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By S. L. Hoyt

The writer has long been interested in seeking an explanation of the upper heat effect in the copper-tin alloys over the a + b range, first described in 1913. These notes are offered, not at all as the final explanation 'of this heat effect, but rather to indicate certain progress which has been made toward establishing what happens over this temperature interval. While working on the thermal analysis of the copper-rich kalchoids (copper-tin-zinc alloys), it was noted that those alloys containing major portions of tin and minor portions of zinc exhibited two marked heat effects, one at about 520' C. and the other at about 600" C., instead of the single effect which is generally observed in either of the two binary series. This matter was discussed with Dr. Guertler, who suggested that a heat effect at about 600" C. in the pure copper-tin alloys might be expected. This led to a more searching examination of the thermal critical points in the pure copper-tin alloys, with the result that a marked, although somewhat weak, heat effect was located at about 600. Somewhat later, this upper heat effect was discussed with Dr. Burgess, and it was requested that the Bureau of Standards make heating and cooling curves of one of these alloys for the purpose of removing any possible doubt as to the actual presence of the heat effect. Results obtained by the Bureau are given in Plate I. In an earlier paper1 differential curves were published showing that the heat effect occurred at constant temperature over the a + B range and increased in magnitude with the amount of B up to a point somewhat above 20 per cent. tin. No heat effect was noticed at this temperature in the eutectoid alloy. The existence of this heat effect seems to require a modification of the present copper-tin diagram in the a + B field, and it has been the object of the work here presented to secure the evidence upon which such a change should be based.

Jan 1, 1919

By Samuel Hoyt

THE writer has long been interested in seeking an explanation of the upper heat effect in the copper-tin alloys over the a + ß range, first described in 1913. These notes are offered, not at all as the final explanation of this heat effect, but rather to indicate certain progress which has been made toward establishing what happens over this temperature interval. While working on the thermal analysis of the copper-rich kalchoids (copper-tin-zinc alloys), it was noted that those alloys containing major portions of tin and minor portions of zinc exhibited two marked heat effects, one at about 520° C. and the other at about 600° C., instead of the single effect which is generally observed in either of the two binary series. This matter was discussed with Dr. Guertler, who suggested that a heat effect at about 600° C. in the pure copper-tin alloys might be expected. This led to a more searching examination of the thermal critical points in the pure copper-tin alloys, with the result that a marked, although somewhat weak, heat effect was located at about 600°. Somewhat later, this upper heat effect was discussed with Dr. Burgess, and it was requested that the Bureau of Standards make heating and cooling curves of one of these alloys for the purpose of removing any possible doubt as to the actual presence of the heat effect. Results obtained by the Bureau are given in Plate I. In an earlier paper1 differential curves were published showing that the heat effect occurred at constant temperature over the a + ß range and increased in magnitude with the amount of a up to a point somewhat above 20 per cent. tin. No heat effect was noticed at this temperature in the eutectoid alloy. The existence of this heat effect seems to require a modification of the present copper-tin diagram in the a + ß field, and it has been the object of the work here presented to secure the evidence upon which such a change should be based.

Jan 12, 1918

By D. C. Seidel, M. C. Fuerstenau, R. J. Roman

The existence of a surface charge on the alkali halide salts is shown, and a flotation mechanism involving surface charge and collector solubility is developed. Data suggest that KC1 is positively charged and that NaCl is negatively charged in saturated brines, and that the neutral molecule RNH,Cl is the collector in the amine-KC1 system, RSO, is the collector in the sulfonate-KC1 system, and RCOONa) is the collector in the fatty acid-NaCl system. A number of hypotheses have been advanced to explain the mechanism of soluble salt flotation; one of these involves exchange between collector ions and surface cations. With this mechanism Gaudin1 suggested that the differences in flotability of halite and sylvite with primary amines are due to the ionic size of the RNH;, Kt, and Na t ions. Fuerstenau and Fuerstenau expanded this hypothesis to include many other alkali halide salts. Several exceptions to this hypothesis are known. That is, this model does not explain why salts containing the same cation, or why salts of different degrees of hydration, respond differently to flotation. For example, why NaI is floated with an amine whereas NaI .2H,O is not. Further, no correlation between ionic size and flotation response can be made with sulfonate or car-boxylate as collectors. In addition, this hypothesis does not explain the effect of magnesium or lead activation, nor does it offer any explanation of the role of temperature in salt flotation. Rogers and Schulman3 realized some of the inadequacies of the ion exchange mechanism and proposed another mechanism based on the heat of solution of the salts. They concluded that weakly hydrated salts can be floated with alkyl amines and sulfonates, that strongly hydrated salts can be floated with fatty acids, and that excessively hydrated salts cannot be floated at all. Their work was not limited to the al-

