no FARM BUILDINGS. 6. 



nevcrthelefs, fuch is the cffctt of time upon 

 walls which arc cxpofcd on every fide to the 

 atmofpherc, that they now hold together 

 with confiderable tenacity. 



To this effcd: of time ; or, more accurate- 

 ly fpeaking, to certain laws of nature which in 

 procefs of time produce this efl'cd: •, we ought 

 perhaps to afcribe the ftone-like contexture 

 of the cements of ancient walls, rather than 

 to any fupeiior flciil in preparing them. 



The cirr.del or central ftronghold of the 

 fortrefs under notice has been built with bet- 

 ter cements, which, however, vary much in 

 outward appearance. One fpecimen which 

 I .have collccled, is a fir.ooth clialk-like 

 fubflance ; another, a coarfe rough mafs 

 comnofed of fand and fmall gravel, with a 

 fmallcr proportion of chalk-like matter. 



In the fofle which furrounds the outer wall 

 lies a fragment (perhaps part of the parapet 

 or theembrafures of theoutfidc wall), whole 

 cement has acquired a Hione-like hardnefs, 

 efpecially the part which is expofcd to the 

 oiirer furface *. 



I have 



* The a^qe of th's fortrefs would pcrh"ps be difficult 

 to afccrtaiu. l*art of the outer wall w;is repaired and 



feme 



