It is possible, I think, to define, at least with some approximation to precision, Michelangelo's employment of his favourite vehicles for several purposes and at different periods of his life. A broad-nibbed pen was used almost invariably in making architectural designs of cornices, pilasters, windows, also in plans for military engineering. Sketches of tombs and edifices, intended to be shown to patrons, were partly finished with the pen; and here we find a subordinate and very limited use of the brush in shading. Such performances may be regarded as products of the workshop rather than as examples of the artist's mastery. The style of them is often conventional, suggesting the intrusion of a pupil or the deliberate adoption of an office mannerism. The pen plays a foremost part in all the greatest and most genial creations of his fancy when it worked energetically in preparation for sculpture or for fresco. The Louvre is rich in masterpieces of this kind--the fiery study of a David; the heroic figures of two male nudes, hatched into stubborn salience like pieces of carved wood; the broad conception of the Madonna at S. Lorenzo in her magnificent repose and passionate cascade of fallen draperies; the repulsive but superabundantly powerful profile of a goat-like faun. These, and the stupendous studies of the Albertina Collection at Vienna, including the supine man with thorax violently raised, are worked with careful hatchings, stroke upon stroke, effecting a suggestion of plastic roundness. But we discover quite a different use of the pen in some large simple outlines of seated female figures at the Louvre; in thick, almost muddy, studies at Vienna, where the form emerges out of oft-repeated sodden blotches; in the grim light and shade, the rapid suggestiveness of the dissection scene at Oxford. The pen in the hand of Michelangelo was the tool by means of which he realised his most trenchant conceptions and his most picturesque impressions. In youth and early manhood, when his genius was still vehement, it seems to have been his favourite vehicle. The use of chalk grew upon him in later life, possibly because he trusted more to his memory now, and loved the dreamier softer medium for uttering his fancies. Black chalk was employed for rapid notes of composition, and also for the more elaborate productions of his pencil. To this material we owe the head of Horror which he gave to Gherardo Perini (in the Uffizi), the Phaethon, the Tityos, the Ganymede he gave to Tommaso Cavalieri (at Windsor). It is impossible to describe the refinements of modulated shading and the precision of predetermined outlines by means of which these incomparable drawings have been produced. They seem to melt and to escape inspection, yet they remain fixed on the memory as firmly as forms in carven basalt.