Yellow, red, orange, green, have been previously noticed as being derived from uranium, and to this list of colours may now be added brown. A warm rich hue of the utmost intensity may be produced, which possesses considerable permanence, although not equal to that of uranium yellow.
275. Zinc Brown.
A yellow-brown, so yellow that it might fairly have been classed with the ochrous colours of that denomination, is made by combining zinc with another metal by the aid of heat. Experience tells us that it is, chemically, a thoroughly good and stable pigment. Safely to be used in admixture, it is a clear, bright colour, affording good greens by compounding with blue. Of no great power, and semi-opaque, this yellow-brown or brown-yellow is superior to some of the pigments at present used, but is probably too much like them in hue and other properties to be of any special value.
Besides the preceding, there are those browns of a citrine or russet cast which are elsewhere described, such as raw umber, madder brown, &c. Moreover, there are numberless other varieties, obtainable from most of the metals, from many organic substances, and from a combination of the two. Of all colours, a 'new' brown is the most easily discovered: success may not be met with in seeking a yellow, red, or blue, or an orange, green, or purple; but it is strange if in the course of one's experiments a brown does not turn up. No difficulty, therefore, would have been found in greatly extending the present list; but it was felt that no advantage could have accrued by further multiplying the notices of a colour, with which we are already furnished so abundantly by nature and art, and which is capable of being produced in such profusion by admixture.
With the exception of ivory and bone browns, and perhaps Cassel and Cologne earths, all the browns commonly employed may be considered more or less durable.
[CHAPTER XVIII.]
ON THE SEMI-NEUTRAL, MARRONE.
We have adopted the term marrone, or maroon as it is sometimes called, for our second and middle semi-neutral, as applicable to a class of impure colours composed of black and red, black and purple, or black and russet, or of black and any other denomination in which red predominates. It is a mean between the warm, broken, semi-neutral browns, and the cold, semi-neutral grays. Marrone is practically to shade, what red is to light; and its relations to other colours are those of red, &c., when we invert the scale from black to white. It is therefore a following, or shading, colour of red and its derivatives; and hence its accordances, contrasts, and expressions agree with those of red degraded; consequently red added to dark brown converts it into marrone if in sufficient quantity to prevail. In smaller proportions, red gives to lighter browns the names of bay, chestnut, sorrel, &c.