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Geological Survey of the State of Maine, Orono, Me. Joseph Conrad Twinem, State Geologist In the years 1837, 1838, 1839, Charles T. Jackson made three reports on the geology of Maine Reports were made in 1861-1862 by C. H Hitchcock entitled, respectively, "General Report on the Geology of Maine" and "Geology of Maine." These old reports are now out of print

Jan 1, 1933

By T. K. Perkins, W. W. Krech

Jan 1, 1969

By T. N. Williamson

The art of drilling tunnels is still in its infancy, although it is 70 years since the first tunnel driver was put into operation. (It was used to drive 6000 ft of tunnel under the English Channel.) But during the next 60 years neither government agencies nor private enterprise could find much of a future in tunnel drivers. It was difficult to justify the heavy investments, labor was opposed to the machines, and there had been some spectacular failures. In the last ten years, however, there have been changes. Tunnel drivers are being tried with increasing frequency-in spite of the fact that a large number of them have had to be abandoned on site.

Jan 7, 1965

By J. A. Capp

For certain classes of electric railways a steel conductor is preferable to the oldcr atld more commonly used overhead trolley-wire. The third-rail presents a rather better appearance, because of the absence of an overhead structure; it is easily installed, cheaply maintai~ied, presents s large area for conducting and collecting the current, and is therefore particularly suitable for high speed and heavy service. With costs calculated on the basis of equal coilductirity in rail aud trollej-wire, the third-rail constrrictiol~ is cl~caper than thc overhead trolley. But the average interurban road will lise a trolley-wire of considerably less conductivity than would be obtained with the smallest size steel rail (about 60 lb. per pard) that mould ordinarily be used, and here the first clost of trolley construction would generally be less thau that of the third-rail. While no third-rail installation has jet bee11 in operation long enough to give figurcs of value, it ~vould appear that the cost of maintenance of the thirdrail construction should be less than that of the overhead trolley. This consideration, together with that of sightliness and adaptability (particularly in the case of terminals, yards and very heavy or high-speed service), will frequently off'set the higher cost of the third-rail construction and make it the preferable means of' conducting the current from thc generator to the car-motor. For the first third-rail installations, old track rails were used when obtainable, and these old rails were supple~rlented with new rails of standard T-section and composition. With the coming of the very heavy, high-speed service during the past few years, the resistance of these old and new standard T-rails was found to be so high that they mould not carry the high currents necessary without too great a drop in the line-potential. The rails would, therefore, have to be suppleme~~ted with addi-

Jan 1, 1904

T. T. READ, Secretary of the Committee on Industrial Organization, presents the following very interesting monthly ad interim report: Reports from London are to the effect that 750 housing schemes for workers, involving the erection of 128,000 new dwellings, have been submitted to the Local Government Board. Birmingham alone needs 14,000 new houses, and the Housing and Town Planning Committee of the City Council considers that 5000 new houses must be built each year for the next 20 years. Nine hundred acres of land has been acquired, on which to build 10 to 12 houses per acre for the next two years. The town of Dudley, which built 300 modern dwellings in 1915-1916, submitted schemes for another 500 houses. There is a shortage of building materials required, specially brick. Financial assistance has been received for reopening brick yards that were closed during the war. W. E. Dickson, vice president of the Midvale Steel & Ordnance Co., is reported in the daily press as stating that his corporation is planning to spend $8,000,000 in improving its plant and assisting its employees in building their own homes. The company will advance 90 per cent. of the cost of the house and extend payments over a period of 12 years. Methods of work employed in building 256 houses at Quincy, Mass., for the workers of the Fore River shipyards are described, by Joseph Meltzer, in the Engineering News Record for May 29, 1919. The approximate cost was about $3500 per house, not including water supply, sewers, streets, and sidewalks. "Comparative Costs of Tenantry and Home-Owning;" "A Plain Talk on Helping Home-builders;" and "More Plain Talk on Home Building" are the titles of three publications of the Information and Education Service of the Department of Labor. These publications should be' of a good deal of service in convincing employees that it is to their interest to own their homes rather than to live in rented houses. The same Service has issued pamphlets discussing the cost of materials.

