and it appears not improbable, that the whole of this now barren plain was once a fertile and thickly wooded valley. In some places the branches of the trees are near the surface; and often, receding from these points in all directions, they are found more deeply buried, indicating an uneven surface of the valley in which they grew.

By sinking wells through the saline soil of the pampas, water has been found in some places at the depth of ten or twelve feet, while in other parts excavations have been made eight or ten times this depth without meeting with it. In general, after passing a few yards through marl, the wells terminate in a layer of coarse sand. On the western border of the pampa are several wells which have been sunk through trachyte, and brackish water obtained at a depth of from twenty to thirty-five feet. In the neighborhood of Almonte, during my visit to that place, workmen were engaged in sinking a well, and had then attained the depth of one hundred and fifty feet without meeting with water. This well passed fifty feet through marl and clay, two feet through coarse sand, eighty feet through clay, ten feet through fine gravel, and terminated in a bed of coarse gravel and pebbles, mixed with large water-worn stones.

In the vicinity of Pica are two hot springs, one of which is 92° and the other 98° Fah. The water contains a small portion of carbonate of soda.

Among the hills which skirt the coast, and at their base on the western side of the pampa, are beds of nitrate of soda, which cover a tract of country not less than one hundred and fifty miles in extent. They are slightly elevated above the level of the plain, and covered by a light, dry, sandy marl, mixed with minute fragments of shells. This covering yields with a crackling noise to the pressure of the feet while walking over it, and thus affords an indication of the presence of nitrate of soda beneath, and is a common guide for those who are in search of it. Below this, and but a few inches from the surface, there is usually a layer of common salt, about a foot thick, possessing a coarse fibrous structure. Under this lies the nitrate of soda, resting on marl impregnated with saline matter and mixed with fragments. of shells.

This salt, technically termed caliche, varies in the quantity or nitrate of soda which it affords, from twenty to seventy five per cent. With it there is generally more or less insoluble matter, consisting of red marl and fragments of shells, in some beds amounting to nine per cent., but averaging not more than three per cent. It possesses a granular structure, arising from irregu lar rhombic crystals, which vary considerably in size in different localities. Some of the beds are exceedingly compact, and when wrought, require to be blasted with gunpowder; while others are easily broken with the aid of a pick and shovel. Cavities are occasionally found partly filled with crystals, regular in form and nearly pure. The color varies in different beds, and in different parts of the same bed. Some specimens possess the whiteness of refined loaf sugar; others are reddish brown, lemon yellow, and gray. Every variety is found in the same bed, but the compact white and yellow is most abundant between the quebrada of Tiliviche and the point called Molina. The composition of average specimens from the beds which are worked, as determined by Mr. A. A. Hayes, is as follows:

We are indebted to the same gentleman for our knowledge of the presence of iodate of soda and chloro-iodate of magnesia in combination with this salt.*

*The "mother" water, at some of the refineries on the pampa, are very rich in iodic salts; their presence was first observed by noticing the deep blue color produced by some crumbs of bread which had accidentally fallen into the vats.

In various parts of the western coast of South America, between 18° and 23° of south latitude, nitrate of soda is found impregnating the soil in connection with other saline matter, and in some instances forming a thin crust on the surface; but no where in extensive beds as in the province of Tarapaca, between 19° 30' and 20° 45' south latitude, and 69° 50' and 70° 5' west longitude, although it has been frequently mentioned by travellers as abundant in other parts of the coast. This error has probably arisen from the general use of the term sallitre, which is applied alike to saltpetre and other salts.

The nitrate of soda of Tarapaca affords employment for a large part of the inhabitants of the province. In 1837 one hundred and fifty thousand quintals were shipped from the port of Iquique; of this, about two thirds went to England, and nearly one third to France. Its recent introduction as a manure will probably greatly increase the demand for it in foreign countries.

The process of refining, through which the crude salt passes before it is transported to the ports for exportation, is rude and simple. The operation is conducted generally by Indians, under the direction of a Spanish major-domo. Each officina or working place, consists of a few rude huts, the walls of which are constructed of cakes of salt, cemented together with the mixed marl and salt obtained from the kettles in use for refining, the roofs being formed of mats, supported by rafters of cactus.

All the work of refining is conducted in the open air. The apparatus consists of a few copper kettles, of the capacity of fifty gallons each, set within walls formed of cakes of salt, and shallow oblong square vats for crystallizing. The salt, as blasted from the bed, which is always near to the officina, is carried in bags on the backs of laborers near to the kettles, where women and children are employed in breaking it into fragments of the size of hens' eggs. About two thirds of each kettle being filled with the broken salt, and water added, a strong fire is maintained until the water becomes saturated, when it is dipped into tubs to settle, and from thence transferred while hot to the crystallizers. The undissolved portion which remains, consisting principally of chloride of sodium and earthy matter, is thrown aside as worthless, although frequently not more than one half of the nitrate has been separated, the same relative proportion of crude salt being at all times used, without regard to its quality.

