Search Documents

By R. H. Richards, A. E. Woodward

In Rittinger's Aufbereitungskunde of 1867 occurs (p. 195) the following table, which shows the rate of falling in water of fragments of minerals, of irregular shapes and of five different specific gravities: Diameter of particles in millimeters. 10 8 6 4 3 2 1 .5 Sp. Or. Velocity in meters per second. Auriferous silver, 16..9 .8 .7 .57 .5 .4 .29 .20 Galena,. ..7.5 .62 .55 .48 .39 54 .28 .20 .14 Pyrites,. ..5.0 .49 .43 .38 .30 .26 .22 .15 .10 Quartz,. ..2.6 -30 .27 24 .19 .17 .14 .10 .07 Coal,. ..1.3 .13 .12 .10 .08 .07 .06 .04 .03 With the purpose of extending this valuable table, to cover a larger number of minerals and sizes of each mineral, and of making it more easy of application in deciding upon a sieve-scale for any group of minerals, we have prepared the curves of velocity of fall of bodies in water shown in Plates I., XI., 111. and IV., using Rittinger's formula V= 2.44d(8 —1) where V= velocity in millimeters per second. " D = diameter of particles in meters. " 8 = specific gravity of the mineral. These curves embrace a large number of specific gravities, and for each specific gravity the relation of the diameter of the mineral particle to the velocity of its fall in water is given for all diameters and velocities used in practice. The second diagram is an enlargement of the lower left-hand corner of the first, the third bears the same relation to the second, and in like manner the fourth to the third. Plate I, therefore, covers the work of the coarsest jigging 2 inches in diameter; and under

Jan 1, 1890

By L. A. Updegraff

Before discussing the application of capacitance for the measurement of moisture content in a moving stream of coal it might be well to first give a brief description of the process and then show how it can be applied to the coal industry. A capacitor may be described as a device having two conductors separated by an insulator, the conductors hereafter being designated as a test cell or test plates and the insulator as the dielectric. Capacitance, therefore, is a measure of the ability of a capacitor to store an electrical charge. Two basic factors that affect capacitance are the dimensions of the capacitor and the dielectric constant of the insulator. Capacitor dimensions which affect its capacity are the area A of the conductive surface, and the distance d between plates. Capacitance is inversely proportional to the distance between plates and directly proportional to area A, so if capacitance is indicated as C and the dielectric constant as K the equation for capacitance would be C = AK/d. The dielectric constant can be described as the ratio of the actual capacitance of any given material to that of a vacuum, which is unity. In industrial applications the area of the plates remains constant as also does the distance between them, leaving the dielectric constant as the only variable to affect the capacitance measurement. Figure 1 is a schematic diagram of an r-f excited capacitance bridge in which a test cell is part of the circuit. This bridge consists of four capacitors in two pairs connected across an a-c voltage source. In one side of the circuit the two capacitors are fixed but in the other side they are variable, one being the rebalance capacitor operated by the servo motor and the other the test plates between which the dielectric passes. Capacity of the plates is a function of the dielectric constant of the material between them and is measured at radio frequency. Within the recording instrument is an r-f oscillator and a 60 c ps modulator. The radio frequency signal is generated by the oscillator, modulated by a 60 cps wave, and sent to the bridge. Therefore the signal entering the capacitive bridge is a radio frequency carrier with a 60 cycle envelope, If the bridge is in balance as the signal enters there would be no voltage drop and so no output by the detector. As long as the dielectric constant remains the same the bridge will stay in balance. However, any change in the dielectric constant, which in this case would be a change in moisture content, would affect the bridge. Higher moisture increases the capacity of the test cell which causes less voltage to develop across it causing imbalance of the bridge. This in turn causes a radio frequency signal to appear at the detector. Output from the detector is a 60 cycle ripple which is in proportion to the imbalance of the circuit. A 60 cycle amplifier boosts the detector signal to enough power to drive the servo motor which positions the recording pen and also rotates the variable capacitor, to which it is mechanically connected, to bring the bridge back in balance. An increase in moisture causes the servo motor to rotate in one direction, but a decrease causes imbalance in the opposite direction, and thus rotates the motor in that direction. This brings the bridge back in balance and stops the motor. The bridge shown in Figure 1 has been modified so as to provide a wide range of adjustments. Coarse and fine span adjustments located in the recording instrument are set to govern the amount of pen movement for a given change in capacitance. A measuring head unit contains coarse and fine zero adjustments for

