stained with reddish oxide of iron. The pure ore contains 65 per cent. of oxide of zinc (which is equivalent to 52 of the metal) and 35 of carbonic acid. The silicate of zinc is found intermixed with the carbonate, which it resembles in appearance. It contains, when pure, silica 25.1, water 7.5, and oxide of zinc 67.4, corresponding to 54 per cent. of the metal. The red oxide is found only at Mine Hill and Stirling Hill, near Franklin, in the extreme northern county of New Jersey. The pure oxide, of which it is almost exclusively composed, contains 80.26 per cent. of zinc and 19.74 of oxygen. The bright red color is probably derived from the small quantity of oxide of manganese present. The ore is mixed with franklinite iron ore, each being in distinct grains, one red and the other black; and with these is associated a white crystalline limestone, either in disseminated grains with the ores, or forming the ground through which they are dispersed. Two beds, consisting of the zinc and iron ores, lie in contact with each other along the south-eastern slope of the Stirling Hill, between the limestone of the valley and the gneiss of the ridge, dipping with the slope of these rocks about 40° toward the valley, and ranging north-east and south-west. The upper bed, varying from 3 to 8 feet in thickness, consists of more than 50 per cent. red oxide of zinc; and the lower bed, which is 12 feet thick and in some places more than this, is chiefly franklinite, changing to limestone below, interspersed with imperfect crystals of franklinite. At Mine Hill, 14 miles northeast from Stirling Hill, two distinct beds are again found together, that containing the most zinc in this case being the under one of the two, lying next the gneiss. These localities have been well explored; the beds have been traced considerable distances along their line of outcrop; and at Stirling Hill the red oxide of zinc has been mined for more than ten years by the New Jersey Zinc Company. Their workings have reached to a depth of about 250 feet, and have af forded the finest specimens of zinc ore ever seen. A single mass of the red oxide was sent in 1851 to the Great Exhibition in London, which weighed 16,400 lbs., and attracted no little attention, from the purity, rarity, and extraordinary size of the specimen. The Passaic Mining and Manufacturing Company also have opened two beds of the same ore on their property at Stirling Hill, adjoining that of the New Jersey Zinc Company, and between 1854 and 1860 took out about 30,000 tons of rich and lean ores. At the depth of 178 feet, the principal Led is 21 feet wide, of which about 2 feet is rich ore, and the rest limestone sufficiently interspersed with oxide of zinc to render it worth dressing. This company completed, in the year 1859, at the mines, very extensive works for dressing the lean ores before they are shipped to their furnaces at Jersey Cty. The principal supplies of their ores hitherto have been of the smithsonite and calamine from the mines in the Saucon valley, Lehigh county, Pennsylvania, of which they mined about 5,000 tons in the first year. These ores are extensively worked to the north of Friedensville, both by this company and the Pennsylvania and Lehigh Zinc Company, whose furnaces are at Bethlehem, in Lehigh county. The mines of the two companies, which are near together, are known as the Saucon mine and the Lehigh Zinc Company's mine. They were first opened in 1853. The two kinds of ore are found together, as is common in the European mines, and more or less blende is interspersed among them. They form very large irregular beds in limestone of the lower Silurian period, and are penetrated by veins of quartz, which traverse both the ore and limestone. Huge masses of limestone lie interspersed among the ores. The deepest workings at the Saucon mine are about 100 feet below the surface; and from this depth galleries have been run in every direction, exposing to view more than 50,000 tons of ore. The ores of best quality are found in the lower workings. Large de About the same time that these mines were opened in Lehigh county, another, producing similar kinds of zinc ore, was discovered near Lancaster, in Pennsylvania; but after being explored it was found to contain so much blende and galena, that it was abandoned as worthless. posits of the same varieties of zinc ore are known to exist in Tennessee; one locality at Mossy Creek, a few miles north-east of Knoxville, and another at Powell's river, a branch of the Clinch river, in Campbell county, about 40 miles north of Knoxville. These beds, examined by the writer in 1858, unquestionably contain very large quantities of excellent ore. The former, being close to the East Tennessee and Virginia railroad, is very conveniently situated; and the other is within half a mile of a river navigable at Below its certain seasons by flat-boats. junction with the Clinch river are beds of bituminous coal, and the river is thence navigable by steamboats. At Kingston it is crossed by a railroad. Very pure ores of similar character have been found in Arkansas. The localities are in a lead mining region in Lawrence, Marion, and Independence counties; but chiefly in the first named. The ores occur in a formation of magnesian limestone, imbedded in red ferruginous clay. They are almost exclusively smithsonite, containing very small proportions of silicate of zinc. Crystals of smithsonite and of blende are found upon the lumps of pure, flesh-colored ore. The district promises to become an important one for the supply of zinc to the western