ALBERT

Description: The accompanying date list includes age determinations completed during the period December 1, 1961 to November 1, 1962. All measurements were made with the 2 L counter described in our first date list (GSC I). Sample preparation, counting procedures, and calculation of dates were as described in GSC I except as outlined below: a.Base and acid treatments were carried out with 1N HCl and 2% NaOH instead of 2N HCl and 4% NaOH, because the less-concentrated solutions were still strong enough to accomplish the desired purification.b.The Mg(C104)2 drying columns were removed from the purification train in order to test their effect, if any, on the purity of the gas. Since there was no detectable change in the purity of the gas these columns were left out of the purification line.c.Ages were calculated using 0.950 of the activity of the N.B.S. oxalic-acid standard as the reference activity and a.d. 1950 as the zero reference year, in line with the recommendations of the editors of Radiocarbon.

Description: The C14Dating Laboratory of the University of Texas has been working on the development of two systems of counting: gas counting with methane, and liquid scintillation counting with benzene. Lack of adequate instrumentation has retarded the work on gas counting, but the liquid scintillation work, supported in part by the Department of Chemistry, finally led to the successful development of a system in which the benzene counting solvent was synthesized from acetylene by pyrolysis (Tamers, Stipp, and Collier, 1961).

Description: This date list contains the results of measurements made during 1961, 1962 and 1963. The method of counting, utilizing acetylene gas, remains essentially unchanged, except for the addition of some solid state electronics. The method of computation, using the Libby half-life of 5568 ± 30 yr, is continued. The error listed is always larger than the one-sigma statistical counting error commonly used, and takes into account known uncertainty laboratory factors, and does not include external (field or atmospheric) variations.Unless otherwise stated, collectors of all samples are members of the U. S. Geological Survey.

Description: C14 measurements reported here were made in this laboratory between December 1, 1961 and October 1, 1962. Sample descriptions are classified as follows: I.Tree-ring dated samples.II.Modern shells from Santa Barbara County, California.III.Archaeologic samples.IV.Palynologic samples.V.Geologic samples.VI.C14 content of caliche.VII.Water samples.VIII.Modern organic sample.

Description: It has been shown that contamination from humic acids, chitin, fungal products, etc., contributing young carbon, and from bitumen and carbonate, contributing old carbon, may not be completely removed from wood and char samples by the usual hydrochloric acid and sodium hydroxide pretreatments of the samples. A procedure is offered for the isolation of a pure chemical substance from such samples, cellulose from wood and uncombined carbon from char, that must represent the original material. Cellulose is prepared by boiling the resin-free sample in 1.25% H2SO4 and 1.25% NaOH, adding Schweitzer's reagent, filtering, and precipitating from the filtrate by acidification. Uncombined carbon is separated from char samples as the flocculant precipitate remaining after boiling in 70% HNO3, followed by settling overnight from a large volume of 6M HNO3. A simple procedure for the chemical examination of char samples is also offered for the estimation of the amounts of bitumen, carbonate, combined, and uncombined carbon in char.

Description: The following is a list of dates obtained since the time of the compilation of List VIII in December 1962. The method is essentially the same as that used for the work described in the previous list. Two CO2-CS2 Geiger counter systems are used. The equipment and counting techniques have been described elsewhere (Crane, 1961a, 1961b). The dates and the estimates of error in this list follow the practice recommended by the International Radiocarbon Dating Conference of 1962, in that (a) dates are computed on the basis of the Libby half life, 5570 years, (b) a.d. 1950 is used as the zero of the age scale and (c) the errors quoted are the standard deviations obtained from the numbers of counts only. In previous Michigan date lists up to and including VII we have quoted errors at least twice as great as the statistical errors of counting, in order to take account of other errors in the over-all process. If the reader wishes to obtain a standard deviation figure which will allow ample room for the many other sources of error in the dating process, we suggest he double the figures that are given in this list. Where there is no comment, it is because the submitter of the sample had none to make.We wish to acknowledge the help of Patricia Dahlstrom in preparing chemical samples and Roscoe Wilmeth in preparing the descriptions. The descriptions and comments are essentially those of persons submitting the samples.

Description: This date list includes samples and sample series finished between January and November 1962. It does not include samples from series not yet been completed, or samples of very limited scientific interest.

Description: Since the publication of the last list of C14measurements (La Jolla I), covering the period from mid-1957 through 1959, the La Jolla Radiocarbon Laboratory has continued to use essentially the same technique. In the summer of 1961 a second Oeschger-Houtermans counter (Houtermans and Oeschger, 1958), purchased from Manufacture Belge de Campes et de Matériel Electronique, S. A., was installed. It has a somewhat higher background (3.1 counts/min at a filling pressure of 880 mm) than the counter obtained from Bern—a point of little significance in the measurements herein reported. Of the tests included in this report only those following LJ-380 were run with the new counter; the others, with the Bern counter.

Description: The first series of C14 dating measurements made in the Gulbenkian Radiocarbon Dating Laboratory, which came into operation in October 1962, are reported in the following list.

Description: The following list includes many of the measurements made since publication of Yale VI, but many are withheld pending receipt of more complete information or additional samples. We report dates in terms of the Libby half life of C14, 5570 ± 30 yr; geochemical measurements, when normalized for C13content, are given as δ in parts per mil, as described in Yale VI. As before, we acknowledge the technical assistance of George Young, Jonathan King, Sheldon Nankin, and now Carolyn Haupt who has also joined our staff. Our work has been supported by the National Science Foundation, under grants G-19080 to Stuiver and G-19335 to Deevey, and by the U. S. Atomic Energy Commission under contract AT (30–1)–2652.

Description: Radiocarbon-age measurements reported here were made at Lamont Geological Observatory between July 1958 and November 1960. Sample descriptions are classified as follows: I.Samples associated with glacial depositsII.Samples associated with marine coastal depositsIII.Samples associated with marine coastal deposits uplifted by glacial reboundIV.Samples associated with pluvial-lake depositsV.Samples from deep-sea coresVI.Samples from cave depositsVII.Miscellaneous samples of geologic interestVIII.Samples of archaeologic interest

Description: The following list presents dates obtained on a fraction of the total number of measurements made during the years 1962 and 1963 and measurements made previously for which sample data has been recently received. The results which do not appear are withheld pending additional information, or at the request of clients.

Description: This date list mainly contains results obtained for archaeological samples which were measured in the Groningen laboratory in the course of the years and which have not hitherto been published in a similar form. As such it is an extension of the previous date list (Groningen IV) and reference is made to this publication for information on the method of presentation, the corrections applied, etc. Samples which are primarily of geological significance will be presented separately in next year's list.

