MINERALCyCY. 87 
inp: and boiling heat, and of holding f^lts and 
aads, can be made. It is found, 
1. Pure, Pur a, 
A, Dilfufible in water. 
1. Coherent and dry. 
af White, from Japan. 
I have feen a root of a tree changed 
into this clay. (Appendix, Sedioa 
cclxxxiii. ) 
2. Friable and dry. 
a. White, is found in clefts of rocks at 
Wefterfilfverberget in Weftmanknd, 
and between the coal, in the coal- 
pits at Boferup, in the province of 
Skone 
2. Mixed with phlogifton, and a very fmall 
quantity of infcparable heterogeneous fub- 
ftances, Terra porcellanea phlogtfio alnfque 
heterogeneis minima portime mixta. Of thefe 
are, 
A. Diffufible in water, 
a. V/hite and fat pipe clay, from Cologne 
and Maeftricht. 
I^efs unftuous is found in fmall Hf. 
fures in a vein of lapis ollaris^ at Swart- 
wik, in the parifti of Swerdfio, in the 
province of Dalarne. 
b. Of a pearl colour, from Maeftricht. 
c. Bluifli grey. La belle ter re glaif efron 
Montmartre, near Paris, in France. 
d. Grey, France, Hefle, Bofempin, Skone.’ 
* Thefe may be called pure, fince after being burnt, they 
are qi^ite white, though they have been expofed to a quick 
melting heat ; and it may be queried, if all fuch clays muft 
not be fomewhat harfh, or at leaft not unduous to the 
touch. 
G 4 e. Black, 
