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By A. W. Furbank

IN reviewing the aerial cameras produced in different countries, it becomes apparent that in nearly all of them an attempt has been made to secure the greatest possible angle of view. This angle, of course, is determined by the objective. The objectives most commonly in use in aerial cameras have a maximum angle of 65°. The objective developed for this new Zeiss camera combines freedom from distortion and brilliant definition, with an angle of 95°. Aerial mapping, it is claimed, has been placed on a different economic basis, and new possibilities presented, par-ticularly in connection with automatic stereoscopic plotting instruments, to which some short references are made. One way of enlarging the angle of view is to couple several instruments with their axes convergent, thereby producing a multilens camera. Typi-cal of cameras of this sort in the United States is the Bagley four-lens camera, which later was developed into the five-lens camera (T3-A) of the U. S. Air Corps. More recently, in order to get away from the unfavorable Maltese cross image field of the five-lens camera, and to obtain a more practical form, two five-lens cameras were combined. By using them in tandem and rotating them by 45° relatively to each other, a ten-lens camera was produced, covering an octagonal ground area, with a total angle of view of 140°. Similar designs have been evolved in other countries. In all of them, however, a number of difficulties have arisen, quite apart from their large weight and high cost. Because of their complex mechanism, numerous shutters and magazines, and the high precision with which these parts must be interadjusted and synchronized, these cameras are far from dependable. Moreover, a multilens camera by itself does not yet constitute a complete outfit for producing pictures suitable for photogrammetric survey. Because all the component pictures, except the central one, are obliques, it is always necessary to employ rectifying apparatus which transforms the marginal views to the perspective of the central one. In multilens cameras with many individual magazines, it is not convenient to

Jan 1, 1938

CONTENTS PAGE MERRISS, M. H.-Direct Electrolysis of Black-copper Anodes of High Nickel-lead Content. Discussed by C. S. Witherell, C. P. Linville, G. E. Dalbey, M. H. Merriss 1 GRISWOLD, GEORGE G.-Calculating the Zinc for Desilverizing Lead Bullion by the Parkes Process. Discussed by C. S. Witherell, George G. Griswold, Milo W. Krejci, Lawrence Addicks, W. F. Gross, H. H. Alexander, A. F. Beasley, C. P. Linville 3 ALEXANDER, H. H. and STACK, J. R.-The Reduction and Refining of Tin in the United States. Discussed by Edward F. Kern, J. R.' Stack, R. L. Hallett, C. R. Hayward, William H. Bassett, R. C. Canby, H. G. S. Anderson 20 GREENAWALT, WILLIAM E.-Greenawalt Electrolytic Copper Extraction Process. Discussed by Stuart Croasdale, Colin G. Fink, Arthur L. Walker, Edward F. Kern, Henry A. Tobelmann, Oliver C. Ralston 26 BENEDICT, C. H. and KENNY, H. C.-Ammonia Leaching of Calumet and Hecla Tailings. Discussed by G. E. Dalbey, C. H. Benedict 34 RALSTON, OLIVER C.-Hydrometallurgy of Lead. Discussed by F. L. Bosqui, Jr., George D. Van Arsdale 34 TAINTON, U. C. and LEYSON, L. T.-Electrolytic Zinc from Complex Ores. Dis¬cussed by W. G. Woolf, C. A. Hansen 39 Direct Electrolysis of Black-copper Anodes of High Nickel-lead Content Discussion of the paper of M. H. MERRISS, presented; at the New York Meeting; February, 1924, and, issued, as Paper No. 1273-M, with MINING AND METALLURGY, September, 1923. C. S. WITHERELL, New- York, N. Y. (written discussion).-This paper is particularly valuable in that it gives the results of operations -carried out under conditions differing from standard practice. In the electrolytic refining of copper, as in other kinds of metal refining, it is occasionally necessary to treat extraordinary foul or complex material, in which cases 'it is valuable to know what other metallurgists have accomplished under similar conditions. As tapping the slimes-covered anodes brought the tank-voltage down to 0.45 to 0.50 volt, the counter electromotive force was, probably not more than 0.1 or 0.2 volt; hence the so-called polarization was, mainly,

