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By H. W. Gillett

Unlike most previous Howe lecturers, I had not the good fortune to be associated with Henry Marion Howe, nor to be directly one of his students. Yet, through his writings, he has been my teacher, as he has of all American metallurgists. Instructive as his writings are—I use the present tense because Howe thought so keenly and reasoned so surely, seeing clearly, as if by intuition, what was hazy to lesser minds, that his writings are still vital—it is not those books and papers, nor even the minds he trained in his classes, that were his most outstanding service. It was the spirit of Howe in his approach to the problems of metallurgy, his broad-mindedness and fairness, his recognition of the need for theories and hypotheses to explain metallurgical phenomena, his willingness to use them as servants, as well as his questioning attitude—his refusal to accept them as masters—that comprise his greatest service. This most thoroughly warrants the honor the Institute pays each year to his memory. These traits I so respect and honor in any man that I glory in this opportunity to do reverence to him in whom they were so notably united. Howe's Discussion of a Creep Problem I have often wished that Howe were still with us to turn his keen insight upon the problems of the use of metals at high temperatures, a field much studied but still very hazy. Indeed, 53 years ago, in a paper1 before this Institute, Howe stated a problem closely allied to some that still perplex metallurgists and engineers dealing with the high-temperature field. Howe was intrigued by a report2 from another old master, Robert Henry Thurston, on the behavior of annealed vs. cold-drawn iron wire, and in order to broaden the foundation for metallurgical generalization, Howe made experiments of his own on copper and silver. In these tests by Thurston and by Howe, the wires were rapidly loaded to determine the

Jan 1, 1939

By L. A. Delano

DURING 1916, the St. Joseph Lead Co. milled 2,505,670 tons of ore. This is a daily operating average of 7855 tons. The economic concentration of such a large tonnage necessarily requires a plant equipped with modern machinery and operated efficiently. The milling process used in producing this output has been a gradual development through the long period of years that the company has been in existence. HISTORICAL SUMMARY OF MILLING PRACTICE Ore was first mined at Bonne Terre, Mo., in 1864. The early milling practice was crude. It consisted of breaking the ore into small pieces by hand, pulverizing in a Blake crusher and a pair of Cornish rolls to approximately minus 6 mm., and jigging in the old-fashioned hand jigs. Only the coarse heavy galena was saved, the gangue being shoveled off and discarded. The output for the first year under this method was only 240 tons of pig lead. The first mill of the company was a combination of extensions and additions built from time to time as the mines developed. It was a museum of early mulling machinery, such as jigs, percussion tables, huddles, dolly tubs, log washers, etc., following no definite flow sheet. The chats, or tailings, were hauled to waste dumps by mule and ox teams, as much as 500 tons per day being moved in this manner, until a railroad was built in 1880. This mill was burned in 1883, at which time the annual output had reached approximately 7300 tons of pig lead. A new mill of 500 tons capacity was designed and built by C. B. Parsons. This mill has been admirably described by H. S. Monroe.1 The ore was crushed in Blake crushers, Cornish rolls, through 6-mm. screens, and treated by jigs of the Parsons type, percussion tables and log washers, or trunking machines, for cleaning the galena. The middlings were recrushed in rolls and treated on Harz jigs. The mill was operated without change, except later installing Gates crushers and en-

