'Why do you say so?' Daniel drew the loose bung out and found that the keg was nearly full. Taking up a copper spoon that Hooke had left near the scale (copper did not make sparks), he scooped up a small amount of powder from the bung-hole and began sprinkling it onto one of the scale's frail golden pans. But his gaze strayed towards the linen bag. In part this was because Hooke, who feared so little, seemed to think it was a hazard. Too, there was something about this bag that was familiar to him, though he could not place it in his memory.