Jan 6, 1924

By T. F. Witherbee

It is proposed to give, first, a description of the works; second, a report of the first six months of the present blast; and third, such improvements as have been suggested by the practical working. The site selected for this furnace was, at the time of commencing work, October, 1872, entirely covered by the navigable waters of Lake Champlain. A coffer-dam was first built of cribs of round timber filled with stone, forming three sides, while the shore answered for the fourth. Considerable excavating was done with a steam-dredge, a hole being left for it to pass out. The opening was then built up, and the cribbing banked up with blue clay from the bottom of the lake, to render it water-tight and the dam pumped out; the remainder of the excavating being done by hand. All of the foundations, with the exception of the elevator-tower, and fifteen feet of the east side of hot blast, rest on the Potsdam sandstone, which forms the shore line, dipping into the lake at an angle of fifteen degrees. Owing to jogs in the formation, a much greater depth was found necessary than was at first anticipated, the foundation under the stack

By T. F. Witherbee

IT is proposed to give, first, a description of the works ; second, a report of the first six months of the present blast; and third, such improvements as have been suggested by the practical working. The site selected for this furnace was, at the time of commencing work, October, 1872, entirely covered by the navigable waters of Lake Champlain. A coffer-dam was first built of cribs of round timber filled with stone, forming three sides, while the shore answered for the fourth. Considerable excavating was done with a steam-dredge, a hole being left for it to pass out. The opening was then built up, and the cribbing banked up with blue clay from the bottom of the lake, to render it water-tight and the dam pumped out; the remainder of the excavating being done by hand. All of the foundations, with the exception of the elevator-tower, and fifteen feet of the east side of hot blast, rest on the Potsdam sandstone, which forms the shore line, dipping into the lake at an angle of fifteen degrees. Owing to jogs in the formation, a much greater depth was found necessary than was at first anticipated, the foundation under the stack

Jan 1, 1876

By A. W. Furbank

In reviewing the aerial cameras produced in different countries, it becomes apparent that in nearly all of them an attempt has been made to secure the greatest possible angle of view. This angle, of course, is determined by the objective. The objectives most commonly in use in aerial cameras have a maximum angle of 65". The objective developed for this new Zeiss camera combines freedom from distortion and brilliant definition, with an angle of 95". Aerial mapping, it is claimed, has been placed on a different economic basis, and new possibilities presented, particularly in connection with automatic stereoscopic plotting instruments, to which some short references are made. One way of enlarging the angle of view is to couple several instruments with their axes convergent, thereby producing a multilens camera. Typical of cameras of this sort in the United States is the Bagley four-lens camera, which later was developed into the five-lens camera (T3-A) of the U. S. Air Corps. More recently, in order to get away from the unfavorable Maltese cross image field of the five-lens camera, and to obtain a more practical form, two five-lens cameras were combined. By using them in tandem and rotating them by 45" relatively to each other, a ten-lens camera was produced, covering an octagonal ground area, with a total angle of view of 140". Similar designs have been evolved in other countries. In all of them, however, a number of difficulties have arisen, quite apart from their large weight and high cost. Because of their complex mechanism, numerous shutters and magazines, and the high precision with which these parts must be interadjusted and synchronized, these cameras are far from dependable. Moreover, a multilens camera by itself does not yet constitute a complete outfit for producing pictures suitable for photogrammetric survey. Because all the component pictures, except the central one, are obliques, it is always necessary to employ rectifying apparatus which transforms the marginal views to the perspective of the central one. In multilens cameras with many individual magazines, it is not convenient to