Jan 9, 1917

By Lewis Reeve

As. part of a program of investigation of the properties of electric arc welds carried out in the laboratories of the A. 0. Smith Corporation, considerable work has been done on the determination of the oxygen, nitrogen and hydrogen content of different types of weld metal, employing for this purpose the so-called "vacuum fusion method." It is the purpose of this paper to describe certain improvements that have been introduced in this method of determining the gas content of metals, with particular references to the steel specimens examined in this investigation. The method and apparatus used at the beginning of the investigation were essentially those of the Bureau of Standards as described by Vacher and Jordan.1 Later a number of changes were introduced which resulted in. more rapid evacuation of the graphite crucibles employed and which enabled larger volumes of gas to be dealt with than could be handled conveniently in the Bureau of Standards equipment. In addition, the analyzing of the gases evolved from a melt in the same apparatus as collected was abandoned in favor of analysis outside the equipment using standard methods of gas analysis. The time required for gas analysis in the apparatus itself, as described by the Bureau of Standards, was found to be considerable, and during this time the rest of the equip-ment was tied up, preventing its use for the analysis of further steel sam-ples. As a result of the modifications introduced, the time required for the analysis of a steel sample for gas content was reduced from about 8 hours to less than 3 hours. Subsequently, the whole procedure of melting the sample and collect-ing the gases evolved was modified so as to enable a distinction to be drawn between the easily reducible oxides such as iron oxide and the more stable oxides such as silica and alumina. At the same time evidence was obtained indicating the probable existence in the steels of other nitrides than those of iron alone and making possible their quantitative determination.

Jan 1, 1933

By H. M. Crankshaw

The early methods of mining anthracite in the steep pitching Mammoth bed consisted in driving breasts up the pitch from the gangways and airways driven in the bed along the strike (Plate 2, Fig. 1). Breasts are simply rooms driven up the pitch the full thickness of the bed (Plate 2, Fig. 2), having a width of from 18 to 30 ft., and a manway or traveling way on one or both sides. (For detail of breast method see Whildin, Trans., vol. 50, p. 704). Many difficulties were encountered, and the maintenance cost of the timbered gangways was so great as to be practically prohibitive. To reduce this expense, the gangways were driven in the thin Skidmore bed underlying the Mammoth, and the coal mined through rock holes. (Plate 2, Fig. 2, A.) It was found that after the breasts were driven up 80 to 100 ft., the coal almost invariably rushed or "ran away," making good ventilation almost impossible and the extraction of coal from the upper portion of the lift very difficult. The economic length of a lift is from 200 to 250 ft., and the percentage of extraction by the old method above mentioned was often under 50 per cent., while the coal recovered was so badly broken up as to reduce materially the percentage of large sizes. Principles of Present Mining Methods The present methods designed for the recovery of a maximum percentage of coal and a maximum yield of the prepared sizes depends largely on the following principles: First.—Formerly the practice in mining bituminous coal was to space rooms so that as much coal as possible could be extracted in first mining (Plate 3). The small pillars were often lost, and an improvement in total extraction was found in the system of driving narrow rooms with wide pillars, with a much larger final recovery (Plate 4). Second.—The early method of ventilation was to maintain a single

Jan 1, 1917

By Frank Speller

WE are here to honor again the memory of Henry Marion Howe, one of the foremost metallurgists of his time, and it is indeed a great privilege to be called upon by the Board of Directors of .this Institute to give the memorial address this year. Professor Howe started active investigation of corrosion of iron from a metallurgical standpoint in 1887, and made several important contribu-tions to the subject from 1895 to 1908.(1) ? The papers named in the bibliography are only a few of his valuable papers, but in all his works he sets a high standard of scientific accuracy, together with a clearness and power of expression rarely equaled in engineering literature. There-fore it seems appropriate on this occasion to review the work on corrosion of this distinguished gentleman and then endeavor to make a brief inventory of what has been accomplished since his time. Howe saw the beginning of the steel industry in America and before he died (May 14, 1922) witnessed it develop to a production of 45,000,000 tons per year. He was naturally very much interested in the infant industry and was quick to see the importance of the question of corrosion. It was my privilege to discuss the subject of corrosion frequently with Professor Howe at various times from 1905 to 1908; in this, as in other metallurgical problems, he sought the truth without bias and always insisted on proving an opinion or conclusion before accepting it. We should remember that when Howe started his investigation of corrosion, in 1887, steel was rapidly supplanting wrought iron. Certain papers in the early eighties (now forgotten) claiming much greater durability for wrought iron than for steel aroused Howe's interest. He could not reconcile the statement that steel was intrinsically and incurably less durable than wrought iron with the continued and widening use of steel,

