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The opening session* was held in the hall of the Franklin Institute, on Tuesday evening, June 20th, President Holley in the chair. The President introduced Mr. Franklin B. Gowen, who addressed the Institute as follows: Mr. President and Gentlemen : It has been made my pleasant duty to welcome you to the city of Philadelphia, but in so doing I shrink, with some natural reluctance, from appearing before an audience so much better fitted than I am to cope with the subjects which are usually presented to your association, and I can assure you that no trembling neophyte, first venturing within the groves of the Academy, or walking, with sacred reverence, in the gardens of Plato, felt more natural dread at the consequence of his own temerity than I do in appearing before an audience composed of geutlenlen belonging to a scientific society of which I am but too sensible that until now I have been a member only in name. In olden times, upon entering a temple sacred to the worship of any deity, it was customary to lay some offering upon the altar, and, in following this custom, it will be my duty, before entering upon the more pleasant part of the task which is assigned me, to call your attention to a subject with which I have been somewhat familiar, and which is entirely within the scope of your investigations, in the belief that I may throw out some hints or some suggestions of a process that may be fully developed by some of you, and eventually lead to the introduction of that which may be of service to the human race. The satirist who described the philosopher whom he met, as engaged in the process of extracting sunbeams from cucumbers,

By Frank E. Woolley, Robert D. Pehlke

Jan 1, 1965

By Albert Sir Kitson

THE manganese ore deposits of the Gold Coast, British West Africa, occur in very ancient rocks, of both sedimentary and metamorphic types. In. certain respects, they strongly resemble those of India and Brazil, as contrasted with those of Tertiary age in Georgia. Viewed from the present condition of the maganiferous rocks, the oldest deposits are in the sediments. Later than these are the progressively metamorphosed representatives of these sediments; youngest are the products of decay and degradation with the concentration of manganese oxide of both areas. The oldest occurrences are in argillaceous and siliceous phyllites and slates, which show only a moderate amount of metamorphism. They belong to a series which also includes mudstones, sandstones, grits, conglomerates and subordinate limestones, with tuffs and lava-flow's largely of basic types. To this series I have given the name Birrim. Its age is unknown, for no definite fossils have been discovered in it. As the characteristics of these non-fossiliferous strata at many places are the same as those of strata in many parts of the world that are suitable for the preservation of fossils and that contain them, it is assumed that the Gold Coast deposits are pre-Cambrian. These rocks of the Birrim series have normally a northeast-southwest strike and are folded, but not to any very great degree except in certain belts. From the Eastern Province of the Gold Coast they may be traversed across their strike for more than 600 miles to the extreme northwestern corner of the Northern Territories. Thence they probably extend much further into French Territory.

Jan 1, 1927

By C. H. Jr. Herty

DURING the past few years frequent reference has been made to a certain type of iron known generally as "bad iron," "dirty iron," etc., both by steelmakers and producers of iron castings.1 Open-hearth operators have claimed that such iron was entirely within the specified limits as to ordinary analysis but it was difficult to make good steel from it. It has been suggested that unreduced material in the iron is responsible, also that most trouble is experienced with the iron when the blast furnace is delivering a product whose analysis is more or less variable. Other reasons suggested are the use of scrap or borings, unsintered flue dust in the burden, a cold hearth, too high a proportion of unsuitable grade of ore, or the form of the carbon in the iron. Accordingly, a subcommittee was appointed at the fall meeting of the Open-hearth Committee of the American Institute of Mining and Metallurgical Engineers held in Pittsburgh in October, 1926, to investigate the reasons for the occurrence of this bad iron and suggest methods for preventing its appearance. This committee enlisted the cooperation of the U. S: Bureau of Mines Experiment Station at Pittsburgh in undertaking a study of pig-iron quality as affecting the open hearth. The following is a report of the findings to date:

