Chapter XL: Section IV (4)

It was remarked by the Jury in 1851, at the Great Exhibition, that this is a valuable dye-stuff, and hitherto not so well appreciated as it deserves, for some of the colors dyed with it are quite as permanent as those dyed with madder, and even more brilliant. Its use however is gradually increasing, and it is unquestionably well worthy the attention of dyers.

LOGWOOD.--The logwood of commerce is the red heart wood, or duramen, of a fine lofty growing tree (_Haematroxylon Campechianum_), growing in Campeachy and the bay of Honduras, and which is also now common in the woods of Jamaica and St. Domingo. It is principally imported as a dye wood, cut into short lengths. We chip, grind, and pack it into casks and bags, ready for the dyers, hatters, and printers' use, who esteem it as affording the most durable deep red and black dyes. It is sometimes used in medicine as an astringent. That grown in Jamaica is least valued that of Honduras, Tobasco, and St. Domingo, fetches a somewhat higher price; but that imported from Campeachy direct, is the most esteemed. The annual imports into Liverpool are about 1,300 tons from Honduras, 100 from Tobasco, and 1,800 from Campeachy.

It thrives best in a damp tenacious soil, with a small proportion of sand. It is imported in logs, which are afterwards chipped, and is of great commercial importance from its valuable dyeing properties. Old wood is preferred; it is so hard as almost to be indestructible by the atmosphere. The albumen is of a yellowish color, and is not imported. The bark and wood are slightly astringent. The imports of logwood into the United Kingdom, were 23,192 tons in 1848, 23,996 tons in 1849, and 34,090 tons in 1850, of which 3,484 tons were re-exported in 1848, and 2,307 tons in 1849. The imports in the past two years of 1852 and 1853, have averaged 20,000 tons, of which about 3,000 tons were re-exported. It is increasing in use, for in 1837, the quantity retained for home use was only 14,677½ tons. The price varies according to quality from £4 to £7 per ton.

We received from Honduras 5,401 tons in 1844; and 55,824 tons in 1845. From Montego Bay, Jamaica, 398 tons were shipped between January and July 1851.

FUSTIC.--This is the common name of a species of dye wood in extensive use, which is obtained from _Maclura tinctoria_, or _Broussonitia tinctoria_, Kunth, a large and handsome evergreen tree, growing in South America and the West Indies. The wood is extensively used as an ingredient in the dyeing of yellow, and is largely imported for that purpose. The quantity entered for home consumption in the United Kingdom was 1,731 tons in 1847, 1,653 in 1848, and 1,842 tons in 1849.

Ninety-one tons were shipped from Montego Bay, Jamaica, in the first six months of 1851.

QUERCITRON.---This bark furnishes a yellow dye, of which about 3,500 tons are annually imported in hogsheads of from half a ton to a ton. 296 tons were imported into Liverpool from Philadelphia in 1849, and 514 tons in 1850.

BRAZIL WOOD.--This very ponderous wood is obtained in Brazil from the _Cæsalpina Braziliensis_, which yields a red or crimson dye, when united with alum or tartar, and is used by silk dyers. It is imported principally from Pernambuco, 1,200 quintals having been shipped to London in 1835, but about 500 tons, worth about £4 a ton, were imported from Costa Rica in 1845.

The tree is large, crooked, and knotty, and the bark is thick, and equals the third or fourth of its diameter.

The imports may be stated at about 600 tons annually, the average price being £50 per ton.

Brazil wood is found in the greatest abundance and of the best quality, in the Province of Pernambuco, but being a government monopoly it has been cut down in so improvident a manner, that it is now seldom seen within several leagues of the coast.

Among the Cuba dye woods is Copey _(Clusia rosea_, Linn).

Braziletto, obtained from _C. Crista_, is one of the cheapest and least esteemed of the red dye woods, imported from Jamaica and other West India islands to the extent of 150 tons per annum, fetching £6 to £8 per ton. 2,361 tons of Nicaragua wood were imported in 1848, 2,701 tons in 1849, and 6,130 tons in 1850.

Spain exhibited various vegetable dyes obtained from cultivated and wild plants furnished by the Agricultural Board of Saragossa.

LICHENS.

The chief lichens employed in the manufacture of orchil and cudbear are the following:--

Angola weed (_Ramalina furfuracea_).

Mauritius weed (_Rocella fusiformis_), which comes also from Madagascar, Lima, and Valparaiso, and then bears the distinctive commercial name of the port of shipment.

Cape weed (_Rocella tinctoria_), from the Cape de Verd Islands.

Canary Moss (_Parmelia perlata_).

Tartareous Moss (_Parmelia tartarea_).

Pustulatus Moss (_Umbilicaria pustulata_).

Velvet Moss (_Gyrophora murina_).

The last three are imported from Sweden.

Of these lichens, the first, which is the richest in coloring matter, grows as a parasite upon trees; all the remainder upon rocks.

_Rocella corallina_, _Variolaris lactea_ and _dealbata_, have been also resorted to.

About 130 tons of cudbear are imported annually from Sweden.

These lichens are found on rocks, on the sea coast. The modes, of treating them for the manufacture of the different dyes is the same in principle, though varying slightly in detail. They are carefully cleaned and ground into a pulp with water, an ammoniacal liquor is from time to time added, and the mass constantly stirred in order to expose it as much as possible to the air. Peculiar substances existing in these plants are, during this process, so changed by the combined action of the atmosphere, water, and ammonia, as to generate the coloring matter, which, when perfect, is pressed out, and gypsum, chalk, or other substances, are then added, so as to give it the desired consistency; these are then prepared for the market under the forms of cudbear or litmus.

