291 Dr Hibbert's Observations on Vilrifud Furts. 



lliesc materials, as tbe outward fence would keep the mound 

 in form. 



The learned writer having thus constructed a fortress of his 

 own, or rather one that was borrowed from an Italian archi- 

 tect, proceeded to develope his newer theory of vitrification, 

 which was, that in a structure composed of combustible and 

 fusible materials, the effects of fire would be accidental ; that 

 they would be induced, not during the construction, but dur- 

 ing the demolition, of a fort. 



" The most formidable engine of attack," remarked his 

 Lordship, " against a structure of this kind, would be lire ; 

 and this, no doubt, would be always attempted, and often suc- 

 cessfully employed, by a besieging enemy ; — and if the be- 

 siegers prevailed in gaining an approach to the ramparts, and, 

 surrounding the external wall, set fire to it in several places, the 

 conflagration must speedily have become general, and the effect 

 is easy to be conceived. If there happened to be any wind at 

 the time to increase the intensity of the heat, the stony parts 

 would not fail to come into fusion, and, as the wood burnt 

 away, sinking by their own weight into a solid mass, there 

 would remain a wreck of vitrified matter tracking the spot 

 where the ancient rampart had stood, irregular, and of unequal 

 height, from the fortuitous and unequal distribution of the 

 stony materials of which it had" been composed."" 



This theory, in its application to a country so well wooded 

 in times of yore as Scotland, merits some notice, though it 

 must be confessed that it is much easier to frame a notion of 

 this kind, which is little more than the offspring of a fertile 

 imagination, than to completely refute it. The chief objection 

 which I have to this hypothesis is, that in many forts which 

 I have examined there is no indication whatever that their 

 structure was at any time different to what they display at the 

 present day ; and that the encompassing stone mounds appear to 

 have afforded a sufficient defence to a savage people, without 

 the addition of ramparts of wood. His Lordship must have 

 anticipated the latter objection, by citing the exceptions to his 

 theory, which he explains after the following manner; — " In 

 those parts," he observes, " where stones would be easily quar- 

 ried of such size and form as to rear a rampart by themselves 



