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with an even spoonful of mastic varnish. This jelly should not be too stiff. A strong content of lead in the black oil, or of mastic resin in the varnish, will tend to make a stiff jelly, as will also a greater proportion of mastic varnish in relation to black oil in the mixture. This jelly should not be thought of as an invariable product. It should be modified according to the requirements for its use. A little essence of turpentine added to the jelly makes possible a fuller brush stroke, and it will take the color out of the suspension that is caused by too stiff a jelly. Venice turpentine, added in a very small quantity, will also, slightly liquefy a jelly that is too strong, and will impart a certain brilliance and suppleness to the brush stroke, but it will, at the same time, reduce the siccative power of the jelly. Stand oil, when added to the jelly, gives the brush stroke a sort of tenacity, or an action of dragging slightly as it is drawn across the canvas; it gives a pearly cast to the colors. Both of these products add to the richness of the medium and make possible a more facile fusion of tones.. It is not possible to give more exact directions for the use of this medium. It is primarily necessary for the artist to keep in mind the respective qualities of each of the ingredients employed and, from this, to regulate their proportion and application. It must be remembered that the quality of the black oil is a softness, which gives it wonderful possibilities for blending. The function of the mastic, on the other hand, is to fix and hold the oil in its place. Also, it is well to avoid the use of any raw oil in connection with mastic as it prevents the latter from drying, The methods by which Rubens seems to have worked have been fully described in Chapter XI. It remains only to remind the artist that it is best not to paint over a half dry surface. This would only retard the drying further. Before repainting any portion of the canvas, it should be lightly gone over with the medium, to bring about a better liaison with the surrounding areas. In making use of this medium, it is well to carry each session of painting as far as possible, for although it is possible to |