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By Donald C. Barton

The theory of gravitation is based on Newton's law that any two bodies exert a mutual attraction which is proportional to the product of their masses and inversely proportional to the square of the distance between them; i. e., A = KMRm2 (1) where K is a constant, M and m are the respective masses of the two bodies, and R the distance between them. In the earth's gravitational system, the earth is one of the bodies; the other may be any body within or without the earth. In theoretical discussions and calculations,in regard to gravity, that other body usually is taken as a unit of mass: in the C:. C:. S. system, a body of one gram in mass. Gravity and Level Surfaces Gravity is defined in geophysics as the force of attraction exerted by the earth, towards itself, on a body of unit mass. The intensity of gravity is usually expressed in dynes of force or in centimeters of acceleration In geophysical work in America, most commonly it is expressed in dynes (per gram) with the "per gram" understood and not directly expressed. In geophysical work in Europe, most commonly it is expressed in centimeters per second per second (cm. /sec.2) and less commonly lrierely as centimeter-gram-second units (c. g. s). At sea level, the intensity of gravity amounts very nearly to 980 dynes. The vertical is the direction along which the attraction of gravity is exerted at any point. In most cases, it is very nearly, but not quite, perpendicular to the earth's surface. The path that would be taken by a body falling freely through space toward the earth is vertical at each point and may be spoken of also as ('the vertical," or as the line of the vertical, or as a line of force of gravity. At the earth's surface it comrrlonly is very nearly, but not quite, a straight line.

Jan 1, 1929

By Fred W. Gordon

The North Chicago Rolling-Mill Co., of Chicago, have four furnaces at South Chicago, built during 1881. Each furnace is 20 feet diameter of bosh, and 75 feet total height, the hearth being 11 feet diameter, and the top 15 feet 4 inches. They are blown through seven 7-inch tuyeres placed 5 feet 6 inches above the hearth level. Cubical contents, 15,000 cubic feet. Each furnace is supplied with 2 blowing engines, 84-inch blowing cylinder, and 36-inch steam cylinder, and 54-inch stroke. These two have one jet-condenser worked by an auxiliary pump. The blast for each furnace is heated by the aid of three Whitwell fire-brick stoves, each 21 feet diameter and 60 feet high. In the batteries of boilers furnishing steam for four furnaces there are 36 double-length boilers, 76 feet long, 48 inches diameter and 16,000 square feet heating-surface. The plant was designed to produce 3600 tons per week, or 900 tons for each furnace, and was fitted as above with such engines, boilers, and hot-blast stoves as were thought requisite for that production ; hence, calculated from the present make—not the least remarkable feature is the economy of construction—there are less engines, less boilers, and less hot-blast power for the iron made than at ally plant within my knowledge, or it could to-day be duplicated for less money per ton of iron made per week than could any plant now in existence, whether using fire-brick or cast-iron stoves for heating the blast. This is a practical demonstration of my assertion in a paper on fire-brick stoves, read before the Institute," that the application of fire-brick stoves in construction really lessens the first cost. In view of the statements just made, I must be most emphatic in assuring the members that nothing is strained or overburdened.

