JULY, 1958
INDUSTRIAL AND ENGINEERING CHEMISTRY
tests of latex rubber compounds (4) it was evident that the water cures adsorbed less moisture than the air cures of the same compound; this behavior indicated that the water removed solubles from the rubber film. This extraction or leaching out of water-soluble nonrubber constituents is well known and is general practice with the manufacturers of latex products. It is carried out before or after cure with equal success, and gives a softer and less water-adsorbent article. The tests discussed were carried out on semidry, uncured latex rubber films, and it is believed that bone-dry or even cured films will produce similar results. However, under no conditions should tests be attempted on latex rubber films which are so wet that they will disintegrate on immersion in water. In practice, latex products are trimmed and may have a bead rolled before vulcanization; in order to accomplish these operations, the film must be comparatively dry. The immersion of a too wet latex rubber film in water for vulcanization causes distortion which vulcanizes in this unnatural condition and is too evident in the finished product.
829
Conclusions No measurable quantity of the water-soluble accelerators tested was extracted from the rubber during the water extraction. Therefore, these accelerators will not be extracted during vulcanization in water. The softening action observed in water-cured latex products is due to the extraction of watersoluble nonrubber constituents from the rubber film. The water-soluble accelerators tested have a selective solubility for rubber which is many times greater than their solubility in water.
Literature Cited (1) Du P o n t d e Nemours, E . I., & Co., Inc., "Properties of Du Pont Rubber Chemicals," p . 7, May 25, 1937. (2) Ibid., p. 9. (3) Ibid., pp. 15 and 16. (4) M a o K a y , IND.ENG.CHEM.,Anal. E d . , 10, 57 (1938). (5) Vanderbilt News, 4, No. 5, 21 (1934) : 7, No. 6, 6-10 (1937). R ~ C E I V EApril D 2, 1938. Presented before the meeting of the Division of Rubber Chemistry of the American Chemical Society, Detroit, Mich.. March 28 and 29, 1938.
Viscosity of Hydrocarbon Solutions' Viscosity of Liquid and Gaseous Propane B. H. SAGE AND W. N. LACEY California Institute of Technology, Pasadena, Calif.
Teneru
HE viscosity of fluids is
The effect of pressure upon the viscosity of liquid and gaseous propane has been determined at five temperatures between 100"and 220" The work includes measurements throughout the superheated gas region and the condensed liquid region at pressures up to 200 pounds per square inch.
Useful in calculating the changes attending their flow by use of the Reynolds criterion. Data of this nature are of special importance in laminar or s t r e a m l i n e flow such as it; often found in the m o v e m e n t of homogeneous h y d r o c a r b o n f l u i d s in the porous strata of natural petroleum reservoirs. Numerous studies have been made of the effect of temperature upon the viscosity of hydrocarbon liquids and gases in the vicinity of atmospheric pressure, and the effect of changes in pressure and composition upon the viscosity 'of such liquids has been ascertained to a lesser degree, Until recently the influence of pressure upon the viscosity of hydrocarbon gases has received little attention, but the investigations reported indicate that the effect of pressure may be as great as that of temperature within the range of conditions encountered in petroleum production. Because of the scarcity of this type of information, a study was made of the effect of pressure and temperature upon the viscosity of liquid and gaseous propane. The data reported cover the single-phase regions from atmospheric pressure to 2000 pounds per square inch at temperatures from 100" to 220" F. * Previous papers in this series appeared in 1935 (page 954) and 1937 (page 858).