states. The following are analyses of ores from the Saucon valley mines; the first three by Prof. John Torrey, of the New York Assay Office, being of specimens, and the last two of samples of large shipments. No. 4 was made at the Assay Office, Hatton Gardens, London; and No. 5 in Paris. METALLURGIC TREATMENT AND USES. Zinc ores are applied to practical purposes, not only to produce the metal, but also the white oxide of zinc, which is considerably used as a paint. The ancients used an ore they called lapis calaminaris, to make brass, by melting it with copper in crucibles, not knowing that another metal was thus formed which produced an alloy with the copper. Although the metal was discovered in the 16th century, the nature of its ores was little known before the middle of the last century. It is now prepared upon a large scale in Belgium and Silesia, and small quantities are produced in England, France, and different parts of Germany. The simple method of obtaining zinc from its ores, called distillation per descensum, was introduced into England about the year 1740, and was derived from the Chinese, who appear to have been acquainted with the metal long before it was known to the Europeans. As now practised in Great Britain, the ores are first calcined, the effect of which is to expel a portion of the water, carbonic acid, and sulphur they contain. They are then ground to powder, and mixed with fine charcoal, or mineral coal, and introduced into stationary earthen pots, or crucibles. When set in the furnace, an iron pipe, passing up through the bottom of the hearth, enters the crucible, and connects with an open vessel directly beneath. About six pots are set together under a low dome of brick-work, through which apertures are left for filling them. Each one has a cover, which is luted down with fire clay; and the iron tube in each is stopped with a wooden plug, which, as the operation goes on, becomes charred and porous, so as to admit through it the passage of the zinc vapors. The tubes are prevented from being clogged with depositions of the condensed zinc, by occasionally running a rod through them from the lower end. The zinc collects in the dishes under the tubes, in the form of drops and powder, a portion of which is oxidized. The whole is transferred to melting-pots, and the oxide which swims upon the surface of the melted metal is skimmed off and returned to the reducing crucibles, while the metal is run into moulds. The ingots are known in commerce as spelter. Bethlehem, erected in 1858-9, and belonging to the owners of the Saucon mine, have a capacity of about two tons of metal daily. however, long continued. In 1858, Mr. Wetherill recommenced the production of zinc, adopting a plan of upright retorts, somewhat like that in use in Carinthia, in Austria, and that of the English patent of In the United States zinc was first made James Graham. Mr. Wetherill had sucby Mr. John Hitz, under the direction of ceeded in procuring good mixtures of fire Mr. Hassler, who, by order of Congress, clays, and his retorts made of these and was engaged about the year 1838 to manu- holding each a charge of 400 lbs. of ore, facture standard weights and measures for proved sufficiently refractory for the operathe custom-houses. The work was done at tion. The works now under his charge at the U. S. arsenal at Washington, the ores used being the red oxide of New Jersey. The expense exceeded the value of the metal obtained, and it has generally been supposed Mr. Wharton, after abandoning the that we could not produce spelter so cheaply method of reduction by incandescent coals, as it can be imported from Europe. The continued his experiments on different plans, next experiments were made at the works of and finally decided on the Belgian furnace the New Jersey Zinc Company, 1850, on the as the best, after having actually made spelBelgian plan. In these great difficulties were ter from silicate of zinc, with anthracite, in experienced for want of retorts of suffi- muffles of American clays, at a cost below ciently refractory character to withstand the its market value. These trials were made in high temperature and the chemical action of the zinc oxide works of the Pennsylvania the constituents of the ore. The franklin- and Lehigh Zinc Company. Their success ite, which always accompanies the red ox- encouraged the company to construct a facide ores, was particularly injurious by rea- tory at Bethlehem for reducing zinc ores, son of the oxide of iron forming a fusible and this was done under the direction of silicate with the substance of the retorts Mr. Wharton in 1860. The capacity of These trials consequently failed after the the works is about 2000 tons per annum, expenditure of large sums of money. The and their actual daily product in the winter next important trial was made in 1856, by a of 1860-1, is over three tons. Four stacks Mr. Hoofstetter, who built a Silesian furnace or blocks are constructed, each containing of 20 muffles for the Pennsylvania and Le- four furnaces. To each furnace there are high Zinc Company at their mine near 56 retorts, making in all 896, working two Friedensville. This proved a total failure, charges in twenty-four hours. Their total and seemed almost to establish the impracti- capacity is about five tons of metal. Becability of producing spelter with the Amer- sides the ordinary spelter of this manufacican ores, clays, and anthracite. About this ture, which, as will be seen by the remarks time Mr. Joseph Wharton, the general man- that follow, is remarkable for its freedom from ager of