This series reports some of the measurements made since the publication of the previous list. Equipment and methods have been previously described (Saskatchewan II).

The list of dates grouped below represents datings made during 1963. The method and the counting techniques have been previously described (Radiocarbon, v. 6, Saclay I).

These analyses were performed from November 1963 to November 1964 with equipment and techniques essentially unchanged since the previous date list. Unless otherwise noted all samples were submitted by Smithsonian staff members, each of whom was most helpful in supplying information pertaining to the samples and in discussion of results.

The C14 dates given below are a continuation of the work presented in our earlier lists (Stockholm I, II, III, IV, and V). The apparatus and technique are the same as described in Stockholm V.

In this paper are reported C14 dates of archaeologic samples from the Neolithic, Harappan and Early Historic sites of India. C14 activity was counted in an Oeschger-Houtermans’ gas proportional counter. The counting gas, acetylene, was synthesized using the technique described earlier (Kusumgar and others, 1963). The dates presented here are based on 5568 yr for the half-life of C14. The conversion to A.D./B.C. scale has been made using a.d. 1950 as the reference year.

This list reports measurements made at this laboratory since the preparation of the last list (Texas II). About twenty measurements are not reported because they are from series which are incomplete. Ages were calculated using a C14 half-life of 5568 yr and 1950 as the reference year. The modern standard used was 95% of NBS oxalic acid activity. The deviations reported are based on the counting statistics of the sample, background, and modern, and are ±1σ except that when the sample count approached either the modern standard or the background, 2σ limits are reported.

The following list covers most of the samples measured at the Uppsala C14 laboratory since the last list (Uppsala IV) except for all of the samples utilized for determining the increase of the C14/C12 ratio due to explosion of nuclear devices.

The following list covers the samples measured since 1962 at the Uppsala C14 laboratory to determine the increase of the C14/C12 ratio due to explosion of nuclear devices.

The measurements reported in this list have been carried out in the Isotope Laboratory of the Institute of Geophysics and Planetary Physics during 1964. They are a continuation of the previously reported date lists UCLA I, II and III. The same counting procedure has been continued: CO2 proportional counting at 1 atm of pressure in a 7.5 L counter with three energy channels. Dates have been calculated according to the recommendations of the Fifth Radiocarbon Conference, Cambridge, 1962, on the basis of a radiocarbon half-life of 5568 yr (Godwin, 1962). The modern standard for organic samples has been based on 95% of the count rate of NBS oxalic acid for radiocarbon laboratories. Background measurements are determined with CO2 derived from marble. The ages of carbonate-containing substances such as shells and tufa have been calculated on the basis of estimates for the corresponding contemporary C14 activity (Broecker and Walton, 1959), as discussed in the respective sample descriptions. New methods of sample preparation are described in context with the date listings.

This list contains the results of measurements made during 1963 and 1964. Samples are counted in the form of acetylene gas, as previously, and ages computed using the Libby half-life of 5568 ± 30 yr. The error listed is always larger than the one-sigma statistical counting error commonly used, takes into account known uncertainty laboratory factors, but does not include external (field or atmospheric) variations.

A radiocarbon dating laboratory was installed at the University of Wisconsin in 1963 as part of a program of climatic research in which meteorologists, archaeologists, chemists, botanists, limnologists, geologists, and soil scientists are cooperating.