Jan 1, 1886

By R. W. Kraft

A comprehensive analysis of the crystallographic and metallographic structure of several Al-CuAl, lamellar eutectic grains solidified under equilibrium conditions has been performed. A consistent pattern was discovered which was interpreted in terms of a detailed atomistic model of an interface describable as: Interface II {111} AL 11 {211} <101>Al <120> ? Several arguments are presented to substantiate the theory. It is compared in detail with another interface model characteristic of the Wid-manstatten precipitate of CuAl2 in A1 at low Cu levels. In addition, a concept is proposed to help explain the structure of the compound CuAl2. It has been shown that the eutectic alloy between A1 and CuA1, can be forced to solidify as substantially parallel lamellae throughout a relatively large volume&apos; by appropriately controlling the solidification parameters of growth rate, thermal gradients, and impurity level and by causing solidification to proceed in a unidirectional fashion from one end of an ingot to the other. A typical ingot solidified in this manner shows three distinct zones along the length of the ingot, Fig. 1. At the head end is a region consisting of many different grains, some of which are elongated slightly in the direction of solidification. After a few centimeters of growth, this polygrained region gradually merges into the second zone which consists of a very few elongated coarse grains. The third zone at the tail end is a region of eutectic colonies caused by segregation of impurities. Microscopic examination of transverse and longitudinal sections of the ingots reveals that during the initial stages of growth (zone I) the lamellar structure is frequently highly distorted and twisted but that it straightens out in zone 11. This characteristic pattern suggests that nucleation of a eutectic grain begins randomly at the head end of the ingot, and that some particular orientation relationship between the phases is more favorable from an energy consideration than others for one reason or another, so that some grains grow and others which are less favorably oriented do not. The favorably oriented or "low energy" grains continue to grow until excess solute rejected at the advancing liquid-solid interface destroys the parallel lamellar structure by forming a cellular rather than a substantially planar interface. When this occurs, the parallel lamellae fan out and eutectic colonies are formed because the lamellae grow perpendicular to the local interface. Questions naturally arise as to the crystallographic nature of the "low energy" grains. What do the grains which persist into zone II have in common? Can this explain the stability of such grains during growth? To answer the first question it is necessary to determine the crystallographic orientation of the lamellae of each phase relative to one another. This has been done for Al-CuAl2 eutectic alloys by two different techniques on specimens prepared in different ways.2&apos;3 The results were different from each other and from a third orientation relationship between A1 and CuA1, reported for overaged A1-Cu alloys.4 The three orientation relationships are summarized below to illustrate their similarities and their differences. (001) ? 11 (001) A1; [l00] ? 11 [l00] Al Eutectic, Ref. 2 (001) 8 1) (001) A1; [1001 ?11 [1101 A1 Eutectic, Ref. 3 (001) ? 11 (001) A1; [l00] ? 11 [310] Al; Widmanstfitten, Ref. 4 It is not surprising that different orientation relationships were found by Ellwood and Bagley,&apos; and Takahashi3 since the solidification conditions were quite different. Nor is it surprising that Mehl, Barrett, and Rhines 4 found still another value since they were studying another type of alloy. Nevertheless, it would be expected that some logical and systematic pattern could be found if all the alloys were at equilibrium since the same two phases are

