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New York Meets first Wednesday after first Tuesday of each month. J. E. JOHNSON, Jr., Chairman EDGAR RICKARD, Vice-Chairman D. M. LIDDELL, Secretary, 7 Wall St., New York, N. Y. C. A. BOHN, Treasurer JOHN V. N. DORR. LEWIS W. FRANCIS Boston Meets first Monday of each winter month. R. L. AGASSIZ, Chairman JAMES G. CARLETON, Vice-Chairman E. E. BUGBEE Secretary-Treasurer, Mass. Inst. of Technology, Cambridge,Mass. W. E. C. EUSTIS G. A. PACKARD Columbia Holds four sessions during year. Annual meeting in September or October. W. H. LINNEY. Chairman OSCAR LACHMUND, Vice-Chairman LYNDON K. ARMSTRONG, Secretary-Treasurer, P. 0. Drawer 2154, Spokane, Wash. STANLY A. EASTON S. SHEDD Puget Sound Meets second Saturday of each month SIMON H. ASH, Chairman I. F. LAUCKS, Vice-Chairman CHARLES SIMENSTAD, Secretary-Treasurer, 425 Lyon Bldg., Seattle, Wash. GLENVILLE A. COLLINS JOHN N. POTT

Jan 10, 1917

By Ronie Magno Pinheiro de Souza

A partir do segundo semestre de 2013, iniciou-se um período de maior dispêndio energético para o controle da resistência à compressão da pelota AFXX. A este problema somou-se o desafio de atingir elevados patamares de produção e chegar à produção nominal da usina. Desta forma, foi necessário fazer a partir de um complexo diagnóstico de todas as etapas do processo para encontrar a causa do problema e determinar a melhor forma de contorná-lo. Observou-se uma elevada geração de superfície específica granular somada à dificuldade de obter granulometria (-325#) na moagem, além da elevação da umidade do filter cake. Além disso, observou-se uma considerável elevação do PPC (perda por calcinação) no período, o que explica as constatações anteriores. Os objetivos do trabalho são avaliar os efeitos do aumento do PPC no pellet feed na produção da pelota AFXX e buscar explicação para a queda da resistência à compressão.

Aug 1, 2018

The Institute assembled in the library of the Sheffield Scientific School at 8 o'clock, Tuesday evening, February 23d. Prof. G. J. Brush greeted the members present on behalf of the Government of the Sheffield School in a few words of cordial welcome, to which President Raymond responded. Dr. Raymond then delivered an address on the History of the Relative Values of Gold and Silver. The Council presented, through the President, a list of names of persons duly proposed for members and associates, with recommendation for election. The following gentlemen were unanimously elected: *Prof. George J. Brush,. .. New Haven, Conn. *Prof. Oscar D. Allen,. .. New Haven, Conn. *C. Constable,.....New York City. *Leven S Goodrich,.... Oxmoor, Jefferson Co., Ala. *Charles J. Nourse,.... Columbia, Lancaster Co., Pa. *J. W. Mickley,.....Hockendauqua, Pa. *Hugh Alex. Crawford,. ..St. Louis, No. *General Ario Pardee,. .. Hazleton, Luzerne Co., Pa. N. W. Lord,.....New Pork City. J. Holme Maghee,.... New York City. *George E. B. Jackson,. .. Portland, Me. *Charles W. Watkis,.... Salt Lake City, Utah. *Charles E. Hall,....Philadelphia. *Charles J. Duval,.... San Francisco, Cal. Joseph Gorlinski,.... Salt Lake City, Utah. * Alfred Wartenweiler,. .. Salt Lake City, Utah. Wilmot J. Bowen,.... Salt Lake City, Utah. *Joseph Stokes,..... Trenton, N. J. Jason P. Brown,.... Boston, Mass. *William Davis Hartshorne,. . Bethlehem, Hunterdon Co., N. J. *Henry Williams,.... Spanish Bar, Clear Creek Co., Cot. *Robert Forsyth ,....Chicago, Ill. *S. T. Wellman,.....Cleveland, Ohio. *H. C. Walton,.....Chicago, 111. *Andrew Roy,.....Columbus, Ohio. *James H. Rittenhonse,. .. Providence, Pa.

