From Chapter 1:
There is little doubt that the smoke of herbs and leaves of various kinds was inhaled in this country, and in Europe generally, long before tobacco was ever heard of on this side the Atlantic. But whatever smoking of this kind took place was medicinal and not social. Many instances have been recorded of the finding of pipes resembling those used for tobacco-smoking in Elizabethan times, in positions and in circumstances which would seem to point to much greater antiquity of use than the form of the pipes supports; but some at least of these finds will not bear the interpretation which has been put upon them, and in other cases the presence of pipes could reasonably be accounted for otherwise than by associating them with the antiquity claimed for them. In any case, the entire absence of any allusions whatever to smoking in any shape or form in our pre-Elizabethan literature, or in mediæval or earlier art, is sufficient proof that from the social point of view smoking did not then exist. The inhaling of the smoke of dried herbs for medicinal purposes, whether through a pipe-shaped funnel or otherwise, had nothing in it akin to the smoking of tobacco for both individual and social pleasure, and therefore lies outside the scope of this book.

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.