Very incautiously, after printing 25 volumes of Radiocarbon, the editors have authorized some personal reminiscence. Like all “Quaternary scientists”—no better collective name is available for our strange profession—I have been engaged in historiography, writing about history, for many years. In 1946, when natural radiocarbon was discovered, my subject, the sedimentary history of lakes, was only one of several kinds of historical record that needed, and soon received, a new reading. At the time, not all custodians of other kinds of record were ready to agree that new readings were conceivable, let alone necessary. The record of their persuasion—some of which has been written by Greg Marlowe (1980) in “W F Libby and the Archaeologists”—is part of the history of historiography. To the bibliography of this dangerously abstract subject I venture to add some minor footnotes. They come, not from historical research like Marlowe's, but from a leaky, selective memory.

Bomb 14C has been used as a tracer for CO2 in ocean surface water to study CO2 exchange between atmosphere and ocean. Using ordinary cargo ships for sampling, we have been able to cover some parts of the Atlantic, Pacific, and Indian Oceans for certain periods. A total number of 520 samples from 89 locations were measured during the last 15 years. The data are presented both in tables and graphs. A maximum 14C concentration (Δ14C) of ca 20% was observed in temperate northern latitudes, and a few per cent lower at southern latitudes. A seasonal trend in the 14C variation, with summer maximum and winter minimum, was observed both in downwelling and upwelling areas.

Selected stable carbon isotope measurements published in Radiocarbon over a 12-year period have been abstracted, plotted, and summarized, to give more reliable estimates of the mean value and range of δ13C for five classes of natural material (human bone collagen, non-human animal bone collagen, plant materials, wood, and charcoal), and to provide a firmer base line for stable carbon isotope dietary and environmental studies.

Although acid leaching of shell carbonates prior to 14C assay is usually desirable, under some circumstances it can worsen contamination by preferentially dissolving unaltered shell and thus increasing the proportion of secondary carbonate. The risk can be eliminated by monitoring the progress of leaching with the help of microscopy and x-ray diffraction.

The following list consists of dates for archaeologic and geologic samples mostly measured from June 1982 to June 1983. The dates were obtained by liquid scintillation counting of benzene using the laboratory procedures outlined in previous lists (see, eg, BM-VIII, R, 1976, v 18, p 16). Dates are expressed in radiocarbon years relative to ad 1950 based on the Libby half-life for 14C of 5570 yr, and are corrected for isotopic fractionation (δ13C values are relative to PDB). No corrections have been made for natural 14C variations. The modern reference standard is NBS oxalic acid (SRM 4990). Errors quoted with dates are based on counting statistics alone and are equivalent to ± 1 standard deviation (± 1σ). Descriptions, comments, and references to publications are based on information supplied by submitters.

The following date list covers samples dated by the La Jolla (Mt Soledad) Radiocarbon Laboratory from January 1979 through August 1982. Most archaeologic, most geologic, and some geochemical samples measured during that period are included here. Results of 14C analyses of samples of tree rings, banded coral rings, and Antarctic seawater dissolved inorganic carbon measured during this period will be published elsewhere. Because of the cessation of all federal grant funding of this laboratory, this is the last date list to be published by it.

The Radiocarbon Laboratory of the Archaeological and Ethnographical Museum in Lódź was established to meet the growing demand for radiocarbon dating of archaeologic and geologic samples. The liquid scintillation technique based on the Polish liquid scintillation counter with a single photomultiplier began operation in 1966. The base for the measurements was ethylbenzene. In 1974 new facilities for the determination of radiocarbon assays were installed. The proportional counter and the electronics supplied by Nuclear Enterprises became routine counting equipment two years later.

The reinstallment, operation, and the 14C measurements reported here were made since 1976 in the LATYR, the Radiocarbon Dating Laboratory of the Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata. Sample preparation is preceded by careful visual separation and hand removal of gross impurities. This is followed in all cases (charcoal, wood) with successive washings of the sample with boiling 2% HCl and 1% NaOH solution for removal of carbonates and humic acids. Thereafter, it is washed with distilled water and acidified to pH = 3. Individual variations in the pretreatment are not described in the date list, but they are usually reported directly to the collector together with the data obtained.

Procedures and equipment used in the University of Wisconsin laboratory have been described in previous date lists. Except as otherwise indicated, wood, charcoal, and peat samples are pretreated with dilute NaOH-Na4P2O7 and dilute H3PO4 before conversion to the counting gas methane; marls and lake cores are treated with acid only. Very calcareous materials are treated with HCl instead of H3PO4. Pretreatment of bone varies with the condition of the bone sample; solid bone with little deterioration is first cleaned manually and ultrasonically. The bone is treated with 8% HCl for 15 minutes, then dilute NaOH-Na4P2O7 for 3 hours at room temperature, washed until neutral, and the collagen extracted according to Longin (1971). Charred bone is treated with dilute HCl, NaOH-Na4P2O7, and then dilute HCl again.

A sodium bicarbonate solution with a 10-fold activity compared to oxalic acid is used as a secondary standard in the Heidelberg 14C Laboratory. All routine checks and counter tests are greatly facilitated because of the high activity of the solution.

A major collective effort was made to develop a data base for establishing the relationship between 14C and calendric ages (Stuiver, 1982). The early “cosmic schwung” fit between the two ages (Suess, 1970a, p 310) and the 10,350 yr period of the grand trend (Suess, 1970b, p 596) have recently been replaced by the period of 12,100 yr (Suess, 1980). The period of the grand trend was estimated by correlating the data with an a priori postulated sine function (Suess, 1970, p 596), or more recently a polynomial fit of the sixth degree was used (Klein et al, 1982). In the detrended data, periods (wiggles) of between 2400 yr and 104 yr were identified by conventional time series analysis. This approach could not be used to estimate the period of the grand trend, because the time series includes less than one cycle, whereas several cycles are required in order to get a meaningful result.

Manuscripts of 14C papers and date lists should follow the recommendations in “Suggestions to Authors of the Reports of the US Geological Survey,” 6th ed, 1978, Superintendent of Documents, Government Printing Office, Washington, DC 20402. All copy, including the references, must be typewritten in double space: manuscripts must be submitted in duplicate. Computer print-out sheets may be used in letter-quality printing form. Manuscripts should be checked with meticulous care before they are submitted, for the author, not the editor, is finally responsible for errors other than those made by the printer. Revised manuscripts must be submitted in duplicate along with the original edited manuscript.