In order to avoid returning the zinc to the smelting-furnace, as is the case when the oxides are added to the lead during cupellation, the attempt was made to separate, by washing, the oxide of zinc free from silver, from the mechanically inclosed argentiferous particles of lead; but a sufficient separation was found to involve too great expense, in consequence of the fine state of division of the mass, and that an oxide of zinc was produced too argentiferous to permit its entire removal.

A series of excursions in Germany during a period of three years, gave the translator opportunities carefully to observe and study all the methods of zinc desilverization in use. Of these he considers the Cordurié process decidedly the best and most economical. With local modifications, this method is suitable wherever the price of zinc is not exorbitant. Its great advantage over that of Pattinson is shown in the preceding article, and its general substitution is merely a question of time.

TABLE 1.-Cost and production, with lead from the Upper Hartz; determined from the treatment of 1,653,450 pounds.

LEAD AND SILVER SMELTING IN SAN FRANCISCO.

The largest lead and silver smelting-works in the United States, at the present time, are undoubtedly those of Mayor Selby, in San Francisco. The Bulletin, of that city, published lately an interesting article in regard to them, which I give in full:

We have in San Francisco the most extensive smelting-works in the United States, which have been quietly growing up during the last four years, in a remote part of the city nd almost unknown beyond the large number of workmen immediately engaged, and the mining and freighting interests which are employed in furnishing ores and crude bulli on. We refer to the lead and silver-smelting works of Mayor Selby, near Black Point, an establishment of the first importance as a means of developing the mines of the Pacific coast, and with reference to the value of its transactions. These works, which we have recently visited, consume the great majority of all the ore and crude bullion shipped to San Francisco, and they are being constantly increased in extent to keep pace with the expansion of the industrial interests with which they are associated. Their present capacity can be enlarged to an unlimited extent; but even now the quantity of crude bullion and ore consumed exceeds that of any other lead and silver smelting-works in the country-probably working up twice the amount used by the Newark Reduction Works, which, at one time, were considered the largest in the United States.

The legitimate place for smelting the ore would seem to be at the mines from which they are extracted; but as they can be more advantageously worked where science, skilled labor, and capital are concentrated, as at the sea-board cities, the nearest and most available locality is undoubtedly San Francisco. From the mines of Nevada and Utah to this city the distance is so small, compared with that to the Atlantic States, as to constitute the former the natural customer for their ores, rendering successful competition from the East out of the question. And we propose to show that in our city the facilities for smelting are superior to what are offered in any other locality. The small shipments of ores which, upon the opening of the Pacific Railroad, went East as experiments, soon established these facts, as well as that higher rates are paid at the smelting-works here than can be obtained elsewhere in the United States, while the cost of transportation is at least a half less in favor of San Francisco, to say nothing of the considerable percentage of ore that is lost by car-shifting and the jolting and sifting incident to so long a transit.

Some of the shippers who for a while gave Newark a trial, soon became satisfied of this, and are now again sending their ores to San Francisco, not only because the work is done cheaper here and the charges are less, but the treatment is more thorough and consequently the yield greater. This same rule as to cheapness applies to ores that have been shipped to Swansea for reduction, and there is this additional fact in connection with that market, that while miners complain of not receiving fair returns

from Swansea, experience has shown them that at Mr. Selby's works they are honorably and promptly paid.

As regards the time consumed in the treatment of ores, miners will find that the advantages, on account of the late improvements, will be largely in favor of San Francisco, and that returns will be made with very little delay. The rule adopted by Mr. Selby is to buy the ores, which is conveniently done, owing to the extent of his connections and agencies throughout the mining region. The works are always ready to pay shipping expenses on ore from anywhere, and meet freight bills promptly on all kinds. the bills of all kinds following the metal.