THE Institute assembled in the library of the Sheffield Scientific School at 8 o'clock, Tuesday evening, February 23d. Prof. G. J. Brush greeted the members present on behalf of the Government of the Sheffield School in a few words of cordial welcome, to which President Raymond responded. Dr. Raymond then delivered an address on the History of the Relative Values of Gold and Silver. The Council presented, through the President, a list of names of persons duly proposed for members and associates, with recom¬mendation for election. The following gentlemen were unanimously elected: *Prof. George J. Brush, - New Haven, Conn. *Prof. Oscar D. Allen, - New Haven, Conn. *C. Constable, - New York City. *Leven S Goodrich, - Oxmoor, Jefferson Co., Ala. *Charles J. Nourse, - Columbia, Lancaster Co., Pa. *J. W. Mickley, - Hockendauqua, Pa. *Hugh Alex. Crawford, - St. Louis, Mo. *General Ario Pardee, - Hazleton, Luzerne Co., Pa. †N. W. Lord, - New York City. †J. Holme Maghee, - New York City. *George E. B. Jackson, - Portland, Me. *Charles W. Watkis, - Salt Lake City, Utah. *Charles E. Hall, - Philadelphia. *Charles J. Duval, - San Francisco, Cal. †tJoseph Gorlinski, - Salt Lake City, Utah. *Alfred Wartenweiler, - Salt Lake City, Utah. †Wilmot J. Bowen, - Salt Lake City, Utah. *Joseph Stokes, - Trenton, N. J. †Jason P. Brown, - Boston, Mass. *William Davis Hartshorne, - Bethlehem, Hunterdon Co., N. J. *Henry Williams, - Spanish Bar, Clear Creek Co., Col.. *Robert Forsyth, - Chicago, Ill. *S. T. Wellman, - Cleveland, Ohio. *H. C. Walton, - Chicago, Ill. *Andrew Roy, - Columbus, Ohio. *James H. Rittenhouse, - Providence, Pa. * Members. † Associates

Jan 1, 1875

By Thomas Egleston

The process of lixiviating silver ores, which do or do not contain gold, by means of hyposnlphite of soda is likely to assume a very great importance in the West, the conditions being such that while it is applicable to very rich ores which do not contain lead enough to smelt, it is also equally applicable to many ores that are either too poor or too impure to be treated by any other process. Western ores are generally divided into four classes: those which contain copper enough to be smelted for copper, from which the gold and silver is extracted in the wet way, as is the practice of the Boston and Colorado works; those in which there is a large quantity of lead, which can be smelted for lead, and the gold and silver extracted from it; ores in which there is neither copper nor lead enough to allow of a process of smelting, but which can be treated in pans, these ores being " free milling " if they require no metallurgical treatment, or '(rebellious" if they have to be roasted with or without the addition of salt; and ores which do not contain enough either of lead or copper for smelting, which are poor both in silver and gold, contain large amounts of sulphur, arsenic, and antimony, and cannot be treated in many places in the West by any of these processes. Roasting with salt would convert the base metals as well as the silver into chlorides, and would give in the amalgamation a very base bullion, and the expense of the process would be SO great that the margin of profit would be very small, the reason being that for the ordinary process of pan-amalgamation, which is the only one suitable for ores containing small amounts of the base metals, and poor in silver and gold, the cost of a plant for milling is so large as not to justify the expense of treating such ores. The electrolytic processes which have been partially successful in Europe have not been tried 'here. While in the near future they will undoubtedly be used, it is hardly possible to consider them now.

Jan 1, 1884

By Samuel M. Cassidy

The exact date of man's first use of coal is lost in antiquity. The discovery that certain black rock would burn was undoubtedly accidental and probably occurred independently and many times in the world over thousands of years. It is quite likely that these independent discoveries were made when primitive man chanced to build camp fires on exposed ledges of a black stone, then was amazed when it caught fire. The Chinese recorded the use of coal 1100 years before the Christian Era. And, from the Bible we learn that King Solomon was familiar with coal in what is now Syria. In Wales, there is evidence that the Bronze Age people used coal for funeral pyres, and it is known that the Romans used this fuel. There are other ancient references. So the knowledge that coal would burn, and even some uses of that knowledge, goes back for thousands of years. However, practical and consistent use of coal seems to date to England in the Middle Ages. COAL IN AMERICA In the Americas, there is evidence here and there of a slight use by the Indians. However, the first recorded discovery of coal, in what is now the U.S., was by French explorers, who reported a "cole mine" on the Illinois River in 1679. Following this, other discoveries were made by French and British explorers, but the first recorded actual usage was in Virginia in 1702, where a French settler was granted permission to use coal for his forge. Earliest recorded commercial mining was in 1750, from the James River coalfield near Richmond, Va., a deposit now abandoned. Besides local consumption from this field, shipments were made to Philadelphia, New Pork, and Boston. During the Revolution this coal was of importance in the manufacture of shot and shell; so important, in fact, that the British sent an expedition in 1781 to destroy the iron works and

