r7Tg2. antiquities in Scotland. 132 
abounded with wood, this purpose would be readily 
effected by building a stack of wood round the whole 
outside of the wall, and then setting it on fire. It 
was probably with a view to enable them to build 
this stack of wood with the greater ease, and to suf- 
fer the fire to act more forcibly and equally upon the 
different parts of the wall, as it gradually consumed, 
that they were induced to incline the walls so far 
from 2 perpendicular position. In an aiter period, 
when the woods had gradually been destroyed, and 
before it was well known how to manufacture peat: 
for fuel, it would be such a difficult matter to pro- 
cure fuel in abundance, that buildings of this kind 
would come to be disused, and the art in a fhort pe-- 
riod, among a people ignorant of letters, to be entires 
_ ly forgotten. . 
You will perhaps imagine that: the above account’ 
of the manner in which these walls have been form- 
_ed'is only an ingenious conjecture, entirely destitute: 
of proof; but that they have indeed been formed in | 
this manner, can, I think, be demonstrated in as-clear 
a manner as the nature of the subject will admit. 
The ingenious Mr Williams, already mentioned,. by 
the permifsion of the board of trustees, caused a sec-. 
tion to be made acrofs the top of the hill of Knock- 
ferrel, which was carried quite through the walls 
on each side, in the line marked FF, on the plan, so 
that any person has now an opportunity of obser- 
ving the nature of these walls, and may judge of the 
manner in which they have been constructed, 