Jan 1, 1962

By W. A. Backofen, G. Y. Chin, W. F. Hosford

The effect of machine stiffness on discontinuous flow and fracture of the 2024 aluminum alloy was studied in tension at 4.2OK. An increase of machine stiffness was found to decrease the amount of elongation and drop in load during discontinuous flow, thereby postponing fracture to larger strains and higher stresses. The possibility of utilizing stiffened tools in deformation processing to suppress shear fracture originating from unstable flow was indicated. The problem of nucleating discontinuous flow and the role of the effective mass of the system in discontinuous flow were also considered. AT low temperatures the plastic flow of metals is often discontinuous, with sudden load drops and elongations.1,3 Basinski1,4 has presented strong evidence that discontinuous flow, at least in aluminum alloys, occurs under nearly adiabatic conditions. During testing the load may drop suddenly and flow become localized when the thermal softening, due to heat generated in plastic straining, is greater than the strain and strain-rate hardening. This instability criterion is more easily satisfied at low temperatures because 1) the volume specific heat is reduced so that relatively large temperature increases are possible in straining, and 2) the flow stress is relatively temperature-dependent. The important role of adiabatic shear in ductile fracture processes has been emphasized,5-1 and consideration has already been given to the influences of thermal and mechanical properties on the tendency of a material to undergo adiabatic shear.17677 By focusing attention on how the mechanical loading system influences low-temperature discontinuous flow, additional insight into adiabatic shear and its effect on fracture may be gained. EXPERIMENTAL PROCEDURE Because of its low thermal conductivity, the 2024 aluminum alloy exhibits a highly consistent discon- tinuous-flow behavior at 4.2°K and was therefore chosen as the material for study. Machined specimens of 0.113 in. diam and 1.125 in. gage length were solution heat-treated at 490°C for 3 hr, quenched into cold water, and immediately immersed in liquid nitrogen until just before testing. Testing was done at 4.2°K by immersion in liquid helium at a crosshead drive rate of 0.03 in. per min. As normally used (hard-machine basis), the spring constant of the testing machine was k = 25,000 lb per in. By inserting beam springs in series with the specimen, this value could be lowered by a factor of about 100. Details can be found elsewhere.? As a result of variable machine stiffness, the actual strain rate ranged from about 3 x 10 5 to 3 x 10-4 per sec from one test to another, as well as within any one test. However, preliminary tests had established that the tensile curves were not altered significantly by this strain-rate variation. Fig. 1 shows a typical load vs plastic-elongation curve for a solution heat-treated 2024 aluminum alloy specimen pulled in the standard hard machine (k = 25,000 lb per in.) at 4.2"K. The elastic extension has been subtracted. Plastic flow proceeded smoothly from yielding at approximately 22,000 psi (load = 220 lb) to a strain of about 4 pct at which point the flow became discontinuous. The magnitude of the load drops as well as the plastic elongation per drop increased with increasing strain until the specimen finally broke abruptly. The load-elongation behavior of a sample tested with a relatively soft machine under otherwise identical conditions is given in Fig. 2. In general, there

Jan 1, 1964

By L. M. Johnson, C. G. Janes

INTRODUCTION In May, 1966, the General Services Administration (GSA) announced a program to encourage additional domestic production of copper in the interest of national security. Upon learning of the copper production expansion program, Duval Corporation entered into negotiations with GSA for development of the Sierrita copper-molybdenum property under the program. Agreements between the GSA and Duval Sierrita Corporation, a wholly owned subsidiary of Duval Corporation, were concluded in 1967, with the Sierrita Concentrator beginning operation in 1970 at a designed capacity of 72,000 STPD. Subsequent additions and modifications have expanded capacity to 90,000 STPD. This property, located approximately 20 miles south of Tucson, Arizona, represents an investment including working capital of about $200 million. These funds were provided from an $83 million loan from GSA, repayable in copper valued at 38 cents per pound, $48.75 million of bank loans subject to U. S. Government V-loan guarantees, and Company capital contributions. Current general operating statistics for the concentrator are listed below: [Ore Grade 0.32% Cu., 0.030"/. Mo. Daily Tons Milled 90,000 STPD Annual Copper Product ion 94,600 Tons Annual Molybdenum Production 15,000,000 Lbs. Annual Silver Production 1,135,000 Ounces]

Jan 1, 1976

F. G. SMITH, Waterbury, Conn.-I would like to ask whether small amounts of iron give the maximum resistance at a low temperature, and if the large amounts of iron raise the temperature at which the maximum resistance occurs? That is, with a small amount of iron, will a maximum be at, say, 10°? F. E. BASH.-With the small amount of iron, the maximum is at a lower temperature, and with the increase of iron, the maximum increases; it seems to come to a maximum and then decrease; that is, increasing the iron up to a certain value increases the temperature at which there is a maximum of resistance, and any increase of iron beyond that value will start decreasing this temperature. With 2 per cent. of iron, the maximum is lower than for 1.5 per cent. which was the value that we found to be satisfactory. F. L. DRIVER,* Jr., Harrison, N. J.-I would like to ask what chance there is of the instrument companies getting together and deciding on standards for both manganin and constantan? We make both of these alloys in this country and we find that each one of the instrument com-panies who buy these materials require different standards of specific electrical resistance and thermal e.m.f. For instance, some of our cus-tomers require an electrical resistance in manganin or therlo of 240 ohms per circular mil foot and others require it with a specific electrical resist-ance of 270 ohms per circular mil foot. They buy these alloys in relatively small quantities so that it means much extra melting and supervision when making up small quantities for each consumer. If something could be. clone to eliminate this, it would be a benefit to the instrument com-panies, who could secure their material more cheaply, and to the manu-facturers, who would not have to spend so much time and effort in special manufacturing.