Jan 1, 1961

By John V. Beall

GOING west from Denver on Route 6, the direct road to Grand Junction, one gets the first glimpse of mining a few miles east of Denver near Idaho Springs where the workings of defunct gold mines are visible on the sides of mountains along the highway. One enterprising company is turning a profit by showing tourists through the mine and mill and then selling them gold samples on the way out. We have always known that mining people are ingenious, but this proves it. About five and a half hours fast driving west from Denver brings one to Rifle, Colo., which is the site of the oil shale mine, retorting plant, and refinery of the U. S. Bureau of Mines. As you drive up to the mine, you can see a portal high on the face of the cliff in front of you where the mine surface plant literally hangs by its toenails. Below, the retorting plant and refinery gleam in the sunlight. Up at the mine, Fred Wright will show you how the oil shale is extracted in two benches (a third bench would be used for commercial mining) by the room-and-pillar method. In mining the top level, an underground crew of thirteen men have been able to produce 1500 tons of shale in each eight-hour shift. To do this, the mine is thoroughly mechanized. The mining method is de- scribed in the September issue of Mining Engineering.

Jan 1, 1949

By John F. McElhiney, Hosseim Kazemi

This chapter is a review of fluid flow and mass trans- port in fractured rocks. The topics include: single-phase and multiple-phase flow theory, formation productivity or injectivity improvement by artificial fracturing, and mass transport associated with fracture acidizing. Possible extension and application of such ideas to in situ mining in fractured rocks are presented.

Jan 1, 1974

Jan 1, 1963

By John D. Morgan, Sylvain J. Pirson

An instantaneous and continuous analysis of a mineral suspension should be of great value in controlling various mineral preparation processes. Described herein is a method of analysis based on the use of high-frequency alternating current, which, under certain restrictive conditions, could be of use. Theoretical Considerations In a suspension of conductive minerals, the electrical effect primarily responsible for the variations in electric conductivity is the capacitance. In Fig Ia, let an alternating voltage E be applied across two electrodes F and F', between which are two rows (S and T) of mineral particles, all of approximately the same size, immersed in a fluid. Let the number of rows of particles between the electrodes be R and the number of particles in each row be N. If A is the area of a particle, D is the distance separating two particles, and k is a constant depending on the fluid, the capacity, CO, of the particle system will be given by: KRA C°= ND Referring now to Fig Ib, let R, the number of rows, be held constant, but let N, the number of particles in each row (S and T), be increased X-fold. The capacity, C1, of

Jan 1, 1949

Low Zinc Prices Close Alcoa Mine Alcoa Mining Co., announced that it will suspend operations at its Hutson mine, near Salem, Ky., because of low zinc prices, January 15. The Aluminum Co. of America subsidiary announced that the low market has made zinc mining un- profitable. About 70 men were employed at the mine, with a production of about 5000 tons of zinc annually. Alcoa said the shutdown would not affect other company operations, with most of the men at Hutson absorbed in the mining firm's fluorspar operations in the same area.

Jan 2, 1953

THE transformation, in a sample of levitation melted iodide titanium, has been studied with a Leitz hot-stage microscope. The specimen was etched in HF:HNO3: glycerine, (1:1:2) giving a structure shown in Fig. 1, and was then heated at approximately 5OC per min. At 870°C (±5OC) the etching product disappeared, the a-grain boundaries showed in relief, and some new grain boundaries (presumably of ß) appeared (Fig. 2, see arrow). Some evidence of ß-grain growth is indicated by the apparent longitudinal movement of a ß-grain boundary shown in Figs. 2 and 3 (see arrows). The specimen was later heated to 1000°C and then cooled at 2°C per min. At 845°C rumpling of the surface was first noticed, Fig. 4, and continued at constant temperature. The photomicrograph reproduced in Fig. 5 was taken 6 sec after Fig. 4, at 845°C. Fig. 6 shows the structure after cooling to room temperature. The room-temperature structure, showing a rumpled surface has been observed by previous investigators.' These structures presumably indicate a sheer transformation ß - a, athermally nucleated, but capable of isothermal progression.