Jan 1, 1934

By Robert E. Hoffman, John B. Hudson

The self-diffusion coefficient of pure lead has been measured at five pressures between atmospheric and 40 kb. over a temperature range of about 150°C near the melting point at each pressure. Measurements were made using a radiotracer technique, samples being sectioned electrochemically after the diffusion anneal to determine the diffusion penetration curve. Pressure was applied in a "belt" type pressure device similar to that used by Hall et al., in the diamond synthesis. The self-diffusion coefficient, D, can be represented by an equation of the form at constant pressure, and an equation of the format constant temperature. An apparent correlation between the effects of pressure on self-diffusion and on the melting point of the material observed by Nachtrieb et al., at pressures below 10 kb. was found to be only approximate as measurements are carried to higher pressures. OVER the course of the past 30 years a large number of studies1-' of the rate of atom movements in solid metals have been carried out. These studies have in general been aimed at increasing the understanding of the detailed atomic process by which atom movements in metals can take place. The largest portion of these studies consisted of measurements of the self-diffusion coefficient, D, as a function of temperature. From such studies con- siderable information regarding the energetics of the motive process has been deduced. Recently such measurements have been extended to the pressure dimension. However, the existing work in this area is scanty and has in the past been limited to the pressures attainable in oil or gas bombs—i.e., up to about 10 kilobars (kb). In the present work, the self-diffusion behavior of pure lead has been investigated using the "belt" type high-pressure apparatus designed by Hall7 over a pressure range from atmospheric to 40 kb at temperatures extending over about a 150°C range close to the melting point at each pressure.

Jan 1, 1962

By E. J. Horwood

The varying physical character and large extent of the Broken Hill lode necessarily involve the employment of a variety of underground methods. The lode had its origin in an extensive fault plane traversing metamorphosed schists conformably, as a rule, with their beds of stratification. The underground waters carrying minerals in solution deposited their contents. in the original cavities formed by the faulting action, and in the enlargements of these cavities due to dynamic forces brought to bear on the rocks, more especially on the hanging-wall side of the fault, This deposition was supplemented by metasomatic replacement of a portion of the original rock contents by the argentiferous sulphides of lead and zinc which form the staple products of the district. Although the orebody is practically continuous throughout the mines, its width varies greatly, ranging from a few feet to about 350 ft. The widest portions occur in conjunction with huge folds in the inclosing country rock, almost exclusively on the hanging-wall side. The ore it these folds pitches to the south in the southern half of the field, and to the north in the northern half; there are, however, undulations in these ore channels evidently due to compression of the rocks in the direction of the channels. In the earlier days, before the orebodies had been opened up: vertical cross-sections across these bulges in the hanging wall gave the lode the appearance of the "saddle formation," so well exemplified at Bendigo in Victoria; but subsequent development of the ore channels ha; long since proved that the formations in the two districts are entirely different. The depth reached by the zone of complete oxidation of the sulphide, varies from about 250 to 550 ft. from the original outcrop while partial oxidation extends in places below the 1,000-ft. level. The result of oxidizing influences has been the production of ore of every grade of cohesiveness, from that of dry sand to that of hard compact rock.

Jan 1, 1916

By Sydney H. Loram

The following notes have been compiled more for the reason that the district is little known to the outside world for its gold production, than for the hope of giving valuable information. The district of Canutillo lies about 15 miles south of the city of Freirina (1at. 28' 50' S. long. 70" 75' W.), and contains nine principal veins, all within a radius of a mile; 50 or more claims have been located on these veins, and this paper refers chiefly to those belonging to the Anglo-Chilean Exploration Go., Ltd., on which the greater part of the development work has been done. In all probability the mines were first worked by the Incas, who, under Tupac Yupangui, captured the country as far south as the Mauli river, between the years 1430 and 1470, and imposed a yearly tribut,e of gold and copper, which was forwarded by carriers on foot to Cuzco, the Inca capital in Peru. In the year 1535, soon after the time of the Spanish conquest, the stories of these consignments, together with those of supposed precious stones, led Diego de Almargro with a band of 400 soldiers to explore as far south as the Incas had gone, in the hope of finding the source of the precious metal, which he believed to have come from some definite point instead of being, as was afterwards proved, the collection of innumerable districts scattered over the entire length of the country. The method of winning the gold used by the Incas or by the natives whom they forced to work seems to have consisted in removing the ore by hard-wood wedges driven by stone-hammers, while a human shoulder-blade worn along its rounded edge, found in one of the mines, had evidently done duty to its second owner as a scraper or shovel. The mining was done by steep inclined workings sunk on the lodes at about 40" from the horizontal, the direction being reversed every 10 or

