For ten years, Walter resolved to have the parlor-door hinge mended: three drops of oil would have done it. Tristram (who hasn't fixed it yet) resolves to do it within his own lifetime.
Corporal Trim has been making model mortars for the fortifications, and he proudly carries them to the parlor to show them to his master. The squeaking hinge wakes up Walter, who is distressed to find that to make the mortars, Trim has cut off the tops of a pair of heirloom boots. He is pacified, however, and "brought into perfect good humour with them in an instant" when Toby says that all of his concern with the fortifications is "for the good of the nation."
Trim tells them that Dr. Slop is in the kitchen, "making a bridge." Toby says, "Tell him I thank him heartily." But Toby is mistaken about what the bridge is, and in order to explain that, Tristram says he must tell about something that should really come in later. He explains the problems of digression again: if he waits till later, "I ruin the story I'm upon, — and if I tell it here — I anticipate matters, and ruin it there." He calls on the "POWERS" to set up a guidepost to show a poor author which way to go.
When Uncle Toby began to court Widow Wadman, Trim courted her maid, Bridget. But when Toby ceased courting his paramour, Trim continued to meet his on the sly for five years. One evening, shortly before the night of Tristram's birth, Trim met Bridget and decided to show her the fortifications by moonlight. Somehow the little Dutch drawbridge "was crush'd all to pieces that very night." Walter has been teasing Toby and Trim ever since; Toby believes it to have been a simple accident (Trim slipped and they both fell on the bridge) and thanks providence that "the poor fellow did not break his leg," but Walter borrows Toby's military metaphor and speaks of the power of Trim's artillery.
