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By Edward H. Bzirdick

THE territory under particular consideration in this article comprises portions of La Plata and Montezuma Counties, situated in the southwestern corner of Colorado, and around the base of the La Plata Mountains. (See Fig. 1.) In southeastern Utah and northeastern Arizona there are several mountain systems whose origin and structure are practically identical with the La Platas so that ore occurrences found in the latter can be hopefully looked for in the former. With this assumption, there is an area around the laccolithic ranges which offers promise for a successful exploration for gold ores. Ore occurrences of the Silverton, Telluride, Rico, or Ouray Districts will not be discussed, although in these areas the Mesozoic sediments are more or less involved within the ore-bearing complex. These have been intensively studied and developed. The idea is to set forth what my mining experience has been within the largely unaltered . Mesozoic horizon which remains around the extreme bases of the La Plazas. This, until recent years, has been almost entirely neglected by prospectors and operators and, so far as similar territory in Utah and Arizona is concerned, so remains.

Jan 1, 1934

By T. F. Witherbee

It is proposed to give, first, a description of the works; second, a report of the first six months of the present blast; and third, such improvements as have been suggested by the practical working. The site selected for this furnace was, at the time of commencing work, October, 1872, entirely covered by the navigable waters of Lake Champlain. A coffer-dam was first built of cribs of round timber filled with stone, forming three sides, while the shore answered for the fourth. Considerable excavating was done with a steam-dredge, a hole being left for it to pass out. The opening was then built up, and the cribbing banked up with blue clay from the bottom of the lake, to render it water-tight and the dam pumped out; the remainder of the excavating being done by hand. All of the foundations, with the exception of the elevator-tower, and fifteen feet of the east side of hot blast, rest on the Potsdam sandstone, which forms the shore line, dipping into the lake at an angle of fifteen degrees. Owing to jogs in the formation, a much greater depth was found necessary than was at first anticipated, the foundation under the stack

By T. F. Witherbee

IT is proposed to give, first, a description of the works ; second, a report of the first six months of the present blast; and third, such improvements as have been suggested by the practical working. The site selected for this furnace was, at the time of commencing work, October, 1872, entirely covered by the navigable waters of Lake Champlain. A coffer-dam was first built of cribs of round timber filled with stone, forming three sides, while the shore answered for the fourth. Considerable excavating was done with a steam-dredge, a hole being left for it to pass out. The opening was then built up, and the cribbing banked up with blue clay from the bottom of the lake, to render it water-tight and the dam pumped out; the remainder of the excavating being done by hand. All of the foundations, with the exception of the elevator-tower, and fifteen feet of the east side of hot blast, rest on the Potsdam sandstone, which forms the shore line, dipping into the lake at an angle of fifteen degrees. Owing to jogs in the formation, a much greater depth was found necessary than was at first anticipated, the foundation under the stack

Jan 1, 1876

By Albert Sauveur

THE following experiments were conducted in order to study the influence of the rate of cooling through and below solidification on the dendritic structure (macrostructure) and microstructure of some hypoeutectoid steel. The steel selected was of commercial grade and had the following composition: C, 0.40 per cent.; Mn, 0.85; Si, 0.70; P, 0.099; S, 0.043. After melting in vacuum in an Arsem furnace, the various samples were allowed to solidify and to cool to room temperature as indicated in Fig. 1. Samples were thus obtained representing all possible combinations of slow and fast cooling through the various ranges of temperatures indicated, namely: (1), zone of solidification or primary crystallization, (2) zone of granulation, and (3) zone of secondary crystallization. The location of the different temperature zones in the iron-carbon equilibrium diagram is shown in Fig. 2. The authors adopted. Belaiew's notations. The designations of the various samples readily indicate their treatment, as will be apparent from Table 1.

