- Colorific Earth. Kirw. 1. 194.
- Yellow Earth. Ditto.
- Gelberde. Werner.
We are often led to seek at a distance natural productions which are to be found near at hand,and perhaps in the greatest perfection at home. Thus it happens with some Ochres. Mr. Kirwan among his colorific Earths, vol. 1. 193, 194, speaks of Yellow Earth; and other authors speak of it also: all which nearly agree with our common English Ochre, which is equally useful, and is often the best that can be procured. This is called Stone Ochre,and is used by artists, painters in oil chiefly. It is not mentioned as such in general, except by Sir John Hill, who has said enough of Ochres to confound the artists in their choice, particularly as he recommends so many.
I here show some varieties, both for the curious mineralogist and the artist. Earths most useful as colours are generally most durable*.
The upper specimen is not fit for that purpose, as it is rather of a loose texture, separating in water, scarcely smooth, and is rather a half-mixed imperfect Ochre.
The middle figure approaches nearer to an useful Ochre; but is rather too loose and gritty. It is a variety brought me by Lady Hippesley from Somersetshire, where there 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 Iron with Clay filtering naturally through a stratum of Sand; they are the best I 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 genera! 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 liberty 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
|Oxide of Iron||40|
|Water acidulated by Sulphuric Acid||10|
- * The Patent Yellow is useful and durable in oil-painting, but in water it soon blackens.
- † Sec my New Arrangement of Colours, &c. The coarser sorts of Ochres are often used for painting ships, being very durable.