Jan 1, 1941

By A. W. Furbank

In reviewing the aerial cameras produced in different countries, it becomes apparent that in nearly all of them an attempt has been made to secure the greatest possible angle of view. This angle, of course, is determined by the objective. The objectives most commonly in use in aerial cameras have a maximum angle of 65". The objective developed for this new Zeiss camera combines freedom from distortion and brilliant definition, with an angle of 95". Aerial mapping, it is claimed, has been placed on a different economic basis, and new possibilities presented, particularly in connection with automatic stereoscopic plotting instruments, to which some short references are made. One way of enlarging the angle of view is to couple several instruments with their axes convergent, thereby producing a multilens camera. Typical of cameras of this sort in the United States is the Bagley four-lens camera, which later was developed into the five-lens camera (T3-A) of the U. S. Air Corps. More recently, in order to get away from the unfavorable Maltese cross image field of the five-lens camera, and to obtain a more practical form, two five-lens cameras were combined. By using them in tandem and rotating them by 45" relatively to each other, a ten-lens camera was produced, covering an octagonal ground area, with a total angle of view of 140". Similar designs have been evolved in other countries. In all of them, however, a number of difficulties have arisen, quite apart from their large weight and high cost. Because of their complex mechanism, numerous shutters and magazines, and the high precision with which these parts must be interadjusted and synchronized, these cameras are far from dependable. Moreover, a multilens camera by itself does not yet constitute a complete outfit for producing pictures suitable for photogrammetric survey. Because all the component pictures, except the central one, are obliques, it is always necessary to employ rectifying apparatus which transforms the marginal views to the perspective of the central one. In multilens cameras with many individual magazines, it is not convenient to

Jan 1, 1941

By A. W. Furbank

IN reviewing the aerial cameras produced in different countries, it becomes apparent that in nearly all of them an attempt has been made to secure the greatest possible angle of view. This angle, of course, is determined by the objective. The objectives most commonly in use in aerial cameras have a maximum angle of 65º. The objective developed for this new Zeiss camera combines freedom from distortion and brilliant definition, with an angle of 95º. Aerial mapping, it is claimed, has been placed on a different economic basis, and new possibilities presented, particularly in connection with automatic stereoscopic plotting instruments, to which some short references are made. One way of enlarging the angle of view is to couple several instruments with their axes convergent, thereby producing a multilens camera. Typical of cameras of this sort in the United States is the Bagley four-lens camera, which later was developed into the five-lens camera (T3-A) of the U. S. Air Corps. More recently, in order to get away from the unfavorable Maltese cross image field of the five-lens camera, and to obtain a more practical form, two five-lens cameras were combined. By using them in tandem and rotating them by 45º relatively to each other, a ten-lens camera was produced, covering an octagonal ground area, with a total angle of view of 140º. Similar designs have been evolved in other countries. In all of them, however, a number of difficulties have arisen, quite apart from their large weight and high cost. Because of their complex mechanism, numerous shutters and magazines, and the high precision with which these parts must be interadjusted and synchronized, these cameras are far from dependable Moreover, a multilens camera by itself does not yet constitute a complete outfit for producing pictures suitable for photogrammetric survey. Because all the component pictures, except the central one, are obliques, it is always necessary to employ rectifying apparatus which transforms the marginal views to the perspective of the central one. In multilens cameras with many individual magazines, it is not convenient to

Jan 1, 1938

By Charles W. Perry

The options of enhanced oil recovery, coal syncrude, and shale syncrude are compared by approximately equivalent economics. The physical constraints for the major enhanced oil recovery processes are described, followed by new estimates of cost. The range for all three options in terms of light syncrude equivalent are $22 to $40 per barrel in 1980 dollars.