Jan 1, 1930

Erwin S. SperRy, Bridgeport, Conn.: The analysis of refined copper is a subject of great importance, and has not received the attention it deserves. Copper metallurgists, therefore, will welcome the paper of Mr. Heath with satisfaction. The state of the art of the chemical analysis of copper has been such that consumers, if they could not afford to run any risk, have been obliged to buy copper from the smelter having the best reputation, and a specification for copper to meet certain requirements could not be drawn up by the mere giving of the chemical constituents. Mr. Heath has brought the analysis of the copper to such a state that when a specification calls for copper " equal to Lake copper " one will know immediately what percentage of the pure metal to expect. It seems to be a pretty well established fact that the copper of Lake Superior is practically free from antimony and bitmuth ; and, with the exception of arsenic, the other elements are easily separated from copper by electro-deposition in an acid solution. The authorities differ in regard to the question whether antimony is deposited with the copper in an acid solution. Classen* recommends the employment of a solution containing 10 per cent. of free nitric acid, sp.gr.1.21, and the strength of the current from 0.3 to 0.4 ampere, in order to prevent the other metals from being deposited with the copper; and for this reason, I presume, the method has been generally used. I, myself, have been accustomed to use such a solution for the analysis of copper-alloys, but have found that for such alloys only a small quantity of nitric acid is necessary, if sulphuric acid is present in sufficient amount to give the solution the required conductivity.

Jan 1, 1898

By Ralph H. Sweetser

MUCH progress in -blast-furnace construction and in the manufacture of firebrick for furnace linings has been made since the publication of Bulletin 130 of the U. S. Bureau of Mines on "Blast-Furnace Breakouts, Explosions and Slips, and Methods of Prevention," by F. H. Willcox in 1917. At the time of publishing this report comparatively little information was available to blast-furnace men as to the fundamental facts relating to the character of blast-furnace refractories. Some of the accepted theories of only a few years ago have been completely reversed. The mortality of blast-furnace linings used to be so great that nearly every furnace plant had one or more complete linings in the brick shed ready for use in case of a lining suddenly "going out"; it was generally accepted that a furnace could not "keep her lines" more than two or three years at best, and often a hot spot in the shell would develop, or a breakout occur in the hearth or bosh within a year or two after blowing in on a new lining. In some respects these frequent relinings were not so detrimental as to he a complete loss because they afforded opportunities to take advantage of advances in blast-furnace practice. At present the cost of relining has greatly increased, but the life of a lining has also increased. Anything less than five years on a lining is now considered a short blast.

Jan 1, 1932

F. E. BACHMAN, Buffalo, N. Y. (Communication to the Secretary) : The investigation so fully described by Mr. Laudig was undertaken with the idea of determining if it is possible to learn by expesiment, without an actual trial in the furnace, what economical results can be expected from the use of a given ore-mixture. The research was necessarily preliminary, and the results obtained are only to be depended upon so far as they relate to the samples treated. With the exception of the ores obtained from the stock-piles of the Buffalo Furnace Company, and several samples taken at a neighboring furnace, there is no certainty that the ores represented the average shipments of any mine. For this reason the publication of the names of the ores might do producers a great injustice. The names of the ores arc therefore withheld, and their identity is further .veiled by leaving out of the analyses the phosphorus-contents. The investigation was begun with the preconceived idea that the rate of reduction would be found to be dependent upon the accessibility of the particles of the ore to the action of the reducing-gas. In other words, a spongy, brown hematite or a very fine Mesabi would be the easiest reduced. I had formed a scale with No. 21 first, No. 30 second, No. 1 third, Nos. 5, 24, 25 and the remaining Mesabis fourth, etc , which is sufficient to show how much actual results differ from a judgment based on physical characteristics. The ore expected to be most easily reduced proved to be 25th in the list, while the one placed

Jan 1, 1897

By Ednlund D. North

Discussion of the paper of Edmund D. North, presented at the Spokane meeting, September, 1909, and published in Bulletin No. 37, January, 1910, pp. 21 to 25. A. SCOTT REID, London, Eng. (communication to the Secretary*) :-As a constructor of several glass mine-models, I have read with much interest the description of the model of the Montana-Tonopah mine-workings by Edmund D. North. As an interchange of ideas and experience is always an advantage, and in view of the fact that such models are coming more and more into vogue, perhaps the following remarks on this subject may prove of interest to mining engineers generally and to Mr. North particularly. In the model of the Waihi gold-mine, New Zealand, which I constructed, a dust-proof case is used. The top, bottom, front, and two ends are of glass; the back only is of wood, painted a dull white, against which the mine-workings show very distinctly. Each mine-level is represented by a horizontal sheet of glass, supported on metal runners fixed to the uprights at each end of the case, in a manner similar to that described by Mr. North. The corner uprights are strengthened by having a metal band screwed to the inside face of each, to which the metal runners or supports for the sheets of glass are screwed in turn. The reason for having this additional strength is that as the mine is developed in depth, and fresh levels are opened, the increasing weight of the glass sheets, added to the model, caused the unsupported wooden uprights to bend slightly, so that the glass sheets-did not fit in with the desired nicety, and co-ordination was, to a considerable extent, lost. Strengthening the uprights in this manner is not important in models of mines in which only a few levels have been opened, or when the sheets of glass are small, but in the Waihi model there are 15 sheets of glass to be supported, and more to be added as development proceeds, and the weight is considerable.

