Final answer:
The question appears to be a misrepresentation of a scene about how the light of sunrise changes the colors at sea. The phrase 'barset seal' does not match the context, and the text actually describes the sea changing from slate to emerald-green, indicating the men in the boat are witnessing morning without realizing its gradual process.
Step-by-step explanation:
The question "What colour is the barset seal in the morning?" seems to be referencing a description of a scene where the natural light from the sunrise alters the perception of colors in the environment. However, the phrase 'barset seal' does not appear to directly pertain to the referenced text. Instead, the text describes the transition from dawn to broad day where the men on a boat observe the color of the sea changing from slate to emerald-green, streaked with amber lights, and the foam appearing like tumbling snow. This transformation of color indicates the dynamic nature of the ocean under the increasing light of the sun. Nonetheless, the men are too preoccupied to note such details or the process of the breaking day, despite its effect on their surroundings.