Jan 1, 1982

By Charles Trotter

AN instrument has recently been developed for determining the inclination and azimuthal direction of boreholes. This instrument is known as the Tro-Pari Instrument and is the invention of C. Trotter and G. Pajari of Sudbury, Ontario. DESCRIPTION The instrument is characterized by a unit mounted in gimbals and provided with a clockwork mechanism to clamp a compass to indicate azimuthal direction and simultaneously to clamp the unit in its plumb position to indicate inclination (Fig I). By means of a timing ring suitably calibrated in 5-min divisions, the unit may be set to lock after a lapse of time sufficient to allow the placing of the instrument at the desired point in the drill hole where readings are to be taken. The maximum time lapse obtainable with the instrument designed for use in EX or AX size holes is 1 hr 30 min which is considered to be ample time to lower to the greatest depths that may be drilled with this size of equipment. Larger sizes could be developed for larger diameter holes such as BX and NX sizes or the larger oil-well sizes and a correspondingly greater time lapse could be provided for. Up to the present time only the EX-AX size has been built. OPERATION Assuming a borehole is to be surveyed at 1000-ft depth and assuming it will take 30 min to lower the instrument to this depth, the timing ring is rotated through seven divisions which represent a time lapse of 35 min (5-min leeway) and is then returned to its zero position. This operation imparts energy to a spring which drives the clockwork mechanism. Simultaneously the compass needle is freed to swing to its magnetic north-south position and the encased mechanism is freed to hang plumb within a semicircular portion of the frame which is graduated in degrees after the fashion of a protractor. This semicircular protractor portion has a V-shaped notch at each degree division of its inner periphery. The instrument, now in its free position, is inserted in a bronze container made to suit the size of hole to be surveyed (Fig 2). Soft rubber washers are provided within the container to prevent undue shock. The container is connected to the drill rods with three 5-ft lengths of brass or aluminum alloy rods separating it from the steel rods in order to prevent distortion of the magnetic field. The assembly is then lowered to the desired point where readings are to be taken and is allowed to remain at rest until a period of time has elapsed slightly in excess of the time for which the timing ring was set. In the example cited above, when the 35 min has elapsed the compass needle is locked in its north-south position and the protractor locking pin is extruded and locks in the V notch opposite its plumb position. The device may now be removed from the borehole and it will remain in this locked position in spite of jarring or shak-

Jan 1, 1947

By R. A. Bergier

The Transactions of the Institute contain nothing, as yet, on the subject of pocket-compasses; and in the belief that American miners, explorers, geologists, and engineers will gladly welcome any infor mation about new forms of apparatus, simple in construction and adapted to rapid use, I offer a short description of an improved French combination pocket-compass, which, if once introduced into use, would seem likely to supersede similar instrumens of older pattern. The instrument in my possession I owe to the kindness of M. G. de.La Bouglise, of Paris. The frame of the compass is a double-bottomed box, 2 1/2 inches square and 9/16 of an inch high, made of white metal, and with its sur faces very carefully planed. The sides of the box make true right angles with each other. Two sides are parallel with, and two are normal to, the north and south line of the principal graduation. The bottom is accurately planed, so that the instrument will lie true on a plane surface. A glass, 2 3/8 inches in diameter, is set in the top plate. The graduation for the needle is engraved on the upper face of a ring, connected with the flat disk, in which the center-pin is in serted. Between this disk and the bottom of the box there is a hollow space a quarter of an inch deep. The needle is 1 7/8 inches in length, and can be balanced by means of a small sliding piece of metal. The graduation extends from 0° to 360°, reading from right to left. The stopping of the needle is effected by a screw, A, on the side of the box near the handle, H (Fig. 1). There is also a clinometer attachment, the graduation for which is engraved on the upper face of the silver-plated disk. The compass has two sights. The north sight, B, is a simple pin, a little more than an inch high, which, when not in use, is kept folded down, and is partially protected by the exterior sliding-plate, C. When raised for use, the sight is stopped in a vertical position by a projecting pin attached to the side of the box.. The south sight, D, is connected with the handle, H, and the sight and handle

Jan 1, 1890

R. W. Raymond, New York, N. Y.: Mr. Bain's introductory statement that there is a growing disposition on the part of the public " to change emphasis " in government from political equality " to " social justice " is somewhat vague; but I gather from his argument that he approves the growing disposition to which he refers, and that the " emphasis " which it demands involves a radical change in the policy hitherto pursued by the United States—the policy under which the Pacific States and Territories have been developed thus far. I do not understand how "social justice" is to be furthered by the sacrifice of " political equality," or how the change is to be effected by "emphasis." But I fancy that the beneficent and necessary

