[M2.8backL]                                                           [M2.8back]									8
                                                                      
[diagrams]                                                            		a. {& because of b} in their centres, would be easily supported by the
                                                                      		shorter span of lintel in a1 (and similarly, weights of
                                                                      		masonry which would break the sloping stones in b. would
                                                                      		be readily sustained by b1) and the second, that supposing
                                                                      		the pillars in a. built of small stones - or even of a
                                                                      		soft single stone, the weight of the separate lintels
                                                                      		would have a tendency to cause fissures in the direction
                                                                      		f f while the stone introduced in a1 equalizes their
                                                                      		pressure over the whole top of the pillar.
                                                                      		(x)   This arrangement is the best possible.  It may
                                                                      		indeed be asked why the process should not be continued,
                                                                      		as in a4.  but in this case the superstructure is evidently
                                                                      		so much raised that it would have been better to
                                                                      		have made the shafts of the pillars longer at once;
                                                                      		better  because simpler and requiring less material:
                                                                      		on the other hand it may be asked, why not dispense
                                                                      		with the upper flat headstone and employ only the
                                                                      		expanding stone beneath;  as a5 (opposite) but, though this
                                                                      		arrangement is admissible in the case of the single
                                                                      		lintel or close set arch, a1 d1 it is evidently weak and
                                                                      		unsafe when the masonry is smaller and bears on the edge
                                                                      		of the headstone as in the cases a2 d2 which would become
                                                                      		a6 d6 both of them evidently unsafe forms if the weight of
                                                                      		the superstructure should happen

[Version 0.05: May 2008]