330 RAMBLES OF A NATUEALIST. 



I would advise my readers to consult the curious 

 sketches which Smeathman has made of different 

 sections of these hillocks. On examining his draw- 

 ings we first see the walls, which are as hard as 

 brick, and measure from one to two feet in thick- 

 ness. More or less cylindrical galleries pierce these 

 walls, and increase in diameter towards the base, 

 where the largest of them are as much as four- 

 teen inches in width, and penetrate between four 

 and five feet under ground. These subterranean 

 galleries are at once quarries and drains for carrying 

 off the extra moisture. It is from here that the 

 materials necessary for the erection of the building 

 have been obtained, while in case of inundation they 

 carry off the water to a considerable depth below the 

 soil, and thus prevent it from reaching the populous 

 quarters of the nest. The other galleries, which 

 pass obliquely in every direction, intersect one 

 another, and by extending to the dome and to the 

 smallest turrets they serve as routes which are used 

 by the workers engaged in building operations. 

 Even this does not constitute the town itself, but is 

 rather to be considered as its ramparts. 



The whole of the interior is not quite filled. Below 

 the dome lies a large free space, occupying the 

 entire width of the hillock. The height of these 

 attics equals very nearly the third of the total eleva- 

 tion. The ceiling is flat and has no opening in it, 

 but some of the galleries which run through the 

 general envelope open on a level with it. Other 

 galleries open at different heights, and are continued 

 by steps resting against the wall like the stairs in 