Jan 7, 1919

By Alton B. Cook, G. B. Spencer, F. P. Bobrowski

In estimating production gas/oil ratios and oil recoveries from reservoirs containing highly volatile oils it is highly important to include condensate that may be recovered from the gas produced from the reservoir. The volume of the hydrocarbon liquid condensed from the production of the solution gas that has been liberated. in some reservoirs may equal or even exceed the volume of recoverable stock-tank oil as estimated by present methods. The usual procedure1, 2, 3 in estimating future reservoir performance includes use of relative permeability data of the reservoir rock to gas and oil and includes material-balance calculations utilizing data on the volume of the reservoir fluids, oil and gas production and reservoir pressure decline, and data on the physical properties of the initial reservoir fluids. The inaccuracy in the procedure results from the false assumption that all of the free or liberated gas that enters the well bore of reservoirs containing highly volatile oils remains in the gaseous phase as it is produced. This paper presents a method for estimating future reservoir performance and oil recoveries based on special labora. tory analyses of reservoir-oil samples and recognition of the additional volume of hydrocarbon liquid that will be recovered at various stages of depletion from a solution.gas.drive reservoir. The method also includes calculations of the volume and composition of the hydrocarbon liquids that can be recovered by processing the produced gas in a natural-gasoline plant. The development of the method resulted from a study of laboratory analyses of reservoir samples and of field data obtained from two reservoirs containing oil of the highly velatile type. Relatively high pressures and temperatures prevail in oil reservoirs discovered at the greater depths of present-day drilling. The contained fluids may have high saturation -Dressures and large volumes of gas in solution. The oils and gases under these conditions may be almost identical in compositions and densities.4,5 Also, engineers have noted that, for a number of oil reservoirs and especially the deeper reservoirs, the API gravity of the stock-tank oil increaees as the production gas/oil ratios increase. They attributed this increase in API gravity of the stock-tank oil to the formation of condensate as the liberated gas in the reservoir is being produced. SOURCE OF DATA FOR CALCULATIONS Subsurface oil samples and well-test data were obtained from the E. Constantin-Lambert Well No. 1 in the Elk City Field, Okla., to demonstrate the need for and a method of calculating future reservoir performance when consideration is given to the recoverable hydrocarbon liquid from the production of solution gas that has been or will be liberated in a reservoir. The Lambert well is located in C, SW 1/4, SW 1/4, Set- 18, T-l0-N, R-20-W, Washita County, Okla. At the time of completion it was on the east edge of the development and Was producing from conglomerate through 30 perforations in the 5 1/2-in. casing at a depth of 9,859 to 9,864 ft. The well Was completed on July 9, 1949, and subsurface oil samples were obtained July 29 and August 1, 1949. Production gas/oil ratio data were obtained during the operation in series of two Separators at high and low-pressures of 314 and 44 psia, respectively, and at an average temperature of approximately 60°F. The flowing bottom-hole pressure at the time of sampling was 3,934 psis. The static bottom-hole pressure was not obtained at the time of sampling, as the well could not be shut in long enough for testing because gas produced from the well was used for fuel at an offset drilling well. However, the initial reservoir pressure was calculated to be 4,364 psia from knowledge of pressure gradients in other wells in the field and the depth of the casing perforations in the Lambert NO. 1 well.