Jan 1, 1973

By George I. Adams

A party, consisting of George I. Adams, of the United States Geological Survey, A. H. Purdue, of the University of Arkansas, and Ernest F. Burchard, was engaged, during the summer of 1902, in the study of the zinc- and lead-deposits of Northern Arkansas. An extensive report on this field is now in preparation. The following preliminary statement of results and conclusions is made in advance of the final publication, which will be accompanied by detailed geologic maps and other illustrations and a fuller treatment of the subject. Location.—The Northern Arkansas field embraces Marion county and adjacent portions of Boone, Baxter, Newton and Searcy counties. Outside of this area there are a few scat tered mines, notably in Sharp and Lawrence counties. The mining development lies north of the Boston mountains, in what is known as the Ozark Plateau. The country has a broken surface, as a result of dissection by streams, and there are numerous exposures of the mineral-bearing horizons in the valley slopes. This has greatly facilitated prospecting. History.—Lead-ore was discovered in Northern Arkansas by the early explorers and pioneers, and at first was utilized for rifle-ballets. Later, it attracted considerable attention, and in the '50's was smelted in the vicinity of Lead Hill. There was a revival of the industry during the "70's, but the cost of transportation was so great that it was practically abandoned. Zinc-ores at first attracted little attention, probably because they were not so well understood. Before the Civil War, however, some zinc was smelted. In the '80's, prospecting was carried on generally throughout the field, and resulted in finding zinc at so many places and so readily accessible that

Jan 1, 1904

By Robert H. Richards

DuRing the winter of 1868-9,I was called upon by Professor F. H. Storer, to put up the Bunsen filter pump in the chemical laboratory of the Masschusetts Institute of Technology. As the laboratory is on the lower floor, it was found necessary to use a great deal of cumbrous pipe and apparatus to get the necessary column. It was then suggested that if an instrun~ent could be devised which would make use of the hydrant pressure in the service-pipe, it would do away with the objectionable features of the Bunsen pump. After using the Bunsen pump for some years, the jet pump to be described in this paper was devised, and it has since been adopted by Prof, Wing in the quantitative laboratory of the school. I am much indebted to Prof. Wing for his aid in starting the manufacture in brass of these jet pumps, whieh are now to be had in Boston. The jet pump much resembles the Giffard injector in form. It, differs from it in the fact that water is the impelling fluid, and air the impelled, while with the injector steam is used to impel water. The principle of condensation of steam, which is availed of in the injector, is entirely wanting in the jet pomp. The jet pump consists in a water jet, w, (see figure), a constriction or waist, a, and a waste tube, o. The success of the jet pump depends on the follow ing conditions: 1. The relation between the sizes of sectional area of a and w. ' 2. The proximity of n and w. 3. The form and angle of the two hollow cones whose vertices make the constriction a. 4. The relative size of sectional area of w and o. 5. The zigzags, or an equivalent means of making foam. In the following discussion, let a, w, and o repre sent the diameters of these parts of the jet pump. A number of experiments were' .tried to ascertain

