Jenks nodded comprehension and followed her example, for by this means their hands were left free.
The black cloud grew more dense each few seconds.

Nevertheless, owing to the slope of the ledge, and the tendency of the smoke to rise, the south side was far more tenable than the north.

Quick to note this favorable circumstance, the sailor deduced a further fact from it.

A barrier erected on the extreme right of the ledge would be a material gain.

He sprang up, dragged the huge tarpaulin from its former location, and propped it on the handle of the pickaxe, driven by one mighty stroke deep into a crevice of the rock.
It was no mean feat of strength that he performed.