Jan 1, 1969

1. List of Manuscripts Seen in America 2. List of Manuscripts Seen in England 3. List of Maps Examined 4. List of Newspapers Examined 5. General Bibliography - Numbered Reference List

Jan 1, 1942

NEW MEMBERS The following list comprises the names of those-persons who became members during the month of January, 1914. Members ADIASSEWICH, ALEXANDER, Dept. of Commerce & Industry, 11, Nadejdinskaia, St. Petersburg, Russia. BEARD, JOHN W., Mine Supt., Lane-Rincon Mines, Inca, Temascaltepec, Mex., Mexico; BORCHERDT, WALTER 0., Supt The Bertha Mineral Co., Austinville, Va BREWSTER, BURT B., Sales Engr., Sullivan Machinery Co., 1127 Central National Bank Bldg., St. Louis, Mo: CHASE, ROGER E., JR., Assayer 3906 No. Baltimore St., Tacoma, Wash. CULBERT, J. VICTOR 7S4 Wellington St., London, Ont., Canada; DICKINSON, ALBERT W., Supt. Of Mines Bevier, MO. DODSON, T. M Mores, Colliery, Schuylkill Co., Pa FORREST, CHARLES N., Chem. Engr Maurer, N. J.

Jan 2, 1914

By Charles Eichrodt

THE ore that is being treated by the present plant lies between the leached zone, or capping, and the mixed sulfide and oxide zone. The principal copper minerals are chalcanthite (CuSO4.5H20), brochantite (CuS04 3Cu (OH)2) and atacarnite, (CuC12.3Cu (OH)2). There are, in addition, some other minerals such as cuprite and kröhnkite (CuSO4. Na2SO4.2H20). These minerals, with many others, occur in a greatly crushed granodiorite rock. Most of the copper-bearing minerals occur in the cracks and veinlets, but there are disseminated values and it is probably the relative proportion of these that accounts for some otherwise unexplainable variations in extraction. The entire mineralization of the ore is complex and varies with depth. This variation, the problems presented thereby, and the effect of various constituents of the ore will be taken up in detail. An analysis of an unweighted composite of the ore treated during 1927 follows:

Jan 1, 1930

NORTH AMERICA. CANADA Canadian Army Overseas. Ball, H. D. Bridges. C. Butterill, H. J. If. Ladner, F. E. Lane, H. C. Alillar, W. A. ALBERTA Calgary.-Chonette, W. C. Clark, L. At. Corbett, C. S. de Hart, J. B. Dingman, C. W. Fath. A. E. Fulton. J. If. Cray, J. G. Johnson. R. V. McCutchin, J. A. *Slipper, S. E. Vin Buckirk H. A.

Jan 1, 1944

Mining examinations are of several kinds and the scope of the investigation depends in each case upon the purpose for which the examination is made. A formal examination of a developed mine is an expensive undertaking; from one to several months are allowed for the work according to the size of the property; many samples are taken; investigation is made of the geological features, including, perhaps, a topographical and geological survey of the surface; the metallurgical treatment of the ore is studied; finally, a determination of costs is demanded. Formal examinations are made for prospective purchasers or as a basis for the consolidation of several properties, and occasionally, in the owner's behalf, to verify the work of resident engineers, or to determine the readiness of a mine for equipment and the kind and capacity of equipment it shall receive. A formal examination of a mine should not be undertaken until a preliminary examination has shown that it is justified. It is regrettable that some engineers are in the habit of prosecuting long and exhaustive examinations of properties whose lack of merit should be, and perhaps is, apparent from the start, or of continuing their investigation long after an unfavorable result is seen to be inevitable. This wasting of a client's money is a species of trickery difficult to prove, and therefore the more contemptible. Preliminary examinations are precisely what the term implies, and are undertaken to determine the advisability of making

