The original document by G. Bergenroth mentioned in the link provided by jeioncs is supposed to have a description of the original procedure. I don't know how/i

The original document by G. Bergenroth mentioned in the link provided by jeioncs is supposed to have a description of the original procedure. I don't know how/if you can get a document from the National Archives of the United Kingdom, though. Edit: Link to the actual Archives entry: http://discovery.nationalarchives.gov.uk/details/r/C12056 http://discovery.nationalarchives.gov.uk/details/r/C12056