(Pressures r e p o r t e d are absolute-) The viscosity of hydrocarbon gases in the vicinity of atm o s p h e r i c pressure has been studied by a number of investigators. Vogel (27) measured the viscosity of m e t h a n e a t 32" F. and atmospheric pressure. This work was substantiated by Rankine and Smith (16) and later by Ishida (11). Day (5) studied the effect of pressure upon the viscosity of n-pentane and isopentane, from approximately 2 pounds per square inch to vapor pressure a t 77" F. Trautz and Kurz (26) measured the viscosity of propane a t atmospheric pressure from 83" to 550" F. The viscosity of air was measured by Harrington (7) by the rotating cylinder method a t 73.4" F. and atmospheric pressure. Kellstrom's recent elaborate investigation (12) of the viscosity of air under these same conditions is probably the most accurate study of the viscosity of any gas so far reported. The effect of pressure upon the viscosity of gases has not been as extensively investigated as the effect of temperature at atmospheric pressure. Phillips (15) studied the influence of pressure upon the viscosity of carbon dioxide at temperatures near its critical point. Stakelbeck (23) recently determined the viscosity of gaseous carbon dioxide and included measurements in the same range of temperature and pressure
830
INDUSTRIAL AND ENGINEERING CHEMISTRY'
VOL. 30, NO. 7
The method consists, brieffy, in measuring the time of roll of a closely fitting steel ball through a fixed distance in a closed, inclined steel tube filled with the fluid. This type of instrument was first developed by Flowers (6) and subsequently modified by Hersey (9) and 0.9C Hoppler (IO). For the present work the tube was inclined at a constant angle which was approximately 15" from the horizontal and had a diameter of 0.5002 inch; the ball was 0.4957 inch in diameter. 0.8C The time of roll was determined by measuring the lapse of time between the breaking of the upper contact, which was coincident with the release of the ball, and the arrival of the ball at the lower contact. This time interval was meas0.70 ured by a chronograph driven by a synchronous motor which operated ftom the alternating current supply of the laboratory. A comparison of time intervals measured in this fashion with those recorded from a pendulum clock indicated that in the intervals involved (10 to 50 seconds) an accuracy of approximately 0.1 per cent was obtained. P The temperature of the apparatus was maintained by immersing it in an oil bath controlled by a mercury-in-glass regulator. Although temFIGURE 1. EFFECTOF REYNOLDS KUMBER ON THE CALIBRATION OF THE perature fluctuations in parts of the bath were INSTRUMENT as great as 0.10" F., a thermacouple attached to the instrument itself indicated a maximum change of 0.02" F. in the temperature of the roll tube in the covered by Phillips. These two sets of data for carbon dicourse of any set of measurements at one temperature. The actual oxide show a satisfactory agreement as to the effect of prestemperature of the bath was ascertained by a calibrated mersure upon viscosity although Stakelbeck found a slightly lower cury-in-glass thermometer and it is believed that the temperature was known within 0.1' F. throughout this investigation. value (3 per cent) for the atmospheric viscosity than did Pressures below 30 pounds per square inch were measured by Phillips. The agreement of the two sets of data obtained in a mercury-in-glass manometer; pressures above this value were somewhat different ways permits some confidence to be placed determined by a fluid pressure balance with a sensitivity of 0.1 in the available information concerning the effect of pressure pound per square inch. This instrument was calibrated directly upon the viscosity of carbon dioxide, especially at temperaagainst the vapor pressure of carbon dioxide (3)a t 32"F., using a value of 505.56 pounds per square inch for the vapor pressure tures near its critical point. under these conditions. It is believed that the pressures within Schroer and Becker (2i) measured the viscosity of ethyl the apparatus were known with an uncertainty of less than 0.3 ether throughout the critical region. Results from their per cent throughout this investigation. This uncertainty was work, as well as the measurements upon carbon dioxide, inprimarily due to difficulty in establishing accurately the mercury height in the variable-volume chamber of the apparatus, thus dicated that large changes in viscosity are encountered with introducing an uncertainty in the magnitude of the pressure corchanges in temperature or pressure in this region. A similar rection which was the result of the hydrostatic head of this mersituation was found for water although in this case there is a cury column. marked difference between the results of Hawkins and coTo avoid contamination of the samples, the apparatus was repeatedly purged with the sample under investigation, followed workers (8) and Sigwart (22). The discrepancy between by long periods of evacuation. Care in this regard is especially these two investigations is a sufficient number of times important for measurements in the vicinity of atmospheric presgreater than the precision of measurement in either case to sure where only a relatively small