Description: Installation of a Sharp CDL-14 Carbon-Dating Laboratory was completed at Ohio Wesleyan University in June, 1962. The unit includes a sample conversion system constructed by Radiochemistry, Incorporated for the conversion of carbonaceous samples to the counting gas, methane. Counting equipment consists of a modified Sharp Low Beta system with a 6kv power supply and dual printout registers which automatically blank the counting circuits for 0.1 min for each 100-min printout. The detector has a sensitive volume of 0.5 L and is housed in a shield consisting of 8 in. of lead, 1 in. of steel, and 1 in. of mercury. Anticoincidence is provided by a cylindrical 2-L detector containing 16 anodes and filled with petroleum-generated methane to a pressure of 96 cm Hg.

Description: The following list covers the measurements in our institute until the end of 1960.

Description: This paper is a direct continuation of the third dating list (Stockholm III), and the entire technique is virtually unchanged, using one 0.5–1 and one 1.0.1 3 atm CO2proportional counter. Ages are calculated according to the recommendation given in the introduction of this book, and δC13has been measured for unknown samples and for the different CO2preparations of the NBS oxalic-acid standard. Since the numerical relationship between the C14activity of our old oak standard and that of NBS was valid for a δC13value of almost exactly −19 for the NBS preparation in question, it still holds true that all dates given in Stockholm I, II and III can be converted to the new scale by subtracting 55 yr. The NBS preparation St-532 measured by Craig (1961) having a δC13value of −17.2 is only one of several preparations with values between −17 and −20. Age figures are given in C14yr before A.D. 1950; the half life for C14is taken as 5568 ± 30 yr.

Description: This paper reports the first ages determined in the C14Dating Laboratory of the Geological Survey of Canada. The C14dating program of the Geological Survey is a cooperative project; geologists of the Pleistocene Section assess and select samples for dating, and the Isotope and Nuclear Research Section, under Dr. R. K. Wanless, developed and operates the laboratory and calculates ages. The first part of this paper, devoted to sample preparation, counting procedure, and interlahoratory check dates was prepared by the first author, who built and operates the laboratory. The date list was compiled by the second author from descriptions of samples and interpretations of dates provided by various collectors. Most samples analyzed so far have originated within the Geological Survey.

Description: This date list covers most of the datings done during the period January 1960 to December 1961.

Description: The Radiocarbon Dating Laboratory of the University of Texas was reorganized in late 1962. The dates reported in this list were obtained from February to November, 1963. The laboratory uses liquid scintillation counting with benzene solutions (Tamers, Stipp, and Collier, 1961; Noakeset al., 1963). The chemical synthesis has been modified and improved in several ways in order to permit one worker to produce a sample per day.

Description: The list of dates grouped below is a continuation of work reported in our earlier lists. In one case (Core A 254-BR-C), an extensive sequence of dates is reported which, for completeness, includes some data presented in an earlier report (Miami II, 1963).We continue to use a 1.0-L CO2 proportional counter operating a 3 atm pressure (see Stockholm V for details). Except for the early incorporation of a counter for tritium analyses within our present shielding house and switching over to transistorized electronics, we do not anticipate changes in our set-up.Wherever possible we have entered the δC13 corrected date as well as the δC13 value determined from that sample. An apparent 400-yr sea-surface carbonate age is subtracted from the calculated age of marine carbonate materials, but not for organic material (Miami I and Miami II).

Description: Dates in this list have been determined at U. S. Geological Survey radiocarbon laboratory, Washington, since our 1960 date list (USGS V). Procedures for the preparation of acetylene gas used in the counting, and the method of counting, (two days in two separate counters) remain unchanged. However, the modern standard used is no longer wood grown in the 19th century, but 95% of the activity of NBS oxalic-acid radiocarbon standard, as recommended at the 1959 Groningen Radiocarbon Conference. Measurement of the oxalic-acid standard at our laboratory indicates 6.2 ± 1% more C14 activity than our modern wood standard; so use of the new standard should make no appreciable difference when comparing samples computed by the old method. W. F. Libby's (1955) half-life average for C14, 5568 ± 30 years, was used for the decay equation.

Description: Radiocarbon-age measurements reported here were made by the carbon dioxide gas-proportional counting method since conversion of the laboratory from the solid-carbon method. Assembly of the shield and construction of the glass system was accomplished during the summer of 1959. By January 1960, shield, anticoincidence ring, counters and electronics were set up and in operation. The first year of operation was occupied with calibration, comparison of dating with other C14laboratories, and the repeating of many of the analyses previously made by the solid-carbon method. Special attention was given to dates open to question from an archaeologic point of view.

Description: In continuance of investigations upon successive annual crops of oats reported in Radiocarbon Supplement, Volume 2, we undertook the analysis of successive annual rings of a tree that had been growing throughout the period covered by the oat-crop assays, namely 1953 to 1959. The selected tree was a straight-boled specimen of Populus nigra from the Forestry Commission's plantations at Santon Downham, near Thetford, Norfolk. It had been planted in 1929 and was felled on 21 October, 1959. Shortly afterwards, it was brought into the laboratory and sawn into slices just over 1 in. thick. The surfaces having been smoothed, the annual-ring contacts were marked, and within each annual ring the inner (spring) wood was marked off from the outer (autumn) wood. The tree had been chosen as one exhibiting rapid growth and it proved fairly easy to dissect off with a chisel all the separate half-rings between spring 1953 and the end of 1959. In the event, activities were determined only upon four of the half or whole rings.

Description: This list covers measurements made at the Radiocarbon Dating Laboratory, Physics Department, University of Bern, from spring, 1959, until summer, 1960. We have now two low-level counters working (Houtermans and Oeschger, 1958).

Description: The following list comprises measurements made since those reported in NPL I and is complete to the end of November 1963.Ages are relative to a.d. 1950 and are calculated using a half-life of 5568 yr. The measurements have been corrected for fractionation and referred to 0.950 times the activity of the NBS oxalic acid as a contemporary reference standard. The quoted uncertainty is one standard deviation derived from a proper combination of the parameter variances, viz. those of the standard and background measurements over a rolling twenty-week period, of the sample measurements from at least three independent fillings, of the δC13 measurements and of the de Vries effect (assumed to add an additional uncertainty equivalent to a standard deviation of 80 yr). Any uncertainty in the half-life has been excluded so that relative C14 ages may be correctly compared. Absolute age assessments, however, should be made using the accepted best value for the half-life and the appropriate uncertainty included. If the net sample activity is less than 4 times the standard error of the difference between the sample and background activities, a lower limit to the age is reported equivalent to a sample activity of 4 times the standard error of this difference.The description of each sample is based on information provided by the person submitting the sample to the Laboratory.The work reported forms part of the research programme of the Laboratory and is published by permission of the Director.