May 1, 1910

By F. S. Crawford

IRON and copper are mined in the Lake Superior district. The iron mines of the district have the best safety record for that industry in the country as a whole, while the copper mines of the district rank second in two of the four years recorded (Table 1). In Utah copper comes mainly from open-pit mines, which enables that state to lead easily in safety. All of the Michigan production comes from deep under-ground workings. About 60 per cent of the iron miners in St. Louis County, Minnesota, are employed at open-pit mines; this favorably affects the combined open-pit and underground accident-frequency rate, as this county pro-vides most of the Minnesota-mined iron ore. In Michigan, however, there are few open-pit mines, the bulk of the production coming from underground mines, while all of the Wisconsin production, just across the state line from Michigan, is from underground mines. In spite of the fact that fewer mines in Michigan use the safer open-pit method, the iron-mining industry of that state maintained a consistently low record from 1931 to 1934; however, it was many points behind its nearest com petitor, Minnesota, with its much greater production from open-pit mines.

Jan 1, 1939

By T. Sterry Hunt

WET processes for the extraction of copper from its ores have of late attracted much attention, especially in Europe, where the use of oupriferous iron-pyrites as a' source of sulphur prevails. These processes present an additional interest, when, as is often the case, the copper-ore's to be treated contain one or both of the precious metals, since the complete separation of these from copper, either in the dry or the moist way, is, as is well known, one of the difficult problems of metallurgy. The principal wet processes hitherto in use for the extraction of copper from its ores, may be included under three classes : I. Those in which the copper in snlphuretted ores is rendered soluble in water by calcining them, after a preliminary roasting which removes the greater part of their sulphur, with a portion of common salt, by which the copper is converted into a chloride (Long-maid and Henderson), or with sulphate of soda, by which sulphate of copper is formed (Monnier). Allied to these is the method by which a portion of the copper is got as soluble sulphate by roasting without addition, a process which is sometimes modified and rendered more complete by re-roasting the lixiviated residues with the addition of a portion of raw sulphuretted ore (Bankart). II. Those methods in which free chlorhydric or sulphuric acid is used to dissolve the copper- from oxidized or roasted ores. These, while simple and efficient, are too costly, except in certain localities where chlorhydric acid is a waste product. Related to them is the plan which consists in exposing the oxidized and moistened ores to the slow action of sulphurous acid mixed with air, by which a soluble sulphate of copper is formed. It has been proposed to decompose the solutions of sulphate or chloride of copper by sulphuretted hydrogen, thus separating the copper as sulphide, and using the liberated acid to dissolve fresh portions of oxidized copper. It is, however, the almost universal practice to throw down the copper from its solutions, however obtained, in the metallic state by the use of iron, either scrap-iron or iron-sponge; although in some instances

