Sentence:  ... they fir'd several Times, making other Signals for the Boat. / At last, when all their Signals and <WSD>Firings</WSD> prov'd fruitless, and they found the Boat did not stir, we saw them by the Help of my Glasses, hoist another Boat out, and row towards the Shore ... 
Meaning of the word marked with <WSD> tags:  The discharge of a gun or other weapon.