amount of the sample is used suggest that the disagreement results from a misinterpretaand traces of impurities would cause significant errors in the composition of the resulting sample. At each temperature measuretion of one or the other sets of data. ments were made for a series of increasing pressures, followed by Miohels and Gibson (IS) measured the viscosity of nitrogen a similar group made with decreasing pressure. In most cases at relatively high pressures and found a significant increase duplicate measurements were made at different times to ascerin viscosity with pressure. Boyd (9) investigated the vistain any effect of changes in the condition of the surface of the ball or tube. Under a given set of conditions the agreement of cosity of nitrogen and hydrogen a t several temperatures under duplicate roll times was usually within the accuracy of the time pressures as high as 2500 pounds per square inch. His remeasurements-namely, 0.1 per cent. sults also indicated a substantial increase in viscosity with pressure, especially a t higher pressures. Nasini and Pastonesi (14) recently reported information concerning the Calibration effect of pressure upon the viscosity of air a t 57.2" F. (14"C.). The instrument used for this investigation was not suited These results were obtained by a modification of the capillary for absolute measurement of viscosity and required calibratube method and appear to be of satisfactory precision. tion with fluids of known viscosity. Details of the parameters They afford the only source of information available to the involved and of the minor corrections necessary when using authors on the effect of pressure upon the viscosity of air. the instrument for liquid were given by Flowers (6),Hersey Sage and Lacey (18)reported data upon the viscosity of (Q), and one of the authors ( 1 7 ) . Since the fluid exerts a methane and two natural gases under pressures from atbuoyant effect upon the ball, the density of the fluid at the mospheric to as high as 3000 pounds per square inch, at temstate in question must be taken into account. When the peratures from 70" to 220" F. flow around the ball is laminar, there is a linear relation between the absolute viscosity of the fluid and the parameter, Method 0 ( p l - p ) , where 0 is the roll time, and po and p represent the density of the ball and fluid, respectively. Since the The apparatus used in the present investigation was redensity of gases is usually small in comparison to the density cently described (18) and is a modification of that employed of steel, relatively small errors are introduced in the pain earlier work upon the viscosity of hydrocarbon liquids rameters by an appreciable percentage of uncertainty in the (17): I.0C
JULY, 1938
INDUSTRIAL AND ENGINEERING CHEMISTRY
density of the gas. I n the present work sufficient data concerning the pressure-volume-temperature relations of propane (60)were available to reduce the uncertainty caused by errors in the evaluation of the density for this correction to less than 0.1 per cent. For measurements of viscosities above 150 micropoises,2the instrument was calibrated against the viscosity of air a t atmospheric pressure and of liquid n-pentane a t 100" F. and vapor pressure. Kellstrom's figure, 183.49 micropoises, for air a t 73.4" F. (1%')was employed for this work. A value of 1981 micropoises was used for the viscosity of n-pentane a t 100" F. and vapor pressure.. This value was interpolated from the measurements of Thorpe and Roger (24) and agrees with a recent measurement of Tousa and Staab (26) a t 68" F. As an added check upon the linear relation between viscosity and the parameter, 0 (po - p ) , measurements were made upon the viscosity of liquid n-pentane a t 167" F.; they were in satisfactory agreement with Bridgman's value (4) for the same temperature. Measurements by the authors (19) were used to determine the density of the n-pentane a t the states in question. At viscosities below 150 micropoises the linear relation between viscosity and the parameter mentioned above no longer strictly applied (1.0 per cent deviation a t a viscosity of 100 micropoises), and it was necessary to establish the behavior by detailed calibration. The viscosity of methane (27) and hydrogen (68) for atmospheric pressure and several temperatures, together with a calculated roll time for the ball a t zero viscosity, were used to establish the calibration in this region. The agreement of the data obtained in the calibration of the instrument with a variety of fluids indicates that the flow around the ball is laminar a t nearly all of the conditions encountered a t atmospheric pressure. With an increase in pressure there is a rapid increase in the density of a gas, and the measurements of Nasini and Pastonesi (14) indicate that there is only a relatively small change in viscosity. Hence there is a rapid decrease in the kinematic viscosity with an
TEMPERATURE
FIGURE3.
f Metric units for viscosity are inconsistent with the other units here used but the general familiarity with the poise as a measure of viscosity makes its use desirable. Multiplication of the value in micropoises by the factor 6.72 X 10-8 gives the corresponding value in engineering units having the dimensions of (Ib.) (see.-]) (ft.-l).
