From Chapter 4:
It is somewhat singular that the Puritans, who denounced most amusements and pleasures, and who frowned upon most of the occupations or diversions that make for gaiety and the enjoyment of life, did not, as Puritans, denounce the use of tobacco. One or two of their writers abused it roundly; but these were not representative of Puritan feeling on the subject. The explanation doubtless is that the practice of smoking was so very general and so much a matter of course among men of all ranks and of all opinions, that the mouths of Puritans were closed, so to speak, by their own pipes. A precisian, however, could take his tobacco with a difference. The seventeenth-century diarist, Abraham de la Pryme, says that he had heard of a Presbyterian minister who was so precise that "he would not as much as take a pipe of tobacco before that he had first sayed grace over it." George Wither, one of the most noteworthy of the poets who took the side of the Parliament, was confined in Newgate after the Restoration, and found comfort in his pipe.

From Chapter 8:
The allusion in these verses to a "satiric wipe" refers to a passage in the poem entitled "Conversation," which Cowper had written in the previous year, 1781. In this passage tobacco is abused in terms which Cowper clearly felt to need modification after his personal intercourse with such a smoker as his friend Bull. In describing, in "Conversation," the manner in which a story is sometimes told, the poet says:

The pipe, with solemn interposing puff,
Makes half a sentence at a time enough;
The dozing sages drop the drowsy strain,
Then pause and puff—and speak, and pause again.
Such often, like the tube they so admire,
Important triflers! have more smoke than fire.