values. The furnace is 5 ft. wide, and has an air-jacket; bituminous coal is used instead of charcoal. In six months there were treated 9,016,000 lb. of ore, containing 7,153,311 lb. of lead, at a cost of $2.4332 per ton. The recovery of lead in the form of pig lead was 84.301 per cent., of white fume 10.355 per cent., of blue fume 2.691 per cent., and of gray slag 2.653 per cent. White and blue fume are returned to the ore-hearth, gray slag is sold.

charge and the potential gradient between the point and the plate. The process has been in successful operation at the Selby lead works near San Francisco, Cal., where the roaster and blast-furnace stacks discharge over 50,000 cu. ft. of gas per minute. The dust is carried down, and the sulphuric acid collected more than pays for the cost of operating.

The ordinary method of disposing of smelter smoke is to allow it to pass off into the open from an elevated point through a high chimney, with the hope that when the dust and acid particles come down again to the earth they will be so dispersed as to be harmless to animal and vegetable

The Blast Furnace.-The Midvale Plant of the United States Smelting Co. at Bingham Junction, Utah, is described by Palmer (Min. Wld., 1911, xxxiv, 1023, 1075). The ore, raw or blast-roasted, is smelted in six life. The law suits between industrial blast furnaces, 45 by 160 in. at tuyeres, of which there are 10 to a side, 3.5 in. diameter. The smelting capacity of a furnace is 200 tons charge in 24 hours. The slag made contains SiO, 37, FeO 27, CaO 22, ZnO 6, Pb 0.50-0.75 per cent.; matte I, containing Cu 7-10, Pb 12-15, Fe 21-23, Zn 3-6, S 21-24 per cent., is crushed, roasted and concentrated in a blast furnace to matte II with Cu 40 per cent.; and the second matte after crushing, roasting and smelting in a reverberatory furnace yields matte III with Cu 80 per cent. and slag assaying SiO, 39, FeO 13, Pb 17 per cent. The blast furnace gases are filtered in a baghouse, and the fume recovered is worked for white arsenic in a separate department.

Smelter Smoke.-The smoke issuing from lead and copper smelting plants consists of suspended particles and of gases. Many methods exist of settling the former and for rendering harmless the latter. Electrical precipitation of suspended particles has received much attention from Cottrell (Min. Scien. Press, 1911, ciii, 255, 286). His process consists in applying a high-tension intermittent direct current to a system of needle-point and plate-form electrodes in a gas flue, when the air-space between the poles becomes highly charged with electricity of the same sign as that of the needle-point. Any body floating through this space receives a charge of the same sign and is attracted to the plate of opposite charge; it moves at a rate which is proportional to its

and agricultural representatives and the closing down of important smelting plants show that the usual method of disposal of smelter smoke does not fulfil ordinary requirements. The Wislicenus smoke dissipator (Austin, Mines and Methods, 1911, ii, 269; Hahn, Eng. Min. Jl., 1911, xcii, 596) appears to solve in a simple manner the distribution of smoke in such a way as to make it harmless. It consists in providing the upper part of a stack with a large number of openings so that the smoke will not leave the throat in the form of a single stream, but be diluted with air and leave in the form of many streamlets, separated by air. The wind striking the perforated part of the chimney at one side, some of the air will enter and dilute the gases and leave with them at the opposite side. The uniting of air and gases is assisted by the formation of eddy-currents. The great advantage of the device is that it is automatic and requires no supervision.

Desilverization.-No

changes or improvements have been recorded during the year in this branch of the metallurgy of lead.

Bibliography.-H. P. Collins has brought out a second edition of The Metallurgy of Lead and Silver; Part I. Lead. (Philadelphia, Lippincott, 1910, pp. 538.) The first edition, 1899, with 368 pages, was welcomed upon its appearance. The general plan of the new edition is the same as that of the first; a great many ad'ditions have been made, but too few

pan. The operation of these plants will be watched with interest. Zinc smelting is more dependent upon the human factor than are many other branches of metallurgy, and for this reason has been chiefly confined to the districts in Silesia, Rheinland, Belgium, Great Britain and the United States where a working population trained in the art through several generations of practice has become established. successful prosecution of zinc smelting at new and remote places has generally been a tedious development, although of course by no means impossible.