Jan 1, 1951

By F. P. Bobrowski, G. B. Spencer, Alton B. Cook

In estimating production gas/oil ratios and oil recoveries from reservoirs containing highly volatile oils it is highly important to include condensate that may be recovered from the gas produced from the reservoir. The volume of the hydrocarbon liquid condensed from the production of the solution gas that has been liberated. in some reservoirs may equal or even exceed the volume of recoverable stock-tank oil as estimated by present methods. The usual procedure1, 2, 3 in estimating future reservoir performance includes use of relative permeability data of the reservoir rock to gas and oil and includes material-balance calculations utilizing data on the volume of the reservoir fluids, oil and gas production and reservoir pressure decline, and data on the physical properties of the initial reservoir fluids. The inaccuracy in the procedure results from the false assumption that all of the free or liberated gas that enters the well bore of reservoirs containing highly volatile oils remains in the gaseous phase as it is produced. This paper presents a method for estimating future reservoir performance and oil recoveries based on special labora. tory analyses of reservoir-oil samples and recognition of the additional volume of hydrocarbon liquid that will be recovered at various stages of depletion from a solution.gas.drive reservoir. The method also includes calculations of the volume and composition of the hydrocarbon liquids that can be recovered by processing the produced gas in a natural-gasoline plant. The development of the method resulted from a study of laboratory analyses of reservoir samples and of field data obtained from two reservoirs containing oil of the highly velatile type. Relatively high pressures and temperatures prevail in oil reservoirs discovered at the greater depths of present-day drilling. The contained fluids may have high saturation -Dressures and large volumes of gas in solution. The oils and gases under these conditions may be almost identical in compositions and densities.4,5 Also, engineers have noted that, for a number of oil reservoirs and especially the deeper reservoirs, the API gravity of the stock-tank oil increaees as the production gas/oil ratios increase. They attributed this increase in API gravity of the stock-tank oil to the formation of condensate as the liberated gas in the reservoir is being produced. SOURCE OF DATA FOR CALCULATIONS Subsurface oil samples and well-test data were obtained from the E. Constantin-Lambert Well No. 1 in the Elk City Field, Okla., to demonstrate the need for and a method of calculating future reservoir performance when consideration is given to the recoverable hydrocarbon liquid from the production of solution gas that has been or will be liberated in a reservoir. The Lambert well is located in C, SW 1/4, SW 1/4, Set- 18, T-l0-N, R-20-W, Washita County, Okla. At the time of completion it was on the east edge of the development and Was producing from conglomerate through 30 perforations in the 5 1/2-in. casing at a depth of 9,859 to 9,864 ft. The well Was completed on July 9, 1949, and subsurface oil samples were obtained July 29 and August 1, 1949. Production gas/oil ratio data were obtained during the operation in series of two Separators at high and low-pressures of 314 and 44 psia, respectively, and at an average temperature of approximately 60°F. The flowing bottom-hole pressure at the time of sampling was 3,934 psis. The static bottom-hole pressure was not obtained at the time of sampling, as the well could not be shut in long enough for testing because gas produced from the well was used for fuel at an offset drilling well. However, the initial reservoir pressure was calculated to be 4,364 psia from knowledge of pressure gradients in other wells in the field and the depth of the casing perforations in the Lambert NO. 1 well.

Jan 1, 1951

By Chester Purington

THE AUTHOR hopes that this paper will meet with criticism and debate by fellow members of the Institute rather than with that attitude of passiv-ity and indifference which one is inclined to adopt when considering a field completely foreign to one's own experi-ence. After several years of study of voluminous literature, maps, and statistics, and many personal journeys and field inspections of various parts of Siberia, the conclusion is reached .that the area adjacent to the Stanovoi, Zhugd-Zhur, and Yablonoi ranges as below defined is that which .is most accessible to the western world and will soonest give results from exploration. HISTORY The first incursion of the Russians into Siberia east of the Yenesei River appears to have been in 1632 when the fort of Yakutsk was founded on the middle Lena. The early expeditions were in quest of furs. As the Siberians say, "the sable beckoned" and the post of Anadyr was founded in 1639, two thousand miles further northeast. Thus nineteen years after the Pilgrims landed in Massachusetts, the Russians had established a trading post within 700 miles of what is now the town of Nome, Alaska. Parties of Cossaks penetrated to the shores of the Okotsk1 Sea early in the seventeenth century, but it was not until 1688 that the town of Okotsk was founded. In 1712 a grand project was elaborated at St. Petersburg for building a port at Okotsk, but it came to nothing. Vitus Bering, the Alaska explorer, built ships at Okotsk, and made this his point of depar-ture. It is stated that the iron work used in these ships was brought overland partly from Yakutsk, and partly even from St. Petersburg, 5500 miles away. Accord-ing to report a copper deposit was worked on the river Urak, not far from the coast, and copper was smelted for sheathing the bottoms. Grassgrown mounds con-taining slag and shots of copper were inspected by the writer last summer, at the site of the ancient shipyard.