Although a large and increasing amount of ore is received at the works from Nevada and Utah, they are by no means dependent on those States for their supply, which arrives from about every important lead and silver locality on the Pacific coast, including the distant mining regions of New Mexico, Arizona, Mexico, and along the Colorado River, whence they are brought by sea via the Gulf of California. No crude bullion nor ores are refused, unless the latter are of too low a grade to admit of profitable reduction. In the early history of the enterprise, ores for a while came too fast for the extent of the works; but with the present enlarged facilities it would be difficult to overtask their capacity, which can at short notice be increased so as to meet any demand likely to be made on them in the future. They were originally designed by Mr. Selby, in joint interest with his New York partner, Mr. P. Naylor, (now on his first visit to California during a business association of twenty years,) for the purpose of supplying their shot-tower in this. city with lead. The idea of manufacturing for Eastern markets, or for exportation, had not then been entertained. For years the experiment was a failure, financially, and a less persistent man than Mr. Selby would have abandoned the enterprise. Costly experiments were necessary, and heavy expenditures attended the enterprise before returns began to be realized. The result is the most important lead and silver smelting establishment in the country, employing, directly and indirectly, more than a thousand men in the various callings with which it is associated. It is the friend of the workingman, for whom it acts as a reliable bank of deposit, and whose labor it converts into ready cash on demand.

The location of the works, which occupy four fifty-vara lots, is on Jefferson street, at the northern extremity of the city, on a point of land projecting into the bay opposite Fort Alcataraz, and at the northern terminus of Montgomery avenue, that is to be. On the bay there is ample wharf frontage, with depth of water sufficient to accommodate the vessels engaged in bringing ores and crude bullion to the works, and carrying away lead and silver. This bulkhead wharf is being steadily pushed out into the bay by the accumulations of slag and other matter, real estate being thus increased at a rapid rate. A railroad for hand-cars extends through the works to the water front, serving the double purpose of conveying market lead to the vessels at the wharf, and for dumping the refuse collections at the bulkhead. The works, which are indicated from a considereable distance by a large stack, are approached by a plank road laid through the sand drifts which here reach nearly to the shores of the bay. Formidable notices of "No Admission," posted over the gateway, remind one that the inmates are supposed to know how to keep their own counsel.

The entire works are under the general supervision of Prentice Selby, a son of the proprietor, who, from the beginning, has aided in bringing them to their present state of efficiency, and who has recently returned from a short visit to examine the smelting facilities in the Atlantic States-a tour of inspection, which, it may be added, showed that the business as conducted in San Francisco is far in advance of any Eastern competition. The immediate superintendent, W. R. Thompson, who entered upon his duties when the works were yet in an experimental condition, explained to us in detail the various processes. We do not propose to risk confidence by an attempt at description. Suffice it to generalize by stating that the ore, landed at the wharf, is brought by railroad into the works, where it is crushed, sampled, and prepared for calcining; thence it goes to the blast-furnace to be smelted; thence to the refining furnaces, where it is cleared of its base matter; thence to the desilverizing furnaces, which separate the silver from the lead. Here it "splits" and takes two directions-the lead going to the refining furnace again, where it is converted into market lead, is stamped with the proprietor's name, and is piled away ready for shipment. The residue from the desilverizing furnace goes back to the smelting and thence to the cupel furnace, where the small percentage of lead still remaining is extracted, leaving the silver pure, or nearly so. This is melted again in crucibles to still further refine it; for although it comes from the cupel-furnace 990-1000 fine, which is suitable for the purposes of the mint, it is not fine enough for shipment to China, where the standard required is 996-1000. The perfection to which this art may be brought is shown in one lot of 10,000 ounces, which assayed nine hundred and ninety-nine and three-tenths one thousandths fine.

Upon entering the works, the visitor is impressed with their extent and the amount of business transacted. A powerful engine carries the blast to the furnaces and drives the crushing-mill; and far and near, through the smoke, the heat of intense fires, the clash of iron implements, the glare of furnaces, and the clank of machinery, indicate a