30 
tion of colours, so they must mix in these proportions, and I know 
nothing more beautiful than to witness it ; yet like many other 
things, it requires some practice to arrive at tolerable perfection. 
This scheme is in its nature perfect, and calculation, measure, &c. 
will prove it; but how far the limited powers of mankind will carry 
it, remains a desideratum. One man can divide a micrometer into 
25 million parts per square inch, in every line of which seems a 
whole suit of colours ; but whether any can carry it much further 
is not known. The chromatometer is capable of every degree of 
extension or of the most minute division. I left off in the upper 
chromatometer nearly in a point ; in the lower one at a determined 
measure about ^d part of an inch. 
OF THE MIXING OF MATERIAL COLOURS, OR THE CHROMATIC 
SCALE. 
The mixing of material colours is very simple, if we dwell upon 
the idea of the three jjrimitives ; otherwise the very beginning is 
absolute confusion, as will be seen in most preceding attempts ; it 
is much easier to comprehend this figure than to mix the chroma- 
tic tints, as the primitive colours are distinctly seen passing into 
each other and forming orange, green, and purple, see 1, 2, 3. The 
centre of the triangle and circle, Tab. 5. and 6. we consider as ana- 
logous to light or white, represented as passing or spreading under 
the triangle, gradually passing to a nearly distinct tint ; that is to 
say, yellow, red, and blue when mixed or in union with certain pro- 
portions of light or white, do not give positive ideas of yellow, red 
and blue, the yellow having a grayer tinge, if I may use the ex- 
pression, and the red rather a bluish tinge, the blue also losing its 
beauty with a duller or grayish appearance *. To make short of it, I 
shall call these the primitive colours diluted, which in the figure are, I 
presume,yet sufficiently to be understood as far as the circle continues, 
* These are analogous to the appearance of whorled mixtures, too often compareJ 
to white, whorling being an aerial dilution of colours. 
