As far as I know, Libby didn't date any skeletal material in his original work, instead confining himself to wood of known age. Presumably this was because the size of the sample required was so large. For example, Oakley used the fluorine method on Piltdown first, and only in 1959 had radiocarbon dating improved to the point at which Oakley was able to date Piltdown without having to destroy the specimens. I think therefore the first scientific dating method used on human skeletal material probably was fluorine dating.
From: British archaeology discussion list on behalf of Mark Hall
Sent: Sat 16/09/2006 18:56
To: [log in to unmask]
Subject: Re: [BRITARCH] A question
On 9/16/2006, "Nick.Thorpe" <[log in to unmask]> wrote:
>The earliest scientific dating method would have been fluorine dating, >undertaken by Oakley in 1949 on 'Piltdown Man' and other claimed early >humans of which he was suspicious.
Libby actually published his first set of radiocarbon dates in 1949; odds
are he probably prepared and ran the samples in 1948 or even earlier.
Best, Mark Hall