Jan 1, 1879

By Robert H. Richards

(Read at the Amenia Meeting, October, 1877.) DURING the winter of 1868-9, I was called upon by Professor F. H. Storer, to put up the Bunsen filter pump in the chemical laboratory of the Masschusetts Institute of Technology. As the laboratory is on the lower floor, it was found necessary to use a great deal of cumbrous pipe and apparatus to get the necessary column. It was then suggested that if an instrument could be devised which would make use of the hydrant pressure in the service-pipe, it would do away with the objectionable features of the Bunsen pump. After using the Bunsen pump for some years, the jet pump to be described in this paper was devised, and it has since been adopted by Prof. Wing in the quantitative laboratory of the school. I am much indebted to Prof. Wing for his aid in starting the manufacture in brass of these jet pumps, which are now to be had in Boston. The jet pump much resembles the Giffard injector in form. It differs from it in the fact that water is the impelling fluid, and air the impelled, while with the injector steam is used to impel water. The principle of condensation of steam, which is Water availed of in the injector, is entirely wanting in the jet pump. The jet pump consists in a water jet, w, (see figure), a constriction or waist, a, and a waste tube, o. The success of the jet pump depends on the following conditions 1. The relation between the sizes of sectional area of a and w. 2. The proximity of a and w. 3. The form and angle of the two hollow cones whose vertices make the constriction a. 4. The relative size of sectional area of w and o. 5. The zigzags, or an equivalent means of making foam. In the following discussion, let a, w, and o represent the diameters of these parts of the jet pump. A number of experiments were tried to ascertain

Jan 1, 1878

Book Review MANAGEMENT AND MEN. By Meyer Bloomfield, Boston. The Century Co., New York, 1919, pp. 584, H.X. 5 1/2. $3.50. This hook is an exposition of English efforts to solve the problem of labor unrest in England. The first six chapters are reprinted from articles published in the Satur-day Evening Post, for whom the author went to England to study the problem at first hand. These articles deal with housing, increased production, eliminating the internal friction in the industrial machine and a chapter each devoted to the view-point of employer and employee. These chapters are written in the easily readable magazine style and give a complete general survey of the particular solution being tried. Perhaps their greatest., certainly not their least, worth lies in the fact that they form a vehicle for unusually voluminous appendices containing in full the famous Whitley Reports which are the basis of the new movement, together with various reports, which, except for this publication, would be largely inaccessible to those inter-ested in this country. The Whitley scheme considers each industry a unit and proposes to establish therein a Joint Standing Industrial Council composed of representatives of employers and employees to consider appropriate matters affecting the industry at large. There is to be a District Council for each industry which will, as its name implies, deal with the clatters pertaining to that interest in. the particular district. The third and last body in this scheme of Industrial Parliament is the Works Committee, which is com-posed of representatives of the management and of the workers employed in particu-lar plants or mines to act in close cooperation With the district quid national machinery. The Whitley or similar schemes have been tried in many communities in England and the book contains interesting comments on the result obtained, it being notable that most of the objections conic from plants which have not tried the scheme. Meyer Bloomfield, the author; is the specialist in industrial personnel problems who organized the industrial service activities of the United States Shipping Board, Emergency Fleet Corporation. P. E. B.

Jan 10, 1919

By William Kent

THE dynamometer herein described is a modification of the one invented by Mr. Samuel Batchelder, of Boston, nearly forty years ago, a description of which may be found in the Journal of the Franklin Institute, 1843, vol. xxxii,.p. 277, and in the Scientific American of August 31st, 1878. The modification consists in providing a method of making an automatic record, and of indicating more minute variations of the power transmitted. The improved dynamometer was designed by the writer in 1877, and was built a few months since by the Class of 1879 of the Stevens Institute of Technology. The accompanying cut, taken from the Annual Announcement of the Stevens Institute, represents the dynamometer without the recording attachment. It consists, as shown, of two stout cast-iron frames, held together by bolts in bearings, in the top of which frames run two shafts, each carrying a pulley at its outer end and a bevel gear-wheel of 45' at its inner end. One of these shafts is the driving-shaft, connected by belt to the engine or other prime mover; the other is the driven shaft, connected by belt to the machine driven. The power is transmitted from one shaft to the other through two other bevel-wheels of 45' gearing with the first, the shaft common to them and on which they run freely being at right angles to the axis of the two shafts first mentioned, and carrying at one extremity a heavy pendulum. The bevel-wheels being connected, as shown, and the power being applied to the driving-wheel, the two intermediate wheels with their common shaft have a tendency to revolve around the driving-axis, which tendency is a measure of the force transmitted, and is resisted by the moment of the weight of the pendulum. In the Batchelder dynamometer the four bevel-wheels and their shafts are used, but

