Some of Ruskin’s sketches of machinery in this notebook appear crude, others refined; most notably, the sketches are in ink, whereas earlier sketches in MSS I and III (1826-28) are in pencil, even though Ruskin had started using ink for text in those notebooks. The drawings in MS IVB of cogs, wheels, and whirligigs may be fantastical or they may reflect actual sightings during the tour of 1828, such as the technique for making  blocks  (for ship’s tackle) extensively detailed in the tour notes, no. 25.