Jan 1, 1905

In many lines of engineering, much excellent standardization work had been done before the war but the war emphasized its importance and showed most clearly the need of cooperation to prevent the confusion caused by the promulgation of overlapping standards by independent bodies. The American Institute of Mining and Metallurgical Engineers, American Institute of Electrical Engineers, American Society of Civil Engineers, American Society of Mechanical Engineers, and American Society for Testing Materials, recognizing the value of what had been done, invited the Government Departments of War, Navy and Commerce to appoint representatives to act with them to continue this work; the body so formed is the American Engineering Standards Committee. It has required time to definitely formulate its objects and to arrange methods for accomplishing them that would be effective without interfering with the many organizations that have been doing such excellent work in this line. The American Engineering Standards Committee has just completed and adopted a revision of its Constitution, which has been sent to the Governing Boards of all the Departments and Societies represented on the Committee with a request for its ratification. The new Constitution changes the name to American Engineering Standards Association as more fittingly indicating the wide scope of the interests involved. The objects of the association are stated as follows: 1. To unify and simplify the methods. of arriving at engineering standards, to secure cooperation between various organizations and to prevent duplication of standardization work. 2. To promulgate rules for the development and adoption of standards, 3. To receive and pass upon recommendations for standards submitted as provided in the Rules of Procedure, but not to initiate, define, or develop the details of any particular standard. 4. To act as a means of intercommunication between organizations and individuals interested in the problems of standardization. 5. To give an international status to approved American engineering standards. 6. To cooperate with similar organizations in other countries and to promote international standardization.

Jan 7, 1919

By W. H. Howard

As the result of a series of analyses and volume determinations of gases discharged from the converters at the Garfield Smelting Co.'s. smelter at Garfield, Utah, it was found that a considerable amount of lead fume was escaping from the stacks of the converter plant, and `that if this lead could be recovered at a reasonable expense an attempt should be made to collect it. Two methods suggested themselves: (1) filtration through bags; (2) electrical precipitation of the condensed fume by a Cottrell plant. Filtration through Bags Tests were made in filtering converter gases through the ordinary woolen bags of lead-smelter bag houses to determine how long such material could withstand the corrosive action of the gases. While blowing on white metal only, the fabric was usually destroyed in 10 to 14 hr. In tests conducted in filtering gases when blowing on matte or slagging stage exclusively and when relatively considerable lead was being volatilized, bags in one instance lasted 60.5 hr. It therefore was evident that the Garfield converter gases did not contain in themselves sufficient neutralizing elements for the purpose of direct bag filtration, even during the slagging stage. Such results were more or less anticipated, but it was thus proved that under all conditions of blowing Garfield mattes a very considerable amount of neutralizing agent, zinc oxide or lime, or both combined, as in the Sprague process, would be required to render bag filtration possible. Again, owing to the constantly changing quantities of SO3 from a given battery of converters, depending on the number blowing at a given time and on the stages of the blow, it would be practically impossible to feed automatically the required amount of neutralizer. In order to safeguard the bags sufficient neutralizer would have to be continuously added to meet the maximum SO3 output, thus. wasting neutralizers and giving an undesirably diluted final product. Such a condition is entirely different