Jan 1, 1913

By P. K. Foster, C. M. Payne, A. McNabb

Some measurements of the rate of loss of hydrogen from cylinders of iron and steel are analyzed in terrns of a trapping theory. The apeement is encozcraging and gives rise to estimates for the density of traps in the metal. Furthermore, the results appear to be consistent with the assumption that the diffusion constant D for the steady flux of hydrogen through iron lies on the extrapolation of the linear curve (log D us 1/T) obtained at higher temperatures. IT has been shown in a previous paper1 that the literature relating to hydrogen diffusion in steels contains sufficient evidence to invalidate the application of Fick's laws to hydrogen diffusion in steel at low temperatures. To account for the deviations from simple diffusion behavior a trapping theory was developed, and the fundamental laws modified accordingly. In the present paper, new data on the evolution of hydrogen from long cylinders are presented, and together with some published data are examined in terms of the requirements of the theory.' Properties of solutions of the basic equations derived previously1 and appropriate to the present experimental conditions are outlined in the first section as they determine the form in which the experimental data must be presented for a comparison of theory and experiment. Two new solutions not previously reported have been derived as described in the Appendix. The experiments and treatment of data are then given in Sections 2 and 3 and the results are discussed in Section 4. 1) THEORETICAL CONSIDERATIONS The hydrogen-diffusion theory1 applied in this paper postulated that lattice-dissolved hydrogen at a concentration C diffuses randomly in accordance with Fick's first law, but that the lattice contains a uniform density N of traps which can capture and delay hydrogen atoms. kC atoms are trapped per second in a region containing unit concentration of vacant traps while p are released per second in a region containing unit concentration of occupied traps. On this basis it was shown (Eq. [30] of Ref. 1) that, when local changes in the lattice-dissolved concentration C are slow enough for equilibrium to be established with the traps, the system is represented in dimensionless form by the equation:

Jan 1, 1965

By B. D. Cullity

Gold and beryllium form an intermediate phase composed of the two metals in equal atomic proportions and having the formula AuBe. According to Winkler,' this phase probably exists in two modifications: beta, stable below about 600°C, and alpha, stable between 600°C and the melting point, about 740°C. Only the low-temperature beta form will be considered in this paper. Experimental Procedure The gold used had a fineness of 999.75 to 999.85, balance mainly silver, and the beryllium purity was better than 99.8 pct. AuBe was prepared by melting the constituents in a beryllia crucible in an evacuated induction furnace. After melting and thorough mixing, the alloy was allowed to solidify in the crucible. No difficulty was encountered in obtaining a homogeneous ingot. Both chemical analysis and microscopic examination of the ingot showed that the alloy was essentially one phase, containing 50 at. pct gold. The alloy was quite brittle and powder samples could easily be prepared by grinding in an agate mortar. The X-ray diffraction patterns were made with CuK-alpha radiation in a Debye-Scherrer powder camera 57.3 mm in diameter. The film was placed unsym-metrically in the camera in order to afford a basis for film-shrinkage corrections. A sample homogenized at 500°C gave the same diffraction pattern as a sample taken from the as-melted ingot. General Results The diffraction pattern of AuBe was readily indexed on the basis of a simple cubic lattice with ao = 4.659 + 0.001kX. If the unit cell is assumed to contain four AuBe "molecules," the calculated X-ray density is 13.46 grams per cc as compared with the measured density of 13.55 gm per cc. The only missing reflections in the diffraction pattern are (100) and (220) (see Table I). Since these missing reflections are not those characteristic of body or face centering, the lattice of AuBe must be simple cubic. To locate the positions of the atoms within the unit cell, two possibilities had to be considered: I. The structure was disordered and there were eight positions to be filled by an LCaverage" gold-beryllium atom. That the structure was disordered seemed unlikely since the lattice parameter did not vary with composition in alloys containing sornewhat more and somewhat less than so at' pet gold, indicating a fixed composition for AuBe.