Description: The measurements reported in this list have been made since the Radiocarbon Dating Laboratory at the Institute of Geophysics, UCLA became operational in August 1961. CO2proportional counting was used for all measurements in an 7 · 5-L counter at 1 atm pressure. Dates have been calculated on the basis of the C14half life of 5568 ± 30 yr, and 95% of NBS oxalic acid as modern standard. It is planned to discuss the half life in the light of the newer measurements at a conference in 1962. Prior to general agreement as to the new best figure we propose that all dates continue to be calculated on the old basis. Samples have been carefully inspected, cleaned, picked free of rootlets, and pretreated with HCl when necessary.

Description: The following is a list of dates obtained since the time of the compilation of List VII in December 1961. The method is essentially the same as that used for the work described in the previous list. Two CO2-CS2 Geiger counter systems are used. The equipment and counting technique have been described elsewhere (Crane, 1961a, 1961b). The dates and the estimates of error in this list follow the practice recommended by the International Radiocarbon Dating Conference of 1962, in that (a) dates are computed on the basis of a half life of 5568 years, (b) a.d. 1950 is used as the zero of the age scale and (c) the errors quoted are the standard deviations obtained from the numbers of counts only. In all previous Michigan date lists we have quoted errors at least twice as great as the statistical errors of counting, in order to take account of other errors in the over-all process. If the reader wishes to obtain a standard deviation figure which will allow ample room for the many other sources of error in the dating process, we suggest he double the figures that are given in this list. The procedures for converting the dates to the more recent half life scale and to a scale having its zero at any time other than 1950 need not be given here as they have been covered in this journal and elsewhere. Where there is no comment, it is because the submitter of the sample had none to make.

Description: The following list covers most of the samples measured at the Uppsala C14 laboratory since the last list (Uppsala III) except for all the samples utilized for determining the increase of the C14/C12 ratio due to explosion of nuclear devices and the few samples measured with a new proportional counter.The technique used is the same as previously described by Olsson (1958) and the pretreatment is that which has been used earlier (wood, charcoal, peat, gyttja and other organic sediments are boiled with HC1, 1 to 2%, washed with distilled water, kept in NaOH, 1 to 2%, at +80°C over night, washed with distilled water and finally acidified to pH about 3 before being dried) except for Foraminifera tests, see below.The reference sample is 95% of the activity of the NBS oxalic-acid standard. Any corrections for apparent water ages are thus not included here, but will be discussed in later papers dealing with the marine samples. Corrections for deviations from the normal C13/C12 ratio (-2S.0% in the PDB scale) are applied for the unknown samples. Our oxalic acid was measured by Craig (1961) and has a C13/C12 ratio of -18.97% and corresponds to the accepted standardized value, -19%, which should be used for age determinations (Editorial Statement in Radiocarbon, v. 3). Two new combustions of oxalic acid have not shown any significant difference in their C13 content relative to the oxalic acid 1 sample measured by Craig.The value 5570 yr has been used for the half-life of C14. Results are expressed in years before 1950 (b.p.). Errors include the standard deviations (a) of the counted particles as well as the error in the δC13 values. When the activity is very low, so that 2σ corresponds to a possibility of infinite age, 2σ has been used instead of σ.Several samples had to be diluted with CO2 from an old source to bring them to the normal working pressure of 3 atm.

Description: The measurements reported in this list have been made in the Isotope Laboratory of the Institute of Geophysics during 1963 and are a continuation of the work reported previously (UCLA I and UCLA II). The same counting procedure—CO2 proportional counting at 1 atm pressure in a 7.5 L counter with three energy channels—continues in use. No barometric effect on the background has been observed, presumably because of the combination of fairly constant barometric pressure in this area and the location of the equipment on the ground floor of a five storey building. Dates continue to be calculated on the basis of a C14 half life of 5568 yr according to the decision of the 1962 Cambridge Conference (Godwin, 1962). The modern standard has been taken as 95% of NBS oxalic acid for all organic samples, while for carbonate material such as shells and tufa, dates have been computed on the basis of estimates of the corresponding contemporary C14 activity (Broecker and Walton, 1959) as indicated in the description accompanying the results.

Description: The following list covers the measurements in our institute from January 1962 to March 1963. Sample preparation and conversion into acetylene are described by Wendt, Schneekloth and Budde (1962).An Oeschger counter with an effective volume of 1.5 L came into operation in 1962. It is shielded by 4 cm of iron and 10 cm of lead. The background amounts to 2.24 cpm, the standard C14 counting-rate 17.05 cpm. In routine measurements, the impure acetylene, after a four-week storing period, is put into the counters. Examination of purity of the gas is carried out by means of an external Cs137 source. In case the gas shows bad plateau characteristics, it is converted by a new process into ethane, using H2 and a palladium catalyst. Thereby, the plateau characteristics improve considerably. The 50%-voltage then is 200 v lower, the slope of the plateau only amounts to 0.2 %/100 v (with external source), and the plateau length increases from 600 v to 1200 v. The additional work amounts to 1/2 hour.

Description: The dates and activity measurements given below have been obtained during the year 1960 (excepting only Q-9 held over from the previous year). They have been made with carbon dioxide at 3 atmospheres pressure in a proportional gas-counter similar to that used for the results given in Radiocarbon Supplement, volumes 1 and 2.

Description: The third series of C14measurements made at the University of Saskatchewan is reported in the present list. The equipment and methods have been described previously (Saskatchewan II). The modern reference standard was 0.950 times the activity of the NBS oxalic-acid standard. The activity of the wood standard used previously corresponded to 0.955 ± 0.009 of the NBS standard, so that no corrections are required to the previous date lists to bring them into line.

Description: The dates and activity measurements given below have been obtained during the year 1961, and have been made with CO2at 3 atmospheres pressure in a proportional gas counter as described in previous contributions from this laboratory.

Description: Natural C14measurements have been performed at Gakushuin University since 1959, using a proportional counter of 400 ml (Kigoshi and Tomikura, 1960). The counter presently in service is made of copper tubing and has an effective volume of 900 ml. Acetylene gas is used as counting gas at pressure 600–760 mmHg and prepared in the same way as in the case of 400 ml counter. The counter is shielded by iron sheets of 23-cm thickness and by anti-coincidence with a multianode propane-flow proportional counter of Houterman's type (Houtermans, 1958). A background of 5.6 counts/min has been attained with this counter arrangement. The modern carbon sample filled at 0°C and 760 mmHg shows an activity of 11.8 counts/min. The samples with code numbers greater than GaK-60 were measured by this counter.

Description: The following list covers the samples measured at the Louvain C14 dating laboratory during a period from May to December 1961.

Description: The following list includes samples dated in the period 1956–1961.Age calculations are based on a contemporary value equal to 95% of the activity of the NBS oxalic-acid standard, and on a half life for C14of 5568 ± 30 yr.