Jan 8, 1914

By H. L. Hartman

The past 15 years have seen rapid advances in the metallurgy of materials for drill machinery and bits, but rock drilling itself continues to be largely an art. Jet piercing, roller bit rotary drilling, and rotary percussion are all promising new techniques, but the percussion rock drill, still used for 90 pct of the blastholes in U. S. hard-rock mining, has undergone no major modification since pneumatic machines were first used successfully in the 1860's. This singular lack of progress stems directly from ignorance of the nature of impact failure of rock and the fundamentals of rock penetration in general. For nearly three-quarters of a century, mining engineers did not know what went on at the bottom of a drillhole. More and more, in recent years, investigators in the field have come to realize that to understand percussion drilling they must study the basic action of percussion bits penetrating rock—not the per- formances of commercial rock drills, with their many attendant variables that cannot be isolated or controlled. Using a vertical drop tester, the writer investigated the sequence of rock failure under the impact. of a simple, chisel-shaped bit when changes were made, singly, in significant variables. Results of this and other research are reported here. BASIC CONCEPTS The formation of a crater in rock under the impact blow of a bit can be observed experimentally. Directly beneath the edge of the bit the rock is crushed into fine powder; toward the sides of the crater it chips out into relatively large fragments. An explanation of these phenomena has been offered by Drilling Research Inc. on the basis of work sponsored by this organization at Battelle Memorial Institute (Ref. 1,1954, Summary, pp. 9-18). High-speed photography and force waveforms obtained from strain gages mounted on the bit near the cutting edges recorded the sequence of events in crater formation with a die-shaped or blunt, wedgc-

Jan 1, 1960

By Wilbur Stout

IN Ohio, the annual output of coke made from native coals has averaged not more than 70,000 tons, or about enough to run a 200-ton blast furnace. Raw coal locally mined from the Sharon, or No. 1, bed was used for iron smelting in Mahoning furnace at Lowellville, Mahoning Co., as early as 1846. This practice was continued in the Youngstown district until the coal became scarce and the Connellsville coke more popular. At present, the Sharon bed contributes a part of the fuel for the production of ferrosilicon iron at Jackson, Jackson Co. About one-third native coal and two-thirds soft coal are used. In this state, coke, on a commercial basis, was first made in Jefferson County probably about 1861 or 1862. The coals used were the Steubenville Shaft, or Lower Freeport, and the Strip Vein or Middle Kittanning. The practice, however, was discontinued before 1880 because of the competition of superior foreign cokes. Beehive ovens, later built at Leetonia, Columbiana Co., were operated for only a few years; the coal used at this place is the Lower Kittanning or No. 5. In a desultory way, slack from the Pittsburgh coal has been coked at a few places in eastern Ohio, and attempts, either for experimental or for commercial purposes, have been made in other parts of the State. Small quantities of coke were made from the Upper. Freeport coal at Salineville, Columbiana Co., and near Nelsonville, Hocking Co.; the results were poor. Tests were made of the Middle Kittanning coal near Zanesville, Muskingum Co., at Moxahala Furnace, Perry Co., and at Washington Furnace, Lawrence Co.; the cokes were all high in sulfur and ash. Attempts were made to coke the Clarion coal at Vinton Furnace, Vinton Co.; a small battery of molding ovens and a pile of high-sulfur coke yet remain to tell the story. The Pittsburgh coal was coked on a commercial scale at Utley and at Lathrop, Athens Co.; but the operations were not successful and were soon abandoned.