Jan 1, 1960

By C. M. Smith

DELEGATES from 26 Local Sections and- Divisions of the Institute had three stimulating sessions during the Annual Meeting, a few topics still remaining to be discussed after the two Monday sessions.. The final session was held on Thursday morning. An abstract of the discussion will be transmitted to each delegate present. The topics included: Student relations. Section operation, membership, employment, MINING AND METALLURGY, a new nonmetallic minerals Division. licensing of engineers, and increased allotments of money to Local Sections. Some of the Sections felt that the present limit of $250 allotted to them - from the national treasury was insufficient to carry on their activities, and that this maximum should he increased. A resolution to this effect was passed for transmission to the Board of Directors.

Jan 1, 1935

By Charles M. Rolker

The Mariposa estate, a grant made by the Mexican Government to Juan 13. Alvarado, during the time when California was still under the dominion of Mexico, was purchased in 1847 by J. C. Fremont, and the United States patent issued to him in 1856. By sale, or its equivalent, money advanced, the property came into the hands of the Mariposa Company, June 25th, 1863, and through a varied existence of work and temporary inactivity, has as yet been kept as an undivided property, and rests at present with the Mariposa Land and Mining Company of California. I pass over this period of 15 years without giving the history of the ups and downs of the estate, partly because it is familiar to many, and also because I think in such a case this paper would assume too much the character of a narrative. The estate is situated in Mariposa County, California, about 170 miles southeast of San Francisco. It begins in lat. 37' 26' 38'' north, and long. 119' 55' west, and runs 6 miles north; thence 69 miles west; thence 5 miles northwesterly towards the Merced River; thence 84 miles southerly; thence 3 miles easterly; thence 1 mile southerly; thence 2 miles easterly; thence 2 miles southerly; thence 2 miles easterly; thence 1 mile southerly; thence 2 miles easterly; thence 1 mile northerly, and thence 2 miles easterly to the place of the beginning; embracing 44,387 acres (70 sq. miles) more or less. To describe this vast estate in detail as to its full geology, its numerous quartz veins, its many facilities to exploit them and work them by cheap methods, would lead me further than I intend to go at present, and I will content myself to describe the latest workings of the company and its immediate field of operations. As long ago as 1860 the late Dr. Adelberg advised the running of an adit from the northwestern edge of the estate at Benton Mills 011 the Mereed River. His object was to undercut the deepest workings of the then paying mines on the estate—the Pine Tree and Josephine. Following this advice, the tunnel known as "River Tunnel " was commenced. Its entrance is in S. 5, T. 4, s. R. 17 E. It is run in

Jan 1, 1879

By John Ward Smith

Dawsonite-bearing oil shale of Colorado's Green River formation offers a unique and vast (more than 5.9 Gt of A120 j) resource of easily extractable alumina. The processing methods required by the thermal reactions of dawsonite and its oil-shale carrier also require production of shale oil, soda ash, and nahcolite as marketable coproducts. These production methods are presented. The alumina production process is contrasted with the Bayer process to describe technical advantages of extraction of alumina from oil shale which may offset the problems associated with processing a relatively lean ore. While alumina production from oil shale requires development of new technology, the technical problems appear solvable. Only the political problems arising from the now onerous and completely unnecessary federal oil-shale withdrawal appear less solvable.

Jan 1, 1982

Carlisle: An old friend and good friend, Alan Bateman, is the Silliman Professor of Geology Emeritus at Yale and editor of the Journal of Economic Geology. Now, Alan, let's start off by telling us something about how you became interested in copper. Bateman: Well, after I left Yale in 1913, I was appointed one of the field members of the Secondary Enrichment Investigation. We spent three years in the field studying all the copper deposits of North America, trying to find out how secondary copper enrichment took place. As part of this investigation, I went up to Kennecott, Alaska, in 1916. After the trip I was asked by the president of the company to become consulting geologist to them. I accepted his offer, and to this day I'm still consulting geologist to the Kennecott Copper Corp. Up at Kennecott, there were both Henry Krumb and my good friend Henry DeWitt Smith, who was general superintendent. He and I had been together at Yale, and I had ushered at his wedding. Interestingly enough, Henry took his bride to Alaska and I took mine there two months later. My assistant was Don McLaughlin, and I think that was his first experience in a mining camp. We published a paper on Kennecott together and cemented a friendship lasting to this day.