Jan 11, 1923

By P. C. Badgley

The purpose of this paper is to demonstrate the usefulness of systematic analyses of weakness patterns. The term weakness here includes structural features such as fractures, foliation planes, lineaments and bedding. Many of these features are mapped by geologists in the field, but analysis of the field date is frequently overlooked. Examples are presented to show the value of such studies in petroleum and mineral exploration, in dam site selection, and in regional tectonic interpretations. Numerous theories have been presented to account for the mechanics and time of origin of fracturing. This is an extensive subject and cannot be reviewed in detail here. The reader may wish to refer to other papers.*"5 It is sufficient to say that most fracture patterns can be related to one or more of the following force mechanisms: compression, tension, torsion and fatigue (inheritance by upward propagation of pre-existing fractures). Fractures generally occur in sets in a district. The angular relationships and other characteristics of the individual sets frequently help in determining the force mechanism and movement history of the deformation. From a geometric point of view fractures are commonly referred to as longitudinal, cross, or diagonal (shear), depending upon their orientation relative to other major structural features such as anticlinal axes and so forth. These terms will be used from time to time and are illustrated schematically in Fig. 1. FIELD PROCEDURE AND TREATMENT OF DATA In fracture studies it is very important to collect adequate field data. Fig. 2 illustrates a notebook sheet for recording significant field observations in sedimentary rocks. Slight adaptations have to be made for igneous and metamorphic terrains. Fracture density and persistence are very important factors in petroleum exploration for fractured reservoirs and mineral exploration. The density for each joint set is recorded in terms of number of joints per linear yard. The total number of joints at any one

Jan 1, 1962

By G. R. Wilms

A study has been made of the structural changes in polycrystalline high purity aluminum during the tertiary stage of creep under conditions of constant tensile load. It appears that there is no basic modification in the particular mechanism of deformation that characterized the preceding secondary stage of creep, but that the changes in crystalline structure produced during the tertiary stage are only a consequence and not a cause of the accelerated strain. Intercrystalline fissures were observed on entry into the tertiary stage, and these might supplement the accelerated rate of strain owing to local stress concentrations. There is evidence that the formation of these fissures may be associated with the presence of surface imperfections, and it is suggested that a more generalized treatment of the results may explain certain creep characteristics of commercial alloys. IN previous work'-4 a study was made of the changes produced when specimens of annealed aluminum were deformed at various temperatures and rates of strain, especially under conditions leading to creep under constant tensile load. It was shown that, as the temperature was increased or as the rate of strain was decreased, elements of the substructure produced within the grains became coarser, and with the strain rate constant at a given temperature, their size tended to an equilibrium value. The preliminary process of the breaking down of the grains into a substructure was identified with primary creep.' The subsequent equilibrium, condition was associated with secondary creep. The question then arose whether the tertiary stage corresponded to any further significant change in the substructure. The question is also of interest in view of the opinion, expressed for instance by Andrade,5 that the tertiary stage is merely an accelerated rate of strain due to the reduced area of section of a specimen under continuous tensile load, and the other opinion, as suggested by the observation by Sully, Cale, and Willoughby6 of a tertiary stage in com-pressive loading, that this third stage is a real effect in its own right. The object of this paper is to record some observations on the tertiary stage of high purity aluminum. Experimental Procedure The material was aluminum of 99.98 pct purity as previously used. The specimens had a rectangular section of l/8 x l/2 in., and extensions were measured over a 1 in. gage length. After machining to shape, the specimens were annealed to give a standard grain size of 0.2 mm and then electropolished. The general procedure involved metallographic and X-ray diffraction examination at progressive stages of elongation (marked by arrows on the curves shown in Figs. 1 and 2), the specimen being extended to fracture under constant load at a given temperature. The X-ray tests were made by the back-reflection method from a stationary specimen, using CoK radiation. The longer edge of the micrographs in the paper corresponds to the direction of applied stress. Results The previous work showed that, in the secondary stage of creep in aluminum, three basic types of structure could be developed according to the temperature and rate of strain. These were: 1—slip, which predominated at the lower temperatures and higher rates of strain and produced the finest and least perfect substructure; 2—cell structure, which superseded slip as the temperature was raised and the rate of strain decreased and which was characterized by a coarser and more perfect structure and an absence of slip lines; and 3—a stage termed "boundary microflow," which predominated at still higher temperatures and lower rates of strain when the cell size had increased and become comparable