the Pennsylvania and Lehigh Zinc injurious mixtures, and is the best commerCompany, and Mr. Samuel Wetherill, of cial zinc in the world, Mr. Wharton also Bethlehem, both hit upon the same plan of prepares from selected ores a pure zinc treating zinc ores in an open furnace, and for the use of chemists, and for purposes in leading the volatile products through incan- which a high degree of purity is essential. descent coal, in order to reduce the zinc ox- This is cast in ingots of about nine pounds ide so formed, and draw only metallic and each, and is sold at the price of ten cents carbonaceous vapors into the condensing per pound. For the supply of chemists, and apparatus. Mr. Wharton constructed his for the batteries employed by the telegraph furnace in Philadelphia, and Mr. Wetherill companies, the American zinc of this manuhis in Bethlehem. The former having com- facture is preferred to all others. The total pleted his trials, filed a caveat for the proc-annual consumption of crude spelter in the ess, but soon after abandoned it as econom- United States amounts to the value of about ically impracticable. The latter continued $600,000; and the value of sheet zinc, nails, his operations, patented the method, and etc., is about as much more. produced some zinc, eight or ten tons of which were sold to the U. S. Assay Office in New York. The manufacture was not, The commercial zincs, it has long been known, are contaminated by various foreign substances, the existence of some of which 2442 is indicated in the finely divided black sub- rarely, and doubtless accidentally." The stance which remains floating or sinking in proportions of lead present in 100 parts of the liquid, when the metal is dissolved in each of the varieties examined were respectdilute acids. The impurities have been ively as follows: in No. 1, 1.46; 2, 0.292; stated by different chemists to consist of a 3, 0.079; 4, 0.000; 5, 0.494; 6, 0.106; 7, great variety of substances, such as lead, 1.297; 8, 1.192; 9, 0.823; 10, 1.661; 11, cadmium, arsenic, tin, iron, manganese, car- 1.516. The New Jersey zinc was found to bon, etc. They injuriously affect the quality contain a sensible quantity of tin, copper of the metal for many of its uses; and the amounting to 0.1298 per cent., iron 0.2088 presence of one of them, arsenic, is fatal to per cent., and an unusually large amount of the highly important use of zinc by chemists, arsenic. Traces of this were also detected as a reagent in the detection of arsenic in in the white oxide prepared from the ores other substances. Arsenic in the form of a of the New Jersey mines, and in the red sulphuret often accompanies the native sul- oxide ore itself; but the same ore afforded phurets of zinc, and its oxide, being volatile, no clue as to the source whence the copper is readily carried over with the zinc fumes was derived, a metal of which not the slightin the metallurgic treatment of blende, and est traces were discoverable in the other may thus be introduced into the spelter. It is zincs. None of the samples contained sufevidently, therefore, a matter of consequence ficient arsenic to admit of its proportion beto know the qualities of the different zincs ing determined, and some were entirely free of commerce, and the exact nature of the from it, as some of the Belgian and Pennsylimpurities they contain. Very thorough in-vania spelter, but traces of it were met with vestigations having these objects in view in other samples from the same regions, inhave recently been made in Cambridge, Massachusetts, by Messrs. Charles W. Eliot and Frank H. Storer of Boston, and the results of these, with a full description of their methods of examination, were communicated, May 29, 1860, to the American Academy of Arts and Sciences, and published in the eighth volume of the new series of their Memoirs. Eleven varieties of zinc from different parts of Europe, and made from the ores of New Jersey, and of the Saucon valley, Pennsylvania, were experimented upon, of all of which large samples were at hand. These varieties were the following: 1, Silesian zinc; 2, Vieille Montagne zinc; 3, New Jersey zinc; 4, Pennsylvanian zinc, Bethlehem, Pennsylvania; 5, Vieille Montagne zinc, employed at the United States mint, Philadelphia; 6, zinc of MM. Rousseau, Frères, Paris, labelled and sold as zinc pur; 7, sheet zinc obtained in Berlin, Prussia; 8, zinc made near Wrexham, North Wales; 9, zinc from the Mines Royal, Neath, South Wales; 10, zinc from the works of Dillwyn & Co., Swansea, South Wales; 11, zinc from the works of Messrs. Vivian, Swansea. All of these, except the Pennsylvania zinc, furnished an insoluble residue, which was found to consist chiefly of metallic lead, and this proved to be the principal impurity of all the samples examined; "the carbon, tin, A large portion of the zinc of commerce copper, iron, arsenic, and other impurities is furnished by the works of the Vieille found in the metal by previous observers, Montagne Company, established near the occur either in very minute quantities, or frontier of Belgium and Prussia, chiefly in dicating that the occasional use of inferior ores, such as blende, intermixed with the carbonates and silicates, might introduce this substance, or possibly it might come over only in the first part of the distillation, and the zinc collected in the latter part might be quite free from it. The Silesian zinc contained minute quantities of sulphur and arsenic; and the English zinc more arsenic than any other, except perhaps the New Jersey. The purest of all the samples was that from