strewn about on the heaps of relaves or tailings, becoming every day more useless from exposure to the scorching sun and dry atmosphere of this elevated valley.

(3). La Sorocayense.-Leaving Señor Fragueiro's works, and proceeding south up the valley of Barrial or Calingasta, about three leagues distant, is situate Hilario, and about two leagues still further south in the same valley, on the Tontal road, are situate the works enjoying the rather unique and to many unintelligible name above expressed. Its derivation is traceable to the system of amalgamation used, and which has its origin in a small place in Bolivia named Sorocaya.

The system employed is properly amalgamation; but the ores are previously subjected to a species of calcination with common salt, having for its ostensible object the conversion of the silver into chloride, and thus rendering it extractable by amalgamation with mercury. This end is not, however, by any means satisfactorily attained, owing to the nature of the ores treated; still, a fair amount of silver is extracted, averaging about six marks, or forty-five ounces, daily. The ore is ground very fine by edgerunners, and passed through a sieve having 3,600 holes to the square inch, after which it is calcined for from five to eight hours in a reverberatory furnace, with about five per cent. of common salt, at a very low temperature, and kept constantly turned and stirred to prevent agglutination. It is then withdrawn, and when cold, is charged into an oblong trough about twelve feet by four, and four deep, accompanied by mercury, where it is gently agitated by a cylinder having a horizontal motion, and kept in intimate contact with the mercury for several hours; when finished, the mass of ore (called tailings) is washed off by water and conveyed into large pits or deposits, where it is allowed to settle, and is again, when dry, subjected to a further calcination, in case it should have retained sufficient silver to pay expenses of treatment. The mercury in the trough, now charged with silver, is drawn off and strained through canvass bags, in which a rich amalgam of silver, combined with about six times its weight of mercury, remains. This is subsequently pressed hard, and placed in an iron retort, connected with a condensing apparatus, where the remaining mercury is distilled off by heat and recovered, leaving the now almost pure silver in a beautiful white porous mass, which may be fused into ingots and sent to market. This silver is, however, rarely so pure as that obtained by smelting the ores with galena, and refining the argentiferous lead.

(4). Hilario. These works are situate in the valley of Calingasta, Tontal district, thirty-three leagues S.S.W. by W. from San Juan city, and fortyeight leagues N.N.W. from Mendoza, in lat. 31 deg. 20 min., S., and long.

69 deg. 90 min. W. from Greenwich, at an elevation of 5,624 feet above sea level, are the largest metallurgical works in the Republic, and adapted to both systems, smelting and amalgamation. The machinery for the latter was made by Messrs. John Taylor and Sons of London, and consists, in part, of barrels on the Freyberg system, and 'tinas' on the Chilian system. The full working power or capacity of both, may be set down at ten tons of crude ore in the twenty-four hours. The motive power is a large turbine with thirty-three feet head, and discharge pipe two feet six inches in diameter. The effective horse-power may be set down at ninety-five. To this turbine is also geared the grinding machinery, edge-runners and a small extra blowing fan.

But by far the largest and most important part of the works is dedicated to the smelting and refining with their attendant ore, charcoal and wood deposits. The ground actually occupied by the establishment covers over twelve acres, not including the houses, stores, &c., for peones, occupying a street without the works.

The system of smelting followed at Hilario has some resemblance, as a whole, to Messrs. Klappenbach's, but is, in detail, very different. It is in fact as nearly as possible the same as the present improved system carried out at Pontgibaud, France, managed by Messrs. J. Taylor & Sons, the celebrated mine agents of London. The ores, mixed in certain proportions, are calcined 'dead' in a reverberatory furnace of peculiar construction having a double' sole, on one of which is completed the agglomeration and fusion into a liquid slag, care being taken that no reduction to metallic lead takes place. The smelting or fusion of this roasted ore is conducted in the class of blast furnaces known as the Castillian furnace, having three 'tuyéres' and large capacity. Each furnace is capable of smelting, of tolerably fusible ore, up to six and eight tons in the twenty-four hours with a consumption of about sixty quintals of charcoal. Two sets of three men are employed at each furnace in shifts of twelve hours each set, and are paid the foreman (English) $60 B. a month, the second hand $30 B., and the third $20 B. per month; all without rations, but with house accommodation and fuel.

The blowing machine is a powerful fan five feet in diameter, driven up to 1800 revolutions per minute by a twenty-five horse power turbine, with 33ft. head and 2ft. 1in. diameter discharge pipe. The wind from this fan is sent to different parts of the establishment, partly in pipes and partly by cemented brickwork flues, so as to be available for the silver lead refining furnaces and the forge fires.

The argentiferous lead produced from the Castillian furnace, being hard,

is first 'improved' or softened in an improving furnace of the reverberatory class, and when freed from any copper, antimony, arsenic, or iron, which may have been reduced with it, is refined direct on a bone-ash cupel or test by what is known as the English system, silver is thus obtained by one cupellation up to 995-thousandths fine.