Jan 1, 1947

By B. D. Cullity

Gold and beryllium form an intermediate phase composed of the two metals in equal atomic proportions and having the formula AuBe. According to Winkler,' this phase probably exists in two modifications: beta, stable below about 600°C, and alpha, stable between 600°C and the melting point, about 740°C. Only the low-temperature beta form will be considered in this paper. Experimental Procedure The gold used had a fineness of 999.75 to 999.85, balance mainly silver, and the beryllium purity was better than 99.8 pct. AuBe was prepared by melting the constituents in a beryllia crucible in an evacuated induction furnace. After melting and thorough mixing, the alloy was allowed to solidify in the crucible. No difficulty was encountered in obtaining a homogeneous ingot. Both chemical analysis and microscopic examination of the ingot showed that the alloy was essentially one phase, containing 50 at. pct gold. The alloy was quite brittle and powder samples could easily be prepared by grinding in an agate mortar. The X-ray diffraction patterns were made with CuK-alpha radiation in a Debye-Scherrer powder camera 57.3 mm in diameter. The film was placed unsym-metrically in the camera in order to afford a basis for film-shrinkage corrections. A sample homogenized at 500°C gave the same diffraction pattern as a sample taken from the as-melted ingot. General Results The diffraction pattern of AuBe was readily indexed on the basis of a simple cubic lattice with ao = 4.659 + 0.001kX. If the unit cell is assumed to contain four AuBe "molecules," the calculated X-ray density is 13.46 grams per cc as compared with the measured density of 13.55 gm per cc. The only missing reflections in the diffraction pattern are (100) and (220) (see Table I). Since these missing reflections are not those characteristic of body or face centering, the lattice of AuBe must be simple cubic. To locate the positions of the atoms within the unit cell, two possibilities had to be considered: I. The structure was disordered and there were eight positions to be filled by an LCaverage" gold-beryllium atom. That the structure was disordered seemed unlikely since the lattice parameter did not vary with composition in alloys containing sornewhat more and somewhat less than so at' pet gold, indicating a fixed composition for AuBe.

Jan 1, 1947

Maps and Mining Data for the Library. I suggest that the Institute Library can increase its usefulness by systematically soliciting from the engineers and mining companies all published reports and maps, and parts of reports and records, not of a private or confidential nature. If this is done an engineer assigned to report on a well-known property or district may depend on finding at the library a large amount of preliminary data and general information from these official and engineering reports relating to his prospective investigation. In many mining reports a large part of the report is of a general technical and scientific character, and there could be no good objection on the part of either the engineer, or his client to making such information thus of record. I believe there would be a great deal of information furnished by the engineers if they were properly solicited under this plan. I have found on different occasions that much work could be saved by such records now in the Library. The plan would also have the advantage of keeping the Library in closer touch with the active engineers, a feature to be desired. I also have in mind that the Library should undertake to collect all the prospectuses and financial literature which is issued in connection with mining. Of course a great deal of this is unreliable, but even this is valuable for record in the matter of legal and other investigations. I shall be glad to co-operate with you, and do anything I can to develop more in detail the general ideas above noted. Yours very truly, KIRBY THOMAS NOTE.-The Library of the Institute makes a specialty of collecting and filing material of this character, and the letter printed above is brought to the attention of members in the hope that they will co-operate by sending in copies of maps, reports of properties, etc.

