To prepare his journals for future reading Gallison left many marginal notes, with additions, observations, and references to previous or subsequent entries being quite common.
One other interesting component of his editing is his deletions. Broadly speaking, he made two kinds. One, transparent and frugal with ink, served to delete an error that he didn’t want to forget completely. A blind alley in his work on Euclid and an unduly pessimistic theological note received that treatment in Volume A.
In a few other places, he resorted to obliteration. His intent for the journals was always that he should be the only reader. Nevertheless, he occasionally wrote reports that might have embarrassed someone were they to be discovered later, and those get a very different treatment.
The link above leads to a conversation with Uncle Sewall in the summer of 1812. Federalists were talking increasingly openly about secession from the union, and Sewall or someone in his inner circle seems to have said something that would have led to censure after the War of 1812’s conclusion.