6. YORKSHIRE, 1(5 



foundation ; and moftly from the inner parts 

 6f the wall (where it has parted) -, not from 

 the outer furface. 



Its appearance that of fandy loam, intcr- 

 fperfed with fpecks of chalk -, fome cf them 

 larger than peas, lis fragility fimilar to that 

 of dried brick earth. 



One hundred grains of this fpecimen yield 

 thirteen and a half grains of air. 



30 grains of rough land, and a few large 



fragments, 

 37 grains of (ilt and fine fand, 

 36 grains of calcareous earth. 



103 grains. 



Obs. There are two caufes of the zveaknefs 

 of this cement : the fmall proportion of lime, 

 and the impurity of the bafe: a heterogeneous 

 mafs of fragments of various kinds, fome of 

 them apparently gypfeous -, of fands of dif- 

 ferent fpecics, principally of a cryftalline 

 afpedt J but chiefly of mere mud, or of fand 

 fo fine as to be impalpable between the fin- 

 gers. It i'S therefore evident, that the mate- 

 rials, in this inftance, have not been wajhcd. 



I 2 Exp. 



