RAMBLES OF A GEOLOGIST. 367 



fied," said Sir George, " of the reason why the signal-fires 

 should be kindled on or beside a heap of stones, we have only 

 to imagine a gale of wind to have arisen when a fire was 

 kindled on the bare ground. The fuel would be blown about 

 and dispersed, to the great annoyance of those who attended 

 The plan for obviating the inconvenience thus occasioned 

 which would occur most naturally and readily would be to 

 raise a heap of stones, on either side of which the fire might 

 be placed to windward ; and to account for the vitrification 

 appearing all round the area, it is only necessary to allow the 

 inhabitants of the country to have had a system of signals. 

 A fire at one end might denote something different from a 

 fire at the other, or in some intermediate part On some 

 occasions two or more fires might be necessary, and sometimes 

 a fire along the whole lina It cannot be doubted," he adds, 

 " that the rampart was originally formed with as much re- 

 gularity as the nature of the materials would allow, both in 

 order to render it more durable, and to make it serve the 

 purposes of defence," This, I am afraid, is still very unsa- 

 tisfactory. A fire lighted along the entire line of a wall in- 

 closing nearly an acre of area could not be other than a very 

 attenuated, wire-drawn line of fire indeed, and could never 

 possess strength enough to melt the ponderous mass of ram- 

 part beneath, as if it had been formed of wax or resin. A 

 thousand loads of wood piled in a ring round the summit of 

 Knock Farril, and set at once into a blaze, would wholly fail 

 to affect the broad rampart below ; and long ere even a thou- 

 sand, or half a thousand, loads could have been cut down, col- 

 lected, and fired, an invading enemy would have found time 

 enough to moor his fleet and land his forces, and possess him- 

 self of the lower country. Again, the unbroken continuity 

 of the vitrified line militates against the signal-system theory. 

 Fire trod so closely upon the heels of fire, that the vitrescency 

 induced by the one fire impinged on and mingled with the 



