416 
NATURE 
minuric acid, and some remarks on the use of lime water in the 
manufacture of bread. Such I believe is the history of the 
direct relationship which has existed between Liebig and this 
Association. Indirectly we can hardly recognise how much we 
owe tohim. Interested as he was in the work of this Associa- 
tion I could not but to-day record the instances of direct aid and 
support which this section has received from him. 
I pass on now to the special subject to which I wish to ask 
your attention. 
It is the history of the vegetable colouring matter found in 
madder. It has been in use from time immemorial, and is still 
one of the commonest and most important of dyes. It is ob- 
tained from a plant largely cultivated in many parts of the world 
for the sake of the colour it yields, and the special interest which 
now attaches to it is, that the chemist has lately shown how this 
natural colouring matter can be made in the laboratory as well as 
in the fields ; how by using a bye-product, which formerly was 
without value, thousands of acres can be liberated for the culti- 
vation of other crops, and the colouring matter which they for- 
merly produced be cheaper and better prepared in the laboratory 
or in the manufactory, That a certain colouring matter could be 
obtained from the roots of the Rubia tinctorum, and other species 
of the same plant, has been so long known, that apparently no 
record of its discovery remains. 
Pliny and Dioscorides evidently allude to it. The former, re- 
ferring to its yalue as a dyeing material, says, ‘‘ It is a plant little 
known except to the sordid and avaricious, and this because of 
the large profits obtained from it, owing to its employment in 
dyeing wool and leather.” He further says, ‘‘The madder of 
Italy is the most esteemed, and especially that grown in the 
neighbourhood of Rome, where and in other places it is pro- 
duced in great abundance.’’ He further describes it as being 
grown among the olive-trees, or in fields devoted especially to its 
growth, The madder of Ravenna, according to Dioscorides, 
was the most esteemed. Its cultivation in Italy has been con- 
tinued till the present time, and in 1863 the Neapolitan provinces 
alone exported it to the value of more than a quarter of a million 
sterling. At the present day we are all very familiar with this 
colouring matter as the commonest that is applied to calicoes. It 
is capable of yielding many colours, such as red, pink, purple, 
chocolate, and black. ‘The plant in which is the source of this 
colouring matter is nearly allied botanically and in appearance to 
the ordinary Galiums, or bed=straws. It is a native probably of 
Southern Europe as well as Asia. It is a perennial with herba- 
ceous stem; which dies down every year ; its square-jointed 
stalk creeps along the ground to a considerable distance, and the 
stem and leaves are rough with sharp prickles. The root, which 
is cylindrical, fleshy, and of a pale yellow colour, extends down- 
wards to a considerable depth. It is from this root, which, when 
dried, is known as madder, that the colouring matter is obtained. 
The plant is propagated from suckers or shoots. These require 
some two or three years to come to full maturity and yield the 
finest colours, although in France the crop is often gathered 
after only eighteen months’ growth. From its taking so long to 
develop, it is evidently a crop not adapted to any ordinary 
series of rotation of crops. The plant thrives best in a warm 
climate, but has been grown in this country and in the north of 
Europe. 
In India it has been grown from the earliest times, and, as 
before stated, has been abundantly cultivated in Italy, certainly 
since the time of Pliny; he also mentions its cultivation in 
Galilee. In this country its culture has often been attempted, 
and has been carried on for a short time, but never with per- 
manent success. The madder now used in England is imported 
from France, Italy, Holland, South Germany, Turkey, and 
India, In 1857 the total amount imported into this country was 
434,056 cwts., having an estimated value of 1,284,989/., and the 
average annual amount imported during the last seventeen years 
is 310,042 cwts. ; while the amount imported last year, 1872, 
was 283,274 cwts., valued at 922,244/, In 1861, it was esti- 
mated that in the South Lancashire district alone, 150 tons of 
madder were used weekly, exclusive of that required for prepar- 
ing garancine. I quote these figures as showing the magnitude 
of the industry that we are dealing with. Another point of 
much interest is the amount of land required for the cultivation 
of this plant. In England it was found that an acre yielded only 
from 10 to 2qQewt. of the dried roots, but in South Germany and 
in France the same amount of land yields about twice that quan- 
tity. The madder cultivator digs up the roots in autumn, dries 
them, in some cases peels them, by beating them with a flail, and 
exports them in the form of powder, whole root, or, after treat- 
ment with sulphuric acid, when it is known as garancine. 
