Horace Walpole, after having made extensive inquiries on this subject, has recorded, that he never could ascertain the authenticity and originality of any portrait of Mary, except of that in the possession of the Earl of Morton, which was painted when she was at Lochleven. Chalmers, in order to come as near the truth as possible, employed Mr Pailou, an artist of ability, to compare the picture belonging to the Earl of Morton, with two or three other undoubted originals which have been discovered since Walpole wrote. Pailou commenced by sketching the outline of his picture from Lord Morton's original. He then proceeded to the examination of three genuine portraits of Mary, one in the Church of St Andrew in Antwerp, another in the Scotch College at Douay, and a third in the Scotch College at Paris. Neither did he forget the profile heads of Mary struck upon her coins, nor the marble figure representing her on her tomb in Henry VII's Chapel, which Walpole thought a correct likeness. Mr Pailou thus made Lord Morton's picture the basis of his own, but, as he advanced, constantly referred to the others, "till he got the whole adjusted and coloured." Though we cannot exactly approve of thus cooking up a picture from various different sources, and should be inclined to think, that too much was left by such a mode of procedure to the arbitrary taste of the artist, we nevertheless feel satisfied that Mr Pailou has hit upon a tolerably accurate likeness. His picture, engraved by Scriven, forms the frontispiece to the second volume of Chalmers's work. The brow, eyes, mouth, and chin, he has given with great success. But the painting is far from being without faults;--the face is a good deal too round and plump, the nose is made slightly aquiline--a decided mistake,--and the neck is much too short, at least so it appears in the engraving.