an authentic copy of a long letter of sigismond bacstrom and sent to mr. hand has been handwritten by frederick hockley in 1839: the "mr. yardley's process". then, this manuscript has been bought in 1913 by the famous bookseller pierre dujols and given to julien champagne, the illustrator of fulcanelli's books. julien champagne wrote the french translation of the "mr. yardley's process" in front of the english text in blank frames that have been previously drawn by frederick hockley on all verso pages. after more than one century, this manuscript owned by champagne's family has been published in facsimile by éditions les trois r (france, 2015-2016).