175 W v)
B
150
Y
I75
>
$
125
8 2
150
>
IW
100
3
wma
125 75
I00 I 100
I
I
I
I
200
300
400
500
PRE7qURE
LE. PER %.IN.
FIQURE2. VISCOSITY OF GASEOUS PROPANE
I
"E
VISCOSITY-TEMPERATURE DIAGRAM FOR GASEOUS PROPANE
increase in pressure for air. The Reynolds criterion indicates that for a given. physical configuration such changes in the kinematic viscosity are conducive to the existence of turbulent flow conditions. A satisfactory calibration of the instrument over a wide range of viscosity a t atmospheric pressure is not sufficient,, therefore, to justify the use of a rolling-ball viscometer at elevated pressures. The Reynolds criterion appears to afford a satisfactory basis for the study of flow processes under comparable conditions. It is nearly impossible, however, to evaluate a Reynolds number for the conditions existing within this instrument which can be compared directly with Reynolds numbers for flow processes in other widely different physical configurations. The relative change in the Reynolds number with changes in the properties of the fluid and the rate of roll of the ball can be ascertained by use of the ratio, p / 0 ~ , where p is the density of the fluid in grams per cc., 8 the roll time in seconds, and 17 the absolute viscosity in micropoises. (Metric density units were employed for this ratio in order to be consistent with the other metric units employed.) This ratio varies directly with the Reynolds number for a given arrangement of the instrument and permits a comparison of the behavior of the apparatus for a variety of fluids a t a number of pressures and temperatures. v) W As long as the flow around the ball is laminar, it is possible to employ the roll time corrected for the buoyancy of the fluid to establish the absolute visI cosity. When the flow is turbulent, however, it is > necessary to take into account the resistance encountered by the ball resulting from this turbulence. The apparent viscosities determined from the roll time v, > and the calibration in the laminar range give values w which are higher than the true viscosity in this region. c 3 Figure 1 depicts the variation of the ratio of the 2 actual viscosity to the apparent viscosity, +, with '8 varying values of the ratio p / 8 q . The values reported for carbon dioxide were based upon the measurements of Phillips (16)and Stakelbeck (%'3), and those for air and nitrogen upon the measurements of Nasini and Pastonesi (14) and of Boyd (a), respectively. The agreement of these data for air, nitrogen, and
1
2
2
83 1
'8
832
INDUSTRIAL AND ENGINEERING CHEMISTRY
'
VOL. 30, NO. 7
Harrington (7) and by Kellstrom ( l a ) . Such a discrepancy in these carefully measured figures causes some doubt as to the accuracy of the other data employed in calibrating the instrument. Changes in the condition of the surface of the ball and tube were found to cause gradual change in the calibration of the instrument with time; in the course of a year this amounted to approximately 1.5 per cent. For values of p / 0 q greater than 2.5 the curve of Figure 1 must be employed to obtain the true viscosity from the apparent viscosity, and this correction is dependent upon the values chosen for the viscosity of carbon dioxide a t elevated pressures. For these reasons it is believed that the results reported here may be in error by as much as 5 per cent, especially a t temperatures and pressures in close proximity to the critical state. The values at atmospheric pressure are probably known with an uncertainty of not more than 2 per cent, since they were determined under PRESSURE LB PER SQ. IN. laminar conditions of flow. These large uncertainties in the recorded values are due FIGURE4. EFFECTOF PRESSUREON THE VISCOSITYOF LIQUIDPROPANE primarily to difficulties in properly interpreting the measured roll times which are consistent among themselves within 0.5 per cent throughout the carbon dioxide a t the lower pressures indicates that the entire range of temperature and pressure, with the exception parameter,. p / 0 q , is a satisfactory index of the flow conditions of the immediate