Jan 9, 1919

By J. P. Sheeha, W. F. Craig, M. Baeyertz

The loss in toughness caused by phosphorus within commercial ranges was studied in AISI-SAE 1340 steel and in molybdenum modifications of this grade. The replacement of part of the manganese by molybdenum in amounts which maintain the hardenability of the standard 1340 grade was shown to counteract to a marked degree the detrimental effects of phosphorus. THIS paper deals with the effect of phosphorus on the toughness of 1340 steel and with the effect on toughness of replacing part of the manganese by molybdenum while retaining the same hardenability as that of 1340. In previous work1 a progressive decrease in toughness was observed when the phosphorus content of 5140 was raised from 0.020 to 0.036 pct; that is, from a moderate phosphorus level to one higher but yet within the AISI-SAE specification for this grade. The structural condition of the steel was tempered martensite. Toughness was evaluated by the transition temperature determined by V-notch Charpy tests. Replacement of a part of the chromium in 5140 by molybdenum provided a factor of safety against loss of toughness caused by phosphorus, especially where the steel was cooled slowly after tempering. Scope of the Study: In view of the improved tolerance for phosphorus obtained by replacing a part of the chromium in 5140 with molybdenum, it seemed desirable to investigate the possibility of obtaining similar improvement in 1340 by replacing part of the manganese with molybdenum. Heats were made at different phosphorus levels, in a series that began with 1340 and ended with steels containing 0.32 to 0.35 pct Mo with 0.82 and 0.90 pct Mn. The analyses of the heats are given in table I. In order to facilitate later discussion, the 1340 heats have been placed together in the order of increasing phosphorus content, and the molybdenum modifications have been grouped according to phosphorus

Jan 1, 1951

By A. J. R. Curtis

THE Portland Cement Association was organized more than a third of a century ago by a group of cement manufacturers, to do cooperatively the educational and research work needed to ensure proper use of their product. Specifically, the Association has a threefold purpose: (1) to search out facts to ensure the best possible service from concrete; (2) to give the widest possible circulation to facts affecting the use of concrete; (3) to urge practical application of those facts on actual building projects. An organization of technically trained men conducts many research projects in the Association laboratories, interprets their findings and applies them practically in the field. The net effect of this work has been to improve the design and prolong the life of roads, bridges, industrial, commercial and public buildings, homes, farm structures and concrete products. The results of this technical research and experimentation are made available to the entire construction industry through bulletins and reports. Information is also released to the general public through newspapers, magazines and Association publications. In addition to a technical staff in the general office in Chicago, the Association has district offices in 22 cities. Field engineers cover 37 states, the District of Columbia and British Columbia, to give service to users of Portland cement. ACCIDENT PREVENTION During the early part of the century, there began a complete transformation in the processes of manufacturing cement. Electricity, with its attendant hazards, was beginning to replace steam; huge rotary kilns and tube mills were being substituted for the vertical kiln and "coffee grinder" mill. Only a few far-sighted leaders realized the import of these innovations, and they also recognized the fact that workmen must be protected against the hazards of the new machinery. By their sincerity and firm purpose they infused into the whole industry the concept of industry's responsibility for safeguarding employees. Even before effective compensation laws had been passed in most states, the Portland Cement Association had assigned to an Accident

Jan 1, 1937

By G. L. Kothny

DEVELOPMENTS of well-surveying instruments, coring and core orientation, were in an advanced state when drilling for oil began-these developments actually originated with the mining industry.1 Surveying of oil wells was not generally used in the United States until Alexander Anderson2 disclosed that the majority of wells drilled with rotary tools were crooked, with average horizontal drifts of about 516 ft. for holes 5000 ft. deep and about 793 ft. for holes 6000 ft. deep. This disclosure brought about the development of many additional instruments for surveying oil wells during the progress of drilling and after their completion. Surveying of boreholes, during the process of drilling at regular depth intervals, became a standard practice in the petroleum industry. Some producing states even established laws making check surveys mandatory, during drilling and under certain conditions also after completion. The surveying of boreholes also brought about changes and improvements in drilling practices. It provides information for the guidance of the hole while drilling, and for plotting the course as the work progresses, enabling the driller to take corrective measures immediately and with the least expense. The reasons for drilling straight holes are too well recognized to warrant any full discussion of them here. Straight holes are less costly to drill, because [ ] they reach the object on the shortest course. Table I shows the horizontal drift and loss in vertical depth for various angles of inclination. It is not surprising, therefore that many drilling contracts for oil wells today limit the drilling contractor to a maximum inclination off the vertical of 2° or 3°. In the mining industry the reasons for drilling straight holes are still more serious. A crooked hole may miss an ore body underground or provide incorrect information regarding an ore body. TYPES OF SURVEYING INSTRUMENTS The surveying instruments used in oil-well drilling may be classed in two types: I. Inclinometers, recording inclination only.