Jan 1, 1880

By William Bent

THE dynamometer herein described is a modification of the one invented by Mr. Samuel Batchelder, of Boston, nearly forty years ago, a description of which may be found in the Journal of the Franklin Institute, 1843, vol. xxxii, p. 277, and in the Scientific American of August 31st, 1878. The modification consists in providing a method of making an automatic record, and of indicating more minute variations of the power transmitted. The improved dynamometer was designed by the writer in 1877, and was built a few months since by the Class of 1879 of the Stevens Institute of Technology. The accompanying cut, taken from the Annual Announcement of the Stevens Institute, represents the dynamometer without the recording attachment. It consists, as shown, of two stout cast-iron frames, held together by bolts in bearings, in the top of which frames run two shafts, each carrying a pulley at its outer end and a bevel gear-wheel of 45° at its inner end. One of these shafts is the driving-shaft, connected by belt to the engine or other prime mover; the other is the driven shaft, connected by belt to the machine driven. The power is transmitted from one shaft to the other through two other bevel-wheels of 45° gearing with the first, the shaft common to them and on which they run freely being at right angles to the axis of the two shafts first mentioned, and carrying at one extremity a heavy pendulum. The bevel-wheels being connected, as shown, and the power being applied to the driving-wheel, the two intermediate wheels with their common shaft have a tendency to revolve around the driving-axis, which tendency is a measure of the force transmitted, and is resisted by the moment of the weight of the pendulum. In the Batchelder dynamometer the four bevel-wheels and their shafts are used, but

Jan 1, 1880

Discussion of the paper of DAVID COLE, presented at the New York meeting, February, 1915, and printed in Bulletin No. 9S, February, 191.5, pp. 431 to 444. R. H. RICHARDS, Boston, Mass.-The Butchart riffle seems to violate, according to our preconceived notions, some of the very essential principles of the Wilfley riffle, and therefore ought not to succeed, but it does. On this account it must conform to other very important principles, or it would not succeed. It would beinteresting to know what these principles are which enable it to succeed. E. P. MATHEWSON, Butte, Mont.-I cannot, explain the principles on which this riffle acts, because I have not given it personal attention. All I can say is that I first saw the riffle in operation several years ago at the Steptoe Valley mill in Nevada, and I was told that a man had been around there guaranteeing that these riffles would make the table do twice as much work and do it better than with the ordinary Wilfley riffles. I heard nothing further about it for a long time. I heard about a year ago, from David Cole, the author of this paper, that the riffles were a success, and that he was using them at Morenci, and if, we were interested he would send the inventor to show us how they worked. As we knew of David Cole's reputation, we invited Mr. Butchart to come up and show us how his riffles worked. We did not have sufficient confidence in the invention to guarantee Mr. Butchart his traveling expenses, but lie came up entirely at his own expense and put in a set of the riffles on one table. It was known as a roughing table in our No.

Jan 5, 1915

By C. W. Andrews

The various methods of by-product coke-manufacture have been quite thoroughly discussed in a number of papers recently published, and I think it would possibly be of interest and value to discuss the growth and probable future of the byproduct coke industry, rather than details of manufacture. The first by-product coke-plant in the United States, consisting of 12 ovens, was put in operation at Syracuse in January, 1893. This installation was followed by one at Johnstown, Pa., in 1895; one at Dunbar, in 1896, and one at Glassport, in 1897. The plant at Syracuse was primarily intended to supply the owners with ammonia for their alkali-works. At Glassport, for the first time, gas was sold for illuminating purposes, although it was mixed with water-gas to make it marketable. The New England Coke & Gas Co. started the plant in Boston in 1899, which was destined to change the whole trend of the establishment of by-product plants, since it manufactured for the first time illuminating-gas suitable for sale without enrichment. This was accomplished by dividing the gas on the battery into two portions. One portion, consisting of the richer part of the gas, was saved for sale, while the remaining, or leaner, portion was used in the battery. This idea was originated by Dr. Schniewind, of the United Coke & Gas Co. The coke was used for domestic, industrial, and locomotive fuel, as its sulphur-content was too high to make it suitable for use in the foundry. The successful operation of this plant led to the building of additional plants at points where the production of illuminating-gas could be sold to advantage and where there was a fair market for the coke-output. The following list of illuminating-gas plants in order of construction will give a good idea of the rapid growth of this method of combined gas- and coke-manufacture: Hamilton, Ohio; Detroit, Mich.; Camden, N. J.; Baltimore, Md.; Chester, Pa.; Milwaukee, Wis.; Duluth, Minn.; Geneva, N. Y.; Chicago, Ill.; Indianapolis, Ind. In addition to these there are now under construction plants at Muncie, Ind.; Joliet, Ill., and Waukegan, Ill., all of which will produce illuminating-gas and metallurgical coke.

