From Chapter 1:
The form and make of the first pipe is a matter I do not propose to go into here; but in connexion with the first pipe smoked in this country Aubrey's interesting statements must be given. Writing in the time of Charles II, he said that he had heard his grandfather say that at first one pipe was handed from man to man round about the table. "They had first silver pipes; the ordinary sort made use of a walnut shell and a straw"—surely a very unsatisfactory pipe. Tobacco in those earliest days, he says, was sold for its weight in silver. "I have heard some of our old yeomen neighbours say that when they went to Malmesbury or Chippenham Market, they culled out their biggest shillings to lay in the scales against the tobacco."

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.