Jan 1, 1932

Aaby, Alton O , (S'47) Univ of Minnesota, Mimeapolis, Minn Aaby, Waldo S , (S?48) Univ of Minnesota, Minneapolis Minn Aalde, Kaare, (S'48) Univ of Nevada, Reno, Nev Aaring, Floyd D , (S'48) Univ of Oklahoma, Nor man, Oka Aaronson, Hubert I , (S'47) Carnegie Inst of Technology, Pittsburgh, Pa Abbott, Peyton Osborn, (S'46) 1502 Westover, Austin 21, Texas Abel, Malcolm D , (S'47) Univ of Texas, Austin, Texas Aberg, Richard S , (S'47) Univ of Minnesota, Minneipolis, Minn Abrahamson, Guy C , (S'43) 420 W Dennis St , Wilmington, Calif Abrahao, Benjamin, (S'46) Escola Politeenica da Unnersidade, de Sin Piulo, Braizil Achter, Meyer R , (S'46) Carnegie Inst of Tech , Pittsburgh, Pa

Jan 1, 1952

By Walter Herd

FoR the past eight years No. 2 mine of the Cumberland Railway & Coal CO., Springhill, Nova Scotia—a subsidiary of the Dominion Coal Co., Ltd.—has had an unenviable reputation for bumps. As the workings extended in certain directions under a greater cover, these bumps increased in severity and it became apparent that some change in the system of extraction was necessary if the mine was to continue to operate. In September, 1924, following several fatalities resulting from bumps, the Mines Department of Nova Scotia requested from the U. S. Bureau of Mines the services of George S. Rice, Chief Mining Engineer of the Bureau, to report on the conditions then prevalent in No. 2 mine, Springhill. This request was promptly and courteously granted. Mr. Rice made a full investigation and a comprehensive and helpful report, which is embodied in the 1924 Annual Report of the Department of Public Works and Mines, Nova Scotia. Prior to 1925, the room and pillar method was employed and in January of that year (there being a cessation of work from March to August due to labor troubles) longwall retreating on the west side, on a limited scale, and in a small section on the east side of the mine was started. The major portion of the east side was not operated on this system till August, 1926, as there was developed a considerable area ready for pillar extraction between an arbitrary boundary and a point up to which bumps of any consequence had not been experienced. In the interval development work for longwall retreating below the 5900-ft. level was vigorously pushed. This longwall retreating system was suggested by Mr. Rice as a possible remedy and was heartily endorsed by the company officials. This paper describes the conditions and happenings subsequent to Mr. Rice's report and more especially the results with the longwall retreating system of mining under the peculiar circumstances pertaining to mining No. 2 Seam, Springhill, at depth, and records the conclusions which experience with several severe bumps under this mode of extraction would suggest. Except where necessary to make the paper intelligible as an entity any duplication of Mr. Rice's report will be avoided.

Jan 1, 1930

By Walter Herd

FOR the past eight years No. 2 mine of the Cumberland Railway & Coal Co., Springhill, Nova Scotia-a subsidiary of the Dominion Coal Co., Ltd.-has had an unenviable reputation for bumps. As the workings extended in certain directions under a greater cover, these bumps increased in severity and it became apparent that some change in the system of extraction was necessary if the mine was to continue to operate. In September, 1924, following several fatalities resulting from bumps, the Mines Department of Nova Scotia requested from the U. S.. Bureau of Mines the services of George S. Rice, Chief Mining Engineer of the Bureau, to report on the conditions then prevalent in No. 2 mine, Springhill. This request was promptly and courteously granted. Mr. Rice made a full investigation and a comprehensive and helpful report, which is embodied in the 1924 Annual Report of the Department of Public Works and Mines, Nova Scotia. Prior to 1925, the room and pillar method wasp employed and in January of that year (there being a cessation of work from March to August due to labor troubles) longwall retreating on the west side, on a limited scale, and in a small section on the east side of the mine was started. The major portion of the east side was not operated on this system till August, 1926, as there was developed a considerable area ready for pillar extraction between an arbitrary boundary and a point up to which bumps of any consequence had not been experienced. In the interval development work for longwall retreating below the 5900-ft. level was vigorously pushed. This longwall retreating system was suggested by Mr. Rice as a possible remedy and was heartily endorsed by the company officials. This paper describes the conditions and happenings subsequent to Mr. Rice's report and more especially the results with the longwall retreating system of mining under the peculiar circumstances pertaining to mining No. 2 Seam, Springhill, at depth, and records the conclusions which experience with several severe bumps under this mode of extraction would suggest. Except where necessary to make the paper intelligible as an entity any duplication of Mr. Rice's report will be avoided.