Jan 12, 1919

By A. E. Beasley, Ike McKinney

Scale is a broad term which includes many types of mineral deposits which have limited solubility in water. These mineral components precipitate when combinations of scale-forming cations and anions exceed their solubility. Scale deposits are tightly bound to each other and to the metal surfaces of a water system. Precipitates that do not readily adhere to each other or to metal surfaces are known as sludges. Sludges are easily removed from a system by flushing. For example, a sludge is formed in the internal treatment of boiler waters with orthophosphates where the calcium is purposely precipitated as hydroxyapatite. Calcium phosphate would have a tendency to adhere to the boiler tubes except for the addition of tannins or lignins. These sludge conditioners maintain the precipitated calcium phosphate as a sludge which can be readily removed by boiler blowdown.

Jan 3, 1973

By M. Metzger, T. A. Read

The strengthening effects of hydroxide and synthetic plastic films in the creep of cadmium crystals were studied. The results were broadly consistent with the naive mechanical model. The dislocation-film reactions and the significance of the macroscopic stresses associated with certain films are discussed in the paper. ALTHOUGH a number of studies have been made of the strengthening of metal single crystals produced by surface films usually less than Ir in thickness, the mechanisms underlying this phenomenon are still not well established. Roscoe&apos; first noted the critical shear stress and the stress-strain curve of cadmium-crystal wires to be raised markedly by the presence of oxide films. Subsequent investigators2-&apos; have confirmed the effect for several metals and films including a number of plated poly-crystalline metal films. Harper and Cottrel1" with a thin film on zinc presumed to have formed as a result of etching and washing treatments) did not detect a strengthening at a rate of extension of 10 &apos; sec-&apos; although at lo-&apos; sec-&apos; the film raised the flow stress by 7 pct at 0.0005 extension and by 22 pct at 0.01. The marked strengthening at moderate strains thus appeared to be the result of a dynamical effect dependent on the rate and amount of plastic flow. Other observations&apos;. " are consistent with this view. The large effects of films on the tensile creep rate of single crystals were demonstrated when the observation of Andrade and Randall," that the creep rate of cadmium crystals increased on immersion in aaueous solutions of certain cadmium salts. was shown&apos; * to hold only when a film was present initially and was explained by the attack of the solution on the film and the removal of its strengthening effect. Changes in the creep rate interpretable in terms of the removal or formation of various films have been observed by other investigators.3,8,10,31 Certain other experiments have been reported in which surface films or liquid environments have affected the plastic behavior of metals, but these are not within the scope of the present work which deals with the effect of solid films on single-crystal slip. Possible Mechanisms—The film does not significantly reduce the load on the crystal in the elastic range (the elastic moduli of film and crystal are not too greatly different and the area of the film is so small that its share of the load is negligible) so that the initial operation of internal Frank-Read sources is not affected. However, as Fisher" has pointed out, a source terminating on the crystal surface requires only half the critical stress for activation as an internal source of the same length and a relatively strong film (even a very thin one) would pin the free ends of the surface sources so that, if surface sources are responsible for plastic flow in a clean crystal. such a film would increase by roughly a factor of 2 the stress necessary for generation of dislocation loops at a given rate. The other general possibility is that the film resists the passage to the crystal surface of internally generated dislocations. If the film is adherent and if the specimen is to exhibit slip of the same general character as a film-free specimen, the film must deform or fail in shear at the active slip planes. The naive mechanical model, where shear-stress relaxation across the active slip plane in the metal transfers load to the film until it deforms and slip can

