104 
was tolerable plenty. It might occasionally be worth while’ 
on some estates to assist the progress of nature in forming 
Ochres, &c., and a good and instructive lesson may be 
learned on this head at Shotover Hill, from whence comes 
the lower specimen, which is more perfect, and gives a 
glossy surface where cut with a knife or rubbed with the 
nail, breaks somewhat conchoidally, but rather ruggedly, 
and is quite necessary in oil-painting. It is often found 
very fine at Shotover Hill near Oxford, from whence my 
specimens were brought, by favour of Dr. Williams, where 
it is curious to see the ochraceous Jron with Clay filter- 
ing naturally through a stratum of Sana; they are the 
best J have seen, especially for the use of landscape-painters, 
who use this substance as a yellow, or red, which latter 
colour it assumes on being burnt, when it is scarcely. 
altered except in colour.—It is found in many other parts 
of England, but in general of an inferior quality. This 
Ochre is commonly called Yellow; but, for the sake of 
some accuracy with regard to colours, I will take the li- 
berty to say it is rather a dull reddish yellow; and as the 
substance itself will not serve well to use as a water colour, 
it was found necessary for representation to put red and 
blue to good Gamboge, which is perfect yellow *. 
That of Upper Saxony is said to contain of 
. Amallld) 20%, di2u .iekhiee signa aiden 
Owide of Fron: laa . Jie aE aoe 
Water acidulated by Sulphuric Acid 10 
* See my New Arrangement of Colours, &c. 
The coarser sorts of Ochres are often used for painting ships, heing very 
durable. 