Jan 1, 1929

By William Paxton Hewitt

The San Carlos lead deposit in northeast Chihuahua yielded approximately one million tons of galena ore from a blanket-like deposit. Countryrock, composed of Cretaceous limestones and calcareous shales as old as late Albian-early Aptian, and an underlying undated quartzite series, has been warped into a northwest trending anticline and has been invaded by a light-colored holocrystalline igneous rock. Magnetite and contact metamorphic minerals heterogeneously mixed with variable amounts of pyrite, sphalerite and galena, are concentrated along the anticlinal axis where they replaced magnesia-rich argillaceous sediments above the quartzite contact. Magnetite and associated silicates were deposited under near-contact conditions. Following a period of post-magnetite shattering, pyrite, sphalerite and galena were introduced at lower temperatures. Galena and associated dolomite or magnesite, the final phase of mineralization, are concentrated at the top of the deposit near the anticlinal crest and extend upward into isoclinally folded dolomitic argillites. INTRODUCTION AND ACKNOWLEDGEMENTS The stoped outlines of the San Carlos Mine are a pattern for a stratiform blanket-like deposit. But the close association of mineralization with an anticlinal axis, an observed relation between high grade galena mineralization and the apices of isoclinal folds, and the petrographic story of mineralization introduced into shattered areas make the deposit an example of structural control of ore de-

Jan 1, 1970

By E. T. Dumble

THE development in the Gulf Coastal Plain for the year 1923 was entirely devoid of any spectacular feature and was considerably less than that of 1922. No large fields were discovered and the principal advances lay in the extension of the old fields and the finding of a new dome and other possible producing structures, which, however, so far, have given only small wells. While the production of some fields, such as those at Hull and Orange, was materially increased at times by comparatively large wells, the output as a whole shows a marked decrease over that of the preceding year. TABLE 1.-Production by Fields in Gulf Coastal Plain in 1923 FIELD BARRELS FIELD BARRELS Anse La Butte 16,942 Jennings 212,376 Barber's Hill 172,660 Markham 39,290 Batson 391,857 North D ayton 74,983 Big Hill (Jefferson County) 13,853 Orange 5,311,995 Blue Ridge 332,445 Pierce Junction 332,565 Damon Mound 822,355 Richmond (Big Creek) 17,545 Edgerley 176,964 Saratoga 700,661 Goose Creek 6,251,761 Sour Lake 2,091,961 High Island 19,018 Spindletop 309,315 Hull... 7,732,139 Vinton 2,134,430 Humble 2,449,744 West Columbia 6,598,589 36,203,448

Jan 3, 1924

By E. T. Dumble

THE development in the Gulf Coastal Plain for the year 1923 was entirely devoid of any spectacular feature and was considerably less than that of 1922. No large fields were discovered and the principal advances lay in the extension of the old fields and the finding of a new dome and other possible producing structures, which, however, so far, have given only small wells. While the production of some fields, such as those at Hull and Orange, was materially increased at times by comparatively large wells, the output as a whole shows a marked decrease over that of the preceding year. TABLE 1.-Production by Fields in Gulf Coastal Plain in 1923 FIELD BARRELS FIELD BARRELS Anse La Butte 16,942 Jennings 212,376 Barber's Bill 172,660 Markham 39,290 Batson 391,857 North D ayton 74,983 Big Hill (Jefferson County) 13,853 Orange 5,311,995 Blue Ridge 332,445 Pierce Junction 332,565 Damon Mound 822,355 Richmond (Big Creek) 17,545 Edgerley 176,964 Saratoga 700,661 Goose Creek 6,251,761 Sour Lake 2,091,961 High Island 19,018 Spindletop 309,315 Hull 7,732,139 Vinton 2,134,430 Humble 2,449,744 West Columbia 6,598,589 36,203,448

