the latter days ofThe text printed in 1818 has "latter days of December," which is clearly a compositor's error unnoticed in the Shelleys' proofreading of the text for the first edition. The mistake, once in print, went unnoticed in all later editions of the novel. In Mary Shelley's draft, however, the word is unmistakably "September." She would have had every reason to adhere to this timeline since, just a few weeks earlier than her fictional schedule, in 1814, it took the Shelley party nine days to cover the distance between Basel and Rotterdam (30 August-7 September) travelling exactly as do Victor Frankenstein and Henry Clerval and, even when adverse conditions delayed their departure from Holland, a three days' crossing brought them to London on 13 September (see Six Weeks' Tour for Switzerland and Holland).
The attenuated journey of the 1818 text is whittled to three months in the shifting of the original departure date in 1831, which, as indicated earlier, may have been done to accommodate the timespan after Victor's return from Mont Blanc rather than his arrival date in England. In the next chapter, as recorded in both the 1818 and 1831 texts, the chronology reverts to a normative calendar and Victor observes that he and Clerval "had arrived in England at the beginning of October" (III:2:5).