Jan 1, 1959

By W. L. Dennen, V. H. Wilson

THIS paper is a description of the opera¬tion and results of a Humphreys Spiral Silt Cleaning Plant at the Powderly Colliery of The Hudson Coal Co. during the first nine months of operation and follows a pre¬liminary description given at the Anthracite Institute in May, 1947, in a paper titled "Preparation of Anthracite Sift for Boiler Fuel in a Humphreys Spiral Test Plant" by H. H. Otto, V. H. Wilson and W. L. Dennen. This plant is considered a full size operating test plant and, like all new plants, numerous minor changes in the methods of operation have been made from time to time to secure the results desired. Views of the silt preparation plant and of the screening house are given in Fig 1 and 2. This plant consists of 48 spirals in 8 batteries of 6 spirals each, 36 of which were to be operated as primary spirals and the remaining 12 as secondary spirals. A brief description of the plant and its operation follows. The only material cleaned at the plant during 1947 was that carried in the underflow from the Thickener which handles the Breaker waste water. This underflow, amounting to approximately 2000 gpm of water and containing 12.6 pct of solids, is pumped .to vibrating screens where the plus 316-in. material is removed. (Fig 3). This oversize material drops into a pocket from which it is trucked to the run-of-mine

Jan 1, 1948

By J. J. K. Daemen, C. Fairhurst

Introduction The stress field around a supported tunnel can be considered as being composed of: i) the virgin (pre-mining) stress in the rock ii) the (elastic) change in this stress field caused by creating the opening iii) the (time-dependent ) change in the stress field produced by (i) and (ii) as a section of the rock breaks up iv) the (time-dependent) influence of the stress build-up in the support. Several authors have examined the conditions necessary to produce static equilibrium between the support, the rock, and the regional (in-situ) stress field. The analysis used by Labasse (1) is typical. Consider a circular tunnel radius R in a hydrostatic stress field (P), and a radial pressure pi exerted by the support. According to Labasse, the radius ‘b’ to which the rock will break* for a given support pressure, pi, can be calculated from: - the equilibrium equation: [ ] As a zone of broken rock develops around the opening, the stress circle for a point on the elastic-broken rock boundary moves to the right in the Mohr diagram until the radial stress in the broken zone s equal to the radial stress in the elastic zone.

Jan 1, 1971

A1 in carbon steel, equilibrium temperature, XLVII, 740-747. A2 and A3 in pure iron, critical ranges, XLVII, 665-739. Abbott, Ai Arthur: [biog. notice, Bulletin No. 27, Mar., 1909, xxvii]; death, XXXIX, . [xl]. Abbott, Arthur Vaughan: [biog. notice, Bulletin No. 16, July, 1907, 6581; death, XXXVII, [xxxix]. [ ]

Jan 1, 1918

By T. E. Eagan, W. R. McCrackin

IN dealing with segregation in babbitt, and its effect on the final cast structure, which is a bearing, it is obviously impossible to cover all of the compositions manufactured. Each composition, of course, will exhibit certain specific types of segregation. However, as examples,, two compositions of babbitt are presented: one a tin-base of well-known analysis and the other a lead-base, which in the past few years has found wide usage. Bearings usually are cast either statically or centrifugally; therefore the effect of these two methods on segregation is presented. EXPERIMENTAL PROCEDURE A slab of babbitt 1/2 in. thick by 5 in. wide and 17 in. long was cast, using a book mold with the long edge vertical. An A.S.T.M. grade 2 babbitt was used (3.5 per cent copper, 7.5 per cent antimony, remainder tin), to which 0.10 per cent tellurium had been added. Unfortunately, no metal without tellurium was available. The mold to hold the babbitt was heated to approximately 300°F., the temperature being judged by the babbitter. The pouring temperature of the babbitt was 875°F. (470°C.). One slab was made by allowing the babbitt to cool without stirring. The other slab was stirred during the entire cooling cycle. This stirring consisted of a vigorous churning or puddling into the mold until complete solidification had taken place. Three samples were removed from these slabs. One was taken at the extreme bottom, another half way to the top, and another at the extreme top, all at the center of the width. Chemical, macroscopic and microscopic examination was made of all samples. Table I shows the chemical analyses obtained at the described positions [ ] in the slab. The analyses show no serious amount of gravity segregation. Microscopic examination from edge to edge of the slab showed little change in structure. From top to bottom there was a progressive coarsening of the grain size in the stirred slab but little change in the slab that was not stirred (Fig. I). No definite exhibit of segregation could be detected. In line with our experimental study on the tin-base babbitts, we cast an almost duplicate slab using A.S.T.M. Alloy No. 15, containing 0.9 to 1.25 per cent tin, 14.75 to 15.5. per cent antimony, 0.80 to 1.25 per cent arsenic and 0.4 per cent copper. The slab was 16 in. long and 3/8 in. thick, cast with the long side vertical. One slab was allowed to cool normally and the other was stirred continually during cooling. The pouring temperature of the babbitt was