Jan 3, 1924

By G. K. Burgess

THE question of the allotropy of iron, in spite of a vast amount of experimental work and perhaps an even greater amount of theorizing, is not yet settled. That there is a definite transformation in iron near 900,° the A3 point, is generally recognized, as well as the fact that the temperature of this transformation is lowered by the addition of carbon and metallic elements. On heating, the transformation Ac3 is always found at a higher temperature than the transformation on cooling, Ar3. Whether the A3 transformation is sharp like the melting point of a pure substance, or extends over a considerable range of temperatures, embracing perhaps as a lower limit the A2 change, appears to be still an open question for pure iron. The nature and identity of the A2 transformation, it would appear from recent publications, has not yet been satisfactorily settled. In the present paper a critical, historical summary is given of the experimental investigations of the location of A2 and A.3 in pure iron, together with brief mention of some of the theoretical aspects of the subject, and an account is given of a series ?of experiments carried out with several samples of very pure iron which were studied by two methods of thermal analysis in the range from 5000 C. to 1,000° C., and which it is believed furnish a contribution of considerable interest as to the location and nature of the A3 and A2 transformations. Great attention has been given to the details of experimental manipulation and to the preparation of the samples, as it was soon found that some of the discrepancies noted in the work of many experimenters may be traced largely to lack of precautions which we have found essential. For example, to anticipate somewhat, it is necessary to provide a suitable practically gas-free furnace, the heating and cooling of which may be regulated to a nicety. To render a minimum the deforming effects on the cooling and heating curves of the poor conduction of the sample, it must be of a form and mass to pass on its heat rapidly and completely to the thermocouple; and finally the sample itself must be freed from gases which, if present, further mask the definiteness of the heating and cooling curves. We, have also varied within wide limits the several factors which may influence the determination of the exact location and shape of the transformation ranges, especially the mass and preparation of sample, rate of heating and cooling, design of furnace; and finally, as nearly as it is experimentally possible, we have worked with a substance approaching pure iron, free from occluded gases and other impurities, and contained within a vacuum.

