Of Jorgenson's unpublished writings, there are five large volumes in the Egerton collection of manuscripts in the British Museum. The first, and the most ambitious, fills 517 closely-written pages, and was composed during the author's detention in Tothill Fields prison, after his brief and merry career as a monarch in Iceland. It is entitled “The Adventures of Thomas Walter,” and is dedicated in a prefatory letter to Sir William Hooker, whom Jorgenson describes as “the only one who has had sufficient courage to address me as ‘My Dear Friend.’” This book is a curious and entertaining mixture of fact and fiction. On the basis of his extensive experience as a traveller in many lands, and a voyager over many seas, Jorgenson has built up a succession of imaginary adventures, evidently in imitation of the manner of Swift and Defoe, some of his stories being tender and pathetic, whilst others are characterised by a coarse, riotous and Rabelaisian style of humour. As an English composition it is far from faultless, but this is not surprising in view of the circumstances under which it was written. “The prisoners are generally either swearing, cursing or fiddling,” says Jorgenson in his preface, “and every moment I am in dread of somebody or other tumbling over me and spoiling all I have written.”