Microscopical Essays. 303 



worked up in their mouths to the confidence of mortar, becomes 

 that folid clay, or ftone, of which their hills and all their build- 

 ings, except their nurferies, are compofed. 



Other galleries again afcend and lead out horizontally on every 

 fide, and are carried under ground near to the furface, a vaft 

 diftance : for if you deftroy all the nefts within one hundred 

 yards of your houfe, the inhabitanis of thofe which are left un- 

 molefted farther off, will neverthelefs carry on their fubterraneous 

 galleries, and invade the goods and merchandizes contained in it 

 by fap and mine, and do great mifchief if you are not very 

 circumfpecX 



But to return to the cities from whence thefe extraordinary ex- 

 peditions and operations originate, it feems there is a degree of 

 necelfity for the galleries under the hills being thus large, being 

 the great thoroughfares for air the labourers and foldiers going 

 forth or returning upon any bufmefs whatever, whether fetching 

 clay, wood, water, or provifions ; and they are certainly well 

 calculated for the purpofes to which they are applied, by the 

 fpiral (lope which is given them ; for if they were perpendicular, 

 the labourers would not be able to carry on their building with 

 fo much facility, as they afcend a perpendicular with difficulty, 

 and the foldiers can fcarce do it at all. It is on this account that: 

 fometimes a road like a ledge is made on the perpendicular fide 

 of any part of the building within their hill, which is flat on the 

 upper furface, and half an inch wide, and afcends gradually like 

 a ftair-cai'e, or like thofe roads which are cut on the fides of hills , 

 and mountains, that would otherwife be inacceffible : by which 



