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.