One characteristic device will be a sufficient specimen.

Swift wrote that a great collection of "_my_ letters to _you_" is somewhere "in a safe hand." He meant, of course, "a collection of _your_ letters to _me_"-- the only letters of which he could know anything.

Observing the slip of the pen, he altered the phrase by writing the correct words above the line.

It now stood-- "your me my letters to you." Pope laid great stress upon this, interpreting it to mean that the "great collection" included letters from each correspondent to the other--the fact being that Swift had only the letters from Pope to himself.

The omission of an erasure (whether by Swift or Pope) caused the whole meaning to be altered.