Jan 1, 1955

COMMITTEE ON INCREASE OF. MEMBERSHIP. C. R. CORNING, Chairman. ADOLPHE E. BORIS, First Vice-Chairman. THOMAS T. READ, .Secretary, Woolworth Bldg., New York, N. Y. Vice-Chairmen. JOHN H. ALLEN, GEORGE M. COLVOCORESSES, RICHARD AL ATWATER, JR., ROBERT PEELS, GEORGE D. BARRON, CHARLES P. PERIN, A. CHESTER BEATTY, JOSEPH A. VAN MATER, J. PARKE CHANNING, ARTHUR L. WALKER. D. C. Bard, Howard Eckfeldt, Philip N, Moore, W. de L. Benedict, R. C. Gemmell, T. H. O'Brien, John C. Branner, F. Louis Grammer, James J. Ormsbee, Palmer Carter, Ernest A. Hersam, Edward W. Parker, Allen J. Clark, Edwin C. Holden, John B. Porter, F. Crabtree, William L. Honnold, R. M. Raymond, George G. Crawford, Reginald E. Hore, Robert H. Richards, O. C. Davidson, C. Colcock Jones, LeRoy Salsich, E. V. D' Invilliers, Eugene P. Kennedy, Frederick H. Sexton, James S. Douglas, Chester F. Lee, Henry L. Smyth, Walter Douglas, - Richard S. McCaffery, F. W. Traphagen, Howard N. Eavenson, James F. McClelland, Elton W. Walker. Milton H. McLean, Meetings of this committee were held at the Institute headquarters on April 18, and May 2 and 15. It was resolved that meetings shall be held monthly on the third Friday of each month.

Jan 6, 1913

ST. LOUIS SECTION H. A. BUEHLER, Chairman, CHARLES T. ORR, Vice-Chairman., THOMAS T. BREWSTER, Vice-Chairman, L. L. HUTCHISON, Vice-Chairman, W. E. McCOURT, Secretary-Treasurer, Washington University, St. Louis. CHARLES J. ADAMI, EUGENE MCAULIFFE, A. C. TERRILL, JAMES A. CASELTON, JAMES D. ROBERTSON. The annual meeting of the St. Louis Section was held at the St. Louis Club, Saturday evening, Mar. 10, 1917. Philip N. Moore, President, and Bradley Stoughton, Secretary of the Institute, were the guests of the Section. The meeting was preceded by a dinner, at which 70 were present, and was presided over by F. W. DeWolf. Addresses were made by Mr. Moore and Mr. Stoughton. The routine reports of the officers were- presented and the Executive Committee named above was elected for the current year. The special business of the meeting was a report of progress concerning the arrangements for the Institute meeting to be held in the St. Louis Section district, Oct. 8 to 13, 1917. The general program for the meeting met with the cordial approval and cooperation of the members of the Section. It was evident that the members are united in an endeavor to arrange a successful meeting. W. E. McCOURT, Secretary.

Jan 4, 1917

DAVID COLE, El Paso, Tex. (communication to the Secretary*).-I notice that Mr. Callow takes issue with me on certain points I have previously contributed to the Transactions, to which I would reply," follows: Regarding Inspiration: Mr. Callow's refinements of gravity methods made just prior to the advent of flotation in the Southwest were intended to be "down to the minute," and the gravity flow sheet for Inspiration ores which he brought out at that time as the result of his long campaign of experimentation was regarded by many as the last word in wet gravity work. It was not my intention to discredit this good work when I said "he threw small light on slime treatment." "Minus 200 mesh," however, is not-synonymous with "real slime." Repeated treatments by gravity methods will result in the separation of a very large percentage of the fine granular sulphides in sizes much finer than 200 mesh, and I gave him due credit for that. The unavoidable losses were made in the "real" slime which I mentioned in the paragraph which Mr. Callow refers to as my "statements on page 1871," and his refinements were not a solution to the real slime problem. Mr. Callow has called attention to the fact that his best results at. Inspiration in gravity work were obtained on Joe Bush ore and he presents a table, viz., Tests Nos. 68, 71, and 72; and asks us to consider and compare these results, made by his refined gravity methods, with the results obtained by 'flotation methods in the new mill "during the second half of 1915 and in August, 1916." Of course, the ore treated in the mill was what happened to come. It was not Joe Bush ore, and therefore comparisons of detail figures are of no value. In regard to Mr. Callow's statements under the caption "Callow Cells Adopted by Arizona Copper Company," I would say that those who have been sufficiently interested to read my paper and' his remarks will notice what amounts to contradictory statements on several points which I cannot allow to go unchallenged. I was on the ground constantly and got my information at first hand. The tables published were the official ones. Mr. Callow was not present during the period and has been laboring under that disadvantage.