The

Production and Consumption.-The zinc industry in 1911 was prosperous, especially in the latter part of the year, when prices rose materially above what may be considered a normal average. This was due to a demand for zinc, both in Europe and America, which strained productive capacity to the utmost. It was fore- In the metallurgy of zinc there seen a year previous that this was was no radical change in 1911. Sevlikely to occur in the United States, eral new works were started in the where the diminishing supply of na- coal fields of Illinois, bearing out tural gas at certain smelting centers previous forecasts respecting the in Kansas augured an insufficient destiny of that state as a zinc-smeltsmelting capacity. Something sim- ing center, but two new plants were ilar happened in Europe, where the also built in the gas fields of Oklaconvention among the smelters had, homa. Smelteries to use natural in Nov., 1910, been renewed for gas as fuel are relatively cheap and a further period of 34 years, with the idea that it was still necessary to control production. As the market developed in 1911, however, it proved that there was not sufficient smelting capacity to afford easy supply to the consumptive demand, and as in the United States unsold stocks became non-existent.

Ore Supplies.-A bountiful supply of ore being available smelters realized larger profits than in several years previous. European smelters received increasing supplies of ore from Broken Hill, New South Wales, while the discovery of large deposits of calamine at Leadville, Colo., and the development of important mines of blende at Butte, Mont., together with augmented offerings of ore from other sources have relieved American smelters from their dependence upon the Joplin district and put them in a comfortable position.

quick to construct, but must be figured on a short duration of fuel supply. Smelteries using coal are more costly, but more permanent. Economic considerations make it necessary that they be provided with a department for the manufacture of sulphuric acid from their roastgas. This also is the general practice in Europe.

Smelting Furnaces.-In all modern coal smelteries the distillation furnaces are of the regenerative type, either reversing or counter-current. In recent years the latter has increased in use. It has certain distinct advantages, but has not generally been considered so economical of fuel as the other system. However, that particular, in either system, is governed largely by the proportions of the furnace, and some excellent results have been reported of counter-current furnaces. As to the form and arrangement of the reNew Smelting Plants.-Noteworthy torts, European practice tends toevents of 1911 were the inauguration ward the Rhenish system; American of zinc smelting by the Broken Hill toward the Belgian. Among AmeriProprietary Co. in New South can works using natural gas the Wales, which has provided itself Iola type of furnace still prevails, with a plant of considerable capa- in spite of certain disadvantages. At city: and the beginning of zinc Cherryvale, where furnaces of the smelting, on a small scale, in Ja- Belgian type were originally in

Hydrometallurgy.-Several

hydrometallurgical processes for zinc extraction were exploited in 1911, one of them rather extensively, but none of these commanded any very serious attention among metallurgists in general, although an elaborate plant for the exploitation of one of these processes is being erected in Tasmania.

stalled, it was possible to adapt | who have been experimenting on them to firing with petroleum when this line are Babe, Blum, Hommel the supply of natural gas failed, but and Witter. Some useful developother smelters in Kansas have been ments may be expected under favorable to use petroleum only in con- able conditions. nection with their roasting furnaces. Electrometallurgy.-Much attention was given in 1911 to the development of electric furnaces for zinc smelting and some optimistic reports were made to the effect that previously baffling difficulties had been Overcome. It was authentically reported that commercial ore smelting had been accomplished at Sarpsborg and Trollhättan, in Scandinavia, Metallurgical Progress.-While the and that the capacity of those works standard method of zine smelting is is to be enlarged. In spite of this frequently pronounced to be quite it must be pronounced that electric backward by metallurgists who have zine smelting is absolutely in its in- but recently become interested in fancy and it is impossible yet to say zinc-ore treatment, it is not so redefinitely that certain metallurgical garded by those who are well versed obstacles have been surmounted, in the art. Many improvements in much less that the electric-smelting details have been made, and are conprocess will offer any commercial ad- stantly being made, with the results vantage. of decreased cost of operation, inPyrometallurgical Concentration.creased extraction of metal and abil A good deal of attention was de- ity to handle successfully ores of voted in 1911 to what may be called considerable impurity. High perthe pyrometallurgical concentration centages of lead and iron have of zinc ore by burning off the zinc ceased to have terrors. Silver and after the fashion of the Wetherill lead contents can be recovered process, but without the refinements either by smelting the entire resithat are necessary when the oxide due from zinc distillation or by subis to be collected for use as a pig- jecting it to mechanical concentrament. Such a process of concentra- tion and smelting the concentrate. tion may find a useful field in the The choice between these alternatreatment of ores and metallurgical tives depends simply upon commerproducts that are not amenable to cial conditions. Available ore supmechanical concentration, and con-plies are constantly being increased sideration of this possibility has by improvements in the art of mebeen inspired by the success of Pape chanical concentration. The art of in extracting zinc from the slags of zine smelting is also far from standOker, in Germany. Among others ing still.