vicinity of the critical state. existing within the instrument. At higher values of p / 0 q , which in general correspond to higher pressures, the agreement between the various sets of data is not as good as might Materials be desired. The disagreement may be due to the failure The air used in the calibration of the instrument was dried of p / 0 q to describe satisfactorily the flow conditions. Howa n d freed from carbon dioxide by passing it over magnesium ever, errors in the determination or interpretation of the perchlorate and sodium hydroxide. The methane which was results of the investigations referred to above could account obtained from the Buttonwillow Field, California, contained for the lack of agreement. Because of the good agreement of 99.7 mole per cent methane and 0.3 mole per cent carbon the isothermal viscosity-pressure coefficients determined by dioxide. It was purified by contact with magnesium perPhillips (16)and Stakelbeck (23), the authors chose carbon chlorate and sodium hydroxide at a pressure of 500 pounds dioxide as a reference material for the calibration of the inper square inch to remove water and carbon dioxide, restrument in the turbulent range. spectively. Traces of oil and other condensable impurities Figure 1 indicates that a t values of p / 0 q below 2.5 the flow conditions within the instrument are laminar, but unfortunately most of the conditions encountered in the investigation of the viscosity of propane were at higher values of this ratio. For this reason nearly all of the values reported, with ;the exception of those for the gas a t atmospheric pressure, are based entirely upon those chosen for carbon dioxide. Any errors in these results or in the assumption that p / 0 q is a satisfactory parameter to use in comparing flow conditions within the instrument are directly reflected in the results reported here. A comparison of the measured increase in viscosity of liquid pentane with pressure to that predicted by interpolation of Bridgrnan's results (4) shows that the pressure corrections of the instrument were less than the experimental uncertainty. The agreement of viscosities measured in the laminar range a t various temperatures with those determined by other investigators indicates that the temperature correction of the instrument is small. In the present work no correction was made for any I J 1 I 1 I temperature or pressure effect on the calibra100 125 150 175 200 tion of the instrument. T E M PERAT uR E, F. There is approximately 1 per cent difference between the values for the viscosity of air a t DIAQRAM FOR PROPANEI IN LIQUID, FIGURE5. VISCOSITY-TEMPERATURE atmospheric pressure and 74.3" F. reported by GASEOUS, AND CRITICAL RBJQIONS 2
JULY, 1938
INDUSTRIAL AND ENGINEERING CHEMISTRY
were removed by partial condensation a t the temperature of solid carbon dioxide. A special condensation analysis of the purified gas indicated that it contained less than 0.03 per cent of ethane or other less volatile hydrocarbons. The nitrogen used was the commercial product and was not further purified except for drying over magnesium perchlorate. The npentane used in calibrating the instrument was obtained from the Philgas Division of the Phillips Petroleum Corporation, and their analyses showed it t o contain 99.3 mole per cent n-pentane and 0.7 mole per cent isopentane. The propane used was obtained from the same source as the n-pentane and was reported to contain less than 0.03 mole per cent impurities. This degree of purity of the n-pentane and propane was further substantiated by their nearly constant vapor pressures during isothermal condensation.
Results
833
in the viscosity of liquids a t pressures in excess of the critical pressure to gases at temperatures above the critical temperature is typified by the behavior of the 700-pound isobar of this figure.
TABLEI. VISCOSITY OF LIQUIDAND GASEOUS PROPANE P , Lb./Sq. In. Abs. Satd as Satd: Equid 14.7 50 100 150. 200 250 300 350 400 450 500 550 600 650 700 750 800 1000 1250 1500 1750 2000
-
100' F.
... 871
80.7 81.4 87.7 105 872
...
885 897
... ...
