[47] [Appendix 19], “Early English Capitals.”
[48] In this case the weight borne is supposed to increase as the abacus widens; the illustration would have been clearer if I had assumed the breadth of abacus to be constant, and that of the shaft to vary.
CHAPTER X.
THE ARCH LINE.
§ I. We have seen in the last section how our means of vertical support may, for the sake of economy both of space and material, be gathered into piers or shafts, and directed to the sustaining of particular points. The next question is how to connect these points or tops of shafts with each other, so as to be able to lay on them a continuous roof. This the reader, as before, is to favor me by finding out for himself, under these following conditions.
Let s, s, [Fig. XXIX]. opposite, be two shafts, with their capitals ready prepared for their work; and a, b, b, and c, c, c, be six stones of different sizes, one very long and large, and two smaller, and three smaller still, of which the reader is to choose which he likes best, in order to connect the tops of the shafts.
I suppose he will first try if he can lift the great stone a, and if he can, he will put it very simply on the tops of the two pillars, as at A.
Very well indeed: he has done already what a number of Greek architects have been thought very clever for having done. But suppose he cannot lift the great stone a, or suppose I will not give it to him, but only the two smaller stones at b, b; he will doubtless try to put them up, tilted against each other, as at d. Very awkward this; worse than card-house building. But if he cuts off the corners of the stones, so as to make each of them of the form e, they will stand up very securely, as at B.