Jan 5, 1917

By John B. Hastings

The origin of the watery vapors of vulcanism has always been an object of interest and speculation to the seismologist, and as theories of the genetic origin of ore-deposits have of late years been pretty well narrowed down to the expiring forces of plutonic action, the same question has attracted mining engineers and geologists, as is well shown by the discussions of the subject in our Transactions. The important part taken by volcanic emanations in the origin of pegmatites and quartz-veins, described in my paper, Origin of Pegmatite,' and their latent power to concentrate into useful deposits such scattered gold as occurs in the Hartsel granite, make a discussion of their derivation but a natural third and final step. It is coilceded that enormous amounts of vapor accompany vulcanism, though perhaps we are apt to forget that steam has 1,700 times the volume of water, besides which the column seen over Vesuvius and other volcanoes is greatly mixed with air; the immensity of such volumes compared with solids and liquids is shown by the experiment of Gautier, who, by heating dessicated granite to 100' C., evolved from it gases 20 times, and steam 90 times, its own volume. Dana appraised the average amount of water left in ordinary rocks as 2.5 per cent. T. M. Read estimated that the Mississippi river carries to the sea annually 150,000,000 tons of rock material. If these Mississippi sediments, as deposited, contained 20 per cent. of water, it would be 600,000,000 cu. ft., or 4,500,000,000 American gallons, annually. Allowing the vapor suspended over a volcanic cone to be mixed with 80 per cent. of air, this amount of water converted into steam would replenish anew, every 9 min., a column 15,000 ft. high, 2,000 ft. in diameter at the base, and • 10,000 ft. at the top. Read's estimate is only half of the amount given in a more recent and probably correct one.2

Jan 1, 1909

By Frank Firmstone

The piece of spiegeleisen, the analysis of which is given below, was collected by my father, together with various other specimens, while he was manager of the Glendon Iron Works. It bears a label stating that it was taken from a building in the town of Newton, New Jersey, erected in 1765 and torn down in 1863. The building belonged, in 1863, to T. N. McCarter, Esq. The label is in the hand-writing of Mr. McCarter, now deceased, well known as a member of the bar of northern New Jersey. The specimen was, no doubt, given by him to illy father, with whom he had business in 1863 and 1864. It is now in the metallurgical collection of Lehigh University. I know nothing further as to the history of the specimen, but there is no reasonable doubt that it was made from ore from the Andover mine, at the old charcoal-furnace which once stood at the village of Andover, about 5 miles south of Newton, on the Sussex railroad. It was probably broken from one end of a bearer over an open fire-place, is about 6 in. wide by 2.5 in. thick, has been cast in open sand and shows the charcteristic fracture of spiegeleisen rather low in manganese, as shown in Table I. One edge has been white-washed. Table I.—Analyses of Spiegeleisen Made from Andover Ore. 1. 11. Per Cent. Per Cent Graphite,.0.101 0.005 Combined carbon,... 4.529 4.212 Silicon,..0.037 0.294 Manganese,..... 5.760 3.750 Sulphur,.0.003 0.031 Phosphorus,.0.060 0.072 Iron,........ 89.440 91.570 99.920 99.934 I. Spiegeleisen made at Andorer (charcoal) furnace not later than 1765. IT. Spiegeleisen made from Andover ore at Phillipsburg, N. J., anthracire-furnwe, 185-. Both analyses were made by Dr. P. W. Shimer.

Jan 1, 1907

By J. B. Dilworth

In estimating the investment-value of a mining-property or plant, the value of which decreases with operation, it is often necessary to know the sum which must be set aside periodically from earnings either to renew the plant at the end of its life, or to return the capital involved when the earningpower of the investment has ceased. In such cases it is manifestly incorrect simply to divide the total amount to be retired by the 'number of periods (usually years) during which the investment shall be active, as the sums periodically withdrawn have a certain interest-earning power varying with the length of time they are held and with the opportunities afforded for their investment. But though the interest may be considered to accumulate regularly year by year, yet the rules and tables for compouiid interest do not apply, owing to the addition of a fixed amount of new money to the total at the beginning of each period. Briefly stated, the problem of sinking-funds is, to find the amount of money which must be periodically set aside at a certain rate of interest, regularly compounded, to yield a certain sum in a given length of time. In most practical cases the interest is compounded and the fresh amount added at the same time—usually once a year—and on this basis the problem may be solved as follows : Let S = total amount to be retired, Let T = interest rate : R = 1 + r, Let n = life of tlie sinking-fund or the amortization-period, Let L = the sum set aside at the end of each year. Then the amouilt of the sinking-fund at the end of first year is 2, which at the end of n years will have illcreased by compound interest to IRn-l. Similarly, another amount, x, will be set aside at the end of second year, which will in turn increase