Jan 1, 1944

By Keijiro Nishio

At a time of great antiquity when our Yomato tribe had not yet found its way throughout the country, there lived in Japan barbarous tribes of the stone age, whose dwellings were vertical caves covered with roof&apos;s of twigs and weeds. In a cave lately discovered at the village of Morita, 10 miles west from the port of Aomori, there were found pieces of micaceous iron-ore and psilomelane, with oval holes pierced from both sides. Apparently these objects were regarded as ornaments or curios, without being applied to any practical use. Among the traditions given in the Nihonshoki, an ancient history of Japan, there is one relating to the mining industry. According to this tradition, in the mythological age Izanami-no-Mikoto gave birth to Kanayamahiko-no-Mikoto, god of mines, and Amaterasu-Okami (the sun-goddess) was armed with swords. It came to pass at one time that she concealed herself in Ama-no-Iwato ("Heavenly Cave"), and several gods made contrivances to entice her out. Among them, Ishikori-dome, a smith, made a mirror with copper obtained from the Ama-no-Kagoyama, by means of a pair of bellows known as the Ama-no-habuki, which was made of a deer-skin. It is recorded also that Susanb-no-Mikoto, her younger brother, observed the abundance of gold and silver in Korea, where his descendants were to reign, and urged them to provide themselves with boats to convey them across the Sea of Japan. In the course of time he accomplished his object, proceeding to Korea with his son, Isotakeru-no-Mikoto. These accounts