Description: The radiocarbon dating equipment previously used (Dorn, Fairhall, Schell and Takashima, 1962) has been moved to a different location. During the resulting hiatus in our dating program we have constructed a new counter with a few novel features. It is similar in concept to the Houtermans-Oeschger counter (Houtermans and Oeschger, 1958), but two changes have been made in the design: (1) The inner counter, constructed of thin, metallized plastic foil of thickness 4.2 mg/cm2, is leak-tight relative to the outer counter. By means of two solenoid valves actuated by a simple differential mercury manometer the outer and inner counters can be filled separately with a pressure differential on the partition of less than 0.5 cm Hg. Thus all of the sample can be introduced into the inner counter while inert gas is fed into the outer counter. As the sample gas is not needed for anti-coincidence filling efficiency increases ca. 30%; (2) The metallic parts are made of commercially available high-purity nickel which is easier to procure than O.F.H.C. copper; nylon is used for the other parts. The outer counter appears to have a very low radioactivity, its α activity being 5 pulses/hr/100 cm2.

Description: The C14-laboratory at the Geological Survey of Finland was started in October 1960 in order to determine ages of Quaternary objects. Only 11 samples that have been measured are ready to be published. Most samples in the following list have been measured many times in order to control the stability of the system and to make all necessary corrections. The C14-system includes two CO2-filled proportional counters. Until now the measurements have used only the first counter system. The second one is now ready for dating.

Description: The following list presents the dates obtained on a fraction of the total number of measurements made during the year 1961. Those results which do not appear are withheld pending additional information or at the request of our clients.

Description: The following is a list of radiocarbon dates obtained since the preparation of the manuscript for the publication of Michigan V, in December, 1959. The method of measurement and treatment of data are the same as those described in the introductions to Michigan lists III and IV. A full statement on the Michigan counter is referred to by Crane (p. 46) in this issue.

Description: The dating equipment at the National Physical Laboratory was completed by the summer of 1960. A series of calibration and intercomparison measurements was undertaken however, using the NBS oxalic acid reference standard, a modern wood standard (1850 oak tree) and other material before starting routine measurements toward the end of 1961. All results have been obtained using a 4.5 L copper proportional counter filled with CO2 at a constant density corresponding to standard conditions of 22°C and an absolute pressure of 150 cm Hg. The counter is shielded by 8 in. of steel, 6 in. of paraffin wax containing boric oxide, 23 Geiger counters arranged as two independent groups and finally by 1 in. of mercury.

Description: In conformance with the request of the editors, ages in this date list have been calculated with the Libby half life value, 5568 ± 30 yr. We should like to mention, however, that the “effective” and, possibly, the true value may differ from this by several hundred years (see discussion by Kohler and Ralph, 1961). The measurements of samples of known age indicate that the “effective” half life value is close to 5800 yr, except for specific recent periods.

Description: The following list comprises a selected number of measurements made up to November 1963. Age calculations are based on a contemporary value equal to 95% of the activity of the NBS oxalic-acid standard, and on a half life for C14 of 5570 ± 30 yr.Results are expressed in years before 1950 and in the b.c.-a.d. scales. Errors quoted include the standard deviations of the count rates for the unknown sample, the contemporary value, and the background. Calculated errors smaller than 100 yr have been increased by rounding to that figure as a minimum. Sample descriptions have been prepared in collaboration with collectors and submitters.

Description: The following list includes most of the measurements made since publication of Yale V; some measurements, such as a series collected in Greenland by A. L. Washburn, are withheld pending additional information or field work that will make better interpretations possible. In addition to radiocarbon dates of geologic and/or archaeologic interest, we give in the third part of the paper, for the first time since 1954 (Deevey and others, 1954), recent assays of C14 in lake waters and other lacustrine materials, now normalized for C13 content. Some of these C13 values have been published separately (Oana and Deevey, 1960), but most have not.

Description: The radiocarbon dating laboratory at the Smithsonian Institution, Division of Radiation and Organisms, was established in September 1962. After careful calibration with known samples and refinements in the methane synthesis system, routine analysis of samples was begun in the spring of 1963.

Description: The measurements reported in this list were made in the Louvain C14 dating laboratory from July 1962 to October 1963.

Description: This list comprises dating determinations of the New Zealand Radiocarbon Laboratory.

Description: The C14 dates given below are a continuation of the work presented in our first list (Miami I) using the same apparatus and techniques described previously. In addition to the dating of marine carbonate materials, however, we have extended our methods to the dating of wood and peat samples. All dated peat and wood samples have been given a standard pretreatment by successive washings with dilute HCl and 2% NaOH solution for removal of carbonates and humic acids (Olson and Broecker, 1958). Where sufficient alkali-soluble “humic acid” was recoverable for analysis, this fraction was dated separately and is included with the date obtained from either the wood or peat.

Description: A complete description of the CO2-CS2 Geiger-counter system which is in operation at the University of Michigan Radiocarbon Dating Laboratory is available in mimeograph form, upon request to the author. It includes a report on research into the characteristics of the CO2-CS2 counter, as well as a full set of instructions and diagrams for the building of such a system for use in radiocarbon dating.

Description: The construction of the dating apparatus started in the summer of 1960 and was completed one year later. The laboratory is located on the bottom floor of a three-story concrete-block building which has two thin concrete floors on concrete beams above the shield. The building is underlain by carbonate mud and coral rock. The geographic location is 25° 43.9′ N Lat, 80° 09.8′ W Long and only a few feet above sealevel. We use a proportional-counting tube with an active volume of 1 L, and a total sample volume of 1.30 L, filled with purified CO2to a pressure of 225 cm Hg (3 atm) at 25°C. The tube is made of copper with brass ends and quartz insulators. The shielding consists of 20 cm of iron, 10 cm of paraffin with boric acid, 2.5 cm of selected lead (Östlund, 1961), and cosmic ray guard counters. The room is air-conditioned but no additional precautions have been taken to exclude outdoor dust.

Description: The Radiocarbon Dating Laboratory of Texas A & M University was initiated as a research facility in the Oceanography and Meteorology Department. The facilities are available to graduate study programs and to other research groups associated with the University.Research was begun in June 1960, towards development of a carbon dating method utilizing liquid scintillation counting. Benzene was chosen as the counting solvent because of its high energy transmitting properties and the high carbon content of benzene which could be totally derived from the sample to be dated. A catalytic method of synthesis of C6H6 at low temperature, as first reported by Shapiro and Weiss (1957), was further developed and modified by Noakes and others (1963) to a procedure suitable for carbon dating. A combined effort of this laboratory and the University of Texas Radiocarbon Dating Laboratory has resulted in a routine procedure for carbon dating, as reported earlier (Texas I).In the dates reported here the sample preparation and the method of conversion of carbon samples to the counting solvent, benzene, was the same as reported in the earlier papers cited. The problem, reported then, of variation in background count rate between counting vials was eliminated by prior determination of the background for each vial used. With the exception of samples TAM 1 and TAM 2, all dates reported here were calculated according to this procedure.