Jan 1, 1929

Discussion of the paper of Godfrey T. Vivian, presented at the Cleveland meeting, October, 1912, and published in Bulletin No. 76, October, 1912, pp. 1103 to 1109. COURTENAY DEKALB, Tucson, Ariz. (communication to the Secretary*) :--Mr. Vivian's paper is interesting as an evidence of renewed attempts to solve the problem of adapting the centrifugal machine to the uses of the metallurgist. It would not seem that the Gee machine has solved the problem, because it is manifestly of use only with quite high-grade material, since low-grade pulp could not stand the cost of treatment by a discontinuous process. The mechanism, however, would seen to accomplish grading more perfectly than the ordinary centrifugal basket. This is an entirely different thing from concentration, which is intended to yield a finished marketable product. The real problem is to design a successful continuous centrifugal machine. Ten years or snore ago a machine, which might be described as having an inverted step-basket, offered much promise, and was constructed and tested at considerable cost, but it presented insuperable difficulties. The construction of a successful continuous centrifugal would be welcomed by the whole industrial world, since its uses would be most extensive. Mr. Vivian suggests the utilization of the centrifugal machine as a substitute for slime filters in the cyanide process, but he, has apparently not tried the experiment. I tested the efficiency of centrifugal machines for this purpose in 1897-8, having to extract the cyanide solution from a highly argillaceous slime of the sticky kind which the Mexican call ?lama." Our filter-presses yielded cakes containing usually :30 per cent. of moisture, and so dense as to preclude washing. The centrifugal machine readily Brought the moisture content down to 9 per cent. and permitted fairly successful washing. Despite these advantages, the cost of power, labor, and repairs, and the loss of time in discharging the cake, exceeded the costs and

Jan 5, 1913

By Francis J. Dennis

Many factors govern the value of dredging-ground, and much capital can be wasted by the mistaken policy of contracting for the purchase of property arid the installation of machinery before a thorough examination has been made. To the uninitiated investor the presence of gold is generally the criterion, and very superficial evidence is necessary to satisfy him as to this point. he couuiclers the comprehensive report of a competent engineer as a wasteful extravagance, aild cannot understand why the engineer requires so much time and money to ascertain the information on which to base his conalusions, when the promoter can furnish him such pleaaing and satisfactory data with but little expenditure of time aud money. The uninitiated investor will often optimistically risk capital for purchase and equipment, and riot uiitil the veuture comes to grief does he learn that the condition8 are wholly unsuited for dredging. In many instances, a short preliminary examination by a competent engineer would have disclosed these facts. The mere presence of gold is by no means suficient; sonie of

Jan 1, 1912

By John B. Pearse

The works heretofore used in carrying out the Bessemer process have been constructed substantially as follows: The whole works or plant has been divided into three parts. 1. The division in which the metals for conversion are melted. 2. The division in which the metals are converted into steel and cast into ingots, or the converting department. 3. The engine and boiler department which supplies the hydraulic power required to move the machinery, and which furnishes the blast used for converting the crude metal into steel.

