In Chapter Seven of Mary Shelley's Frankenstein, I saw the following sentence:
I remembered also the nervous fever with which I had been seized just at the time that I dated my creation, and which would give an air of delirium to a tale otherwise so utterly improbable.
Judging by the structure, one might be tempted to analyze the sentence as having two relative clauses modifying the nervous fever:
I remembered also the nervous fever (a) with which I had been seized just at the time that I dated my creation, and (b) which would give an air of delirium to a tale otherwise so utterly improbable.
However, the plot apparently contradicts this analysis. Two paragraphs before the quoted passage, Victor said:
Two years had now nearly elapsed since the night on which he first received life
This specification of his creation as happening approximately two years before took place during the night prior to his return to his father's house. In other words, he dated his creation during the night, when he encountered the monster. It is thus rather likely that the boldfaced prepositional phrase is meant to describe the time of Victor's recalling the fever, and should have been positioned to modify the main clause, not the relative clause.
Note also that his nervous fever didn't strike him until after his friend Henry Clerval had visited him, and that was already some time after he created the monster:
"My dear Victor," cried he, "what, for God's sake, is the matter? Do not laugh in that manner. How ill you are! What is the cause of all this?" "Do not ask me," cried I, putting my hands before my eyes, for I thought I saw the dreaded spectre glide into the room; "he can tell.—Oh, save me! save me!" I imagined that the monster seized me; I struggled furiously, and fell down in a fit. Poor Clerval! what must have been his feelings? A meeting, which he anticipated with such joy, so strangely turned to bitterness. But I was not the witness of his grief; for I was lifeless, and did not recover my senses for a long, long time. This was the commencement of a nervous fever, which confined me for several months. During all that time Henry was my only nurse.