From Chapter 2:
The properly accomplished gallant not only professed to be curiously learned in pipes and tobacco, but his knowledge of prices and their fluctuations, of the apothecaries' and other shops where the herb was sold, and of the latest and most fashionable ways of inhaling and exhaling the smoke, was, like Mr. Weller's knowledge of London, "extensive and peculiar." It was knowledge of this kind that gained for a gallant reputation and respect by no means to be acquired by mere scholarship and learning.

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.