ELECTRONIC COPY OF THE ORIGINAL
Dr. Francis P. McManamon
Dear Dr. McManamon:
Attached are the results of carbon-isotope measurements on the Kennewick bone sample, which we have given the identification number AA34818, Sample B. The treatments of this sample are described in detail in my message to you of 13 December, 1999, and forwarded to you today. The sample from which the attached results were obtained is the one labeled "Sample B" in that message. I am anxious to make several comments.
1.) The carbon yield for this sample was 0.05%. The yield is defined as the mass of carbon obtained after all of the treatments of the bone have completed, divided by the initial mass of bone used.
2.) This is well below the yield for which we would usually quote a result. In fact, for bones with a yield as low as this, we generally will not even make a radiocarbon measurement.
3.) Because of the unusual nature of this sample, we have indeed made a radiocarbon measurement of the carbon obtained from it, and the result of that measurement is on the attached report.
4.) I emphasize that, because of the low yield, we do not have confidence in the result. Since contamination would most probably be more recent than the bone material, we would expect that our result is a limit, and represents a minimum of the radiocarbon age.
We are certainly very interested in measurements on the Kennewick bone. Please keep us posted, and if further measurements are to be made, we would be anxious to participate.
/s/ Doug Donahue