Editions of the Rubáiyát appear in all kinds of forms: one text only, more than one text, selections, variorum editions etc. There are different ways to organize a catalog or a bibliography. A look at the Contents page shows how Potter handled this complicated matter.
The work consists of four parts: 1) versions in English, including FitzGerald and other translators; 2) versions in foreign languages, oriental and biblingual editions; 3) prose and verse on the rubáiyát in books and articles, the rubáiyát in music, drama, art and commerce and parodies; 4) manuscripts and lithographed texts. In total there are 1308 titles.
We also may distinguish between a text, a version and an edition. For example, titles in I-IV are editions of a specific version of a text. Potter ignores this distinction and describes them all as ‘versions’. How complicated matters are is shown by the way Potter handled the various versions by Le Gallienne: nos. 342-345 or the York Powell versions:.
All items are numbered. In Part I they also have specific names, except those in Chapter X. For example: (1) First Edition, (2) Ashley Library Edition, (3) MacDougall Edition. Some titles bear the same edition name: (78) and (79) Foulis Books Edition, and all of the Roycroft books are Roycroft Editions, so these names are not unique.
Consequence of Potter’s grouping (FitzGerald’s versions published abroad (Chapter VII) and FitzGerald’s versions published in the USA (Chapter VIII) is that for instance FitzGerald’s first version are listed at least three chapters.
Taylor and Forrest (2016) identified a number of duplicate entries, i.e. no. 56: “Edward FitzGerald 1809-1909. Centenary celebrations souvenir. [1909]”, which is also listed as no. 647 (Part 3, Chapter I: Prose works pertaining to the Rubáiyát) and as no. 1017 (Part 3, Chapter VII: Verse on the Rubaiyat in Books)
In Part Three of the Bibliography (Prose works pertaining to the Rubáiyát) we find a number of editions that include selections from FitzGerald’s translation: nos. 590, 603, 605, 610, 620, 621, 623, 638, 648, 652, 655, 657, 661, 667, 675, 661, 667, 675, 680, 685, 880, 885 etc. All this as far as I have been able to check these titles.
There are three chapters in Part Three that show works in periodical publications: Chapters IV, VIII and X. Here the titles are grouped under the name of the periodical, for example in item # 726 – Atlantic Monthly: “A Dialogue in Hades”(6/1902) and “A Persian Poet” (4/78). There are many more similar examples which means that the total number of titles in the Bibliography is much higher than 1308.