From Chapter 4:
Gardiner evidently follows this account, for his version of the story is: "Newcastle strolled towards his coach to solace himself with a pipe. Before he had time to take a whiff, the battle had begun." The incident was made the subject of a picture by Ernest Crofts, A.R.A., which was exhibited at the Royal Academy in 1888. It shows the Duke leaning out of his carriage window, with his pipe in his hand.

From Chapter 8:
Notwithstanding the unfashionableness of tobacco, there were still some noteworthy smokers to be found among the clergy. Dr. Sumner, head master of Harrow, who died in 1771, was devoted to his pipe. The greatest of clerical "tobacconists" of late eighteenth century and early nineteenth century date was the once famous Dr. Parr. It was from him that Dr. Sumner learned to smoke. When he and Parr got together Sumner was in the habit of refilling his pipe again and again in such a way as to be unobserved, at the same time begging Parr not to depart till he had finished his pipe, in order that he might detain him, we are told, in the evening as long as possible.