Aside from the want of economy displayed in the refining process, the affairs of the officinas are well conducted. Each branch of the operation, from the breaking the salt from the bed up to the time when it is placed on board vessels for exportation, is conducted by a distinct class of laborers, who receive for their work a fixed sum on each quintal of the refined salt produced. The cost to the refiner for labor, for each one hundred and two pounds, is about five reals, or 62 cents; for fuel, from two and

a half to three reals; for powder and tools, about one real; and for transportation to the port, from five to six reals; making in all $1 87, which is probably something more than the average cost of nitrate of soda, exclusive of bags for packing, and the expense of constructing, keeping in repair, and superintending the establishment.

Ores of silver, antimony, and copper, are found in the porphyritic hills on the coast-the two former near Iquique, in extensive veins, the latter in inconsiderable quantity near Pisagua and in the vicinity of Tanna. Copper also occurs at the extreme southern and eastern part of the province, in veins traversing feldspar. The ores are sulphurets, carbonates, and muriate. In the same range of hills, a little further south, and without the limits of the province of Tarapaca, this latter ore has been found in such quantity as to give rise to extensive workings. It is procured by the Indians, and sold, under the name of arenilla, as sand for letter writing.

ART. 7.-IRON TRADE OF SWEDEN AND NORWAY.-BY H. SCRIVENOR.

SWEDEN has been long celebrated for its mines and mineral productions, particularly iron, which still forms one of the principal exports, although it has much decreased of late years. By an account taken by the government in the year 1748, we find that, at that time, there were 496 foundries, with 539 large hammers, and 971 small ones, for making bar and other manufactures of iron, which produced 304,415 ship-pounds*, or nearly 40,600

tons.

The government established an office in 1740 to promote the production of iron, by lending money on the ore, even at so low a rate as 4 per cent.; a correct register was then made of the mines, which is still continued. Each forge has its particular mark stamped on the bars of iron it produces, which is correctly copied into the manuscript, with the name of the place where the establishment is situated-the names of the proprietors of the work-the commissioner or agent for the sale of the iron-the assortment each makes, and to what country it is generally shipped-the quantity annually made by each work-the quantity which each work delivers to the government (which is about 1 per cent. on the quantity of the iron produced)—the estimation of the quality of the iron of each work, which is variable-the place and province in which the works are situated--the place from whence the iron is generally shipped, and how many hammers each work has: all which particulars are regularly and alphabetically described and arranged.

*7 to a ton.

As the working of the mines is attended with considerable expense, and the sale of the iron uncertain, the Bank of Stockholm receives that metal as a proper security for a loan. The iron being duly appraised, and lodged in the public warehouse, the proprietor receives three fourths of its value, at the interest of 3 per cent., and when he can find an opportunity to dispose of his iron, it is again delivered to him, on producing a certificate from the bank, that the loan upon it is duly discharged.

The iron mine of Dannemora, the most celebrated in Sweden, is situated in the province of Upland, about one English mile from Osterby, and thirty English miles north of Upsala. This mine was discovered in the year 1448, and though it has now been wrought for four centuries, it still yields abundance of the best iron in Europe.

The iron mine is on a hill so little elevated above the surface of the neighboring country as easily to escape observation. It is about two English miles long, and nearly half a mile broad; it is almost surrounded by lakes--those of Dannemora, Films, and Grufve, lying quite contiguous to it. On the side where there are no lakes there is a turf moss. The ore forms a large vein in this hill, which stretches in a north-west and south-east direction. The mine was some years ago inundated by the water from the adjacent lakes; a strong wall, however, has been built to keep off the water. It is drained by two steam-engines, kept at work by means of wood for fuel.

It was first wrought as a silver mine, the silver being extracted from galena. This source of emolument soon failing, or becoming unproductive, the iron ore began to be extracted and smelted, and the excellent quality of the iron gradually drew to it the attention of the public. At first it belonged to the King of Sweden, but that monarch consigned it over to the Archbishop of Upsala as a part of his revenues; at present it belongs to a number of private individuals, who work it separately, each on his own account.

At the side of the mine is a large opening, about fifty fathoms deep and fifty wide, and at the lower part of this is the entrance to the mine, which is wrought about thirty fathoms deeper than this opening. The mines are thus described in "Coxe's Travels," who visited them in the year 1790:-"The pits are deep excava tions, like gravel pits, and form so many abysses or gulfs. The descent is not, therefore, as is usual in mines, down a narrow subterraneous shaft. At the side of the mine I stepped into a bucket, and, being suspended in the open air, in the same manner as if a person was placed in a bucket at the top of Salisbury spire, was gradually let down to the ground by a rope and pulley. The inspector accompanied me to the bottom, and while I was placed at my ease in the inside upon a chair, he seated himself on the rim of the bucket, with his legs extended to maintain the