Jan 1, 1882

By T. Sterry Hunt

Jan 1, 1882

By Charles Trotter

An instrument has recently been developed for determining the inclination and azimuthal direction of boreholes. This instrument is known as the Tro-Pari Instrument and is the invention of C. Trotter and G. Pajari of Sudbury, Ontario. Description The instrument is characterized by a unit mounted in gimbals and provided with a clockwork mechanism to clamp a compass to indicate azimuthal direction and simultaneously to clamp the unit in its plumb position to indicate inclination (Fig I). By means of a timing ring suitably calibrated in 5-min divisions, the unit may be set to lock after a lapse of time sufficient to allow the placing of the instrument at the desired point in the drill hole where readings are to be taken. The maximum time Lapse obtainable with the instrument designed for use in EX or AX size holes is I hr 30 min which is considered to be ample time to lower to the greatest depths that may be drilled with this size of equipment. Larger sizes could be developed for larger diameter holes such as BX and NX sizes or the larger oil-well sizes and a correspondingly greater time lapse could be provided for. Up to the present time only the EX-AX size has been built. Operation Assuming a borehole is to be surveyed at 1000-ft depth and assuming it will take 30 min to lower the instrument to this depth, the timing ring is rotated through seven divisions which represent a time lapse of 35 min (5-min leeway) and is then returned to its zero position. This operation imparts energy to a spring which drives the clockwork mechanism. Simultaneously the compass needle is freed to swing to its magnetic north-south position and the encased mechanism is freed to hang plumb within a semicircular portion of the frame which is graduated in degrees after the fashion of a protractor. This semicircular protractor portion has a V-shaped notch at each degree division of its inner periphery. The instrument, now in its free position, is inserted in a bronze container made to suit the size of hole to be surveyed (Fig 2). Soft rubber washers are provided within the container to prevent undue shock. The container is connected to the drill rods with three 5-ft lengths of brass or aluminum alloy rods separating it from the steel rods in order to prevent distortion of the magnetic field. The assembly is then lowered to the desired point where readings are to be taken and is allowed to remain at rest until a period of time has elapsed slightly in excess of the time for which the timing ring was set. In the example cited above, when the 35 min has elapsed the compass needle is locked in its north-south position and the protractor locking pin is extruded and locks in the V notch opposite its plumb position. The device may now be removed from the borehole and it will remain in this locked position in spite of jarring or shak-

Jan 1, 1949

Time as a Factor in the Making and Treating of Steel. By John Johnston. (Howe Lecture) (T.P. 1478) Influence of Chromium and Molybdenum on Structure, Hardness and Decarburization of 0.35 Per Cent Carbon Steel. By R. F. Miller and R. F. Campbell. (T.P. 1345) Mechanical Properties of Iron-manganese Alloys. By F, M. Walters, Jr., I. R. Kramer and B. M. Loring. (T.P. 1369) The Instability of Low-expansion Iron-nickel-cobalt Alloys. By I. R. Kramer and F. M. Walters, Jr. (T.P. 1370) The S-curve of a Chromium-nickel Steel. By B. M. Loring. (T.P. 1383) A Magnetic Determination of the A3 Transformation Point in Iron. By B. A. Rogers and K. 0. Stamm. (T.P. 1388) Rapid Tension Tests Using Two-load Method. By A. V. de Forest, C. W. MacGregor and A. R. Anderson. (T.P. 1393) Effects of Scrap in the Blast-furnace Burden. By C. L. T. Edwards. (T.P. 1270) Temperature Gradients through Composite Carbon Columns and their Application to Blastfurnace Linings. By F. J. Vosburgh and M. R. HatFIeld. (T.P. 1363) Correlations of Some Coke Properties with Blast-furnace Operation. By H. W. Johnson. (T.P. 1402) The Technical Cohesive Strength and Yield Strength of Metals. By D. J. McAdam, Jr. (T.P. 1414) Effects of Eight Complex Deoxidizers on Some 0.40 Per Cent Carbon Forging Steels. By George F. Comstock. (T.P. 1417) Significance of the Bessemer End Point. By H. T. Bowman. (T.P. 1428) Structural Diagrams of Nickel Irons and Steels. By J. T. EasE and N. B. Pilling. (T.P. 1432) Carbides in Low-chromium Steel. By Walter Crafts and C. M. OFFenhauer. (T.P. 1436) Hardenability Calculated from Chemical Composition. By M. A. Grossmann. (T.P. 1437) Recrystallization of Silicon Ferrite in Terms of Rate of Nucleation and Rate of Growth. By J. K. Stanley and R. F. Mehl. (T.P. 1438) The Solubility of Carbon as Graphite in Gamma Iron. By R. W. Gurry. (T.P. 1440) An Evaluation of the Factors Affecting Iron Oxide in the Open-hearth Bath. By J. E. Gould and H. J. Hand. (T.P. 1442) Precision in Creep Testing. By J. A. Fellows, Earnshaw Cook and Howard S. Avery. (T.P. 1443) Lattice Relationships in the Decomposition of Austenite to Pearlite, Bainite and Martensite. By G. V. Smith and R. F. Mehl. (T.P. 1459) Rate of Nucleation and Rate of Growth of Pearlite. By F. C. Hull, R. A. Colton and R. F. Mehl. (T.P. 1460) Weight Change as a Criterion of Extent of Decarburization or Carburization. By R. W. Gurry. (T.P. 1470) Observations in the Making and Use of Sulphite-treated Steels. By E. L, Ramsey and L. G. Graper. (T.P. 1476) Diffusion in Metal Accompanied by Phase Change. By L. S. Darken. (T.P. 1479) Engineering Properties of Heat-resistant Alloys. By Howard S. Avery, Earnshaw Cook and J. A. Fellows. (T.P. 1480) Distribution of Manganese and of Sulphur between Slag and Metal in the Open-hearth Furnace. By L. S. Darken and B. M. Larsen. (T.P. 1481)