By Y. A. Chang

Phase relationships in the system Cr-Si have been established based on the melting point, X-ray, metallo-graphic, and DTA studies. The three intermediate phases, Cr3Si, Cr5Si,, and CrSi,, melt congruently at 177V ± I@,Cr3Si, 1680"i 20°, and 1490" *20°C, respectively, while the fourth intermediate phase CrSi, melts peritectically at 1413" i 5°C to Cr5Si3 and a melt containing 51 at. pct Si. The temperatures and compositions of the four eutectic isotherms occurring in this system are given below: DTA and metallographic evidences indicate that Cr5Si, undergoes a phase transformation at 1505" i20°C. The high-temperature form of this phase could not be retained by the quenching techniques used in this study. TECHNOLOGICAL interest in the developing of composite systems, consisting of Sic on the one hand as a fiber-reinforced material and metallic substances such as chromium, nickel, or Cr-Ni alloys as a binding agent on the other hand, stimulated the present investigation of phase relationships in the binary system Cr-Si. Earlier works concerning this system have been evaluated and summarized by ansen and Anderko.' Their phase diagram was based mainly on the works of Kieffer, Benesovsky, and schroth2 and Kurnakov.~ According to these authors, the three intermediate phases Cr3Si, CrSi, and CrSi, all melt congruently at approximately 1730°, 1600°, and 1550°C. However, they did not agree on the compositional stability of the fourth intermediate phase between Cr3Si and CrSi. Later Parthe, Nowotny, and schmid4 determined the structure of this phase to be tetragonal T-1 type using the single-crystal method, and concluded that this phase had a formula of Cr5Si3. Since the compilation of Hansen and Anderko,' a new phase diagram for the system Cr-Si has been proposed by Elliott5 based on the works of Goldschmidt and rand,' Guseva and ~vechkin,~ and Trusova, Kuzev, and Ormont8 and the earlier works quoted by Hansen and Anderko.' According to this proposed phase diagram, all four intermediate phases have large ranges of homogeneity and all melt congruently. More recently, Svechnikov, Kocherzhinskii, and yupkog studied the system Cr-Si by the DTA-method. According to their findings, the three intermediate phases, Cr3Si, Cr5Si3, and CrSi,, melt congruently at 1700°, 1720°, and 1475"C, respectively, while the fourth intermediate phase, CrSi, melts peritectically at 1475°C to Cr5Si3 and a melt containing 50 at. pct Si. The temperatures and compositions of the four eutectic isotherms were found to be: In view of the discrepancies existing in the literature concerning the system Cr-Si, it was decided to rein-vestigate the phase relationships in this system. EXPERIMENTAL a) Starting Materials. Chromium disilicide and chromium or silicon powders were used in the present study to prepare the melting point and DTA samples. CrSi, was obtained by directly reacting cold-pressed elemental powders in an atmosphere of Hz at a temperature of about 1250°C. Chromium powder, purchased from Stark Chemical Co., had the following impurities in ppm: Fe, 200; Mg, 1000; and 0, 250; while silicon powder, purchased from the Welded Carbide Co., had the following impurities in ppm: Ca, 700; and Fe, 3500. b) Melting-Point Determination and Differential Thermal Analysis. Cylindrical melting-point samples of approximately 13 mm in diam and 30 mm in length with a rectangular groove in the center were prepared by hot-pressing of well-mixed powder mixtures in graphite dies. Before the melting-point determination, the hot-pressed samples were ground on a sand paper to remove any minute surface contamination of graphite. A small hole of 1 mm in diam, drilled on the center portion of the samples, served as a blackbody cavity for the temperature measurements. DTA samples approximately 13 mm in diam and 15 mm in length were prepared in a manner similar to the melting-point samples. Melting points were determined using the Pirani technique under a helium atmosphere of 40 psi. The design, performance, and operation of this apparatus have been described in detail by Rudy and ~ro~ulski.'~ The temperature measurements were carried out with a calibrated disappearing-filament-type micro-pyrometer. The measured temperature was corrected for losses from the quartz window of the melting-point furnace and for deviations from blackbody conditions of the observation hole. The procedure for temperature correction has also been previously described." The DTA method of Heetderks, Rudy and Eckertl' was also used to check any phase transformations of selected alloys in the system Cr-Si. It was not possible to make remated runs on the same sample once melt-

Jan 1, 1969

By R. D. Mollison

"For his contributions to mining which are highlighted by perseverance; successful exploration, particularly the Kidd Creek deposit; technological advancement and sound management policies; and for his lecture, "Exploration-The Diversificiation and Development of a Mining Company." Recipient of the 1983 D.C. Jackling Award

Jan 1, 1984

By Clifford S. Wilson

ScReened pipe is designed with the view of restraining the fine, free-running sands of the production zone from entering oil wells. Its successful use is dependent on a number of factors. The nature and effects of some of these factors can be determined through experiment and observation, but some of the elements that have a distinct bearing on the use of screened pipe can be evaluated only by estimate. The important subsurface conditions which affect the use of screened pipe are: 1. Depth of production zone. 2. Extent of production zone. 3. Reservoir pressure. 4. Character and relative quantity of oil and gas. 5. Character of sediments: a. Cossolidation of beds. b. Variation in beds. c. Grain-size gradation of sands. d. Free-running characteristics of sand from different levels. Aside from the use of mechanical equipment and tools, the measures to be taken in the installation of screened pipe involve: 1. Size of liner. 2. Length of liner. 3. Design and mesh of screen. 4. Portion of liner to be screened. 5. Manner of setting liner. 6. Preparation of or washing of the well before or during the setting of the screen. 7. Manner of bringing in the well. 8. Manner of flowing the well. Values applicable to the actual subsurface conditions that exist at any well can only be approximated. The accuracy of the estimate will be measured by the amount and quality of the evidence at hand and the personal factor of ability to interpret the evidence fairly, whether

