Speaking exactly, this was but an application to the general execution of a work of a process adopted long before by etchers and line engravers as a means of partial execution. Jean Morin, Boulanger, Gérard Audran himself, and many others, had habitually made use of dots to supplement the work of the burin or the needle, or to effect transitions between their lights and shadows, or the larger of their outlines and subtler details of their modelling. Moreover, before their time, Jan Lutma, a Dutch goldsmith, invented a method of "engraving in dots," which, produced by means of his etching needle and aquafortis, were deepened and enlarged with chisel and hammer: whence the name of _opus mallei_ bestowed on his results. Bartolozzi, therefore, and the English engravers who, like Ryland, made use of stippling, did but revive and extend in their own way the boundaries of a method already known. They displayed remarkable skill, it is true, but their work, like the rest of its kind, displays a feebleness of form that is almost inevitable, and is touched with a coldness inherent in the very nature of the process. In stipple engraving, the burin and the dry point are used alternately, according to the degree of vigour or delicacy required. The parts that are to come light in proof are done with the dry-point; while those to come dark are covered with dots ploughed deeper with the burin. Round the edge of these, by the mere act of ploughing, there is raised a rim, or rampart--technically called a "burr"--which the engraver, to regain the ground thus lost, has to rub down with the burnisher. In this way he goes on dotting and burnishing till he gets a close enough grain. Immensely successful during the last years of the eighteenth century, stipple engraving soon went out of fashion, not only in France, where it scarce survived the first attempts of Copia, but even in England, where the example of Bartolozzi and Ryland had been followed with such eager diligence. Such, too, somewhat later, was the fate of a somewhat similar process--the "crayon engraving," of which Gilles Demarteau, born in Liège, but bred and trained in Paris, may be considered, if not the inventor, at least the most active, skilful, and popular practitioner.[47]