Jan 11, 1913

By Clyde Ross

The Thunder Mountain mining district is in eastern Valley County, Idaho. It is of undefined extent but nearly all of the development is confined to the ridge between Monumental and Marble creeks in unsurveyed T. 19 N., R. 11 E. (Fig. 1.) The district is still remembered among the mining men of Idaho because of the ill-advised rush there in 1902, but available evidence indicates that optimism regard-ing the future development of the gold deposits of the district is warranted. The former disappointment arose from the fact that many who took part in the early rush hoped for bonanza deposits, whereas the district is characterized by large masses of low tenor. In 1926 the writer,, assisted by C. Y. Behre, 3r., incidental to other work in the region, devoted four days to the detailed examination of the then access-ible workings in the district. Tha major workings in the Sunnyside, Venable, Standard and H-Y mines, most of which were still in good shape, were examined., Surface exposures at the Dewey were studied, but the main workings there have long been caved. The time available did not permit more than a cursory examination of the surface at a distance from the mines. Sufficient data have been gathered, how-ever, from published and unpublished accounts, production records and mine maps so that the major features of this deposit, by far the most productive in the dis-trict, can be summarized. The kindness of Messrs. Dan McRae and R: A. Davis in making available information regarding the mines of the district, a rd of these men and others in recounting early history and their observations in now inaccessible workings, have aided materially in preparing the present paper. A brief summary of the salient characteristics of the district has already been published.1/ Cir-cumstances have contributed to delay in the publication of the full official report, which will contain mine maps and ?such other detailed data as could be ontained. In view of the present interest in gold deposits it seems desirable to present here a summary of results of the study.

Jan 1, 1933

By O. C. Wheeler

The total oil production from Colombia during 1939 amounted to 23,774,151 bbl., constituting a new high record. Of this amount the Tropical Oil Co. produced 22,374,151 bbl. from its De Mares concession and the Colombian Petroleum Co. produced 1,400,000 bbl. from its Barco concession beyond the eastern Andes. The Socony Vacuum Oil Co. produced a small amount of crude from its Las Monas wells north of the Sogamoso River in the Magdalena Valley for consumption on its own property, but this is not included in the figures given above. The South American Gulf Oil Co. provided the outstanding development in the country by the completion, late in the year, of its 12-in. pipe line from the Colombian Petroleum Company's Barco concession to the coast at Covenas. This was a notable accomplishment, achieved in the face of tremendous natural obstacles. With the completion of this line there are now two crude-oil outlets from the interior of Colombia to the coast, the other being the Andian National Corporation's line down the Magdalena Valley from Barranca Bermeja. The Barco property becomes the second major producing area in Colombia. The acquisition of prospectivc oil lands continued at about the same level as during the prcvious year. Most of the lands taken up or applied for had their subsurface rights vested in the National Government. Relatively little interest was taken in the leasing of privately owned lands. Tropical surrendered its Putana concession on the Sogamoso River after finding it to he nonproductive. The status of applications for National lands that had been accepbed or on which concession contracts had been awarded at the end of the year is shown in Table 3. In the Magdalena Valley wildcat drilling in the search of new fields was conducted to the east of Puerto Berrio by the Compania de Petroleo Shell de Colombia, Compania Coloinbiaila de Petroleos El Condor and by the Sociedad Nacional del Carare; further down the valley to the cast of Puerto Wilches, the Socony T'acuum was drilling two wildcats. No discoveries resulted from this exploratory work. On the Barco conces-

Jan 1, 1940

By O. C. Wheeler

The total oil production from Colombia during 1939 amounted to 23,774,151 bbl., constituting a new high record. Of this amount the Tropical Oil Co. produced 22,374,151 bbl. from its De Mares concession and the Colombian Petroleum Co. produced 1,400,000 bbl. from its Barco concession beyond the eastern Andes. The Socony Vacuum Oil Co. produced a small amount of crude from its Las Monas wells north of the Sogamoso River in the Magdalena Valley for consumption on its own property, but this is not included in the figures given above. The South American Gulf Oil Co. provided the outstanding development in the country by the completion, late in the year, of its 12-in. pipe line from the Colombian Petroleum Company's Barco concession to the coast at Covenas. This was a notable accomplishment, achieved in the face of tremendous natural obstacles. With the completion of this line there are now two crude-oil outlets from the interior of Colombia to the coast, the other being the Andian National Corporation's line down the Magdalena Valley from Barranca Bermeja. The Barco property becomes the second major producing area in Colombia. The acquisition of prospectivc oil lands continued at about the same level as during the prcvious year. Most of the lands taken up or applied for had their subsurface rights vested in the National Government. Relatively little interest was taken in the leasing of privately owned lands. Tropical surrendered its Putana concession on the Sogamoso River after finding it to he nonproductive. The status of applications for National lands that had been accepbed or on which concession contracts had been awarded at the end of the year is shown in Table 3. In the Magdalena Valley wildcat drilling in the search of new fields was conducted to the east of Puerto Berrio by the Compania de Petroleo Shell de Colombia, Compania Coloinbiaila de Petroleos El Condor and by the Sociedad Nacional del Carare; further down the valley to the cast of Puerto Wilches, the Socony T'acuum was drilling two wildcats. No discoveries resulted from this exploratory work. On the Barco conces-