Absolute Viscosity, Mioropoises 130° F. 160' F. 190' F. 142 164 206 712 573 440 87.7 93.2 98.2 89.1 94.2 99.6 92.7 97.4 102 106 102 103 115 110 111 130 119 117 131 123 147 131 iii 576 140 ... 152 iQ9 177 449 762 619 468
...
...
220'3.
... ...
102 103 106 110 115 120 126 133 142 150 159 168 172 182 280 369 389 443 488 525 556 585
The results of the experimental measurements upon the ... ... ... viscosity of propane in the gaseous region are presented in 922 . . . ... ... ... Figure 2. The dual ordinate scales were employed in order ... ... ... 501 ... . . . ... to avoid crowding of the data, which would have resulted 94i 785 649 525 from the use of a single plot. The curves presented, except 674 566 969 808 that for 220" F., were extrapolated to vapor pressure. The 704 604 995 837 637 1018 863 732 data indicate that the viscosity of the saturated gas may be 1040 ' 888 760 668 696 , 1063 912 785 as much as twice the value at atmospheric pressure. This large effect of pressure overshadows the smaller changes in viscosity with temperature that occur a t atmospheric pressure. The points indicated on these curves were, in general, The data presented in Figures 2 and 4 were interpolated taken from two sets of data obtained at different times and graphically to even values of pressure and temperature and with different samples of propane. It was impossible to are recorded in Table I. Although these data are consistent study the viscosity of the saturated gas directly because within 0.5 per cent of one another, there may be an uncerminute traces of oil in packing glands and elsewhere distainty as great as 5 per cent in the absolute values, as stated solved Eiome of the propane and caused the formation of small earlier. quantities of liquid, which produced erratic viscosity measI n many engineering applications kinematic viscosity is of urements. This difficulty was more pronounced a t the lower more direct utility than absolute viscosity. For this reason temperatures where the gas was more soluble in the oil. Figure 6 was prepared to show the effect of temperature upon Figure 3 presents the change in the viscosity of gaseous the kinematic viscosity for a series of pressures. It is appropane as a function of temperature. The relatively small parent that the kinematic viscosity of a gas increases rapidly effect of temperature at atmospheric pressure is again inwith decrease of pressure a t low pressures. Therefore it dicated. These values for atmosaheric Dressure are in substantial agreement with those of TraLtz and Kurz (26). At higher pressures an increase in temperature is accompanied by1 a decrease in viscosity in regions adjacent to saturated gas. The data obtained by Beattie (1) and co-workers were used to establish the critical pressure and temperature for this material. The viscosity near the critical state could not be determined with high precision, since small changes in either temperature or pressure caused such large changes in viscosity that the precision of measurement in this region was markedly reduced. > t I n Figure 4 the experimental results obv, 3000 tained for the viscosity of liquid propane v, are depicted. In order to aid in the visuali> zation of the general behavior of this hydrocarbon, the diagram was extended to include a curve for 220" F. in the gaseous region. The viscosity of the saturated liquid and gas was also included in this figure. These results indicate that the effect of pressure upon the viscosity of the liquid is I I I I I I 100 125 150 I75 200 greater at the higher temperatures. Figure 5 shows the effect of temperature TEMPERATURE F. upon the viscosity of both liquid and gaseous propane. The continuous change FIGURE VISCOSITY-TEMPERATURE DIAGRAM FOR PROPANE 6. KINEMATIC
INDUSTRIAL AND ENGINEERING CHEMISTRY
834
was necessary to omit data for the lower pressures in Figure 6 in order to show the behavior adjacent to the two-phase region on a satisfactory scale. At pressures below the critical value there is an increase in the kinematic viscosity of the gas phase with temperature. On the other hand, the kinematic viscosity of the liquid phase decreases with an increase in temperature but at a much smaller rate than the corresponding absolute viscosity. Again, it must be emphasized that the values in the vicinity of the critical state, as depicted in Figure 6, are subject to considerable uncertainty because of the rapid change in the viscosity and density with pressure and temperature in this re,’gion.
