What the Franco-Russian artist had done was to reveal the alluring possibilities placed at the command of the shadow-pantomimist by the ingenious employment of perspective; and there remained only one more step to be taken for the final development of the art to its ultimate capacity. This was the addition of color; and this step was taken by an associate of Caran d'Ache in the exhibitions given at the Chat Noir--Henri Rivière. Color could be added in two ways. In the first place, the outlines of lanterns and of battle-flags could be cut out, and slips of appropriately tinted paper could be inserted in the openings so that the light might shine thru. This relieved the monotony of the uniformity of the sable figures, and added a note of amusing gaiety. But this was an innovation of very limited scope; and it could have been earlier utilized in the flat figures of Lemercier de Neuville, for example, if he had happened to think of it. Far wider in its artistic possibilities was the second of Rivière's improvements. For the ordinary lamp which cast a steady glow on the white screen whereon the profile figures appeared, he substituted a magic lantern, the painted slides of which enabled him to supply an appropriately colored background. Then he went further and employed two magic lanterns, superimposed; and these enabled him to get the effect of "dissolving views" whereby he could vary his background at will. The immediate result of this ingenious improvement was that the artist could bestow upon his shadow-pantomime not a little of the richness of color which delights our eyes in the stained glass of medieval cathedrals. Rivière was not only an inventor, he was also an artist, richly gifted with imagination; and his imagination suggested to him at once the three or four themes best fitted for treatment by his novel apparatus. One of these was the 'Wandering Jew'; another was the 'Prodigal Son'; and a third was the 'Temptation of Saint Anthony'--all legends of combined dramatic and pictorial appeal. Yet the most effective of all the experiments in this new form was due not to Rivière himself but to the collaboration of two of his disciples, M. Fragerolle and M. Vignola. This was the 'Sphinx,' in which the artists most adroitly combined all the advantages of the original flat profiles, and of the long files of figures in perspective such as Caran d'Ache had employed, with varied backgrounds due to the aid of the magic lantern first utilized by Rivière. Of all human monuments no one has had so marvelous a series of spectacles pass before its sightless eyes as the Sphinx, reclining impassive at the edge of the desert, and at the foot of the pyramids. Race after race has descended into the valley of the Nile, and lingered for a little space, a few centuries more or less, and departed at last. Conqueror after conqueror has come and gone again; and the Sphinx has kept its inscrutable smile.