PHYSICAL PROPERTIES OF METALS AND ALLOYS

JAMES S. MACGREGOR

During the past year many addi- demands of the engineer for matertional data relative to the physical ials having various properties for properties of metals and alloys have specific purposes are greater than been produced. The development of ever, and are an incentive to experiresearch along these lines is due to increased facilities in the nature of laboratory equipment, as well as the inauguration in recent years of research laboratories in many of our industrial concerns. Further, the

mentation along these lines. The development of the aeroplane and automobile, for example, has had a remarkable influence in bringing about investigations on alloy steels. Abrasion. Abrasive qualities are

very important where materials are tained from weather-exposure tests subjected to the rubbing or wearing and sulphuric-acid tests, the latter action of machine parts. Experi- being an accelerated test. These tests ments to ascertain the effect upon abrasive qualities of the addition of various elements to steel and cast iron have been conducted.

Vanadium in Cast Iron.-George L. Norris has studied the effect of the addition of vanadium to cast iron. He states that the effect of the addition of this element is to expel oxygen and nitrogen, to make the elements of the casting more coherent and to increase the wearing qualities of the crystalline structure. Fur- very pure steel with copper added ther, the structure shows less ten- gave similar results. The presence dency to break along cleavage planes. The strength of cast iron is increased from 10 to 25 per cent.

magnesium, 3.5 to 5.5 per cent. cop-
per, and 0.5 to 0.8 per cent. man-
ganese showed very marked effects
upon the strength, ductility, hard-
ness, and resistance to corrosion of
the metal. The following is a sum-
mary of the physical properties of
the alloy.

Shearing Strength, lb. per sq. in...
Tensile Strength, lb. per sq. in..
Modulus of Elasticity.
Specific Gravity..

Effect of High Temperatures on Cast Steel.-Experiments have been conducted both abroad and in this country relative to the effect of high temperatures upon steel and cast iron. Up to the present year, however, no data were obtainable relative to the effects of high temperature on cast steel. Experiments conducted by Messrs. Perrine and 10,000,000 Spencer under the direction of the 2.8 Testing Laboratory, Columbia University, throw light upon this subject. The following table gives a summary of the results obtained:

42,700

71,200

The hardness of the alloy is three times that of pure aluminum. It is stated that this material is used by the British Army in the construction of airships. The values of strength coincident with extreme lightness ture, Degrees Elongation, in. are quite remarkable.

Expansion of Nickel Steels.-Steel containing high percentages of nickel has an extremely low coefficient of expansion. This fact should make

Tempera

F.

Ultimate strength, lb. per sq. in.

75

27.3

81,310

400

25.8

73,180

600

26.5

77,930

800

31.1

63,520

1000

its use in the manufacture of instruments of precision widespread. C. E. Guillaume (Comptes Rendus, Vol. CVII, pp. 189) has during the A perusal of the results shows a past year determined the coefficient slight decrease in strength at a temof expansion of steel containing perature of 400° F., a marked revarying percentages of nickel. The covery at 600° F., and then a gradresults show a minimum expansion ual falling off for further increase for a nickel content of 36 per cent. of temperature. The results are of The coefficient for this percentage is considerable importance because of only one twenty-eighth that of ordi- the use of steel castings for steam nary steel. fittings, etc.