Acknowledgment This investigation was carried out as part of a general program of research being conducted by Research Project 37 of the American Petroleum Institute, relating to the physical and thermal properties of hydrocarbons. Cooperation and financial support from this institute are acknowledged. J. B. Hatcher and 5. V. Reynolds assisted in making many of the measurements reported.
Literature Cited (1) Beattie, Poffenberger, and Hadlock, J . Chem. Phys., 3, 96 (1935).
VOL. 30, NO. 7
(2) Boyd, Phys. Rev., 121 35, 1284 (1930). (3) Bridgman, J . Am. Chem. SOC.,49,1174 (1927). (4) Bridgman, Proc. Am. Acad. A r t s Sci., 61, 58 (1926). (5) Day, Phys. Rev., [2]40,281 (1932). (6) Flowers, Proc. Am. SOC.Testing Materials, 14,565 (1914). (7) Harrington, Phys. Rev., [2]8, 738 (1916). (8) Hawkins, Solberg, and Potter, Trans. Am. Xoc. Mech. Engi-s., 57, 395 (1935). (9) Hersey, J . W a s h . Acad. Sci., 6, 525 (1916). (10) Hoppler, Chem.-Ztg., 57, 62 (1933). (11) Ishida, Phys. Rev., [2]21, 550 (1923). (12) Kellstrom, Phil. Mag., 23,313 (1937). (13) Michels and Gibson, Proc. Rou. Soc. (London), A134, 288 (1931). (14) Nasini and Pastonesi, Gam. chim. ital., 63, 821 (1933). (15) Phillips, Proc. Rou. SOC.(London), A87, 48 (1912). (16) Rankine and Smith, Phil. Mag., 42, 615 (1921). (17) Sage, IND. ENQ.CHEM.,Anal. Ed., 5, 261 (1933). (18) Sage and Lacey, Am. Inst. M i n i n g Met. Engrs., Tech. P u b . 845 (1937). (19) Sage, Lacey, and Schaafsma, IND. EKG.CHEM.,27, 48 (1935). (20) Sage, Schaafsma, and Lacey, Ibid., 26, 1218 (1934). (21) Schroer and Becker, 2. physik. Chem., A173, 178 (1935). (22) Sigwart, Forsch. Gebiete Ingenieurw., 7, 125 (1936). (23) Stakelbeck, 2. ges. Ktllte-Ind., 40, 33 (1933). (24) Thorpe and Roger, Trans. Roy. SOC. ( L o n d o n ) , A185, 397 (1895). (25) Tousa and Staab, Petroleum Z., 26, 1117 (1930). (26) Trauts and Kurs, Ann. P h y s i k , [5]9,981 (1931). (27) Vogel, Ibid., [4]43, 1235 (1914). (28) Yen, Phil. Mag., 38, 582 (1919).
I
RECEIYPD November 29, 1937.
THE ALCHEMIST (Artist Unknown)
ary 1938, page 70 where also is shobn No. S6 and.deiails for obtajning Dhotoeranhic comes of the orininals. No. Sg appears dn page 145, February issue. No. 87, page 269, March issue. No. &3, page 427,. April issue; No. 89’ page 500, May issue; No. 90, pagd 630 June issue. The photogfaphs of the& paintings are SUP lied in black and white o&,
Again we extend hearty thanks to Sir William J. Pope for his continued cooperation in sending a photograph of one of his fine collection of alchemical paintings. The original, on canvas, is 141/2 by 19 inches in size, and presents several new ideas, not seen in any other paintings in this series, namely, the bird-cage with the tame bird sitting on top; the sword, indicating t h a t here our alchemist was a nobleman; and a shark, a n owl, and a garfish instead of the usual single crocodile.
I n composition this painting resembles somewhat the work of Douglas (No. 49) and t h a t of Wijck, several examples of which we have shown. This is No. 91 in the Breolzheimer series of Alchemical and Historical Reproductions.
D. D. Berolzheimer 50 E a s t 41st Street, New York, N. Y.
