hematical laws. In their paintings earlier Renaissance artists had applied the rules of linear perspective, by which objects appear smaller in proportion as they are farther away from the eye of the spectator. Leonardo joined this principle to two others: perspective of clarity (distant objects progressively lose their separateness and hence are not drawn with outlines) and perspective of color (distant objects progressively tend to a uniform gray tone). He wrote about both of these phenomena in his notebooks.The Adoration of the Magi was, as noted above, left unfinished. In his later career Leonardo often failed over a period of years to finish a work, essentially because he would not accept established answers. For example, in his project for a bronze equestrian statue he began his work by delving into such matters as the anatomy of horses and the method by which the heavy monument could be transported from his studio to its permanent location. In the case of the Magi altarpiece, however, the unfinished state may merely result from the fact that Leonardo left Florence in 1482 to accept the post of court artist to the Duke of Milan. In leaving, Leonardo followed a trend set by the leading Florentine masters of the older generation, Verrocchio and Antonio Pollaiuolo, who went to Venice and Rome to execute commissions larger than any available in their native Florence.Leonardo presented himself to the Duke of Milan as skilled in many crafts, but particularly in military engineering, asserting that he had worked out improved methods for shooting catapults and diverting rivers. Such inventions, as well as the remarkable machinery that Leonardo produced in Milan for stage pageants, point to his profound interest in the laws of motion and propulsion, a further aspect of his interest in living things and their workings. Again, this preoccupation differs from older artists only in degree.Leonardo's first Milanese painting is the altarpiece Vir...
