[M2.15backL]                                                          [M2.15back]									15
                                                                      
                                                                      		diameters shall be of due proportion to the roof weight
                                                                      		The successive floors are nothing but so many ties upon
                                                                      		the shaft, which may be theoretically considered as
                                                                      		continuous and bound by the intermediate floor in order to
                                                                      		prevent its bending:  Evidently {however} it is more secure
Note:  The superimposition of shafts with level architraves           		{and more graceful} to construct the elevation of successive
  a style not enough worked out, except in round end of               		shafts, with the floors laid upon them by means of true
 Pisa and baptistery of Parma.                                        		capitals than of one continuous shaft with the floor tied {let in}to it.
                                                                      		When a shaft is detached, its strength and best form is
                                                                      		one tapering slightly to the top;  and swelling as it descends:
                                                                      		but when it is tall and supported by a wall,
                                                                      		such a form would be inconvenient, and indeed in very
                                                                      		narrow shafts imperceptible:  Such shafts are {true}
                                                                      		verticals therefore and of constant sections.
                                                                      		When a roof is raised high upon continuous shafts the
                                                                      		wall veil between them has the function of a buttress;
                                                                      		and their just proportion is that which appears adequate
                                                                      		to the support of the roof at an ordinary height; and which
                                                                      		only requires the aid of the walls to prevent its great
                                                                      		length from bending;  the External buttress have
                                                                      		exactly the same function;  and each pier of such a
                                                                      		building may be considered as supported by wall buttresses
                                                                      		on three of its four sides.

[Version 0.05: May 2008]