From Chapter 3:
It is pretty clear that not a few of the druggists who sold tobacco were great rascals. Ben Jonson has let us into some of their secrets of adulteration—the treatment of the leaf with oil and the lees of sack, the increase of its weight by other artificial additions to its moisture, washing it in muscadel and grains, keeping it in greased leather and oiled rags buried in gravel under ground, and by like devices. Other writers speak of black spice, galanga, aqua vitæ, Spanish wine, aniseeds and other things as being used for purposes of adulteration.

From Chapter 8:
Another famous parson, the Rev. John Newton, was a smoker, and so was Cowper's other clerical friend, that learned and able Dissenter, the Rev. William Bull, whose whole mien and bearing were so dignified that on two occasions he was mistaken for a bishop. Cowper appreciated snuff, but did not care for smoking, and when he wrote to Unwin, describing his new-made friend in terms of admiration, he concluded—"Such a man is Mr. Bull. But—he smokes tobacco. Nothing is perfection 'Nihil est ab omni parte beatum.'" Bull, however, was not excessive in his smoking, for his daily allowance was but three pipes. In his garden at Newport Pagnell, Bull showed Cowper a nook in which he had placed a bench, where he said he found it very refreshing to smoke his pipe and meditate. "Here he sits," wrote Cowper, "with his back against one brick wall, and his nose against another, which must, you know, be very refreshing, and greatly assist meditation."