TOLERATION. The avowed object of the Reformation was, to remove from Christianity the pagan ideas and pagan rites engrafted upon it by Constantine and his successors, in their attempt to reconcile the Roman Empire to it. The Protestants designed to bring it back to its primitive purity; and hence, while restoring the ancient doctrines, they cast out of it all such practices as the adoration of the Virgin Mary and the invocation of saints. The Virgin Mary, we are assured by the Evangelists, had accepted the duties of married life, and borne to her husband several children. In the prevailing idolatry, she had ceased to be regarded as the carpenter's wife; she had become the queen of heaven, and the mother of God. DA VINCI. The science of the Arabians followed the invading track of their literature, which had come into Christendom by two routes--the south of France, and Sicily. Favored by the exile of the popes to Avignon, and by the Great Schism, it made good its foothold in Upper Italy. The Aristotelian or Inductive philosophy, clad in the Saracenic costume that Averroes had given it, made many secret and not a few open friends. It found many minds eager to receive and able to appreciate it. Among these were Leonardo da Vinci, who proclaimed the fundamental principle that experiment and observation are the only reliable foundations of reasoning in science, that experiment is the only trustworthy interpreter of Nature, and is essential to the ascertainment of laws. He showed that the action of two perpendicular forces upon a point is the same as that denoted by the diagonal of a rectangle, of which they represent the sides. From this the passage to the proposition of oblique forces was very easy. This proposition was rediscovered by Stevinus, a century later, and applied by him to the explanation of the mechanical powers. Da Vinci gave a clear exposition of the theory of forces applied obliquely on a lever, discovered the laws of friction subsequently demonstrated by Amontons, and understood the principle of virtual velocities. He treated of the conditions of descent of bodies along inclined planes and circular arcs, invented the camera-obscura, discussed correctly several physiological problems, and foreshadowed some of the great conclusions of modern geology, such as the nature of fossil remains, and the elevation of continents. He explained the earth-light reflected by the moon. With surprising versatility of genius he excelled as a sculptor, architect, engineer; was thoroughly versed in the astronomy, anatomy, and chemistry of his times. In painting, he was the rival of Michel Angelo; in a competition between them, he was considered to have established his superiority. His "Last Supper," on the wall of the refectory of the Dominican convent of Sta. Maria delle Grazie, is well known, from the numerous engravings and copies that have been made of it.