OF CORNWALL. 67 
by a knife, and compreffed by the hand ; as we walked a few 
yards farther down, the left hand cliff became a perpendicular folid 
face of black hard done, at the foot of which was a channel or 
vein about eight feet over, of the deatites, of different colours, milk- 
white, draw coloured, and veined with green, ruddy, and purple. 
There are alfo in this wide courfe, feveral dony fubdances, of no 
affinity to the deatites : as we came farther down, and nearer to 
the level of the fea, we obferved the vein of deatites, contracted 
into a courfe fourteen inches wide, but of more uniform confidence, 
the folid rock making a fmooth wall for it on either fide : there is 
a fmall vein or two more in the fide of this cliff, and the feveral 
forts of deatites, contained in all the veins, which I have examined 
here, and at the forementioned cove are as follow : 
N°. I. The pure white, is a clofe-grain’d gloffy clay, diffolves foon sect.xv. 
in water, is tadelefs, dicks a little to the tongue, depofits a yel- Different 
lowidi pulpy fettlement at the bottom, above which a cloud of the £2°' Stea ~ 
fined parts continues fufpended ; mixed with oil, it becomes greafy; 
tis alfo too fat to make a body of colour for painting in water, and 
makes no effervefcence with aqua fortis. It is very abforbent, and 
takes fpots out of filk, without injuring the colour, and is poffibly 
the fame, which Biffiop Pontoppidan calls the u white Talc-done, 
“ of fuch a whitenefs, that it is ufed in Norway for powder, as it 
tc may be pulverized into an impalpable finenefs.” This is care- 
fully feieCted from the other forts of clay, barrelled up, and almod 
wholly engroffed, by people employed under the managers of the 
porcelain manufactures. 
N°. II. A white, dry, chalky earth, dicks drongly to the tongue, 
tadelefs, diffolves eafily in water into a pulp, with acids makes no 
effervefcence. 
N°. III. fhe fame chalky earth equally mixed with a red earth ; its 
water ruddy, like red chalk ; its depofit more gritty than the fore- 
going : makes no effervefcence with acids. 
N .IV. The next fort of this clay is very white, clouded here and 
there, but not veined, with purple. It diffolves in water with more 
difficulty than N°. I. and tinges the water with purple ; as to the 
red agreeing in all its properties with N°. I. This is probably the 
cimolia purpurafcens , or ad purpurijfum inclinans of Pliny, lib. xxxv. 
chap. xvii. 
N°. V. A gloffy, pearl-coloured, hard clay, approaching nearly to 
the confidence of a white opaque fpar ; foon cleaves itfelf into gra- 
nules when immerfed in water, yet diffolves no farther ; but with 
water grinds foon into a defh-coloured milky pulp : ’tis much harder 
than foap and wax, faws free and greafy ; there is a more dony variety of 
