26 M A N U 11 E S. ^ 



regains its weight, and falls in a fnoiv-ivbite 

 mucilage, which dries to a nearly white powder. 



Therefore, one hundred grains of this chalk 

 contains. 



Ninety-eight grains of a matter, diflbluble 

 in the acid of fea-fak, and is probably a 

 pure, or nearly a pure, chalk ; and. 



Two grains of indiflbluble matter, whofe 

 properties I have not, yet, fufficiently afcer- 

 tained. 



This chalk contains the greateft proportion 

 of diflbluble matter, — or, in other words, is 

 the purell calcareous earth, I have yet anaT 

 lyzed. The chalk of Betchworth-Hill (a 

 continuation of Box-Hill, near Dorking in 

 Surrey), celebrated as a manure (for which 

 purpofe it is fetched, twelve or fourteen miles, 

 by the farmers of SufTex), affordg a refiduum of 

 more than one-tenth of its weight : whereas the 

 fhalk of Thorp-next-Nprwich affords only 

 one-fiftieth. 



4. The Hard Chalk of Sv/affhaa^. 



In its natural fiate, it is fituated in an exr 

 tended rock, riung to near the furface, and 

 \i'orlccd ten or twelve feet deep, as a lime- 

 quarry. 



