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                                                                      	increased when they become large;  The reader will at once
                                                                      understand this differentiation of strength in the masses,
                                                                      by considering that a small stone may project from over a
                                                                      wall as op 1 opposite, without smallest change of the por-
                                                                      tions a a breaking off. but a great rock cannot overhang[d] in
                                                                      the same proportion, as at 2,without considerable danger
                                                                      of portions of the overhanging mass giving way:  much
                                                                      more if superincumbent weight be added;  whose pressure
                                                                      shall be confined to the overhanging portion;  Now this
                                                                      principle directly applied to the capitals of shafts, even
                                                                      when they are considere4d as crowning masses without any
                                                                      superimposed weight, so that for instance the capital b of
                                                                      the shaft 3, might with perfect safety project ½ a foot
                                                                      if the shaft were only a foot in diameter and five feet
                                                                      high but might not with safety project six feet from a
                                                                      shaft 12 feet in diameter and sixty feet high;  But the
                                                                      diminution of security is, s ill greater, when the ino
                                                                      crease of superincumbent but weight is considered, an  not
                                                                       only its increase;  but its less perfect diffusion;
                                                                      for wh[g]en the capital is small, in all probability the
                                                                      weights will be laid on it as at c or c2 and the lines of
                                                                      pressure thrown through it to the shaft, but if the
                                                                      capital and be very large the weight will in all proba-
                                                                      bility be thrown on it as at d, or d2, and some of the
                                                                      lines of resistance

[Version 0.05: May 2008]