Jan 1, 1933

By William L. Fink, E. H. Dix, L. A. Willey

The results of a preliminary investigation of the aluminum-iron-manganese system showed that small amounts of iron (0.10 per cent) substantially reduce the solid solubility of manganese in aluminum. This is clearly shown in the photomicrographs of three alloys, Figs. 1 to 3. Fig. 1, of an alloy containing 1.04 per cent manganese after a heat treatment at 626° C. for 45 hr., shows only solid solution. This alloy contained less than 0.008 per cent iron. Fig. 2 shows the abundance of a constituent (which undoubtedly contains aluminum, manganese and iron) in an alloy containing 1.00 per cent manganese and 0.11 percent iron after a solution heat treatment at 625" C. for 63 hr. For comparison, Fig. 3 is included to show the relatively small amount of constituent (FeA13) in a similarly heat-treated aluminum alloy containing 0.10 per cent iron but no manganese. These data necessitated a reconsideration of the binary aluminum-manganese diagram that was previously presented,' inasmuch as the alloys used in that work contained from 0.02 to 0.05 per cent iron. This paper is the fourteenth of a series from the Research Laboratories of the Aluminum Company of America reporting the results of investigations of equilibrium relations in aluminum-base alloys of high purity. The purpose was to determine the phase relations in aluminum with aluminum-manganese alloys containing the smallest amount of iron that could be realized with the purest material available at the present time (less than 0.01 per cent iron). Since the previous publication from these laboratories, five investigations of the aluminum-manganese system have been reported. Krings and Ostmannz assigned the formula MnA14 to the compound at the aluminum end of the syst,em, and found a eutectic between this compound and aluminum at 649" C. and 3 per cent manganese.

Jan 1, 1933

By Edward Saibel, W. T. Lankford

DURING the course of an investigation of the plastic flow of aluminum aircraft sheet under combined loads, several problems arose in which analyses of the conditions leading to unstable plastic flow were needed. In order to provide these analyses, and in the hope of attaining a better understanding of the general problem of unstable plastic flow, the present study was undertaken. It is well known that unstable plastic flow is associated with a form of mechanical instability frequently observed during the plastic deformation of ductile metals. This instability is characterized by the fact that, at its onset, plastic straining will proceed at a constant magnitude of the externally applied forces. It is further typical that the resulting unstable flow is generally accompanied by the formation of a neck, a local bulging, or some other form of heterogeneous deformation. Perhaps the most familiar example of unstable plastic flow to the metallurgist is the formation of the neck in the ordinary tension test. It is well known that in this test most metals exhibit a maximum in the externally applied load, followed by the process commonly referred to. as "necking down." Instability in the simple tension test has been frequently discussed and numerous investigators 1,2.3,12 have derived the criterion for instability in terms of a critical rate of strain hardening. It is the purpose of the present study to extend the criterion for unstable flow to the more general case where the body undergoing flow is subjected to combined loads. It is hoped that the problems considered will provide a more consistent picture of the general features of this important form of mechanical instability. The most practical implications of instability in plastic flow arise in connection with sheet metal forming operations. In the formation of a great many sheet metal parts, the deformations are produced primarily by stretching. If the conditions which lead to unstable flow are fulfilled in such a formation, and if the resultant instability leads to a pronounced localization of flow, then the useful limit of ductility of the material will have been reached. It is also essential that the effects of instability be taken into consideration in any study of the plastic flow and rupture of metals under combined stresses. In general, when unstable plastic flow is initiated, straining becomes localized, the geometry of the test specimen changes, and the state of stress in that portion of the specimen undergoing plastic flow is no longer under external control. In many past studies of the effects of combined stresses on flow and rupture, account has not been taken of the fact that, although a given test may be started under constant

Jan 1, 1947

Welfare endeavor in connection with both the metal and the coal mines of Utah has shown gratifying progress during recent years and both the operators and their employees are deserving of much credit for the efforts put forth to better living, working, educational and receational conditions in most of the mining camps of the state. In the older metal mining camps of Utah, where the towns are incorporated and independent of the mining properties operating in the vicinity, less opportunity is presented for the companies to exercise efforts looking towards improved welfare conditions than is the case of camps located on company ground and under the full control of operators.