Jan 1, 1913

By R. Sporcic, P. J. Mudra

During the past year personnel of the Roof Control Research Group of the Bureau of Mines designed and developed encapsulated hydraulic cells for measuring pressure changes in coal in situ. Preliminary results from feasibility tests in progress in the laboratory and field indicate that the cells respond favorably to changes in pressures associated with a coal-mining environment. The ultimate objective is to use these cells to obtain engineering information relating to coal bump or coal outburst phenomena. Mining research has experienced a remarkable growth during the past decade and from all indications should surge forward at even a greater pace in the future. This increased interest in mining research has been brought about by the ever-multiplying number of technical problems being encountered by the mining industry in its effort to produce pay-dirt tonnages safely and economically from greater underground and surface pit depths. Among the various divisions in the field of mining research, the study of ground stress has received a large part of the overall attention. Numerous technical papers have been written with regard to ground stress conditions around mine openings and yet the total usable knowledge concerning this subject is extremely limited. Research teams around the world are endeavoring to bridge the gap between theoretical and laboratory approaches and the solution to design problems in the field. The problem of ground stress is not a new one for the coal mining industry. Operators in both eastern and western coal fields of the United States as well as in many foreign countries have long been plagued with a number of ground stress problems, one of which is commonly referred to as the coal-mine bump. This term or phenomenon has been aptly defined by earlier investigators as the violent and sudden failure of coal and adjacent rock. Direct results of such failures have been the loss of human lives and thou- sands upon thousands of dollars of sustained mine damages. In an effort to alleviate the magnitude and frequency of these failures, mine operators have employed and are presently employing various corrective techniques. These include: Inducing failure in heavily stressed areas by augering large-diameter holes into stressed pillars, using extensively yield-able steel arches in both long-term haulage and short-term face entries, backfilling unused or abandoned entries with mine waste to gain additional support, and using systematic pillar coal panel extraction techniques including mechanized longwall mining. The Health and Safety Activity of the Bureau of Mines has for a number of years contributed considerable time, funds, and talent in an effort to define better the ground stress problems associated with coal-mine bumps. As a part of this investigative program, in situ ground pressures are presently being studied in coal mines located in West Virginia and Utah. The description and development of the device being used to measure these pressures is the specific topic of this paper. CHOICE OF INSTRUMENTATION After consideration and evaluation of the various instruments and techniques that are being used by researchers in the field of rock mechanics to detetmine in situ stresses, a simple hydraulic system was selected for detailed investigation. Aside from simplicity, a hydraulic system is relatively inexpensive and also eliminates the need for electricity in its installation and operation. The hydraulic device referred to is, in essence, a simple unidirectional pressure-measuring cell. Hydraulic cells, which had been used for measurement of pressures in hard rock, were investigated but found not entirely suitable for use in coal, particularly since they involved (1) preparation and emplacement of cement grout at the test site, and (2) a waiting period before the cells became operational. At the outset, it was decided that certain design parameters be established. The cell should be simple and inexpensive, constructed of materials readily obtainable and easily built in the laboratory or field by unskilled labor. It was further decided that it was desirable to encapsulate the cell in a suitable mate-

Jan 1, 1963

By KENNETH W. GREENAWALT, William Greenawalt

THE patent system, through which an inventor is given exclusive right to his invention for a limited period as a reward for his industry and in reimbursement of his expenditures, originated in England in the famous "Statute of Monopolies," enacted in 1623. The first patent granted in America was to Samuel Winslow, in Massachusetts, in 1641. The basis of the patent system of the United States is a provision in the Constitution giving Congress the power to secure to inventors for a limited time the exclusive use of their discoveries. The first legislative enactment was the law of 1790, which was placed on the statute book after Washington had addressed Congress in its favor. Under this law, the Secretary of State, the Secretary of War, and the Attorney General constituted the board for the examination of patent applications and the granting of patents. The first Secretary of State, Thomas Jefferson, became the first administrator of the patent sys- tem in this country. He personally examined every application filed during his term of office.

Jan 1, 1930

JOHN W. BELL,* Montreal, Canada (written discussion?).-Mr. Hardinge&apos;s "hammer" theory is, I believe, a sound one; but, unfortunately, at the very place in the Hardinge mill where there should ,be a large number of small "hammers," there is room for only a very few. The results in Mr. Van Winkle&apos;s paper seem to indicate that the practical development of the theory can best be accomplished by stage crushing, using cylindrical mills. It would be very interesting to know if any stage-crushing experiments have been made at Inspiration with Marry mills. Mr: H. Kenyon Burch says:1 "The Marcy mill also proved to be a most excellent intermediate crusher, handling as high as 800 tons of 3-in. feed and under, to pass an 8-mesh screen without return of oversize." It seems reasonable to suppose that a large part of this output would be a finished- product; consequently, if it were possible to send the oversize from two of the primary mills to one secondary mill using balls of small diameter, a considerable saving in power might be realized, provided it were not necessary greatly to enlarge the secondary mill. It does not seem reasonable to suppose that fine material can he crushed as quickly or as efficiently in a primary ball-mill as in a re-crushing mill especially designed for that work. Experimental data, of course, are essential in deciding questions of this kind.

