Their researches had a special bearing on the theory of complementary colours and on the means of establishing some laws concerning the reaction of tones in such manner as to draw up a kind of tabula.  Georges Seurat and Paul Signac were the promoters of this research.  Seurat died very young, and one cannot but regret this death of an artist who would have been very interesting and capable of beautiful works.  Those which he has left us bear witness to a spirit very receptive to theories, and leaving nothing to chance.  The silhouettes are reduced to almost rigorously geometrical principles, the tones are decomposed systematically.  These canvases are more reasoned examples than works of intuition and spontaneous vision.  They show Seurat’s curious desire to give a scientific and classic basis to Impressionism.  The same idea rules in all the work of Paul Signac, who has painted some portraits and numerous landscapes.  To these two painters is due the method of Pointillism, i.e. the division of tones, not only by touches, as in Monet’s pictures, but by very small touches of equal size, causing the spheric shape to act equally upon the retina.  The accumulation of these luminous points is carried out over the entire surface of the canvas without thick daubs of paint, and with regularity, whilst with Manet the paint is more or less dense.  The theory of complementary colours is systematically applied.  On a sketch, made from nature, the painter notes the principal relations of tones, then systematises them on his picture and connects them by different shades which should be their logical result.  Neo-Impressionism believes in obtaining thus a greater exactness than that which results from the individual temperament of the painter who simply relies on his own perception.  And it is true, in theory, that such a conception is more exact.  But it reduces the picture to a kind of theorem, which excludes all that constitutes the value and charm of an art, that is to say:  caprice, fancy, and the spontaneity of personal inspiration.  The works of Seurat, Signac, and of the few men who have strictly followed the rules of Pointillism are lacking in life, in surprise, and make a somewhat tiring impression upon one’s eyes.  The uniformity of the points does not succeed in giving an impression of cohesion, and even less a suggestion of different textures, even if the values are correct.  Manet seems to have attained perfection in using the method which consists in directing the touches in accordance with each of the planes, and this is evidently the most natural method.  Scientific Chromatism constitutes an ensemble of propositions, of which art will be able to make use, though indirectly, as information useful for a better understanding of the laws of light in presence of nature.  What Pointillism has been able to give us, is a method which would be very appreciable for decorative paintings seen from a great distance—­friezes or ceilings in spacious buildings.  It would in this case return to the principle of mosaic, which is the principle par excellence of mural art.