From Chapter 4:
It is certain that the armies of the Parliament were great smokers, for the finds of seventeenth-century pipes on the sites of their camps have been numerous. A considerable number of pipes of the Caroline period, with the usual small elongated bowls, were found in 1902 at Chichester, in the course of excavating the foundations of the Old Swan Inn, East Street, for building the present branch of the London and County Bank.

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.