Jan 11, 1964

By O. U. Bradley

THE extent of losses, due to evaporation, sediment, and water, in crude oil stored in steel tanks, is a very interesting question, and particularly so at this time, when every reasonable measure should be employed to eliminate all possible losses of this important natural product. Available information on this subject is incomplete; e.g., during the development of the Cushing Field, considerable surplus oil was stored in steel tanks, but from time to time, owing to changes in weather, somelosses by evaporation and short storage room on the leases, these tanks were topped out, thus rendering inaccurate any system designed to determine the average rate of evaporation or other losses of the oil over a given period. , Furthermore, the losses, as shown by the records at the time, as a result of hasty gages, failed to take into account the temperature and gravity of the oil. Losses may be classified roughly as occurring from evaporation, presence of sediment and water, and leakage. The coefficient of expansion and contraction of crude oil, in relation to temperature conditions, is of material importance; also, the rate of evaporation is dependent upon the gravity of the oil, as the escape of the lighter hydrocarbons in fresh Cushing oil, of from 40 to 42 gravity, on a warm day is considerable, and from available records of temporary storage, it is safe to assume that a loss of 1 to 13 per cent. in volume will easily occur in light crude oil of Cushing grade over a period of. 6 months, including the summer season. The presence of sediment, water, and other impurities, in the oil will also cause, more or less deterioration in quality, particularly when the fresh production is run direct from the. gage tanks, or from the wells on the lease to steel storage, as is often the case when an oil field is being rapidly developed. The bad oil will settle to the bottom of the tanks and may be determined by thiefing and running a centrifuge test on the sample. The amount of water in the oil depends entirely on the conditions under which it is produced. Sometimes in large producing wells, with heavy gas pressure, some water may come in with the oil, particularly if the well has been drilled to the top of a water sand. Under these conditions, cut oil is often produced, which, if not settled out, is carried over into the steel tanks.

Jan 7, 1918

By Henry Schwellenbach

LABOR shortages, rising wages, and changes in moisture and fines content of the ore necessitated a review of the flowsheet at Warren Foundry & Pipe Co's. Mt. Hope, N. J. Mines Div. This plant had been designed prior to World War II, and started operations in January 1945. When this operation was designed there was an oversupply of labor in the area, wages were at a reasonable level, the run-of-mine ore was low in moisture, and there was a limited amount of fines. These factors all favored use of hand picking for cleaning rougher lump concentrate. Since that time, many changes have occurred. The proximity of defense industries and large military installations, has created one of the most acute labor shortages in the country. This labor shortage together with present wage levels, and the increase in moisture and fines in the ore created several problems. The increase in moisture and fines may be attributed to changed mining methods, the extensive use of sprays, and the opening of new mining areas bringing an increase in ground water. [ ] Two problems were presented by the increase in moisture and fines. The first was that lump ore arrived at the open hearth in an unacceptable condition, due to the segregation enroute of the large amount of fines that had adhered to the lumps. The second problem was that high magnetite content fines coated the large lumps, making it difficult for pickers to distinguish middling by other than the relative weight. [ ]

Jan 1, 1952

By E. H. Wells, A. Andreas

Greater progress than in any previous year was accomplished by the oil industry in New Mexico in 1936. The total number of completions in the state was 631, of which 549 were oil wells, 21 were hydrocarbon gas wells, three were carbon dioxide gas wells, and 58 were dry holes. The total oil production for the year was 26,804,446 bbl. Compared with the production for 1935 of 20,228,947 bbl., this represented a gain of 32.5 per cent. Of the total production, 25,337,382 bbl. came from Lea County. The average daily nonmarginal well allowable for that county was 115 bbl. the first of the year and 86 bbl. at the close. Production was regulated by the New Mexico Oil Conservation Commission,