The quality of the root varies much, that from the Levant, 
known as Turkey root, is most valued. According, how- 
ever, to the colour to be produced, is the madder from one 
source or another preferred. 
To obtain the colouring matter, which is but very slightly 
soluble in water, from these rootsythey are mixed, after being 
ground, with water in the dye-vessel, and sometimes a little 
chalk is added. The fabric to be dyed is introduced, and the 
whole slowly heated ; the colouring matter gradually passes from 
the root to the water, and from the water to the mordanted 
fabric, giving to it a colour dependent of course on the nature of 
the mordant. ; 
To trace the chemical history of this colouring matter, we 
have to go back to the year 17y0, when a chemist of the name 
of Watt precipitated the golouring matter of madder by alum 
from neutral, alkaline, and acid solutions : he obtained two differ- 
ent colouring matters, but could not isolate them, and many dif- 
ferent shades of colours. Charles Batholdi asserted that madder 
contained much magnesic sulphate, and Hautmann observed the ~ 
good effect produced on madder by the addition of calcic car- 
bonate. In 1823, F. Kuhlmann made evidently a careful analysis 
of the madder-root, and describes a red and a fawn colouring 
matter; but the first really important advance made in our 
knowledge of the chemical constitution of this colouring matter 
was by Colin and Robiquet in 1827. They obtained what they 
believed to be, and what has since really proved to be, the true 
colouring principle of madder, and obtained it in a state of 
tolerable purity. Their process for preparing it was very simple. 
They took Alsace madder in powder, digested it with water, 
obtaining thus a gelatinous mass, which they treated with boilin 
alcohol, then evaporated off four-fifths of the alcohol, oa 
treated the residue with a little sulphuric acid, to diminish its 
solubility. Then, after washing it with several litres of water, they 
got a yellowish substance remaining. Lastly, they found that on 
moderately heating this product in a glass tube, they obtained a 
yellowish vapour formed of brilliant particles, which condensed, 
giving a distinct zone of brilliant needles, reflecting a colour 
similar to that from the native lead chromate. They named this 
substance alizarine, from the Levant name for madder, Alizari, 
the name by which it is still known there. * 
A few years later we find other chemists attacking this same 
subject ; in 1831 Gaultier de Claubry and J. Persoz published the 
account of a long research on the subject; they described two 
colouring matters, a red and a rose one—the red one was ali- 
zarine and the rose one was another body nearly allied to it, and 
now well known as purpurine. Runge also made an elaborate 
examination of the madder root; he found no less than five 
different colouring matters in it—madder-red, madder-purple, 
madder-orange, madder-yellow, and madder-brown. The first 
thse he considers to be suited for dyeing purposes, but not the 
ast two. 
Runge’s madder-red is essentially impure alizarin, and his 
madder-purple impure purpurine. He does not give any 
analysis of these substances. During the next ten years this 
subject seems to have attracted but little attention from chemists, 
but in 1846 Shiel prepared the madder-red and madder-purple of 
Runge, by processes very similar to those employed by Runge, 
and analysed these substances. For madder-red he gives the 
formula Cy,H,,0,, which differs only by H,O from the formula 
now adopted. For the madder-purple he gives the formula 
CogH)0,5, and for the same substance, after being sublimed, 
C,H,O,4. The chemist who has worked most on this subject, 
and to whom we are principally indebted for what we know with 
regard to the different constituents contained in the madder root, 
is Dr. Schunk of Manchester. In Liebig’s Annalen for 1848 he 
gives a long and interesting account of his examination of madder; 
he isolated and identified several new substances which are most 
important constituents of the root, and has since this time added 
much to our knowledge of the chemical constitution of madder. 
In the paper above alluded to he confirms the presence of the 
alizarine, and gives to it the formula C,,H, Q4. The principal 
properties of this body may best be sketched here. Its vola- 
tility and brilliant crystalline appearance have already been men- 
tioned ; it is but slightly soluble in cold water, but much more 
so in alcohol, in ether, and in boiling-water. The colour of its 
solution is yellow, and whenit separates out from a liquid it has 
a yellow flocculent appearance, differing thus greatly from the 
red brilliant crystalline substance before described. In order tow 
[ Sept. 18, 1873. 