Jan 1, 1942

By Charles Trotter

AN instrument has recently been developed for determining the inclination and azimuthal direction of boreholes. This instrument is known as the Tro-Pari Instrument and is the invention of C. Trotter and G. Pajari of Sudbury, Ontario. DESCRIPTION The instrument is characterized by a unit mounted in gimbals and provided with a clockwork mechanism to clamp a compass to indicate azimuthal direction and simultaneously to clamp the unit in its plumb position to indicate inclination (Fig I). By means of a timing ring suitably calibrated in 5-min divisions, the unit may be set to lock after a lapse of time sufficient to allow the placing of the instrument at the desired point in the drill hole where readings are to be taken. The maximum time lapse obtainable with the instrument designed for use in EX or AX size holes is 1 hr 30 min which is considered to be ample time to lower to the greatest depths that may be drilled with this size of equipment. Larger sizes could be developed for larger diameter holes such as BX and NX sizes or the larger oil-well sizes and a correspondingly greater time lapse could be provided for. Up to the present time only the EX-AX size has been built. OPERATION Assuming a borehole is to be surveyed at 1000-ft depth and assuming it will take 30 min to lower the instrument to this depth, the timing ring is rotated through seven divisions which represent a time lapse of 35 min (5-min leeway) and is then returned to its zero position. This operation imparts energy to a spring which drives the clockwork mechanism. Simultaneously the compass needle is freed to swing to its magnetic north-south position and the encased mechanism is freed to hang plumb within a semicircular portion of the frame which is graduated in degrees after the fashion of a protractor. This semicircular protractor portion has a V-shaped notch at each degree division of its inner periphery. The instrument, now in its free position, is inserted in a bronze container made to suit the size of hole to be surveyed (Fig 2). Soft rubber washers are provided within the container to prevent undue shock. The container is connected to the drill rods with three 5-ft lengths of brass or aluminum alloy rods separating it from the steel rods in order to prevent distortion of the magnetic field. The assembly is then lowered to the desired point where readings are to be taken and is allowed to remain at rest until a period of time has elapsed slightly in excess of the time for which the timing ring was set. In the example cited above, when the 35 min has elapsed the compass needle is locked in its north-south position and the protractor locking pin is extruded and locks in the V notch opposite its plumb position. The device may now be removed from the borehole and it will remain in this locked position in spite of jarring or shak-

