Semenza emulated Guido in both his manners, and displayed more correctness, erudition, and strength. His pictures at Araceli and other places sufficiently distinguish him from the immense crowd of fresco-painters at Rome. There too are many of his altar-pieces, none more beautiful, perhaps, than the S. Sebastian, at S. Michele in Bologna. Gessi surpassed him in spirit, invention, and rapidity, for which last quality even Guido envied him. This enabled him too, from the first, to vary his works in point of manner until he hit upon the right one, as in his very beautiful St. Francis at the Nunziata, little inferior to Guido, as well as in several others conducted in his earlier and best days. To these he was indebted for his name of a second Guido; but subsequently he abused his talents, as is the case with those who are held in slight esteem for performing much and rapidly. Thus Bologna abounds with his pictures, in which, with the exception of their fine character and much delicacy, there is nothing to commend; his pictures are cold, his colouring is slight; the shape and features are often too large, and not seldom incorrect. He is known to have invariably affected the second manner of Guido, and hence he is always more feeble, dry, and less harmonious than his master. By these distinctions are the differences between salesmen and purchasers usually decided, as to whether such a piece be a poor Guido or a Gessi. Yet Gessi had a numerous school at Bologna, on Guido's retiring, and formed scholars of some reputation, such as Giacomo Castellini, Francesco Coreggio, and Giulio Trogli, who, devoting himself to perspective, under Mitelli, and publishing a work entitled Paradossi della Prospettiva, went ever afterwards by the name of the _Paradox_. Ercole Ruggieri was a faithful follower of Gessi's style, insomuch as at first sight to be mistaken for his master. He was called Ercolino del Gessi, and his brother Batistino del Gessi, an artist of rare talent, commended by Baglione, and much esteemed by Cortona, in whose arms he breathed his last. Batistino was first a pupil of Domenichino, as before mentioned; and might more properly be named dello Zampieri than del Gessi, from his education and his style. He accompanied Gessi to Naples, and subsequently became his rival, and surpassed him at S. Barbaziano in Bologna. Finally he fixed his residence at Rome, where remain some of his paintings in fresco, in the cloister of the Minerva, in the Cenci palace, and elsewhere, which shew in him the promise of a very distinguished artist; but he did not survive his thirty-second year.