Description: With few exceptions the C14 measurements reported here were made in this laboratory between October 1, 1962 and November 1, 1963.

Description: This list covers part of the measurements made at the Radiocarbon Dating Laboratory, Physics Department, University of Bern from summer 1960 until summer 1962. Two low-level counters with incorporated anticoincidence arrangement (Houtermans and Oeschger, 1958) are used for routine C14 measurements.

Description: During 1962 the La Jolla Radiocarbon Laboratory continued to follow essentially the same technique as in previous years. Three counters were used: 1.The “Bern Counter,” an Oeschger-Houtermans instrument manufactured at the Physical Institute of the University of Bern; described in La Jolla I (p. 197).2.The “Brussels Counter,” another Oeschger-Houtermans instrument, manufactured in Brussels by Manufacture Belge de Campes et de Matériel Électronique, S. A.; characterized in La Jolla II (p. 204).3.The “400-cc La Jolla Counter,” recently constructed at the University of California, San Diego to facilitate the age determination of samples containing less than 1 g of carbon. Because the first model, now in use, was constructed of brass—not the optimal material—the background count is relatively high (ca. 5.0 counts/min). Advantages lie in its high stability. For samples that yield 0.5 L or more of acetylene, this counter can be used quite satisfactorily. Check runs, using the same sample in this counter and in the Bern and Brussels counters, agree closely.

Description: Natural C14 measurements at the Institute of Physical and Chemical Research (RIKEN) became routine in 1962. The counters presently used are made of stainless steel with a volume of about 2.7 L. They are surrounded by 2.5 cm of pure lead, a ring of 22 propane gas-flow anticoincidence counters, about 10 cm of boric acid and 20 cm of iron. When filled with dead CO2 up to 2 atm, they gave a background counting rate of about 9 cpm (Hamada, 1960).In this article, results obtained for geologic and archaeologic samples since 1962 are described. Dates have been calculated on the basis of the C14 half-life of 5568 yr, and 95% of NBS oxalic acid as modern standard. Correction for isotopic fractionation was not applied.

Description: The third series of radiocarbon measurements made at the British Museum Research Laboratory is reported in the following list. Equipment and method used are as described previously (British Museum I) and, as in previous lists, the error terms are not based solely on counting statistics, but are widened to include contributions of ±80 years for possible isotopic fractionation effects and ±100 years for the de Vries effect. Ages are calculated on a half-life of 5568 ± 30 years. NBS oxalic acid is now used as a reference standard in place of 100-yr-old oak. The latter gave an age-corrected value almost exactly 95% of the oxalic-acid activity and thus no corrections are required to our previous date lists to bring them into line with the new standard.

Description: Radiocarbon analyses have been performed at Isotopes, Inc. since 1957 using proportional-counting techniques. Carbon dioxide is employed as the counting gas at pressures up to two atmospheres. The counter presently in service is electrolytic copper and has an active volume of just under two liters. It is shielded by one in. of mercury, a ring of 23 G-M counters operated in anti-coincidence with the sample counter, 4 in. of paraffin wax, and 18 in. of hot-rolled steel. A background of 9.2 counts/min has been attained with this arrangement.

Description: The dates and activity measurements given below have been obtained during 1962 and 1963, and have been made with CO2 at 3 atm pressure in a proportional gas-counter very little modified from those described in previous contributions from this laboratory.

Description: The paper seeks to determine what transverse oscillatory movements a slender fish can make which will give it a high Froude propulsive efficiency, $frac{hbox{(forward velocity)} imes hbox{(thrust available to overcome frictional drag)}} {hbox {(work done to produce both thrust and vortex wake)}}.$ The recommended procedure is for the fish to pass a wave down its body at a speed of around $frac {5} {4}$ of the desired swimming speed, the amplitude increasing from zero over the front portion to a maximum at the tail, whose span should exceed a certain critical value, and the waveform including both a positive and a negative phase so that angular recoil is minimized. The Appendix gives a review of slender-body theory for deformable bodies.

Description: Experimental data are presented for the growth of vapour bubbles in various superheated liquids, such as carbon tetrachloride, benzene, ethyl alcohol, and methyl alcohol. These data are compared with the theoretical results obtained by Plesset & Zwick (1953) who derived these results by taking into account the heat diffusion across the bubble boundary. The agreement in all cases between experiment and theory is found to be good. The growth of vapour bubbles in slightly superheated water is also presented in the form of experimental data for bubbles just beginning to grow from a point of equilibrium which is presumed to be dynamically unstable. The radii corresponding to the points of equilbrium are of the same order of magnitude as those predicted by theoretical considerations. © 1960, Cambridge University Press. All rights reserved.

Description: This paper continues an investigation into the mixing of a dense layer of salt solution in a turbulent pipe flow in order to obtain a more detailed understanding of the underlying physical processes. The effect of the density difference on the velocity profile in a sloping pipe is calculated using a simplified model, and the results compared with direct measurements obtained by timing streaks of dye at various levels in the pipe. These velocity profiles are also used in conjunction with density profiles to estimate the dependence of the transfer coefficients for salt and momentum K S and K M , on stability. It is found that K S is much more greatly affected by the density gradient than K M , and that the ratio K S /K M may be represented, to the accuracy of the experiments, as a function of the local Richardson Number Ri. The results agree with what is known of K S /K M in neutral and very stable conditions, and they confirm an earlier prediction by Ellison that the critical flux Richardson number, at which K S becomes zero, is much less than unity. Finally, a crude semi-empirical method is outlined which indicates how the new measurements of the transfer coefficients may be related to the overall properties of the flow discussed in the first part of the paper. © 1960, Cambridge University Press. All rights reserved.

Description: When a concentrated pressure travels with constant velocity over the free surface of water, it carries with it a familiar pattern of ship waves. Let viscosity and surface tension be neglected, let the free-surface condition be linearized, let the depth of water be assumed infinite, and let initial transient effects be ignored. Then, as is well known, the wave motion everywhere can be found by standard methods in the form of a double integral. The wave pattern at a great distance behind the disturbance can be found by an application of the ordinary method of stationary phase, which shows that the wave amplitude is considerable inside an angle bounded by the two horizontal rays θ = ± θc from the disturbance, where [formula omitted]. But the method fails in two regions, near the track θ = 0 of the pressure point, and near the critical lines θ = ±θc. These two regions are treated in the present paper. It is shown that near θ = 0 the linearized surface elevation oscillates with indefinitely increasing amplitude and indefinitely decreasing wavelength. (This result holds only when the pressure is concentrated at a point and applied at the free surface.) Near the critical lines the surface elevation at a greater distance behind the pressure point can be expressed in terms of Airy functions, and this expression goes over into the known wave pattern inside the critical angle. It is shown that near the critical lines the crest length increases as the cube root of the distance, and that the separation between crests remains constant. Contour maps of the wave surface are given for three distances behind the moving pressure point. © 1960, Cambridge University Press. All rights reserved.

