4017103A Treatise on Painting — Of StatuaryJohn Francis RigaudLeonardo da Vinci

Chap. CCCLXI.Of Statuary.

To execute a figure in marble, you must first make a model of it in clay, or plaster, and when it is finished, place it in a square case, equally capable of receiving the block of marble intended to be shaped like it. Have some peg-like sticks to pass through holes made in the sides, and all round the case; push them in till every one touches the model, marking what remains of the sticks outwards with ink, and making a countermark to every stick and its hole, so that you may at pleasure replace them again. Then having taken out the model, and placed the block of marble in its stead, take so much out of it, till all the pegs go in at the same holes to the marks you had made. To facilitate the work, contrive your frame so that every part of it, separately, or all together, may be lifted up, except the bottom, which must remain under the marble. By this method you may chop it off with great facility[1].

  1. The method here recommended, was the general and common practice at that time, and continued so with little, if any variation, till lately. But about thirty years ago, the late Mr. Bacon invented an entirely new method, which, as better answering the purpose, he constantly used, and from him others have also adopted it into practice.