Read it through once

We took our leave early, and left together. Even when we were groping among Mr. Jaggers’s stock of boots for our hats, I felt that the right twin was on his way back; and we had not gone half a dozen yards down Gerrard Street in the Walworth direction, before I found that I was walking arm in arm with the right twin, and that the wrong twin had evaporated into the evening air.