You will notice that the engraver has begun his work in fine, parallel lines, close together, in the upper corner of the plate. The print thus presents one aspect of the use--conjointly--of etching and engraving, which had then come into universal use. Another example of the combined use of the two processes, blended into a rich harmonious tone, is the portrait of Gellius de Bouma by one of the great portrait engravers of the seventeenth century, Cornel Visscher, an artist who tolerated no hard-and-fast system in the graphic arts. Here is a vigorous, well-modeled figure, broadly treated in so interesting a manner that the means of expression are quite forgotten in the enjoyment of the effect achieved. A new element now enters the sphere of our interest: the problem of light, bright or subdued, in infinite gradations. Interiors with the light focused on one spot; night effects partially brightened by a torch or lantern, or by a fire, all else enfolded in darkness. The pioneer in this _clair-obscur_ manner is the painter, Adam Elzheimer, but no one made more effective use of this play of light and shade in the graphic arts than Rembrandt. Take the “Adoration of the Shepherds” as an instance, with the feeble light of the lantern and the rich tone of surrounding darkness, with indistinct forms of figures and objects half seen and half guessed, which gain shape as we look more closely. In the famous plate known as the “Three Trees” our attention is at first attracted by the vast expanse of threatening sky, with its lofty thunder-clouds, and the immense plains, with dikes and level fields stretching to the distant horizon. As we look at the picture, details appear,--the team behind the trees, the people in the fields, the couple in the bushes. They are overlooked, then seen, just as they would be in nature; they keep their subordinate places, and do not intrude and disturb the general effect of grand simplicity. Color is so well suggested by differentiations in handling and varying intensities of tone that one almost forgets the simple black and white presentation of the scene. As an example of Rembrandt’s mastery in etching applied to portraiture, no better print could be chosen than the “Janus Lutma,” especially if we can see it in the glorious richness exhibited by the first state of the plate. All the resources of the process are in evidence here,--they are seen in the subtle modeling, in the insensible gradations of tone, in the brilliancy of the accents, in the depth of the velvety shadows. It will be readily understood that such delicate, almost breathlike differences in shading, cannot long withstand the wear and strain to which they are subjected at each successive impression. Every print taken from the plate means rubbing the ink into every one of these delicate incisions in the copper; then comes the severe pressure as the plate passes through the press. A soft metal like copper soon shows the effect of