M. Chevreul, the _Directeur des Gobelins_, has presented to the French
Academy a plan for a universal chromatic scale, and a methodical
classification of all imaginable colours. Mayer, a professor at
Göttingen, calculated that the different combinations of primitive
colours produced 819 different tints; but M. Chevreul established not
less than 14,424, all very distinct and easily recognised,--all of
course proceeding from the three primitive simple colours of the solar
spectrum, red, yellow, and blue. For example, he states that in the
violet there are twenty-eight colours, and in the dahlia forty-two.