at shaft, or may be carried to the ground in front of it,
or through it, _b_, Fig. XXXVI.; in which latter case the main shaft
divides into two or more minor shafts, and forms a group with the shaft
brought down from above.

Sec. IV. When this shaft, brought from roof to ground, is subordinate to
the main pier, and either is carried down the face of it, or forms no
large part of the group, the principle is Romanesque or Gothic, _b_,
Fig. XXXVI. When it becomes a bold central shaft, and the main pier
splits into two minor shafts on its sides, the principle is Classical or
Palladian, _c_, Fig. XXXVI. Which latter arrangement becomes absurd or
unsatisfactory in proportion to the sufficiency of the main shaft to
carry the roof without the help of the minor shafts or arch, which in
many instances of Palladian work look as if they might be removed
without danger to the building.

Sec. V. The form _a_ is a more pure Northern Gothic type than even _b_,
which is the connecting link between it and the classical type. It is
found chiefly in English and other northern Gothic, and in early
Lombardic, and is, I doubt not, derived as above explained, Chap. I. Sec.
XXVII. _b_ is a general French Gothic and French Romanesque form, as in
great purity at Valence.

The small shafts of the form _a_ and _b_, as being northern, are
generally connected with steep vaulted roofs, and receive for that
reason the name of vaulting shafts.

Sec. VI. Of these forms _b_, Fig. XXXV., is the purest and most sublime,
expressing the power of the arch most distinctly. All the others have
some appearance of dovetailing and morticing of timber rather than
stonework; nor have I ever yet seen a single instance, quite
satisfactory, of the management of the capital of the main shaft, when
it had either to sustain the base of the vaulting shaft, as in _a_, or
to suffer it to pass through it, as in _b_, Fig. XXXVI. Nor is the
bracket which frequently carries the vaulting shaft in English work a
fitting support for a portion of the fabric which is at all events
presumed to carry a considerable part of the weight of the roof.

Sec. VII. The triangular spaces on the flanks of the arch are called
Spandrils, and if the masonry of these should be found, in any of its
forms, too heavy for the arch, their weight may be diminished, while
their strength remains the same, by piercing them with circular holes or
lights. This is rarely necessary in ordinary architecture,