Sentence:  By two <WSD>lunar</WSD> obſervations the long[itude] was 9° 57′ 30″ E. agreeing within 37′ by the watch, though the day before the long. by moon and watch differed 2° 35′. 
Meaning of the word marked with <WSD> tags:  Of, pertaining to, or resembling the Moon (that is, Luna, the Earth's moon); Lunar.