Jan 1, 1947

Time as a Factor in the Making and Treating of Steel. By John Johnston. (Howe Lecture) (T.P. 1478) Influence of Chromium and Molybdenum on Structure, Hardness and Decarburization of 0.35 Per Cent Carbon Steel. By R. F. Miller and R. F. Campbell. (T.P. 1345) Mechanical Properties of Iron-manganese Alloys. By F, M. Walters, Jr., I. R. Kramer and B. M. Loring. (T.P. 1369) The Instability of Low-expansion Iron-nickel-cobalt Alloys. By I. R. Kramer and F. M. Walters, Jr. (T.P. 1370) The S-curve of a Chromium-nickel Steel. By B. M. Loring. (T.P. 1383) A Magnetic Determination of the A3 Transformation Point in Iron. By B. A. Rogers and K. 0. Stamm. (T.P. 1388) Rapid Tension Tests Using Two-load Method. By A. V. de Forest, C. W. MacGregor and A. R. Anderson. (T.P. 1393) Effects of Scrap in the Blast-furnace Burden. By C. L. T. Edwards. (T.P. 1270) Temperature Gradients through Composite Carbon Columns and their Application to Blastfurnace Linings. By F. J. Vosburgh and M. R. HatFIeld. (T.P. 1363) Correlations of Some Coke Properties with Blast-furnace Operation. By H. W. Johnson. (T.P. 1402) The Technical Cohesive Strength and Yield Strength of Metals. By D. J. McAdam, Jr. (T.P. 1414) Effects of Eight Complex Deoxidizers on Some 0.40 Per Cent Carbon Forging Steels. By George F. Comstock. (T.P. 1417) Significance of the Bessemer End Point. By H. T. Bowman. (T.P. 1428) Structural Diagrams of Nickel Irons and Steels. By J. T. EasE and N. B. Pilling. (T.P. 1432) Carbides in Low-chromium Steel. By Walter Crafts and C. M. OFFenhauer. (T.P. 1436) Hardenability Calculated from Chemical Composition. By M. A. Grossmann. (T.P. 1437) Recrystallization of Silicon Ferrite in Terms of Rate of Nucleation and Rate of Growth. By J. K. Stanley and R. F. Mehl. (T.P. 1438) The Solubility of Carbon as Graphite in Gamma Iron. By R. W. Gurry. (T.P. 1440) An Evaluation of the Factors Affecting Iron Oxide in the Open-hearth Bath. By J. E. Gould and H. J. Hand. (T.P. 1442) Precision in Creep Testing. By J. A. Fellows, Earnshaw Cook and Howard S. Avery. (T.P. 1443) Lattice Relationships in the Decomposition of Austenite to Pearlite, Bainite and Martensite. By G. V. Smith and R. F. Mehl. (T.P. 1459) Rate of Nucleation and Rate of Growth of Pearlite. By F. C. Hull, R. A. Colton and R. F. Mehl. (T.P. 1460) Weight Change as a Criterion of Extent of Decarburization or Carburization. By R. W. Gurry. (T.P. 1470) Observations in the Making and Use of Sulphite-treated Steels. By E. L, Ramsey and L. G. Graper. (T.P. 1476) Diffusion in Metal Accompanied by Phase Change. By L. S. Darken. (T.P. 1479) Engineering Properties of Heat-resistant Alloys. By Howard S. Avery, Earnshaw Cook and J. A. Fellows. (T.P. 1480) Distribution of Manganese and of Sulphur between Slag and Metal in the Open-hearth Furnace. By L. S. Darken and B. M. Larsen. (T.P. 1481)

Jan 1, 1942

By D. C. Jillson

BRIDGMAN1,2 melted metals in a graphite or hard glass tube and lowered the tube through a furnace to make it cool from one end only. Because of the difficulty of eliminating all vibration of the mold, others have raised the furnace instead. Neither way seems as desirable as a setup with no motion of either the mold or the furnace. A furnace in which both the shape and the slope of the temperature gradient could be controlled and varied over a wide range and in which such a gradient could be moved from one end of the furnace to the other, freezing the specimen from one end to the other, at any desired rate, all by means of isolated external control, seemed to offer definite advantages. In addition to eliminating the possibility of vibration due to moving parts, it might also give better control over the direction and rate of heat flow. Such an apparatus was assembled and is shown schematically in fig. 1. Equipment Furnace: A clay-carborundum tube of 3 1/2 in. ID with a % in. wall thickness was used as the core. This had a main winding of No. 12 B.&S. gauge Nichrome V with some compensation for heat loss at the ends. Taps to this winding were made at points 12 in. from each end. Fig. 2 shows details of this winding and of the two end windings. Each end winding was wound over Micanite over the main winding. No. 15 B.&S. gauge Nichrome V was used for these, and again taps were supplied at two inter-mediat,e points on each. The tube was supported in an 18 in. OD black iron shell with brick insulation. The input to each of the windings was regulated by means of a variable transformer. Temperature Regulation: A chromel-alumel thermocouple located near the furnace wall in the center of the furnace was connected with a Celec-tray controller, type PIC, 300" to 900°C range, which opened and closed a shunt across an external variable resistance in the main winding circuit. An "anticipatory response" device also was incorporated to minimize the cyclic effect of the control mechanism. Eleven survey couples in a common pyrex glass protection tube were located near the furnace wall and spaced 2 in. apart. The couple leads went to a common reference junction box where they were connected to copper leads from a selector switch which, in turn, was connected to a type K potentio-meter. This arrangement permitted rapid temperature surveys. The knob on the controller dial was replaced with a threaded brass spool turned at a controlled rate by a thin iron wire one end of which was attached to a gear train and the other to a small weight heavy enough to prevent slipping of the wire on the spool. The gear train, driven by a 1-rpm Telechron motor, contained a series of different sized interchangeable gears and threaded drums permitting a range of travel speeds from 0.10 in. per hr up to a hypo-

