Sentence:  The word in the original (as St. Hierom tells us from the Hebrew traditions) implies, that the Spirit of God sat <WSD>abrood</WSD> upon the whole rude mass, as birds upon their eggs, ... 
Meaning of the word marked with <WSD> tags:  Upon a brood; on a hatch. (Attested from around (1150 to 1350) until the late 19th century.)<ref name=SOED>(page=8)</ref>