I should here observe that Pattinson's process of crystallising out pure lead and concentrating the silver for refining, as practised at Pontgibaud and other works, is not used at Hilario. But this omission is by no means prejudicial; on the contrary, very little; if any, advantage would be derived by its adoption there, because the argentiferous lead produced direct from the blast furnace averages over one per cent of silver, and it is a recognized fact that any attempt at enriching lead, by Pattinson's process, beyond 2 per cent. has commercially failed. Hence the concentration is rarely carried beyond this figure, and, the system is only adapted where there are large quantities of poor lead produced, which would be unprofitable to refine direct."

At Hilario there are three furnaces of the reverberatory class, with one refining furnace on the English system, and two Castillian blast furnaces. The ore deposits are capable of storing over a thousand tons, divided into compartments with tiled floors, and numbered. Each compartment having its Dr. and Cr. account in a separate book for entries from mines and deliveries to the furnaces, hence at a glance it may be determined what stock remains on hand, and how much has been worked up, without the trouble of re-weighing.

The Chemical Laboratory for analysis and assays by the humid method is a complete department in itself, and most perfectly fitted up.

In succession follows the weighing room with its fine assay balances indicating up to the 1000th part of an English grain; also large bullion balances for weighing the silver in ingots, with the corresponding sets of stamping numbers and letters in steel for marking their weight and fineness. Next to this room is the assay laboratory proper, with its rows of miniature furnaces and muffles, for assaying and experimenting on the ores by the 'dry' methods; here, when in full work, up to 100 assays are made daily.

In the same range of buildings are the carpenters-shop and smithy, separate, for all sorts of repairs and work necessary about the establishment. Turning lathes, drilling machines, and the various tools necessary for mechanical engineering, may be seen about, for, being isolated as the works are, in the heart of the Andes, it is essential to have all these conveniences for any emergency which might arise.

The wood 'cancha' for piling the fuel for the furnaces is extensive and conveniently situate on a slight elevation above the reverberatory furnaces, for only in these is crude wood used. On a lower level, in a large open space, may be seen the immense, Noah's ark shaped, mounds of wood charcoal, as prepared for the blast furnaces. Each pile is 200 feet long by 18 feet wide and 12 feet high, composed chiefly of algarroba and retamo wood, laid longitudinally and evenly, with their ventilating flues beneath, so as to graduate the admission of atmospheric air, and thus govern the slow combustion of volatile gases in order to produce good charcoal. This branch of operations at Hilario requires almost as much study and care as any other, although apparently so simple and common-place. The wood when well charred, produces about 30 per cent. of hard, solid, shining charcoal, but if carelessly prepared the produce is much reduced, and the quality, as a caloric and reducing agent, seriously deteriorated. The mounds of wood are overlaid with long grass or reeds (totora) and covered with earth. The time necessary to burn one of these mounds varies from eight to fifteen days, and requires other fifteen days careful attention to extinguish.

The charcoal, delivered at the furnace house, costs 50 cents per quintal of 100, made by contract with natives who cut and carry the wood from the camp, preferring to make it at the works; although apparently much more advantageous to them to make it where the wood is cut, and thus reduce the weight carried by 70 per cent.

The manager, however, prefers the charcoal made at the works, as in the first place it is produced under his immediate supervision, and is delivered almost intact, thereby avoiding the waste of a large percentage of small coal, totally useless, and highly injurious in the blast furnace.

The manufacture of firebricks, also forms a most important feature in the works; for were it necessary to import from Europe or Chile this indispensable and largely consumed article, the cost would be very great. Fire-clays abound in the neighbourhood, and by a careful selection, the mixture used at Hilario, affords a very excellent refractory brick, well suited for lead furnaces.

They are made by dry pressure, and some turned out during the present year at a cost of $20 Bol. per, thousand have been used in a blast furnace which ran 178 days without a single brick having to be replaced. The cost of best Stourbridge fire-bricks (Ruffords) imported from England and placed at Hilario, is about 40 cents each, or $400 per thousand.

Beyond the immediate precincts of the works but forming part of the property are several houses, in which are general dry goods and provision

stores, baker's and butcher's shops, as also a café or hotel with billiard room, &c., rented to outsiders, and forming a most essential part of the establishment. When in full work, the concourse of miners, employés, ore vendors, muleteers, &c., which accumulate, is sometimes astonishing, and the occupiers of these houses make a fair business on their own account. Some distance from the works is a grass farm rented for the use of the animals required about the establishment.

The tariff for the purchase of silver ores, delivered at Hilario, is as follows (Bolivian currency):

The Messrs. Babié & Co.'s tariff differs considerably from the above as they base their calculations on a different system of working. They deduct, in the first place, from every cajon of fifty quintals fourteen marks of the silver contained therein, and pay for the remainder at the rate of $10 bol. per mark of pure silver, according to assay.

MENDOZA.

Although this Province, 'during Spanish rule, was celebrated for its mineral wealth, and large quantities of silver were annually extracted from the ores produced in the Paramillo de Uspallata, it has so degenerated in metallurgical and mining enterprise, that were it not for a few energetic and persevering individuals, now toiling in the old mines of that district, it scarcely merits a passing notice in this work.