363 
In plate 1, No. 13, we have two principal, and one subsi- 
diary buttress ; the line of the cap of each, lohen produced^ 
cuts the angle of the sills. This example is from Lincoln 
Cathedral. Again, in the example from York Cathedral, No. 
14, we find the same circumstance occur; and again in No. 
17, also from York Cathedral. In Beverley Minster transept, 
plate 2, No. 10, the line of the buttress-cap. A, produced, cuts 
the centre of the central window sill, and the line of the pin- 
nacle, B, produced, cuts the sill at the same point. 
Similar instances occur in Salisbury, Norwich, and other 
Cathedrals, in buttress-caps of the thirteenth century. The 
reason is, obviously, to give a pyramidical form to these fea- 
tures, the great object of attainment in the works of the 
middle ages, in which the impartial critic will find nothing 
arising from whim — nothing from mere fancy or caprice, but 
everything exhibiting the exercise of mature judgment and 
correct taste. The flying buttresses, or " arcs boutants," 
are, however, of much greater importance, and must be con- 
sidered in connection with vaulting, from the introduction of 
which they naturally and necessarily arose. 
VAULTING AND FLYING BUTTRESSES. 
N.B. The letters of reference on the plan and section cor- 
respond. 
I have selected the vaulting of the nave of Salisbury 
Cathedral, on account of its simplicity. In many of our 
cathedrals, &c., the main rib is found to assume an undulating 
form, as in the case of the vault of the chapel of King's Col- 
lege, Cambridge, which " has been rather a subject of 
" wonder than inquiry. The vault of this chapel is divided 
" into parts, called severies, each severy subtending an 
" oblong, consequently the curves of the inverted quadrants 
" intersect each other before the quadrant of the circle is 
completed, whence the intersections form an undulating 
" ridge or orbit. In an early investigation of vaulting, this 
