rel="nofollow" href="#n36" type="note">36 but as far as it has to hold firm, it is divided and clawed, with wide projections,—look at an eagle’s.
§ X. Now observe. In proportion to the massiness of the column, we require its foot to express merely the power of bearing up; in fact, it can do without a foot, like the Squire in Chevy Chase, if the ground only be hard enough. But if the column be slender, and look as if it might lose its balance, we require it to look as if it had hold of the ground, or the ground hold of it, it does not matter which,—some expression of claw, prop, or socket. Now let us go back to Fig. XI., and take up one of the bases there, in the state in which we left it. We may leave out the two lower steps (with which we have nothing more to do, as they have become the united floor or foundation of the whole), and, for the sake of greater clearness, I shall not draw the bricks in the shaft, nor the flat stone which carries them, though the reader is to suppose them remaining as drawn in Fig. XI.; but I shall only draw the shaft and its two essential members of base, Xb and Yb, as explained at p. 65, above: and now, expressing the rounding of these numbers on a somewhat larger scale, we have the profile a, Fig. XII.; b, the perspective appearance of such a base seen from above; and c, the plan of it.
§ XI. Now I am quite sure the reader is not satisfied of the stability of this form as it is seen at b; nor would he ever be so with the main contour of a circular base. Observe, we have taken some trouble to reduce the member Yb into this round form, and all that we have gained by so doing, is this unsatisfactory and unstable look of the base; of which the chief reason is, that a circle, unless enclosed by right lines, has never an appearance of fixture, or definite place,37—we suspect it of motion, like an orb of heaven; and the second is, that the whole base, considered as the foot of the shaft, has no grasp nor hold: it is a club-foot, and looks too blunt for the limb,—it wants at least expansion, if not division.
Fig. XII.
§ XII. Suppose, then, instead of taking so much trouble with the member Yb, we save time and labor, and leave it a square block. Xb must, however, evidently follow the pillar, as its condition is that it slope to the very base of the wall veil, and of whatever the wall veil becomes. So the corners of Yb will project beyond the circle of Xb, and we shall have (Fig. XII.) the profile d, the perspective appearance e, and the plan f. I am quite sure the reader likes e much better than he did b. The circle is now placed, and we are not afraid of its rolling away. The foot has greater expansion, and we have saved labor besides, with little loss of space, for the interval between the bases is just as great as it was before,—we have only filled up the corners of the squares.
But is it not possible to mend the form still further? There is surely still an appearance of separation between Xb and Yb, as if the one might slip off the other. The foot is expanded enough; but it needs some expression of grasp as well. It has no toes. Suppose we were to put a spur or prop to Xb at each corner, so as to hold it fast in the centre of Yb. We will do this in the simplest possible form. We will have the spur, or small buttress, sloping straight from the corner of Yb up to the top of Xb, and as seen from above, of the shape of a triangle. Applying such spurs in Fig. XII., we have the diagonal profile at g, the perspective h, and the plan i.
§ XIII. I am quite sure the reader likes this last base the best, and feels as if it were the firmest. But he must carefully distinguish between this feeling or imagination of the eye, and the real stability of the structure. That this real stability has been slightly increased by the changes between b and h, in Fig. XII., is true. There is in the base h somewhat less chance of accidental dislocation, and somewhat greater solidity and weight. But this very slight gain of security is of no importance whatever when compared with the general requirements of the structure. The pillar must be perfectly secure, and more than secure, with the base b, or the building will be unsafe, whatever other base you put to the pillar. The changes are made, not for the sake of the almost inappreciable increase of security they involve, but in order to convince the eye of the real security which the base b appears to compromise. This is especially the case with regard to the props or spurs, which are absolutely useless in reality, but are of the highest importance as an expression of safety. And this will farther appear when we observe that they have been above quite arbitrarily supposed to be of a triangular form. Why triangular? Why should not the spur be made wider and stronger, so as to occupy the whole width of the angle of the square, and to become a complete expansion of Xb to the edge of the square? Simply because, whatever its width, it has, in reality, no supporting power whatever; and the expression of support is greatest where it assumes a form approximating to that of the spur or claw of an animal. We shall, however, find hereafter, that it ought indeed to be much wider than it is in Fig. XII., where it is narrowed in order to make its structure clearly intelligible.
§ XIV. If the reader chooses to consider this spur as an æsthetic feature altogether, he is at liberty to do so, and to transfer what we have here said of it to the beginning of Chap. XXV. I think that its true place is here, as an expression of safety, and not a means of beauty; but I will assume only, as established, the form e of Fig. XII., which is absolutely, as a construction, easier, stronger, and more perfect than b. A word or two now of its materials. The wall base, it will be remembered, was built of stones more neatly cut as they were higher in place; and the members, Y and X, of the pier base, were the highest members of the wall base gathered. But, exactly in proportion to this gathering or concentration in form, should, if possible, be the gathering or concentration of substance. For as the whole weight of the building is now to rest upon few and limited spaces, it is of the greater importance that it should be there received by solid masonry. Xb and Yb are therefore, if possible, to be each of a single stone; or, when the shaft is small, both cut out of one block, and especially if spurs are to be added to Xb. The reader must not be angry with me for stating things so self-evident, for these are all necessary steps in the chain of argument which I must not break. Even this change from detached stones to a single block is not without significance; for it is part of the real service and value of the member Yb to provide for the reception of the shaft a surface free from joints; and the eye always conceives it as a firm covering over all inequalities or fissures in the smaller masonry of the floor.
§ XV. I have said nothing yet of the proportion of the height of Yb to its width, nor of that of Yb and Xb to each other. Both depend much on the height of shaft, and are besides variable within certain limits, at the architect’s discretion. But the limits of the height of Yb may be thus generally stated. If it looks so thin as that the weight of the column above might break it, it is too low; and if it is higher than its own width, it is too high. The utmost admissible height is that of a cubic block; for if it ever become higher than it is wide, it becomes itself a part of a pier, and not the base of one.
§ XVI. I have also supposed Yb, when expanded from beneath Xb, as always expanded into a square, and four spurs only to be added at the angles. But Yb may be expanded into a pentagon, hexagon, or polygon; and Xb then may have five, six, or many spurs. In proportion, however, as the sides increase in number, the spurs become shorter and less energetic in their effect, and the square is in most cases the best form.
§ XVII. We have hitherto conducted the argument entirely on the supposition of the pillars being numerous, and in a range. Suppose, however, that we require only a single pillar: as we have free space round it, there is no need to fill up the first ranges of its foundations; nor need we do so in order to equalise pressure, since the pressure to