Jan 1, 1946

By Arthur E. Hall

Tax operation of "softening" in lead refining is designed, as the word implies, to separate from the bulk of the lead the elements that tend to make lead hard. These elements, which invariably are present in argentiferous lead, interfere with the desilverization, and must be almost entirely absent in refined desilverized lead. They are mainly copper, antimony, arsenic and tin. The properties utilized in accomplishing this separation are the low solubility of copper or copper sulphide in lead at its freezing-point temperature, and the greater and selective affinity for oxygen of the other elements at temperatures of the order of 700° to 900' C., or, in the prcsence of sufficient, alkali, at a temperature of about 500' C. The major problems of softening lead bullion lie in the necessary subsequent treatment of the by-products of the primary operation, which contain, either chemically or mechanically, lead or reagents that must be isolated for market or re-use. Therefore an important objective of the primary operation must be the highest practicable concentration of these elements in the by-products. Within the past three decades, during which the writer has been engaged in lead refining, the technique of softening lead bullion has had as many variations as there were lead refineries. This was the result of the variation in composition and character of lead bullion recived. The writer has received for refining shipments of lead bullion varying as widely as indicated by the following table: Sb, Per CEnt As. Per Cent Sn, Per Cent Cu. Per Cent Ag. Oz. per Ton 1.00 0.05 nil 0.05 70 0.50 2.50 2.00 0.50 200 3.50 0.50 nil 0.30 350 At times these have been received uniformly and at other times irregularly with a variation from week to week as wide as those shown. Under such conditions, establishment of a universal softening technique presented many problems. Such variations existed because refinery tolls too often were based on a ton of bullion, whatever its composition, and

Jan 1, 1937

By Ellen H. Richards

The water-supply of a country may be considered from three points of view: (1) its abundance and availability for agricultural purposes; (2) its chemical properties in their relation to manufacturing purposes; and (3) its quality and quantity as affecting domestic consumption. This paper concerns only those characteristics which may affect manufacturing and domestic uses. The so-called sanitary analyses deal not only with the common mineral elements found in water, but with organic matter and with those substances which, by their presence, indicate changes taking place through the agency of living organisms. Since these living organisms are frequently accompanied by others, capable, as are believe, of causing disease, the products of their action are looked upon with suspicion even when, as in the case of nitrates, that action may have taken place at a time long past. Therefore, upon the quality of the water-supply depends much of the history of a country, when rightly read, as well as much of its promise for the future. Thus, the hardness," or content of calcium and magnesium salts, gives a means of distinguishing at once between the waters traversing only igneous or other siliceous rocks and those coming from calcareous deposits. The presence of decomposing organic matter and intermediate products betrays a use of the water as the public carrier of refuse, which renders doubtful its fitness for domestic supply. In certain regions, one of the most valuable historical records is made by the relative amount of chlorine in the different waters. In the absence of rock-deposits carrying salt,, the chlorine present in rain and snow, and hence in mountainstreams and springs, appears to be derived from the air-borne, finely divided salt spray resulting from the beating of the ocean waves on the coast. If this be true, then the amount of chlorine found in a given water not contaminated with chlorides