Jan 1, 1913

By Earl S. Bardwell

In his paper entitled, Development of Hindered-Settling Apparatus, Dr. Richards has related the history of the development of the hin-dered-settling classifier and given illustrations of the several types of this apparatus which he has designed.' An earlier paper,2 Close Sizing Before Jigging, shows the nature of the hindered-settling phenomenon and the results which it produces. In the first-mentioned paper Dr. Richards describes the method of getting hindered settling and shows the relation that the constriction bears to the classifier. The question of proper ratios between the area of the sorting column and the area of the constriction opening Dr. Richards leaves open, aside from certain statements as to the ratios which have been found to give good results in practice. While working with a hindered-settling classifier of the type now in use at the Boston & Montana Reduction Plant of the Anaconda Copper Mining Co. a number of interesting facts were brought out which have thrown considerable light on the question of proper ratio between the area of the sorting column and the area of the constriction and which will be made the subject of this paper. Free and Hindered Settling.—If a mineral particle be dropped into a vessel containing still water, the particle will sink in accordance with the laws of free settling in water, which are as follows: 1. Of two grains having the same specific gravity but differing in size, the larger will settle in still water at the greater velocity. 2. Of two grains having the same size but differing in specific gravity, the heavier grain will settle at the greater velocity. From these laws it becomes evident that the velocity of settling depends primarily on the specific gravity and the size of the mineral grain. The fracture of the mineral may exert a very considerable

Jan 1, 1914

By M A. Knackstedt

Coupling between deformation processes and rock permeability is a major factor influencing the architecture of fluid migration and the localisation of ore deposition in several types of hydrothermal ore systems in middle to upper crustal regimes. Permeability in many hydrothermal systems is controlled by a dynamic competition between deformation-induced porosity-creation processes and porosity-destruction processes. Localisation of deformation within faults, fractures and shear zones leads to flow localisation, with large-scale flow systems forming when active faults and shear zones link to create percolation networks. Numerical modelling techniques are used to explore the growth of fracture networks and evolution of network connectivity during progressive deformation. Initial results indicate that networks reach a percolation threshold at very low strains. Near the percolation threshold, flow is localised along a small proportion of the total fracture population and favours localised ore deposition. At higher strains, flow is distributed more widely throughout the fracture population and may provide reduced potential for production of high-grade deposits. The distribution of mesothermal gold deposits along a small subset of the total population of co-active faults and shear zones in the Archaean Yilgarn Craton in Western Australia indicates that some hydrothermal systems maintain themselves near the percolation threshold for a substantial part of the lifetime of the system. Fluid-driven growth of fault/fracture/shear networks may lead them to self-organise near the percolation threshold.

Jan 1, 1999

By R Hall

Subduction zone magmatism is a direct response to tectonic and chemical processes operating at convergent margins. Changes in the tectonic configuration of plate boundaries in SE Asia during the Cenozoic had consequences for the nature and volume of magma produced. Retreat or advance of the trench hinge has probably been an important process in controlling the presence or absence of magmatism in SE Asian subduction zones. This process also provides a means of replenishing the mantle wedge and counteracting the effects of melt extraction in depleting the wedge. Changes in the nature of recycled material and lithologies of the over-riding plate also have the potential to influence the lavas that are erupted in arcs. Several locations in SE Asia have experienced magmatism bearing the geochemical signature of subduction but are remote from coeval subduction zones. Such magmatism requires an earlier period of mantle enrichment by subduction but may result from localised extension. The distribution of such magmatism may provide information of tectonic value. Some adakitic magmatism occurred in tectonic settings where there is no evidence for subduction of young oceanic crust at the time of magma genesis. Slab melting in such settings is not possible and alternative mechanisms are required to explain the occurrence of, at least some, adakitic lavas.