Jan 1, 1925

By Henry S. Munroe

THE plan of organizing a summer class of students of the School of Mines, for the practical study of mining and miner's work, received at the outset the following cordial indorsement : I have thought over the plan proposed by you of taking the students to the mines during the summer, and of having them actually take part, under the direction of skilled workmen, in all the various kinds of mining work; and of using them as a carps of engineers to make Inside and outside surveys, particularly with a view to the detailed study of the geology of the mine. I have no hesitation in saying, that if the students have been previously instructed in the theoretical part of their studies, by lectures and practice during the winter, the plan would be an admirable one. Of course experience will suggest modifications of detail. From the work you have done at our mines this spring, I feel sure that you would be perfectly competent to carry out your plan, and I shall gladly aid you in any way I can. "Yours, sincerely, T. B. Coxe." The plan of the proposed summer school thus indorsed by Mr. Coxe was adopted by the trustees of Columbia College, and an appropriation of one thousand dollars, or so much thereof as might be necessary, was voted for the experiment. A volunteer class of thirteen students was formed, and the first summer school was held at Drifton, in July and August of that. year (1877). The following extract, from an editorial notice in the Engineering and Mining Journal, of August 11, 1877, will give an idea of the 'organization of the school and the work required of the students. "The students, on reporting to Professor Munroe, were divided into squads of two or three men each, and on Monday, July 2d, were assigned to the Care of skilled miners, selected for the purpose by the mine boss, for instruction in gangway work. Half of the students worked in the morning and the other half in the afternoon, one squad at a time with each miner. The times of going and coming to and from work were so arranged that each student spent four to four and a half hours in the mine each day. While in the mine they assisted the miner to load his car, thereby learning readily to distinguish 'slate ' and

Jan 1, 1881

By A. J. Opinsky

THE purpose of this note is to indicate the locations and sizes of various interstitial holes in the orthorhombic uranium lattice based on a hard-sphere model. First, plane configurations of three and four atoms will be examined, and then the true interstices surrounded by four atoms in space and by five atoms in space will be obtained. The data and notation contained in a report by Tucker' will be used. Plane Configurations Fig. 1 presents the orthorhombic uranium lattice made of spheres touching at the closest interatomic distance. The three light-colored spheres in the ab plane are illustrative of the first type of configuration to be examined. If one edge of the unit cell is taken as the origin, the three atoms can be represented by the vectors [Oi + Oj + Ok], [ai + Oj + Ok] and [(a/2)i + (b/2)j + Ok] where i, j, and k are respectively parallel to a, b, and c. In the future, this notation will be shortened to [000], [a00] and [a/2 b/2 0], respectively. A vector R = [r s t] de-scribes the position of the hole surrounded by the atoms. Since the center of the hole must be equidistant from the three atoms R2 = r2 + s2 + t2 = (r-a)2 + s2 + t2 = (r-a/2)2 + (s-b/2)2 + t2. R = [a/2 (b/4) - (a2/4b) 0] is the solution of these

Jan 1, 1955

By E. L. Mooney, D. F. Gibson, T. E. Lehman

This paper outlines the features of a computerized planning system, which was developed to aid surface mining and reclamation evaluation. Essential features of the system include three main modules: production, reclamation, and impact analysis. In addition, the system incorporates a large number of computerized data analyses and display features, which are described and illustrated in this paper.

Jan 1, 1983

By L. L. Foley, C. V. Millikan

The discovery of Bromide production in the Fitts field, shallow production in Jackson County of Southwestern Oklahoma, abundant production in the Edmond field, and discovery of many small pools in all parts of the state, were the events that made petroleum history in Oklahoma in 1934. Wildcatting was much more active, as evidenced by a number of new discoveries. There was no important development in the older fields. The rapid decline of the potential of the Oklahoma City field was an important feature of the history of the year. The accompanying tabulation of oil fields (Table 1) is not complete. Many of the early records of operators and pipe line companies are lost and it will be impossible to work up complete statistics for a number of the older fields. The table includes most of the important fields of the state and includes fields of a number of different types. It is hoped that a great many additional fields may be worked up for next year's report. Fitts Pool.—The Fitts pool, in Pontotoc County, was discovered in 1933. Before the middle of 1934, the Pennsylvanian sands yielded -some oil at depths ranging from 1400 to 2800 ft. The Hunton series (Siluro-Devonian) produced most of the oil with considerable gas. In July, 1934, a well in sec. 25, T.2N., R.6E. was completed in the Bromide (Ordovician " Wilcox ") with an initial production of about 300 bbl. a day. Less than a month later a second Bromide sand well was completed in sec. 30, T.2N., R.7E., which made over 200 bbl. an hour. This started an active drilling campaign, which was accelerated when some of the major companies paid good prices for adjacent acreage. At the end of the year, 23 wells had been completed and the rate of development was increasing rapidly. It is a major oil field. The Fitts pool opened a new geological province for oil production. The structure is a faulted anticline in a graben. The producing formation (Bromide) and the Arbuckle lime below it crop out about 2 miles south of present production. The Hunton lime crops out about 2½ miles north. The field is in a sharply folded and faulted area on the northeast side of the Arbuckle uplift. Heretofore, it was generally considered not favorable for oil production, although some gas had been found in various places. The play has extended east into the McAlester coal basin, and southeast toward the