Jan 1, 1902

By William Meyer

DURING the seventeen years Fairchild has been making aerial surveys and aerial photographic equipment many changes and improvements have been made in the equipment and in the technique of using it. Aerial photographic operations have, been developed from the crude methods and apparatus of wartime to a science upon which exact engineer-ing calculations can be based. In the early days there was no airplane specially designed to meet aerial photographic requirements. One type of camera was used in all types of operations. Projects were made to conform to the products we could make and deliver. Obviously this entailed definite limitations. We now have airplanes designed specially for aerial photographic operations in accordance with the conditions encountered in actual service experience. We have cameras for every photographic purpose and our laboratory technique and equipment have been developed to the point where it is possible to make contour maps from vertical aerial photographs with contour intervals as close as five feet. Therefore, the selection of equipment now can be made in accordance with the time at our disposal, the justifiable cost, the scale desired, and the general requirements of the client. This does not mean, however, that arbitrary deliveries can be set for aerial photographic products. The factors in each project vary and each job must be considered in accordance with the factors involved. This accounts for the fact that products of aerial surveys may readily vary from $1.25 to $200 a square mile. Sherman M. Fairchild became interested in the design of a radically different aerial camera during the war. At its close he was about ready to demonstrate his design to the War Department. By 1920, he was able to bring out his first completed model. It had a number of radical features, one of which was the first dependable high-speed between-the-lens shutter, which makes for accuracy in aerial photographic work. Another feature was the use of metal throughout, eliminating the wooden parts that had been employed in wartime cameras. Another feature was the interchangeability of parts.

Jan 1, 1936

By J. F. Wilkinson

A high degree of accuracy is often required in mine-surveying, in order that expensive mining work may not be misdirected. The making of underground connections by drifts or shafts located as the result of surveys presents a crucial test of correctness not usually involved in any other class of surveying. In view of these considerations, the present notes and description of a survey made in June, 1890, for the San Francisco shaft of the New Almaden quicksilver-mines, may be of interest to members of the Institute who are surveyors. The purpose of this survey was to locate on the surface a vertical 2-compartment shaft (3.5 by 7 ft.), to connect with another vertical shaft, of practically the same size, which had been sunk a number of years before from an adit-level about 240 ft. vertically below the surface, to a deeper, so-called 600-ft. level. It will be seen, of course, that the most important matter was to secure an exact coincidence in vertical line, so that the resulting continuous vertical shaft from the surface should have no offset or irregularity at the point of junction between its two parts. The levels were of less importance; but, as the hoisting-works were to be placed in position and the new shaft permanently timbered from the start, its correct alignment was an essential requirement. The important features of the work, therefore, were the methods used in determining with certainty : 1. That the shaft was located in the right place in a general way; 2. That the ordinary inaccuracies of linear and angular measurements were so reduced as to insure correctness of location within certain defined and allowable limits. Instruments.—Thc instruments used were: a Buff and Berger transit-theodolite, with a 6-in. horizontal plate, reading to 10 seconds; a Heller and Brightly Y-level; a Chestermán steel tape, graduated in tenths and hundredths of a foot; and New York leveling-rods, graduated to thousandths of a foot.

Jan 1, 1901

TO THE BOARD OF DIRECTORS OF THE AMERICAN INSTITUTE OF MINING AND METALLURGICAL ENGINEERS Gentlemen: - I herewith present a report of some. of the more important activities of the Institute for the year of 1922. The outstanding feature of the year is the optimism felt by our members despite the continued depression in the mining industry. January 1, 1921, found many of our members out of employment or drifting into other industries to tide them over the depression, but almost universally the feeling has been that this was but a temporary condition and that sooner or later the necessary production of raw materials would enable these members to return to their former activities and renew their participation in Institute affairs. As the year passed conditions improved and, before it ended, many had found employment in their previous occupations. Bearing in mind that this depression has been very real, we have reason to be well satisfied with the work that the Institute has been able to do. The loss of members through inability to pay, dues has been large, and income has been correspondingly reduced, but it proved to be materially in excess of that anticipated early in the year, so that a substantial and unanticipated balance was carried forward toward the activities of 1923. PUBLICATIONS Following the example of other technical societies, and to conserve our resources, no Year Book was published in 1922. The lack of an up-to-date membership list for the use of our members was regrettable, but the saving of $5000 proved to be worth while. During the year, Volumes LXV, LXVI, and LXVII were printed and sent to members. These volumes were composed largely of the papers of 1920 and 1921, publication of which had been delayed partly through lack of funds and partly for the purpose of segregating into volumes those papers dealing with the same general subject. The segregation of papers had been suggested by a number of members who had advised that they were not primarily interested in all subjects

Jan 1, 1925