350 The N.Z. Journal of Science and Technology. [Nov. 
synthesized, trade in this dye is threatened by artificial substitutes of 
practically equivalent value. Jamaica,* * * § which contains only half a 
million acres of forest, exported over 75,000 tons of logwood and fustic 
in 1916, as well as much logwood-extract, the value of her natural-dye 
exports having risen from £300,000 in 1914 to £800,000 in 1916, 47*5 per 
cent, of which latter went to the United Kingdom. 
Weld (Reseda luteola ) has already been mentioned, and recent writers 
praise it. Of late years the greatest amount of this dye-plant has been 
used in dyeing cloth for Government contracts, but tartrazin and similar 
artificial yellows are taking its place. 
As showing the great increase caused by the war in the use of natural 
dyes in America, a. British Government reportf states that in the United 
States of America during 1917, while forty-six firms reported a total 
monthly output of 5,000,000 lb. of coal-tar dyes, thirteen firms reported 
a total monthly production of 8,183,500 lb. of vegetable dyes and extracts. 
These colours include blacks and greens for calico-printing, logwood blue, 
khaki dyes, cutch, archil and logwood extract, cudbear, flavines, Osage 
orange, sumach, and natural indigo. 
CrookesJ gives as a recipe for dyeing 100 lb. of wool a “ reddish- 
brown ” a dye-bath which is made from 481b. fustic, 321b. madder, 8J lb. 
camwood, 8J lb. sanderswood, 5J lb. sumach—total, lOlf lb. For u fiery 
red,” on 1001b. of wool to bear fulling, after mordanting with 12 per cent, 
alum, 10 per cent, tartar, and 2 per cent, oxalic acid, he recommends 50 lb. 
madder. For “ brownish-red ” Hummel§ recommends mordanting the 
wool with 6 to 8 per cent, aluminium sulphate and 5 to 7 per cent, tartar, 
and dyeing with 60 to 80 per cent, madder. 
It will thus be seen that, compared with the above formulae, the use of 
1 part of fresh coprosma to 1 of wool is quite a reasonable dose. It must 
also be pointed out that the quantities used as described in this article 
(p. 267) are not necessarily those which would be used in practice. Some 
ground for criticism in the use of vegetable dyes arises from the fact that 
the land used in producing vegetable-dye crops might be more economically 
occupied in growing foodstuffs. This argument does not, of course, hold 
good for coprosma dyes, the plants growing vigorously and thickly on waste 
lands, forest clearings, mountain-tops, and seashores. The fruit of all the 
species is a drupe or berry, in which the two plano-convex seeds are 
surrounded by a pulpy, sweet substance of which the fruit-eating birds 
are inordinately fond. The seeds are swallowed and spread far and wide 
by birds, and germinate freely in any cover on which the birds alight. 
Under the pine plantations on Somes Island there is a dense growth of 
coprosma springing up. Similarly in clearings at the top of Day’s Bay 
ridge coprosma is the dominant growth—in many places an almost impene¬ 
trable thicket. 
In conclusion, the author would urge the practical trial of dyes from 
coprosmas, which, on account of their wide and abundant distribution, 
quick growth, and capacity for peopling waste lands, and for the varied 
and lasting colours which they give on wool suitably mordanted, are worthy 
of the fullest investigation, especially in home industries. 
* TJ.S. Com. Rep., 3rd May, 1918. 
t Board of Trade Journ., 9th May, 1918. 
$ Dyeing and Tissue-printing, p. 183, 1882. 
§ The Dyeing of Textile Fabrics, 1885. 