Jan 1, 1935

By J. R. Long, T. R. Graham, R. G. Feustel, R. S. Dean

THE comprehensive study of the copper-manganese-zinc alloy system in the Bureau of Mines Laboratories has so far been principally concerned with alloys that lie within the alpha solid solution field of the system. Two regions, one centering about 65 per cent copper, 10 manganese and 25 zinc, and the other centering about 70 per cent copper, 20 manganese, 10 zinc, have been carefully examined.1,2 These have indicated that when the alloys are made with electrolytic manganese considerable amounts may be readily introduced and that the strength and hardness are increased without excessive losses in ductility. In the course of the work of establishing the limits of the alpha solid solution range,3 enough of certain of the alloys was prepared to permit determination of their physical properties at a future date. The 60 per cent copper alloys concerned here are part of that series. They cross through the alpha field and into the adjacent alpha plus beta and alpha plus X fields, and are of interest because they offer some information on the effects of manganese on alloys lying in these fields. COMPOSITION AND FABRICATION OF ALLOYS The chemical composition of the alloys involved is given in Table I. They were intended to contain 60 per cent copper with manganese increasing from 5 to 25 per cent in 5 per cent steps and zinc decreasing [ ] from 35 to 15 per cent. The analyses are so close to the intended composition that the alloys will be referred to hereafter by their nominal compositions. They were finished into sheet by cold-rolling and intermediate annealing procedures calculated to produce sheet 1/16 in. thick, cold-reduced by 20, 40, 60, and 80 per cent in thickness. Physical properties were determined on standard flat tensile specimens with 4-in. gauge length, although the test gauge section used was 2 in. The properties were obtained on cold-worked material and on material annealed at temperatures ranging from l00° to 1500°F. after 60 per cent cold reduction. Since an annealing temperature of 1200°F.

Jan 1, 1946

By C. E. Wood

THIS paper is a brief report of experimental work undertaken to determine whether barium oxide in any quantity increases the desulfurizing action of blast-furnace slags. Industrial furnace operation with slag containing small quantities of barium oxide, referred to later, interested S. A. Sanford of the Commercial Chemical Co., Youngstown, Ohio, to conduct experiments to furnish comparative results on desulfurization with normal slag and slag containing small quantities of barium oxide. The U. S. Bureau of Mines agreed to assist on the problem because of the possible saving in fuel if the desulfurizing action of blast-furnace slag can be substantially increased, also because the experiments would yield new information on sulfur elimination in general, a matter of economic importance in furnace practice. A more complete and fundamental study of desulfurization of iron by slag is in progress.

Jan 1, 1929

By Louis Huntoon

THE USE of the aeroplane in engineering work is quite recent. Its general application to all branches of engineering, including mining and metallurgical engineering, is increasing and its possible uses are most promising. Comparatively little has been published on the sub-ject in the mining and metallurgical press, and it is for this reason that the following notes are recorded. In March, 1922, Prof. E. L. Bruce published an article in the Transactions of the Canadian Mining Institute showing the possible applications of the aeroplane to preliminary geological surveys. In October, 1922, Mr. DeShea, representative of the Fairchild Aerial Survey Co., of New York, discussed the subject before the New York Section of the Mining and Metallurgical Society. The writer has been in correspondence with the Laurentide Air Service of Montreal and engineers who have flown. Canada, with its many lakes and rivers-favorable landing places, meets the prerequisite for successful use of the aeroplane in an unexplored and uninhabited or sparsely inhabited country. During the open season hydroplanes are used, and during the, winter season ski runners are attached to the axle in lieu of wheels. With skiis attached it has been found practicable to take off and land on any depth of snow quite readily. Winter flying in northern Canada is quite common. The Laurentide Lumber Co., appreciating the value of the aeroplane, used them for two or three years for timber cruising, and about 1921 turned their equip-ment over to the Laurentide Air Service of Montreal, who operate flying machines. The photographic and engineering work in Canada is done by the Fair-child Aerial Surveys Co. under a contract with the Laurentide Company.

Jan 12, 1923