§ XIX. So far of bases of detached shafts. As we do not yet know in what manner shafts are likely to be grouped, we can say nothing of those of grouped shafts until we know more of what they are to support.
Lastly; we have throughout our reasoning upon the base supposed the pier to be circular. But circumstances may occur to prevent its being reduced to this form, and it may remain square or rectangular; its base will then be simply the wall base following its contour, and we have no spurs at the angles. Thus much may serve respecting pier bases; we have next to examine the concentration of the Wall Veil, or the Shaft.
[35] The experiment is not quite fair in this rude fashion; for the small rolls owe their increase of strength much more to their tubular form than their aggregation of material; but if the paper be cut up into small strips, and tied together firmly in three or four compact bundles, it will exhibit increase of strength enough to show the principle. Vide, however, [Appendix 16], “Strength of Shafts.”
[36] [Appendix 17], “Answer to Mr. Garbett.”
[37] Yet more so than any other figure enclosed by a curved line: for the circle, in its relations to its own centre, is the curve of greatest stability. Compare § XX. of [Chap. XX.]