We have never heard Seurat, Cross, Luce, Van de Velde or indeed Van Rysselberghe or Angrand speak of dots. We have never seen them be preoccupied by Pointillism. Read these lines, dictated by Seurat to Jules Christophe, his biographer: 'Art is harmony; harmony is the analogy between opposites and between similar elements of tone, tint and line. By tone I mean light and dark; tint is red and its complementary: green, orange and its complementary: blue, yellow and its complementary: purple.. .The method of expression relies on the optical mixture of tones, tints and their reactions (shadows that follow very strict rules).