Jan 1, 1937

By H. E. Strauss

The time-to-fracture test has been applied to pure platinum and to two alloys of platinum under the special conditions of small cross-sectional area of the specimens and of a test temperature above the annealing temperature. While the results are similar in character to those secured with large specimens of steel at temperatures below the annealing temperatures, two differences are noted: (I) an upward inflection in the curves for log stress vs. log time for the alloys, and (2) a sharp break in the curve for log stress vs. log time for pure platinum when single crystals filled the wire. The experiments showed that: (I) platinum and 10 per cent rhodium-platinum maintained their strengths at IIOO°C. better than did to per cent iridium-platinum, and (2) the rhodium-platinum after a time exceeded the iridium-platinum in strength at IIOO°C. Platinum alloys in their service at high temperatures encounter conditions somewhat similar to those that exist in the usual form of the "time-to-fracture"l test with steel. This paper is intended primarily to present results obtained by a "time-to-fracture" test under conditions approximating actual service for platinum (at the temperature IIOO°C. under oxidizing conditions) with three materials, pure platinum (99.99 per cent), a platinum alloy with 10 per cent iridium, and a platinum alloy with 10 per cent rhodium. The experimental procedure differed from that previously used in this type of measurement in that the samples were of small diameter (0.010 in.), were fully annealed, and were tested at a temperature definitely above their annealing points (600°C., IOOO°C. and 1050°C., respectively, for 60 per cent cold reduction and 15 min. heating time2,3). The experimental arrangement was similar to that previously described,' using as heating unit a small, horizontal, platinum-wound furnace, ½ by 12 in., maintained at constant temperature by an automatic controller. The samples were 0.010-in. wires, which had been annealed at 1200°C. by drawing them slowly through the furnace. The time-to-fracture was measured electrically. Elongation was not determined because of the difficulties inherent in the experimental arrangement. Life—that is, the time-to-fracture—was considered the important property in these first tests. No attempt was made to measure the reduction in area, but the types of fracture were noted qualitatively; in the text they are referred to as (I) the normal, plastic, or necked fracture, (2) the knife-edge fracture, and (3) the brittle or intercrystalline fratture with small reduction of area. Results for different constant applied stresses are plotted in Fig. I. In all cases at least two trials were made for each stress, although they cannot always be indicated separately on the curves. The breaking Stresses drop very rapidly to a small frat-286

Jan 1, 1943

By H. E. Strauss

The time-to-fracture test has been applied to pure platinum and to two alloys of platinum under the special conditions of small cross-sectional area of the specimens and of a test temperature above the annealing temperature. While the results are similar in character to those secured with large specimens of steel at temperatures below the annealing temperatures, two differences are noted: (I) an upward inflection in the curves for log stress vs. log time for the alloys, and (2) a sharp break in the curve for log stress vs. log time for pure platinum when single crystals filled the wire. The experiments showed that: (I) platinum and 10 per cent rhodium-platinum maintained their strengths at IIOO°C. better than did to per cent iridium-platinum, and (2) the rhodium-platinum after a time exceeded the iridium-platinum in strength at IIOO°C. Platinum alloys in their service at high temperatures encounter conditions somewhat similar to those that exist in the usual form of the "time-to-fracture"l test with steel. This paper is intended primarily to present results obtained by a "time-to-fracture" test under conditions approximating actual service for platinum (at the temperature IIOO°C. under oxidizing conditions) with three materials, pure platinum (99.99 per cent), a platinum alloy with 10 per cent iridium, and a platinum alloy with 10 per cent rhodium. The experimental procedure differed from that previously used in this type of measurement in that the samples were of small diameter (0.010 in.), were fully annealed, and were tested at a temperature definitely above their annealing points (600°C., IOOO°C. and 1050°C., respectively, for 60 per cent cold reduction and 15 min. heating time2,3). The experimental arrangement was similar to that previously described,' using as heating unit a small, horizontal, platinum-wound furnace, ½ by 12 in., maintained at constant temperature by an automatic controller. The samples were 0.010-in. wires, which had been annealed at 1200°C. by drawing them slowly through the furnace. The time-to-fracture was measured electrically. Elongation was not determined because of the difficulties inherent in the experimental arrangement. Life—that is, the time-to-fracture—was considered the important property in these first tests. No attempt was made to measure the reduction in area, but the types of fracture were noted qualitatively; in the text they are referred to as (I) the normal, plastic, or necked fracture, (2) the knife-edge fracture, and (3) the brittle or intercrystalline fratture with small reduction of area. Results for different constant applied stresses are plotted in Fig. I. In all cases at least two trials were made for each stress, although they cannot always be indicated separately on the curves. The breaking Stresses drop very rapidly to a small frat-286

