Sentence:  As they have no hour glasses, they measure their time by a kind of clepsydra. It is a small brass basin, about four inches in diameter, made thin enough to float on the water, with a hole in the bottom which admits as much as to fill it exactly in one gurry, or twenty-two and a half minutes. The sinking, therefore, of the vessel, is the signal for striking the <WSD>gurry</WSD>, and warning the inhabitants. 
Meaning of the word marked with <WSD> tags:  A circular gong that was struck at regular intervals to indicate the time.