This section is from the book "Chromatography; Or, A Treatise On Colours And Pigments, And Of Their Powers In Painting", by George Field. Also available from Amazon: Chromatography, or A Treatise on Colours and Pigments, and of Their Powers in Painting.
This pigment, hardly less celebrated than the great painter whose name it bears, is a species of peat or bog-earth of a fine, deep, semi-transparent brown colour. The pigment so much esteemed and used by Vandyke is said to have been brought from Cassel; and this seems to be justified by a comparison of Cassel-earth with the browns of his pictures.* The Van-
In the tribe of browns - in oil-painting one of the finest earths is known, at the colour-shops, by the name of Castle-earth, or Vandyke's brown." - Gilpin's Essays on Picturesque dyke browns in use at present appear to be terrene pigments of a similar kind, purified by grinding and washing over: they vary sometimes in hue and in degrees of drying in oil, which they in general do tardily, owing to their bituminous nature, but are good browns of powerful body, and are durable both in water and oil. The Campania brown of the old Italian painters was a similar earth. See Cappagh Brown.
Beauty, etc. Essay iv. p. 33.