From Chapter 4:
But to turn from this worthy Exeter citizen to more famous names: I do not know of any good evidence as to whether or not Cromwell smoked, although he is said to have taken an occasional pipe while considering the offer of the crown, but John Milton certainly did. The account of how the blind poet passed his days, after his retirement from public office, was first told by his contemporary Richardson, and has since been repeated by all his biographers. His placid day ended early. The poet took his frugal supper at eight o'clock, and at nine, having smoked a pipe and drunk a glass of water, he went to bed. Apparently this modest allowance of a daily evening pipe was the extent of Milton's indulgence in tobacco. He knew nothing of what most smokers regard as the best pipe of the day—the after-breakfast pipe.

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."