Rosa da Tivoli's pictures usually represent pastoral subjects, with herdsmen and cattle, or shepherds with sheep and goats, which he frequently painted as large as life. He designed everything from nature, not only his animals, but the sites of his landscapes, ruins, buildings, rocks, precipices, rivers, etc. His groups are composed with great judgment and taste, and his landscapes, backgrounds, skies, and distances are treated in a masterly style. His cattle and animals, in particular, are designed with wonderful truth and spirit; his coloring is full of force, his lights and shadows are distributed with judgment and his touch is remarkably firm and spirited. ROSA DA TIVOLI'S FACILITY OF EXECUTION. Rosa da Tivoli acquired a wonderful facility in design and execution, for which reason he was named _Mercurius_ by the Bentvogel Society. A remarkable instance of his powers is recorded by C. le Blond, then a student at Rome. "It happened one day," says he, "that several young artists and myself were occupied in designing from the bassi-relievi of the Arch of Titus, when Roos passing by, was particularly struck with some picturesque object which caught his attention, and he requested one of the students to accommodate him with a crayon and paper. What was our surprise, when in half an hour he produced an admirable drawing, finished with accuracy and spirit." It is also related that the Imperial Ambassador, Count Martinez, laid a wager with a Swedish general that Roos would paint a picture of three-quarters' size, while they were playing a game at cards; and in less than half an hour the picture was well finished, though it consisted of a landscape, a shepherd, and several sheep and goats. ROSA DA TIVOLI'S HABITS. Rosa da Tivoli unfortunately fell into extravagant and dissipated habits, which frequently caused him great inconvenience. From his facility, he multiplied his pictures to such an extent as greatly to depreciate their value. It is related that he would sit down, when pressed for money, dispatch a large picture in a few hours, and send it directly to be sold at any price. His servant, possessing more discretion than his master, usually paid him the highest price offered by the dealers, and kept the pictures himself, till he could dispose of them to more advantage. LUCA CAMBIASO'S FACILITY IN PAINTING.