Sentence:  Then shewed the devil the booke unto the friar, and the friar saw it was an uncut unique of incalculable value; the height of it was half a cubit and the breadth of it the fourth part of a cubit and the thickness of it five <WSD>barleycorns</WSD> lacking the space of three horsehairs. 
Meaning of the word marked with <WSD> tags:  The length of such a grain; a unit of length of approximately one third (or sometimes one quarter) of an inch or eight millimetres, still used as a basis for shoe sizes