He began by making a critical revision of João Ferreira de Almeida's version: according to The Bible of every Land, published by Samuel Bagster in 1848, Boys "appears to have completed the revision of the New Testament, and to have published small editions of the Gospels of Matthew and Mark, and of the Psalms".
Then, in 1837, the Trinitarian Bible Society decided to publish a new Portuguese translation from the Greek and Hebrew texts, and appointed Boys to carry out the work.
In 1832 he published The Suppressed Evidence, or Proofs of the Miraculous Faith and Experience of the Church of Christ in all ages, from authentic records of the Fathers, Waldenses, Hussites.., .
[1] He was a frequent contributor of sketches and papers to Blackwood's Magazine, mostly descriptive of his experiences during the Peninsular War.
His acquaintance with the literature and antiquities of the Jews was very thorough, but perhaps the best proofs of his extensive learning are to be found in the numerous letters and papers, sometimes under his own name, and sometimes under the assumed name of "Vedette", contributed to the second series of Notes and Queries.
Of these the twelve papers on Chaucer difficulties are a most valuable contribution to the study of early English literature.