Bethlehem, Pennsylvania, some of it yielding no impurity, except a trace of cadmium. The source of a trace of arsenic in another sample is supposed to be in the use of the crust of oxide of zinc from the operations connected with the manufacture of white oxide of zinc, no particular care being taken in that process to reject inferior ores, and this crust being taken to the other works where the metal is prepared and mixed with the selected ores employed for this use, it has thus introduced the arsenic. As the authors of the paper remark, there seems to be no reason why zinc of uniform purity should not be obtained from the excellent ores of the Saucon valley mines. EUROPEAN MANUFACTURE. the province of Liege of the former country. | seven large smelting establishments belongA large number of mines are worked in this ing to the Vieille Montagne Zinc Mining region, the most important of which is that Company, on the borders of Belgium and of the Vieille Montagne or Altenberg, sit- Prussia, comprising 230 furnaces. The anuated in the village of Moresnet, between nual product of these is 29,000 tons of spelAix-la-Chapelle and the town of Liege. It ter, of which 23,000 tons are converted into is said that the great body of carbonate of sheet zinc, and about 7000 tons are rolled at zinc found here was worked as long ago as mills not the property of the company. They the year 1435, and that for four centuries it also manufacture oxide of zinc in three eswas not known that the ore was of metallic tablishments devoted to this operation, to character, but it was used as a peculiar earth the amount of about 6000 tons annually. The adapted for converting copper into brass. company also purchases spelter very largely. The ore lies in a basin-like depression in strata of magnesian limestone, and is much mixed with beds of clay intercalated among its layers. The ore is chiefly carbonate mixed with the silicate and oxide of zinc. Some of it is red, from the oxide of iron intermixed, and this produces only about 33 per cent. of metal. The purer white ore yields about 46 per cent., and is moreover much preferred on account of its working better in the retorts. The furnaces employed in the distillation of these ores are constructed upon a very large scale, and on a different plan from those in use in Great Britain. The general character of the operations, however, is the same. The ores are first calcined, losing about one fifth of their weight. They are then ground in mills, and charges are made up of 1100 lbs. of the powdered ore mixed with 550 lbs. of fine coal. The mixture being well moistened with water, is introduced into cylindrical retorts, which are three feet 8 inches long and 6 inches diameter inside, set inclining outward, to the number of 42 in a single furnace, and 4 such furnaces are constructed in one stack. The open end of cach retort connects, by means of an iron adapter 16 inches long, with a wrought-iron cone, the little end of which, projecting out from the furnace, is only an inch in diameter. After the charges have been sufficiently heated, the sublimed zinc condenses in the neck of the retort and in the adapter and cone. The last two are then removed, and the zinc and oxide are collected from them, and the liquid metal in the neck of the retorts is drawn out and caught in a large ladle, from which it is poured into moulds. The zinc thus obtained is remelted before it is rolled. Two charges are run through in twenty-four hours, each furnace producing from 2200 lbs. of ore about 620 lbs. of metal, which is about 30 per cent. From a late report of these operations it appears that there are The metallurgy of zinc has, within a few years past, become an important branch of industry in Upper Silesia on the borders of Poland, and not far from Cracow. In 1857 there were no less than 47 zinc works in this part of Prussia, one of which, named Lydogniahütte, at Königshütte, belonged to the government, and the remainder were owned by private companies and individuals. In that year their total production was 31,480 tons of spelter, valued at about 17,660,000 francs. Many of the establishments belong to the Silesian Company, which also owns several coal mines near their works, and a number of zinc mines. The government works are supplied with ores from their own mines, and also from all the others, being entitled to one twentieth of their product. From a description of the operations published in the sixteenth volume of the Annales des Mines, fifth series, 1859, it appears that the processes are the same which had been employed for full twenty years previously, and each establishment presents little else than a repetition of the works of the others. The furnace in use is a double stack, furnished along each side with horizontal ovens, into each of which three muffles or retorts are introduced. These are constructed of refractory fire clays, and are charged, like the retorts of gas furnaces, by conveying the material upon a long charger or spoon into the interior. Their dimensions are about 4 feet long, 22 inches high, and 84 inches wide, and the weight of the charge introduced is only about 55 pounds. The ovens on each side of the stacks contain as many as 20 and sometimes 30 retorts. The same stack contains besides, 1st, an oven in which the ores belonging to it are roasted for expelling the water and a portion of the carbonic acid they contain (a process in which they lose about their weight); 2d, an oven for baking the retorts, each establishment making its own; and 3d, a furnace for remelting and purifying |