Description: This paper deals theoretically with the problem of the hydrodynamic stability of a stratified flow of a viscous fluid. The primary flow consists of two laminar streams of viscous fluids of different densities flowing in opposite directions between two parallel inclined planes under the action of gravity. The effect of surface tension at the interface of the two fluids is included in the formulation of the problem. Since instability can be expected to occur at low Reynolds numbers when the inclination is nearly vertical, the solution of the Orr–Sommerfeld equations is developed as a power series in the transverse space co-ordinate. It is shown that for the vertical case, the flow is unstable for all values of the Reynolds number. Surface tension is found to influence both the direction and celerity of the disturbance. Results are also given for inclinations slightly away from the vertical, where small critical Reynolds numbers do exist. © 1960, Cambridge University Press. All rights reserved.

Description: The flow of a viscous incompressible electrically conducting fluid past a sphere is studied; the uniform ambient flow field is colinear with the ambient uniform magnetic field. The force exerted on the sphere is computed for various conductivities and Reynolds numbers; of particular interest is the distinction in behaviour between the flow with ambient particle speed greater than ambient Alfván speed and that with particle speed less than Alfván speed. © 1960, Cambridge University Press. All rights reserved.

Description: In a previous paper (1953b) it was shown theoretically that just below the boundary layer at the surface of a free wave the mass-transport gradient should be exactly twice that given by Stokes's irrotational theory. The present paper describes careful experiments which confirm the higher value of the gradient. The results have an implication for any oscillatory boundary layer at the free surface of a fluid; such a boundary layer must generate a second-order mean vorticity which diffuses inwards into the interior of the fluid. © 1960, Cambridge University Press. All rights reserved.

Description: The hydromagnetic stability of a basic two-dimensional parallel flow of an incompressible conducting fluid in a uniform magnetic field parallel to the flow is considered. By use of the generalization of the Orr–Sommerfeld equation for an electrically conducting fluid, it is shown that any given small wave disturbance can be stabilized by a sufficiently strong magnetic field if the Reynolds number is finite and the magnetic Reynolds number small. Stability of velocity profiles with a point of inflexion at small magnetic Reynolds number and infinite Reynolds number is considered in detail. Perturbation methods are developed to find stability characteristics in two cases, when the magnetic field is weak, and when the disturbance is a long wave. These methods are applied to the jet and the half-jet, which are both found to be unstable to long-wave disturbances, however strong the magnetic field. Nonetheless, these two flows can be stabilized for any given harmonic disturbance of finite wavelength. The analysis of the jet reveals the surprising result that the magnetic field makes inviscid long-wave disturbances more unstable. © 1960, Cambridge University Press. All rights reserved.

Description: The steady motion of an infinitely long solid cylinder parallel to its length in a conducting fluid in the presence of a uniform magnetic field is discussed. Due to Alfván waves originating at the cylinder we find two opposite “wakes” parallel to the applied magnetic field. A formula which relates the total drag on the cylinder to the electric potential difference δϕ between the two undisturbed regions outside these two wakes is derived [formula omitted] where ρν is the viscosity and σ is the conductivity of the fluid. The reduction to a classical boundary-value problem is made for the case of an insulating cylinder. Exact solutions are obtained for the case of a perfectly conducting or an insulating flat strip of semi-infinite width. These give a clear picture of the field, especially in the transition region near the edge of the strip. The case of a strip of finite width is also discussed with special reference to the viscous and the magnetic drags, Df and Dm. We find that [formula omitted], on a perfectly conducting strip, is equal to the viscous drag on an insulating strip for which Dm is zero. Precise values of these drags are given. © 1960, Cambridge University Press. All rights reserved.

Description: When a thin film of viscous fluid is produced by passing it through a small gap between a roller or spreader and a flat plate, it often presents a waved, or ribbed, surface. An analysis is given here in terms of lubrication theory to show why in many cases flow leading to a uniform film is unstable. Account is taken of surface tension which proves to be a stabilizing factor. The most unstable values of the wave-number, n (characterizing the disturbance), are calculated as functions of the dimensionless variable T/μU0, and of the geometry of the system; T is the surface tension, μ the viscosity and U0 a representative velocity of the fluid. For the particular case of a spreader in the form of a wide-angled wedge, these predictions are compared with experimental observations. Agreement is obtained for values of T/μU0 between about 10 and 0.1, but for smaller values of T/μU0 it is clear that other considerations, involving only viscous and pressure forces, determine the nature of the secondary flow. © 1960, Cambridge University Press. All rights reserved.

Description: The flow produced by an infinite rotating disk when the fluid at infinity is in a state of solid rotation is investigated numerically. When the fluid at infinity is rotating in the same sense as the disk, physically acceptable solutions exist in all cases. When the fluid at infinity is rotating in the opposite sense to that of the disk, the only physically acceptable solutions appear to be those in which there is a uniform suction present acting through the disk. © 1960, Cambridge University Press. All rights reserved.

Description: In the steady flow of an incompressible, inviscid, conducting fluid past a magnetized sphere, the first-order effects of the magnetic field and the conductivity are studied. Paraboloidal wakes of vorticity and magnetic intensity are formed, the former being half the size of the latter. The vorticity, generated by the non-conservative electromagnetic force, is logarithmically infinite on the sphere. For the case of a dipole of moment M at the centre of a sphere of radius a, the drag coefficient is [formula omitted] where μ and μ′ are the permeabilities of the fluid and sphere, respectively, β is the ratio of the representative magnetic pressure μM 2 /2a 6 to the free-stream dynamic pressure, and R M is the magnetic Reynolds number. © 1960, Cambridge University Press. All rights reserved.

Description: This article has a twofold purpose: (1) to analyse the available theoretical and experimental knowledge concerning flow in the inlet region of a smooth round tube, and (2) to point out that the e9 amplification factor method apparently predicts natural transition correctly over a significant fraction of the entire inlet lenght of the tube. The successful prediction indicates, but does not prove, that flow in a smooth round tube becomes turbulent at higher Reynolds numbers because transition occurs in the inlet lenght–not in the fully developed Poiseuille rágime. The close agreement between theory and a test result obtained by Pfenninger indicates that the e9 method is valid for a wide variety of flows having x Reynolds numbers of transition ranging from 570,000 to 40 million. The results are applicable to both plane and axially symmetric flows. © 1960, Cambridge University Press. All rights reserved.

