OF CORNWALL. 6 y 
burnt umber colour, but, like the reft, too fat for painting. This 
is however much coveted, and barrelled up for London, the rea- 
fons concealed, but for the porcelain likely, or glafs manufaflure, 
or both. In tne fame vein there is a fmall courfe of real fpar (very 
unufual in our Cornifh lodes) about three fourths of an inch thick, 
N ° f ' This f P ar lies not m a folid lode, but in a lhattery teffella- 
ted irate, like fo many dies, loofe and fide by fide ; it ferments 
immediately with aqua fortis ; is fubtranlparent, and breaks into 
quadrangular prifms, the bafe a Rhombus. 
Thefc are all the forts of this foffil, which I have difcovered near 
the Lizherd, and in Cornwall we call the produds of all thefe 
veins Soap-rock, and though the tender clays can with no propriety 
be called fo, yet indeed, the three laft forts may be as moperly 
termed fo as fteatites, they having no more of fuet in them ‘than 
they have of foap. Both names are equally founded upon the 
Of this foffil learned men have thought differently, and given us 
very different accounts, owing, as I ffiould think, to their not being 
Jufficiently furnifhed at one and the fame time with the various forts 
which theie cliffs afford. Dr. Grew, in his Mu feu m, R. S page 
321, feems to have had before him only N°. VI. which has indeed 
all the colours, white, red, purple, and green, ( the purple predo- 
minant) is hard as fuet, and has ftriated fibres, like the Amianthos. 
Dr. Woodward, in his Catalogue of Foffils, vol. I. page 6. has 
faintly defenbed. N\ IV. VI. VIII. but it muft not be denied, that 
he firft recommends, at leaf! as far as I have feen, this foffil earth 
for the porcelain manufacture p . Dr. Hill (Natural Hffiory of Foffils, 
page 22) has more fully noted the properties of the laft-mentioned 
numbers, but feems to have had none of the reft in his reach, as is 
evident by his giving the general name of Cimolia purpurafeens ; 
whereas feveral varieties have not the leaft purple tinCture. Another 
learned Naturalift thinks he can prove it to be the Parzetonium of Pliny, 
(lib. xxxm chap. 5) not the Cimolia, and indeed it is moft likely 
that the white and pureft N°I. may be the Paratonium ; but I do 
not, I muft own, fee the ufe of difputing, what was the Cimolia, 
or any other earth, clay, or ftone of the ancients, for it is well 
known, that one ingredient, or property either quite omitted, or 
not well charaCferifed, will tnrow us into an uncertainty whether 
i ings are the fame 01 not ; befides, the deferiptions of the ancients are 
not always fo well underftood (if they were at firft accurate) as to be 
eci ive -’ an< ^ * n climates and ages fo diftant, many things may ap- 
peal to be like, which are eflentially much otherwife. Such difputes 
p Ibid. 
T 
therefore 
