Before his death, Shelley completed many corrections to a manuscript edition of his work, but many of these changes were not carried over into Mary Shelley's edition. William Rossetti, in his 1870 edition, questioned Mary Shelley's efforts: "Mrs. Shelley brought deep affection and unmeasured enthusiasm to the task of editing her husband's works. But ill health and the pain of reminiscence curtailed her editorial labours: besides which, to judge from the result, you would say that Mrs. Shelley was not one of the persons to whome the gift of consistent accuracy has been imparted". Later, Charles Locock, in his 1911 edition of Shelley's works, speculated: "May we suppose that Mrs. Shelley never made use of that particular list at all? that what she did use was a "preliminary" list, – the list which Shelley "hoped to despatch in a day or two" (10 November 1820) – not the "formidable list"... which may in the course of nine years have been mislaid? Failing this hypothesis, we can only assume that Shelley's 'formidable list' was not nearly so formidable as it might have been".