Jan 4, 1918

GOD the Almighty has all things well ordered; in G particular, the effects and attributes of the seven planets whose reign and course (by the grace of God) determine for the most part not only our own life and death but also the growth and decay of vegetable and mineral life, so that the aforesaid planets generate and develop in a wondrous way the ores of gold and other metals in minerals, rocks, and earths. Specifically, the Sun develops the ores of gold, the Moon the ores of silver, Venus the ores of copper, Saturn the ores of lead, Jupiter the ores of tin and bismuth, Mars the ores of steel and iron, and so on. Since, however, no ore is made alone but each is made and wrought so that it is associated with other ores, it is necessary to know the art of separating the thus-made ores after they have become metals; as for instance, silver from lead and copper; gold from silver, and so on. [2]* If this is to be done usefully, you must be able to assay and must understand everything that is needed in connection therewith. It is obviously true and clear as light of day that some kinds of copper contain silver and some kinds of silver contain gold. In order that you may be able to separate them, so that each is obtained by itself and can be worked with profit and re ward you need first of all a true assay for the values of such metal. The assay, by revealing how great they are, whether the pure has been obtained separate from the worthless matter, and what the admixture is, advises you whether it would be worth the expense and the effort to start mining operations. Assaying also indicates how much silver there is in a centner of ore or how much copper and lead there are in

Jan 1, 1949

By Robert McKay

THE practical study of corrosion requires consideration off its economic aspects. It must be based on sound scientific principles, but it should be borne in mind that probably the most important object of a corrosion test is to determine what metal in corrosion-resisting construction will produce the greatest operating profit. Thus the corrosion test must be directly connected with money values or it is not a practical corrosion test. This, perhaps unusual, connection between corrosion and economics is partially due to the fact that corrosion deals only with the time factor or duration of equipment, and it is almost the only test which deals with this feature. In these statements a departure is made from the academic definition of the word corrosion and it is done deliberately. The use of the term corrosion is unusual. It is as though we spoke of a tensile test as. a "breaking" test. We are not interested primarily in the break but in the strength of the metal. There is no English word which expresses our main interest in corrosion-testing, but let us have clearly in mind that we make corrosion tests to prevent corrosion. Our real interest is in this corrosion-prevention, not in the corrosion. Previous to 1922, it was common comment that "it is impossible to determine the course of corrosion by laboratory testing." This statement was true at that time in that the technique of laboratory testing for corrosion resistance was so vague that tests in the laboratory gave untrue results almost as often as true ones. This was so, even in the simple case of determining which one of two metals better resists a given solution. While this is no longer true the number of misleading "corrosion tests" still being ground out by laboratories is too large in the light of our present knowledge. There are two important features of corrosion testing whose neglect is a large contributing factor to misleading results: (1) The economic relations of the corrosion tests to other tests; (2) testing technique.

Jan 1, 1929

During the year 1915 the Committee received 161 manuscripts, which were treated as follows: 3 accepted for. New York Meeting (110th) . 64 accepted for San Francisco Meeting (111th) 49 accepted for New York Meeting (112th) 3 accepted for Arizona Meeting (113th) 29 rejected 4 returned to authors for revision and not yet accepted 9 in committee. 161 Every paper which was presented at the San Francisco Meeting was published in advance in the Bulletin with one exception. The work of the Committee has been systematized and. the Executive Committee of the Committee on Papers and Publications has given prompt attention to all manuscripts, with the result that every paper received by the Committee on Papers and Publications is in the hands of the, printer within 30 days thereafter, unless delays occur owing to questions as to acceptability, in obtaining from the author permission for revision, or other like causes.

Jan 2, 1916

By R. C. Ellman

In the United States, the consumption of lignite and subbituminous coals is increasing. A variety of energy-oriented companies have leased large blocks of reserves, new large power plants are in operation and being constructed, and new producing mines are being developed. The Bureau of Mines has maintained an active interest in the utilization of low-rank coals for many years. In 1951, with the completion of the Bureau&apos;s Grand Forks Coal Research Laboratory, an organizational unit was established for studies in lignite preparation. Since that time, numerous investigations have been completed. This research has dealt almost exclusively with lignite, but since subbituminous coals have many similar characteristics, the findings can often be applied to both types of coal.

Jan 1, 1970