Jan 10, 1913

By J. J. Gilman

The data presented indicate that the critical shear stress and strain-hardening Thedatapresentedrate of a zinc monocrystal depend on the orientation of its slip direction with respect to its external boundaries. The tendency of a crystal to form deformation bands also depends on its shape. THE plastic behavior of pairs of zinc monocrystals in which both members of the respective pairs had the same orientation with respect to the longitudinal axis, but each had different orientations with respect to their rectangular external shapes, were compared in this investigation. The purpose of the investigation was to see what influence the shape or surface of a zinc crystal has on its mechanical properties. In a previous investigation of triangular zinc monocrystals,1 anomalous axial twisting was observed which seemed to be related to the triangular shape of the crystals. Wolff,' in 400°C tensile tests of rectangular rock-salt crystals bounded by cubic cleavage planes, found that, of the four equivalent slip systems, the two with the "shorter" slip directions yielded and produced slip lines at lower stresses than the other two. This observation and the work of Dommerich³ as formulated by Smekal4 as a "new slip condition" for rock-salt: "among two or more slip systems permitted by the shear stress law, with reference to the formation of visible slip lines by large individual glides, that slip system is preferred which has the shortest effective slip direction." More recently, Wu and Smoluchowski5 reported essentially the same effect for ribbon-like (20x2x0.2 mm) aluminum crystals at room temperature. Experimental Chemically pure zinc (99.999 pct Zn), purchased from the New Jersey Zinc Co., was the raw material. Glass envelopes, containing graphite molds and zinc, were evacuated while hot enough to outgas the graphite but not melt the zinc. At a vacuum of about 0.2 micron the envelopes were sealed off and then lowered through a furnace at 1 in. per hr so as to melt and resolidify the zinc and produce mono-crystals. One-half of one of the molds is shown in Fig. la. Each mold consisted of four pieces from a cylindrical graphite rod that was split longitudinally and transversely at its midpoints. Rectangular milled grooves 0.050 in. deep and % in. wide formed the mold cavity when the split halves were assembled with twisted wires. Fig. lb shows the specimen shape obtained when the top and bottom mold-halves were rotated 90" with respect to each other. Good fits prevented leakage and excess zinc was necessary to provide enough liquid head to fill the mold completely. In removing soft crystals from the molds it was impossible to avoid small amounts of bending. However, manipulations were carried out whenever possible with the crystals protected by grooved brass blocks. All specimens were annealed prior to testing. From the top and bottom sections of each crystal, X-ray specimens and tensile specimens 7 to 8 cm long were sawed. The tensile specimens were annealed inside evacuated tubes for 1 hr at 375°C. Next the crystals were cleaned and polished by 2-min dips in a solution of 22 pct chromic acid, 74 pct water, 2.5 pct sulphuric acid, and 1.5 pct glacial acetic acid.' Cleaning was followed by a 10-sec dip in a 10 pct caustic solution, then washed in water and alcohol, and dried. This treatment results in a bright surface covered by an invisible oxide film. The testing grips were a slotted type with set screws and were supported in a V-block during the mounting operations in order to avoid bending the crystals. A schematic diagram of the recording tensile-testing machine is shown in Fig. 2. The machine has been described elsewhere.' The head speed was 0.3 mm per sec for all tests. The crystal orientations were determined by the Greninger X-ray back-reflection method with an estimated accuracy of 1. Description of Crystal Geometry A schematic picture of a rectangular zinc mono-crystal is shown in Fig. 3. ABD designates the front edge of a basal plane (0001) of the crystal, the only active slip plane for zinc at room temperature. Of the three possible (2110) slip directions, the active one is indicated by an arrow. Cartesian coordinates are taken parallel to the specimen edges. The normal, n, to the basal plane (n is parallel to the hexagonal axis) has the direction cosines a, ß and ?. X0 = 90 — y is the angle between the longitudinal axis and

Jan 1, 1954

By John T. Galey

In southwestern Pennsylvania 151 wells1 were completed during 1938, a total of 61 less than the preceding year. Of this number 81 were gas wells and 28 oil wells, which shows a considerable decline from 1937, when 108 gas wells and 64 oil wells were completed. However, 42 dry holes were drilled during 1938, which is two more than the previous year. Shallow Development—Gas No new extensions to old pools, or new wells that would indicate any substantial reserves, mere found during the year. However, a number of commercial wells and many dry holes were drilled to the Big Injun sand in Menallen township, Fayette County. One well had an initial open flow of 6 million cu. ft. In Rich Hill township, Greene County, one well producing, from the Big Injun sand, 2 million cu. ft. was brought in. Several other gas wells were completed in Shaler township, Alleghany County and Center township, Greene County, both of which had initial open flows of 1 million cu. ft. from the 30-ft. sand. Another well, in Aleppo township, Greene County, had an equal volume from the Gordon Stray sand. Oil Development has proceeded at a retarded rate because of the low price of Pennsylvania-grade crude. A total initial of only 205 bbl., an average of 7.3 bbl. per well, was developed. This is 1785 bbl. less than during 1937 and no new repressuring operations have been contemplated to prevent the declining production. The average price received for oil was $1.56 per barrel, with a high of $1.88 and a low of $1.34. This oil costs $1.94 per barrel2 to produce. The average price paid for Bradford