Jan 1, 1951

By John G. McLain

OF all the zinc that the world consumed in 1936-'38 the United States took about 31 per cent, and almost 14 per cent of the world's zinc supply in that period was used for galvanizing purposes in the United States. Further examination of the statistics shows that about 71/2 per cent (147,500 tons in 1939) of the world zinc consumption goes into the galvanizing of sheets in the United States, which is what I am going to talk about in this paper. There is nothing especially new about galvanizing; in every year since 1921 somewhere between 41 and 49 per cent of the country's zinc consumption has been used for this purpose, and yet few people not specialists in its manufacture know much about how it is made. You take an iron or steel sheet and dip it in molten zinc and there you have a galvanized sheet-that about epitomizes popular knowledge of the subject even among engineers.

Jan 1, 1941

By Benjamin Gi ldersleeve

Uniquely colored, thin-bedded quartzite is quarried between Crossville and Crab Orchard in Cumberland County, Tenn. It is produced in all sizes up to the limits of transportation from beds usually ranging in thickness from less than 1/2 in. to 6 in. The stone is very resistant to wear and weathering and is marketed throughout the country for many different purposes in exterior and interior construction. The annual production exceeds 36,000 tons, valued at nearly $1,000,000.

Jan 1, 1950

By J. C. Bayles

Jan 1, 1885

IlAbad, Leopoldo F , Min Engr , Div of Mines, Bureau of Science, Manda, P I '23 ||Abadilla, Quince, A , Cia Minera de Petrolco El Aguila, S A Box 86, Puerto Mexico, Ver , Mexico '20 ||Abarquez, Ramon F , Met , Bureau of Science Manila, P I '24 ||Abbey, Robert Graham, Student, Case School of Applied Science Cleveland, Ohio '21 Abbott, A N , Mines Supt, Mazapil Copper Co , Ltd Concepcion del Oro, Zac , Mexico '23 Abbott, Clarence E , Gen'l Supt , Iron Mines Div , Tenn Coal, Iron & R R Co , 1405 Minnesota Ave , Bessemer, Ala '04 Abbott, Louis Benjamin, Chief Engr , Consolidation Coal Co , Elkhorn Div Jenkins, Ky '15 Abbott, Robert R , Met Engr , Peerless Motor Car Co Cle veland, Ohio '12 ||Abbott, Wells Osborn, Ray Consolidated Copper Co Hayden, Ariz '23 Abeel, George H , Jr, Cons Min Engr 4612 W 17th St, Los Angeles, Cal '18 Abel, Albert E, Asst to Pres, Valley Mould & Iron Corpn Sharpsville, Pa '19 Abernathy, George Elmer, Prof Geol & Min , Kansas State Teachers College Pittsburg, Kans '20 Abey, Hiroshi, Min & Met Engr, Takata & Co , 2 Yeirakucho, Nichome, ICojimachi-ku, - Tokyo, Japan '17 ||Aborn, Robert H 24 Groveland St , Auburndale, Mass '19 Abouchar, Sylvain Sley, Min Engr & Geol , Care of S H Sekaly, 13 Rue El Nimr, Cairo, Egypt '17 ?Abraham, Arthur W 1626 N Alexandria Ave, Los Angeles, Cal '21 Abrahams, Alexander I, Gen'l Mgr, Ricon Electrical Co Slough, London, England '13 ||Abrahamson, C Walter, Min Engr, Brule Min Co Stambaugh, Mich '21 Abrams, Charles Jackson, Mill Supt, Utah Apex Min Co Bingham Canyon, Utah '21 Abrams, David H, Cons Min Engr 182 Worth St, Johnstown, Pa '20 ?Acker, E O'C , Met 128 East Washington Lane, Germantown, Philadelphia, Pa '86

Jan 1, 1923