Jan 1, 1999

(Members are urged to send in for this column any notes of interest concerning themselves or their fellow-members.) Members and guests who registered at Institute headquarters during the period May 10 to June 10: Rene de Sallier, New York, N. Y. Karl Koelle, San Luis Potosi, Mexico. H. S. Chamberlain, Chattanooga, Tenn. W. A. Wilson, Salt Lake City, Utah. F. R. Pretyman, Oyster Bay, N. Y. P. E. Barbour, Candor, N. C. R. Eustice, South Australia. R. C. Blanchard, London, England. F. C. Darby, South Australia. S. K. Tong, Shanghai, China. Grant H. Tod, Livermore, Cal. W. T. Burns, Great Falls, Mont. J. Murray Clark, Toronto, Canada. F. W. Bacorn, Butte, Mont. J. H. Adams, Birmingham, Ala. H. B. Pulsifer, Chicago, 111. A. Faison Dixon, Encontrador, Venezuela. Dwight E. Woodbridge, Duluth, Minn. C. W. Merrill, San Francisco, Cal. Heinrich Ries, Ithaca, N. Y. Francis Church Lincoln, Boston, Mass. H. L. Slosson, San Francisco, Cal. Frank R. Corwin has severed his connection with the Arizona Copper Co., Clifton, Ariz., and is now shift superintendent at the smelting plant of the Copper Queen Consolidated Mining Co.. Douglas. Ariz.

Jan 7, 1914

By S. F. Emmons

By far the greater number of the members of this Institute are men who are engaged in the strenuous work of the technical part of their profession, and find little time for the abstract scientific work which is less distinctly practical and pecuniarily remunerative. There is, however, a small but increasingly nu, merous class whose members devote themselves to broad geological problems which underlie the systematic development, and whose work, theoretically, ought to precede and form a basis for that of their more practical brethren. These are the so-called mining or economic geologists, who are, for the most part, connected with State or National geological surveys. Prom the character of their work, the life of these men necessarily follows rather different lines from that of most of their colleagues, and is not generally familiar to them. It seems admissible, therefore, that to the life of a prominent member of this class, who died during the past year, having literally sac-rified his life to his work, a more extended notice should be given than the relatively small number of his contributions to the Transactions night seem to justify. George Homans Eldridge, son of Ellery and Sarah (Mathews) Eldridge, was born on Cape Cod at Yarmouth, Mass.; Christmas day, 1854. His boyhood education in the public school at Yarmouth was followed by a six years' course in the Public Latin School at Boston, from which he entered Harvard University in 1872, being graduated with the highest rank in his class in the natural sciences in 1876. During his college course he spent the summers of 1875-6 at Cumberland Gap, Ky.,as volunteer aid to Prof. N. S. Shaler, who was then in charge of the State Geological Survey of Kentucky. This vacation work, undertaken by him rather as a pastime, gave him his first leaning toward geology. Soon

Jan 1, 1907

By J L. Mauk

Gladstone Hill, a volcanic-hosted low-sulfidation epithermal prospect in the Coromandel Peninsula, is less than 1 km from the world-class Martha Hill Au-Ag deposit. Gold-silver-bearing quartz veins occur in Late Miocene andesitic volcanic rocks of the Waipupu Formation that are extensively altered. The occurrence, spatial distribution and temporal relationships of hydrothermal minerals have been determined along two cross sections that transect the Amaranth, Gladstone, Cowshed and Moonlight veins. Quartz and pyrite are ubiquitous along these sections. Adularia and chlorite are widespread, but both are scarce in wall rocks adjacent to the Moonlight and Cowshed veins. By contrast, rare hydrothermal albite and epidote are restricted to wall rocks surrounding the Amaranth vein. Illite, which replaces adularia, is widespread and grades laterally eastwards into a zone of interstratified illite-smectite that envelops the Moonlight and Cowshed veins. During late-stage hydrothermal activity, rare calcite formed at depth and uncommon kaolinite and alunite formed at shallow levels. The overall clay mineral zonation with illite grading eastward into interstratified illite-smectite reflects paleothermal gradients of >220¦C to -170¦C towards the margin. The alteration assemblage of quartz, adularia, chlorite, albite, epidote, illite, interstratified illite-smectite and pyrite reflects formation from a near-neutral to weakly alkaline pH chloride water that contained low concentrations of CO2, Late calcite formed from very local descending steam-heated CO2rich water, whereas the rare assemblage of kaolinite and alunite formed from shallow steam-heated acid-sulfate water. Analysis of the available data indicates that the Martha Hill deposit and the Gladstone Hill area formed within a single large geothermal system. We infer that the Martha Hill deposit formed in the main upflow zone, whereas the Gladstone Hill area may have formed adjacent to this upflow zone.

Jan 1, 2001