Note 19 — Chapter XIX · VISUAL ANALOGUES
Reading edition
As an instance of this I may mention the experiment which I saw on the quick fusion of metals exhibited at the Royal Institution by Sir William Roberts-Austen (1901), where, owing to the glare and the dense fumes, it was impossible to see what happened in the crucible. But I was able to see every detail on closing the eyes. The effects of the smoke, being of less luminescence, cleared away first, and left the after-image of the molten metal growing clearer on the retina.