Description: When a hollow circular cylinder with its axis horizontal is partially filled with water and rotated rapidly about its axis, an almost rigid-body motion results with an interior free surface. The motion is analysed assuming small perturbations to a rigid rotation, and a criterion is found for the stability of the motion. This is confirmed experimentally under varying conditions of water depth and angular velocity of the cylinder. The modes of oscillation (centrifugal waves) of the free surface are examined and a frequency equation deduced. Two particular modes are considered in detail, and satisfactory agreement is found with the frequencies observed. © 1960, Cambridge University Press. All rights reserved.

Description: The instability of the accelerated interface between a liquid (methanol or carbon tetrachloride) and air has been investigated experimentally for approximate sinusoidal disturbances of wave-number range from well below to well above the cut-off. The growth rates are measured and compared with theoretical results. A third-order theory shows the phenomena of overstability which is found in the experimental results. Some measurements of later stages of growth agree moderately well with the available theory and disclose some additional phenomena of bubble competition, Helmholtz instability with transition to turbulence, and jet instability with production of drops. © 1960, Cambridge University Press. All rights reserved.

Description: The hot-wire anemometer, used for recording speed variations in turbulent flow, involves in its working principle the unsteady heat transfer from a hot fixed surface to a fluctuating air stream moving past the surface. If the wire is maintained at a constant (high) temperature, the rate of loss of heat from the wire changes with the velocity of the incident stream, and the compensating rate of gain of heat, produced by the Joule heating effect of the electric current, changes, correspondingly. The accompanying change of current can be measured, and used to calculate the varying velocity of the air stream. The hot wire may have a diameter as low as 10−4 in. and the Reynolds number of the flow is then of the order of 0.05 for each ft. per sec of velocity. With low velocities, of the order of 10 or 20 ft./sec, the flow past the wire is in the range of small Reynolds number, and the exact equations of flow may be approximated by simpler equations in the manner of Oseen's theory (Lamb 1932). The approximate equations are not easy to solve when the flow is compressible, as it will be in the presence of the large temperature differences imposed by the heat of the wire. If, however, the temperature differences are assumed to be small, the approximate energy equation is no longer linked with the equations of continuity and momentum, and it may be solved without knowledge of the velocity field. The purpose of this note is to give the solution for the temperature field when a warm circular cylinder or a warm sphere is held at rest in a fluctuating stream.

Description: Measurements of mean velocity, mean flow direction, normal turbulent stress in the direction of flow, and mean static pressure are reported for the subsonic flow field generated by identical twin jets of air issuing from parallel slot nozzles in a common wall and mixing turbulently with ambient room air. At the low nozzle velocity employed (72ft./sec), the two-dimensional plano-symmetric flow was effectively incompressible. Since the end walls prevented interjet air entrainment from the surroundings, a region of highly convergent flow was formed near the nozzles. In this region, contour maps clearly reveal (1) the sub-atmospheric static pressure through that accounts for the jet convergence, (2) a free stagnation point on the plane of symmetry, (3) stable symmetrical contrarotary vortices which recycle air on the concave side of each converging jet, and (4) the super-atmospheric static pressure mound that redirects the merging jet streams in a common downstream direction. Comparisons are made between the development of the flow, in both the region of jet convergence and the region of combined jet flow, and that of the single-jet counterpart which was previously reported. © 1960, Cambridge University Press. All rights reserved.

Description: The results of numerical calculations are presented for the motion of a bore over a uniformly sloping beach. The shallow water equations are solved in finite difference form, and a technique is developed for fitting in the bore at each step. The results are compared with the approximate formula given by Whitham (1958) and close agreement is found. The approximate theory is considered further here; the main addition is a rigorous proof that, within the shallow water theory, the height of the bore always tends to zero at the shoreline. © 1960, Cambridge University Press. All rights reserved.

Description: When a body moves through a stratified fluid, i.e. one whose density decreases upwards, gravity waves are set up and this causes a resistance to motion. An axisymmetric case is considered in which a body moves steadily and vertically through a fluid whose density decreases exponentially upwards. The fluid is supposed perfect, incompressible, and unbounded in all directions. The equations of motion are linearized, and with a fairly general initial motion of the surrounding fluid, the limit of the solution as t ⇒ ∞ is evaluated. Transform methods are used to solve the equation of motion, and the methods of steepest descents and stationary phase are used to obtain approximate solutions. Streamlines and the distortion of the constant density levels for a spindle-shaped body are shown. The curves of resistance against a function of the velocity for the circular cylinder, the sphere, and a spindle-shaped body are also given. A criterion is given for when the maximum wave resistance for a sphere may be expected, and an estimate of this maximum resistance is made. © 1960, Cambridge University Press. All rights reserved.

Description: Townsend (1954) has shown that turbulent vorticity may rotate and strain a diffusion wake, thereby increasing the contribution of molecular diffusion to the total mean dispersion over short diffusion times. To test whether any such effect occurs at longer diffusion times, the lateral dispersion of both helium and of carbon dioxide in air were measured downstream from a continuous point source in the turbulence produced by a grid in a wind tunnel. The data show that, for long diffusion times, accelerated molecular diffusion is negligible, so that molecular diffusion makes only an independent contribution to the total dispersion. © 1960, Cambridge University Press. All rights reserved.

Description: The theoretical study presented in this paper was inspired by the recent report (Krämer 1960) of experiments showing that considerable reductions in the drag of an underwater solid body were achieved by covering it with a skin of flexible material; apparently this effect was due to the boundary layer being stabilized in the presence of the skin, so that transition to a turbulent condition of flow was prevented or at least delayed. The stability problem for flow past a flexible boundary is here formulated in a general way which allows a full exploration of the possibility of a stabilizing effect without the need to assign specific properties to the flexible medium; the collective properties of possible boundaries are represented by a ‘response coefficient’ α (a sort of ‘effective compliance’) measuring the deflexion of the surface under a travelling sinusoidal distribution of pressure.A remarkably simple analytical connexion is established between the present general problem and the corresponding stability problem for the boundary layer on a rigid plane wall, and hence many details of the existing theory of hydrodynamic stability are immediately useful. However, the presence of the flexible boundary admits possible modes of instability additional to those which already exist when the boundary is rigid, and clearly every mode must be considered with regard to practical measures for stabilization—that is to say, it might be useless to inhibit one mode by a device which lets in another. What is believed to be an essentially complete interpretation of the over-all possibilities is deduced on recognizing three more or less distinct forms of instability. The first comprises waves resembling the unstable waves which can arise in the presence of a rigid boundary, but now being modified by the effects of flexibility. These waves tend to be stabilized when the boundary has a compliant response to them, which means the respective wave velocity has to be less than the velocity of free surface waves on the boundary; but it is found that the effect of internal friction in the flexible medium is actually destabilizing. The second form of instability is essentially a resonance effect and comprises waves travelling at very nearly the velocity of free surface waves. These waves can only be excited when the latter velocity falls below the free-stream velocity; they are scarcely affected by the viscosity of the fluid since the ‘wall friction layer’ is largely cancelled, so that damping due to the medium itself becomes the only stabilizing factor. The third form is akin to Kelvin–Helmholtz instability.This interpretation of the theoretical results seems to point to the essential factors in the operation of a flexible skin as a stabilizing device, and accordingly in the concluding secttion of the paper two alternative sets of criteria are proposed each of which would provide a logical basis for designing such a device. The principle of the first alternative explains the success of Gamer's invention, but the second appears equally promising and the relative advantages of the two can really be proved only by further experiment.