Jan 1, 1940

THE CHAIRMAN (J. W. RICHARDS, South Bethlehem, Pa.)-The first point on which I wish to speak is that sufficient attention has not been given to the quality of the ores, in estimating the reserves. I made this same criticism of the work on the iron-ore resources of the world issued by

Jan 12, 1918

By W. C. Ellis

IN an ingot of germanium solidified progressively from the bottom by a method' devised by J. H. Scaff and H. C. Theuerer, examination discloses ex- IH. C. Torrey and C. A. Whitmer, Crystal Rectifiers. p. 364. 1948. New York. McGraw-Hill Pub. Co. tensive twin relationships. A slice taken about midway in a cylindrical ingot approximately 3/4 in. in diameter and 1 1/2 in. in length, after etching and polishing to delineate different orientations, is shown in fig. la. The orientations of the regions designated with letters were determined by Laue X-ray back-reflection methods and plotted on stereograms. The orientation relationships of the designated components were determined by comparing the values for the nine angles between the three respective cube poles of each orientation with the values calculated in a formal treatment of octahedral multiple twinning in cubic crystals. Germanium, diamond cubic in structure, has the octahedral twinning habit. I am indebted to K. H. Storks for the calculation of the angular relationships of cube poles in octahedral twinning to four orders. The set of values for the nine angles is distinctive of the order of twinning. Confirmation for a multiple twin relationship is obtained from the determined indices of the mirror planes. These exist for all orders of twinning through the third and for some of the fourth." If the orientations are not those for twinning, then the nine angles for the cube poles do not correspond in value and distribution to those formally calculated. Since all nine angles must correspond in values and distribution of values to the calculated ones, the Laue method with a precision of one or two degrees is adequate to establish or deny with confidence the existence of multiple twins. Regions of the same orientation can also frequently be identified by the optical reflections. For example, the narrow twin bands in A at 2: 00 o'clock have orientation B1. The interesting twin relationships shown schematically in fig. lb were found for the section in fig. la. Most of this slice was made up of orientation, A, appearing in widely separated regions. Of the four possible first order twins of A, three were present in this slice and are designated by B with subscripts. Four second order twins of A are designated by C with subscripts. It is worth emphasizing that two of these, C, and C,, are second orders of A through the first order missing in this section. Two regions, designated by D with subscripts are third order twins of A. D2 is a sixth order twin of D,. All orientations found were ascribable to multiple twinning, as if the orientations in this section originated earlier in solidification from a single nucleus. The presence of extensive multiple twinning to- gether with the absence of other orientations appears to be a characteristic result in many instances of solidification of germanium. Fertile conditions for twinning probably exist in the array of atoms in the diamond cubic structure. The high order twins in the section shown, it is reasonable to presume, are the result of progressive octahedral twinning through several generations in the material freezing earlier. Some of these generations do not appear in this section, it is suggested, because their orientations with respect to the growth direction were unfavorable for survival. The extensive twinning is probably promoted during solidification by constraint imposed by volume increase, and to an irregular growth front. Twinning may also be due, in part, to the attempt of the solidifying region to attain the orientation most favorable to the growth direction (maximum thermal gradient). The nucleus for a twinned orientation could have its origin in a "stacking fault" on the close-packed octahedral plane. Further work is being done in which the course of twinning throughout an ingot is being studied. The results appear to be important in the general theory of solidification.

Jan 1, 1951