Jan 1, 1911

By Charles Fettke

IN 1914, the officials of the Brundred Oil Corpn., faced with the problem of introducing new methods to increase production in the old and nearly depleted pools of Venango County, became interested in the Smith-Dunn (Marietta) process which was at that time being tried out in southeastern Ohio and which was already yielding very encouraging results. A license to use the process in Pennsylvania was secured from the owners of the patents. These patents were later declared invalid. The method was first used in Pennsylvania on a property consisting of about 434 acres, of which 300 are productive, at Hamilton Corners, 15 miles northeast of Oil City, in Cherry Tree and Oakland Townships, Venango County. The producing horizon is the First Sand of the Venango Group. A small oil pool was opened up in this vicinity in 1904. By July, 1916, when the compressed air was first introduced to restore pressure, the production had dropped to a point where it was no longer possible to continue profitable operation. From that time until March, 1927, over 100,000 bbl. of oil have been recovered from the tract. The property is being operated at present by the Brundred Oil Corpn. and Lux. The 1926 production, amounting to 10,650 bbl., was only 400 bbl. short of the maximum reached during any year of the 10-year period that the process has been in operation. Inasmuch as the Hamilton Corners pool is the first one in Pennsylvania in which the Marietta process was tried out, and the one in which it has been longest in continuous operation, considerable interest attaches to the results obtained. Through the courtesy of H. D. Brown and W. J: Brundred, officials of the Brundred Oil Corpn., all their data on this operation were made available to the writer in connection with an investigation of rejuvenation methods in the State for the Pennsylvania Geological Survey.

Jan 1, 1928

THE first session of the production engineering group on Wednesday, morning, with J. B. Umpleby as chairman, recorded the principal developments since the Fort Worth meeting. Added to this was a lively discussion of pressure maintenance. Recent advances in the air-gas lift have resulted from the need of applying the method to smaller wells at lower costs. In many places intermittent flow has given excellent results, and numerous mechanical de-vices for its automatic control have been, developed. Papers by C. V. Millikan on the Mid-Continent field and by A. H. Bell on California, fields formed the basis for discussion. The maintenance of initial sand pressures was ably discussed for two Texas fields by t. V. Foran in a paper that not only outlined the technic of operation and the results obtained but also contained noteworthy cost data in terms of increased ultimate production. Mr. Foran recommends the use of air in the first stages of pressure maintenance as a means of determining sand conditions and directions of flow, later turning to gas, if available, because of its greater solubility on oil. A round table discussion on petroleum engineering educational problems, with H. G. George as chairman, brought out much interesting discussion that is difficult to summarize. The other Wednesday morning session was a refinery engineering symposium with T. G. Del-bridge as chairman and the economical application of heat for the general topic. A paper on the modern pipe -still, by H. S. Bell, and another by C. W. Stratford on the modernization of the cylindrical still elicited a lively discussion.

Jan 3, 1928

By M. J. Swan, W. C. Foshee, R. R. Klimpel

The large volume of water used in coal preparation plants makes water recycling a necessity. Economical cleaning of dirty water usually requires flocculation with an efficient organic polyelectrolyte. This paper discusses identification of optimum flocculant systems. Supporting laboratory data with on-site tests and full-scale field trails supplies information necessary for matching the polymer to the plant.

Jan 1, 1983

By Thomas T. Read

EVERYONE engaged in the teaching of mining engineering will, I suppose, agree that the most difficult subject to teach is "Mining Methods." One primary difficulty is that the students taking the course have either had no previous experience in mining, or else they have had; either seeming to be somewhat of a drawback. The students who are unfamiliar with mines find it difficult to visualize underground conditions, as described and illustrated with sketches and maps, while those who have had underground experience seem to 'find it difficult to visualize anything much different from that which they have already seen. This reminds one of the remark about the Presbyterian doctrine of predestination, to the effect that "you are damned ,if you do; and damned if you don't."

Jan 1, 1930