Description: In the flow past a slender delta wing at incidence one can observe a roughly axially symmetric core of spiralling fluid, formed by the rolling-up of the shear layer that separates from a leading edge. The aim in this paper is to predict the flow field within this vortex core, given appropriate conditions at its outside edge. The basic assumptions are (i) that the flow is continuous and rotational, and (ii) that viscous diffusion is confined to a relatively slender subcore. In addition it is assumed that the flow is axially symmetric and incompressible. Together, these admit outer and inner solutions for the core from the equations of motion. For the outer solution the subcore is ignored, and the flow is taken to be inviscid (but rotational) and conical. The resulting solution consists of simple expressions for the velocity components and pressure. For the inner solution, which applies to the diffusive subcore, the flow is taken to be laminar, and certain approximations are made, some based on the boundary conditions and some analogous to those of boundary-layer theory. The solution obtained in this case is a first approximation, and has been computed. A sample calculation yields results which are in good qualitative and fair quantitative agreement with experimental measurements. © 1961, Cambridge University Press. All rights reserved.

Description: Recently Kraichnan (1959) has propounded a theory of homogeneous turbulence, based on a novel perturbation method, that leads to closed equations for the velocity covariance. In the present paper, this method is applied to the theory of turbulent diffusion and closed equations are derived for the probability distributions of the positions of marked fluid elements released in a turbulent flow. Two topics are discussed in detail. The first is the probability distribution, at time t, of the displacement of an element from its initial position. In homogeneous flows, this distribution is found to resemble that for classical diffusion but with a variable coefficient of diffusion which is proportional to and which approaches a constant value ≑ lv 0 for t t 〉 l/v 0 (l = macroscale, v 0 = r.m.s. turbulent velocity). The second topic treated is the joint probability distribution of the displacements of two fluid elements. Particular attention is focused upon the probability distribution of relative displacement, i.e. Richardson's distance-neighbour function. This is found to be Gaussian for separations r which are large (〉 l). For smaller separations (r 〈 l), its behaviour at high Reynolds numbers is found to be quite well expressed in terms of a variable diffusion coefficient K(r,t), as suggested by Richardson (1926). For all but extremely short times, K(r,t) is found to depend only on r and on the form of the inertial range spectrum E(k). On assuming [formula omitted] is very sensitive to the spectrum. © 1961, Cambridge University Press. All rights reserved.

Description: In turbulent flow past rigid boundaries, there can be distinguished regions close to the wall in which the local rates of energy production and dissipation are so large that aspects of the turbulent motion concerned with these processes are determined almost solely by the distribution of shear stress within the region and are independent of conditions outside it. These regions are here called equilibrium layers because of the equilibrium existing between local rates of energy production and dissipation. Three kinds of equilibrium layer have been studied experimentally, the constant-stress layer, the transpiration layer and the zero-stress layer, but there are other possible forms. One that is of importance in the theory of self-preserving flow in boundary layers and in diffusers is the ‘linear-stress’ layer in which the stress increases linearly with distance from the wall. The properties of these various equilibrium layers are considered and the distributions of mean velocity are derived from the equation for the turbulent kinetic energy and certain assumptions of flow similarity. The theory of self-preserving wall flow, usually expressed as a combination of the law of the wall and the defect law, assumes compatibility between the outer flow and the equilibrium layer, and the course of development depends on the kind of equilibrium layer. Earlier work by the author, which assumed the defect law, is only valid if the whole of the equilibrium layer is a constant-stress layer and this is not true in strong adverse pressure gradients. A consistent theory is developed for these flows by assuming a ‘linear-stress’ layer, and the solutions show the relation between flows of finite stress and of zero stress and provide a plausible explanation of the phenomenon of downstream instability observed by Clauser. Self-preserving flow in wedges is treated on similar lines. © 1961, Cambridge University Press. All rights reserved.

Description: Investigations into the behaviour of the gas flowbehind spherical or cylindrical blasts have shown that secondary shocks arise within the original detonation gases. The secondary shock, at first weak, is carried outward with the expanding gases. Subsequently it strengthens and bends back toward the origin, arriving there with high intensity. By using some recently developed techniques in shock dynamics and extending them where necessary, a theory is developed by which the motion of the main shock wave, as well as the formation and subsequent motion of the secondary shock, are given by explicit formulae. In addition, a method for determining, also by explicit formulae, the location of the contact surface between the detonation gases and the outside atmosphere is given. The results of a specific problem, which has been solved by numerically integrating the total equations of motion, and has also been checked experimentally, are compared with the results of the present theory. © 1961, Cambridge University Press. All rights reserved.

Description: This paper is a study of the flow of a viscous incompressible fluid in the immediate neighbourhood of a saddle point of attachment, near which the external flow is irrotational with components {ax, by, −(a + b)z}, where a 〉 0 〉 b. It is shown that the flow is of a boundary-layer character, and that part of the boundary-layer flow is reversed when b/a 〈 − 0·4294. On the assumption that such flows are physically plausible, the problem may be solved for all values of b/a ⩾ −1. Even in the limiting case b/a = −1, an effect of the boundary layer is everywhere to draw fluid towards the wall, so that vorticity is still convected towards the wall. Numerical solutions have been computed, and some of the results are presented in the tables and diagrams. © 1961, Cambridge University Press. All rights reserved.

Description: It is shown that for the steady isoenergetic rotational flow of an ideal gas, both the specific enthalpy and the speed of sound can be expressed as functions of the velocity. As a result, it is possible to formulate the equations of motion so that the velocity is the only dependent variable. For a gas whose enthalpy and sound speed are functionally related, the results are a generalization of those for a perfect gas. If the enthalpy and sound speed are independent variables, the new formulation leads to a single vector equation whose solution completely determines the flow.

Description: A dispersion relation is derived for plane space-charge waves of finite amplitude in a plasma containing two oppositely charged streams of particles. The relation may be expressed simply in parametric form; it can also be quite well approximated, in two different ranges of amplitude, by expressions for the wavelength in terms of the maximum variation of the electrostatic potential.