Jan 1, 1943

By J. C. Reed

CINNABAR was discovered in southwestern Arkansas on Little Missouri River in sec. 1, T.7S., R.26W., in April, 1930, and near Antoine Creek in sec. 28, T.6S., R.23W., some 15 miles farther east in May of the same year. It was not, however, until June, 1931, that cinnabar was identified as such in a specimen from the original discovery area sent to W. M. Weigel1 by Walter F. Hintze of Murfreesboro. Almost simultaneously2, in July, 1931, Moritz Norden of Hot Springs identified specimens from the Antoine Creek area as cinnabar. Immediate interest in the district followed the identification of cinnabar and by January, 1932, the district was known to extend as a mineralized belt about one mile wide trending east-northeast from sec. 13, T.7S., R.27W., in Howard County-across central Pike County and into Clark County to sec. 19, T.6S., R.23W., thence extending southeast into sections 33 and 34 of the same township. Since then, cinnabar has been found in sec. 6, T.7S., R.22W., thus giving a total east-west length to the district of approximately 30 miles. Interest focused mainly on the two discovery areas, with the result that mining development has progressed most rapidly in those localities. In the Antoine Creek area the Arkansas Quicksilver Co. has done con-siderable exploration work and has retorted the high-grade ore so .obtained. In the Little Missouri area the Southwestern Quicksilver Co. has had a 12-ton rotary furnace in more or less continuous operation since April, 1932, and has been the largest producer in the district.

Jan 1, 1935

By Arthur V. Corry

GOLD was discovered in Alder Gulch, Virginia. City, Mont., on May 26, 1863. In a short time some 6000 people flocked to the new discovery, and on the banks of Alder Gulch six settlements sprang into existence, the principal one, Virginia City, alone surviving. This town today has a population of 800, and is the county seat of Madison County. It is estimated that between forty and fifty million dollars in gold was produced up to 1904. Virginia City is situated at the mouth of Alder Creek where that stream leaves the narrow canyon that cuts the steep foothills flanking Old Baldy Mountain, elevation 9572 ft., 12 mi. south. Virginia City itself is 5700 ft. above sea level.

Jan 1, 1936

By David B. Burrows, Francis R. Conley

INTRODUCTION A prerequisite to the evaluation and management of oil properties is accurate information derived from the analysis of core samples; but reliable data, such as porosity and permeability, can result only if all oil and water have been removed from the core samples analyzed. The most common method of core cleaning used to date has been Soxhlet extraction—a somewhat static technique, which depends upon the slow diffusion of hot solvent through the core sample. Soxhlet extraction performs satisfactorily only with highly permeable samples and at best requires long cleaning periods. The centrifuge method was developed in 1951 by Continental Oil Co. to overcome the inefficiencies inherent in the Soxhlet method. The new method is basically an operation in which hot solvents are caused to flow through the samples under the influence of centrifugal force. The centrifuge unit has proved so successful that samples which formerly required days for partial extraction can now be completely cleaned in approximately one hour. The original idea was conceived in 1950 by Elmer S. Messer, whose early experiments consisted of flowing solvent over sandstone samples suspended in a revolving basket and driven by a vertically mounted vacuum cleaner motor. Results were so outstanding that more permanent units were constructed. A modified model using this basic design was recently built by Core Laboratories, Inc., and is now used regularly in their operations. DESIGN Fig. 1 shows a photograph of the two extractors routinely used to clean small core plugs in the Production Research Div. of Continental Oil Co.'s Ponca City laboratories. For illustrative purposes, the basket from one of the units has been removed, and because both extrac- tors are of identical design only one is described in the following discussion. Each extractor unit consists of a centrifuge and a solvent still. The core basket of the centrifuge is made of mild cold rolled steel 7 1/2 in. in diameter and 1 1/8 in. deep. The basket holds 18 1-in. samples (cubical or cylindrical) and is attached directly to a cone fitted to the shaft of the motor. Both the outer rim and the hollow hub of the basket contain perforations for the passage of solvent and extract. The solvent is delivered to the perforations by means of a copper tube inserted into the hollow hub. The motor is a vertical tool post grinder motor; (115 v, 5.6 amp, 0-60 cycles, AC-DC, rated at 1/3 hp). It has a rated speed of 10,000 rpm under full load and 15,000 rpm with no load. Variation of speed is obtained by the use of a variable transformer. The solvent still was constructed from one end of a stainless steel oxygen bottle by inserting a heating element, sight glass, and piping as shown on the schematic diagram, Fig. 2. The heater used was a three-position, 1,000 w, 115-v, immersion type. Intermittent flow of solvent to the centrifuge is obtained by means of a siphon bottle inserted between the condenser and the centrifuge.

Jan 1, 1957