Wood engraving kept its ground for a considerable period, especially in Germany, but copper in the end supplanted it, and owing to the beauty and clearness of the maps produced by a combination of engraving and etching it still maintains its ground.
A little before his death he had also formed a scheme of writing a Discourse on the Arts of Painting, Sculpture, Etching, &c., but when he died he had made but little progress with it.
These regions present magnificent examples of dry erosion by wind-borne sand, which acts as a powerful sand blast etching away the rocks and producing most beautiful sculpturing.
Besides these three masterpieces of line-engraving, the same years, 1512-1515, found DUrer occupied with his most important experiments in etching, both in dry-point ("The Holy Family and Saints" and the "St Jerome in the Wilderness") and with the acid bath.
His work in black-and-white, his admirable illustrations in brushwork of Edinburgh and its neighbourhood, and also his pen-drawings, about which it has been declared that "his work contains all the subtleties and refinements of a most delicate etching," must also be noted.
In some places wood-carving has been brought to considerable perfection; and native artists know how to engrave on metal both by etching and the burin.
Dark coloured micas are strongly pleochroic. Accurate determinations of the optical orientation, as well as the symmetry of the etching figures on the cleavage planes, seem to suggest that the micas, except muscovite, may be anorthic rather than monoclinic in crystallization.
In the " etching " process the surface of the glass is etched by the chemical action of hydrofluoric acid, the parts which are not to be attacked being covered with a resinous paint.
Schwanhart of the process of etching on glass by means of hydrofluoric acid, and the rediscovery by J.
In the 17th and 18th centuries the processes of scratching, engraving and etching were brought to great perfection.
Fluorides can be readily detected by their power of etching glass when warmed with sulphuric acid; or by warming them in a glass tube with concentrated sulphuric acid and holding a moistened glass rod in the mouth of the tube, the water apparently gelatinizes owing to the decomposition of the silicon fluoride formed.