CONSTRUCTION VIII. THE SHAFT 115

from one extremity to the other. To cut it into a true straight-sided cone would be a matter of much trouble and nicety, and would incur the continual risk of chipping into it too deep. Why not leave some room for a chance stroke, work it slightly, very slightly, convex, and smooth the curve by the eye between the two extremities? you will save much trouble and time, and the shaft will be all the stronger.

This is accordingly the natural from of a detached block shaft. It is the best. No other will ever be so agreeable to the mind or eye. I do not mean that it is not capable of more refined execution, or of

the application of some of the laws of ęsthetic beauty, but that it is the best recipient of execution and subject of law; better, in either case, than if you had taken more pains, and cut it straight.

§ 4. You will observe, however, that the convexity is to be very slight, and that the shaft is not to bulge in the centre, but to taper from the root in a curved line; the peculiar character of the curve you will discern better by exaggerating, in a diagram, the conditions of its sculpture.

Let a, a, b, b, at A, Fig. 13, be the rough block of the shaft, laid on the ground, and as thick as you can by any chance require it to be; you will leave it of this full thickness at its base at A, but at the other end you will mark off upon it the diameter, c, d, which you intend it to have at the summit; you will then take your mallet and chisel, and working from

[Version 0.04: March 2008]