Jan 1, 1939

The Colorado Scientific Society, Denver, Colo Charles Henderson, President, 519 U. S Custom House, Denver, Colo. Beginning in 1882, up to. about 1919, the Society published 11 volumes containing many valuable papers From the informa¬tion at hand, the papers in those volumes are now only available in libraries or on file at institutions. Vols 12 and 13 are the current volumes, and the list of the geologic papers contained in them are given here For any information as to price and availa¬bility, address the above. Vol 12 (1929-31) No 1, The geology of the Sangre de Cristo Mountains, by J H Johnson, 2, Relation of the ore deposits of the southern Rocky Mountain region to the Colorado Plateau, by B S Butler; 3, Mosquito Range and the Leadville district, by C H Behre, Jr , 4, Geologic history of the Front Range, by T S Lovering, 6, Revision of geologic structure and stratigraphy in the Ouray district, by W S Burbank, 7, Localization of ore in the schists and gneisses of the Mineral Belt of the Front Range, by T. S. Lovering, 8, Relation of the ore deposits of the southern Rocky Mountain region to the Colorado Plateau, by J. B. Tenney; 9, Preliminary geologic map of the Alma mining district, by Q D. Singewald and B S Butler, 10, The Climax molybdenum deposits of Colorado, by B S Butler and J W. Vanderwilt, 12, Localization of ore bodies at Rico and Red Mountain, by G. F Collins, and Geology of Mount Lincoln and Russia mines, by Q D Singewald and B S. Butler. Vol 13 (1932- ): No. 1, Preliminary geologic notes on Galena Mountain, by J. W Vanderwilt, and High plains of Colorado and New Mexico (Late Tertiary history), by F. M. Van Yuyl and J M. Coke

Jan 1, 1933

By John T. Galey

In southwestern Pennsylvania 151 wells1 were completed during 1938, a total of 61 less than the preceding year. Of this number 81 were gas wells and 28 oil wells, which shows a considerable decline from 1937, when 108 gas wells and 64 oil wells were completed. However, 42 dry holes were drilled during 1938, which is two more than the previous year. Shallow Development—Gas No new extensions to old pools, or new wells that would indicate any substantial reserves, mere found during the year. However, a number of commercial wells and many dry holes were drilled to the Big Injun sand in Menallen township, Fayette County. One well had an initial open flow of 6 million cu. ft. In Rich Hill township, Greene County, one well producing, from the Big Injun sand, 2 million cu. ft. was brought in. Several other gas wells were completed in Shaler township, Alleghany County and Center township, Greene County, both of which had initial open flows of 1 million cu. ft. from the 30-ft. sand. Another well, in Aleppo township, Greene County, had an equal volume from the Gordon Stray sand. Oil Development has proceeded at a retarded rate because of the low price of Pennsylvania-grade crude. A total initial of only 205 bbl., an average of 7.3 bbl. per well, was developed. This is 1785 bbl. less than during 1937 and no new repressuring operations have been contemplated to prevent the declining production. The average price received for oil was $1.56 per barrel, with a high of $1.88 and a low of $1.34. This oil costs $1.94 per barrel2 to produce. The average price paid for Bradford

Jan 1, 1939

By William E. Ford, Edward Salisbury Dana

296. Definition of Specific Gravity. - The specific gravity of a mineral is the ratio of its density * to that of water at 4' C. (39'2' F.). This relative density may be learned in any case by comparing the ratio of the weight of a certain volume of the given substance to that of an equal volume of water; hence the specific gravity is often defined as: the weight of the body divided by the weight of an equal volume of water. The statement that the specific gravity of graphite is 2, of corundum 4, of galena 7-5, etc., means that the densities of the minerals named are 2; 4, and 7'5, etc., times that of water; in other words, as familiarly expressed, any volume of them, a cubic inch for example, weighs 2 times, 4 times, 7.5 times, etc., as much rn a like volume, a cubic inch, of water. Strictly speaking, since the density of water varies with its expansion or contraction under change of temperature, the comparison should be made with water at a fixed temperature, namely 4' C. (39'2' F.), at which it has its maxi- mum density. If made at a higher temperature, a suitable correction should be introduced by calculation. Practically, however, since a high degree of accuracy is not often called for, and, indeed, in many cases is impracticable to attain in consequence of the nature of the material at hand, in the ordinary work of obtaining the specific gravity of minerals the temperature at which the observation is made can safely be neglected. Common variations of temperature would seldom affect the value of the specific gravity to the extent of one unit in the third decimal place.

Jan 1, 1922