HENNA (_Lawsonia inermis_), is an important dye-stuff, and the distilled water of the flowers is used as a perfume. The Mahomedan women in India use the shoots for dyeing their nails red, and the same practice prevails in Arabia. In these countries the manes and tails of the horses are stained red in the same manner. The _Genista tomentosa_ yields red petals used in dyeing, and containing much tannic acid.

ORCHILLA WEED.--The fine purple color which the orchilla weed yields, is in use as an agent for coloring, staining, and dyeing. About 30,000 lbs. is obtained annually in the island of Teneriffe. 460 arrobas (or 115 cwt.) of orchilla were exported from the Canary Isles in 1833. In 1839, 6,494 cwts. paid duty, and 4,175 cwts. in 1840. The average imports of the three years ending with 1842, was 6,050 cwt. A little comes in from Barbary and the islands of the Archipelago.

Dr. W.L. Lindley, in a very interesting paper, read before the Botanical Society of London, in December, 1852, on the dyeing properties of the lichens, stated--

The subject of the _colorific_ and _coloring_ principles of the
lichen has, within the last few years, attracted a due share of that
attention which, has been increasingly devoted to organic chemistry.
Since 1830, Heeren, Kane, Schunck, Rochleder and Heldt, Knop,
Stenhouse, Laurent and Gerhardt, have published valuable papers on
these principles; but, here again, we have to regret the great
discrepancy in the various results obtained, and there is therefore,
here also, imperatively demanded re-investigation and correction
before _any_ of the results already published can he implicitly
relied upon, and before we can have safe data from which to
generalise. I have no doubt that a great proportion of the obscurity
overhanging this subject depends on the circumstance that many of
the chemists, who have devoted attention to the color-educts and
products of the lichens, were not themselves botanists, and have
therefore probably, in some cases at least, analysed species under
erroneous names, and also because their investigations have
comprehended a much too limited number of species.

Their utility in the arts, and especially in dyeing--including the
collection of a series of the commercial dye lichens, _i.e._, those
used by the manufacturers of London, &c., in the making of orchil,
cudbear, litmus, and other lichen dyes. While investigating the
dyeing properties of the lichens, I made experiments, with a view to
test their colorific power, on as many species as I could obtain in
sufficient quantity, to render it at all useful to operate on--that
number, however, being very limited (between forty and fifty).

Dr. Lindley adds, many parties may be able to aid his
investigations, by furnishing information on their economic uses,
and on their special applications in dyeing and other
arts--(particularly on their employment, as dye agents, by the
natives of Britain and other countries)--with specimens of the
lichens so used, and their common names--specimens of fabrics dyed
therewith--notes of the processes employed for the elimination of
the dyes, &c. Parties resident in, or travelling through our western
Highlands and Islands, the northern Highlands, Ireland, Wales,
Norway, Iceland, and similar countries, are most likely to be able
to afford this description of information--many native lichens being
still used by the peasantry of these countries to dye their homespun
yarn, &c.

He proceeded to treat--1. The vast importance of this humble tribe
of plants in the grand economy of nature, as the pioneers and
founders of _all_ vegetation. 2. Their importance to man and the
lower animals, as furnishing various articles of food. 3. Their
importance in medicine, and especially in its past history, at home
and abroad. 4. Their importance in the useful and fine arts, and
especially in the art of dyeing. 5. Their affinities and analogies
to other cryptogamic families, and to the Phanerogamia. 6. Their
value as an element of the picturesque in nature; and, 7. Their
typical significance.

He then adverted more especially to the subject of his
communication, under the ten following heads:--

I. The colors of the Thallus and apothecia of Lichens--their causes, and
the circumstances which modify and alter them.

II. History of the application of their coloring matters to the art of dyeing.

III. Chemical nature and general properties of these coloring matters.

IV. Tests and processes for estimating qualitatively, and quantitatively the
colorific powers of individual species--with their practical applications.

V. Processes of manufacture of the Lichen-dyes, on the large and small
scale in different countries--with the principles on which they are founded.

VI. Nomenclature of the dye-Lichens, and of the Lichen-dyes.

VII. Botanical and commercial sources of the same.

VIII. Special applications of the Lichen-dyes in the arts.

IX. Commercial value of the dye-Lichens, and their products.

X. Geographical distribution of the dye-Lichens--with the effect of climate;
situation, &c., on their colorific materials.

Of the four first sections of his paper, the following is a very
short summary or synopsis:--

Under the first head, the author spoke of chlorophylle and various
organic and inorganic substances, which enter into the formation of
the colors of the thallus and apothecia of lichens, and of the
modifications of these colors depending on various degrees of--1.
Exposure to air and light. 2. Temperature. 3. Moisture, &c. 4.
Atmospheric vicissitudes. 5. Season of the year. 6. Nature of the
Gonidic reproduction (_i.e._, gemmation). 7. Nature of habitat. 8.
Organic decomposition. 9. Coalescence of parts, monstrosities, &c.

Under the second section, he traced historically the manufacture of
Lichen-dyes, and the native use of Lichens as dye agents, among
different nations, from the times of Theophrastus, Dioscorides, and
Pliny, down to the present day, sketching briefly the ancient end
modern history of orchil, cudbear, and litmus, and specifying the
native use of lichen-dyes in different, countries of Europe, Asia,
and America. He alluded more particularly to their application to
the dyeing of yarns, &c., by the Scotch Highlanders, under the name
of "_Crottles_." "The process of the manufacture of the various
crottles, generally consisted in macerating the powdered lichen for
two or three weeks, in stale urine, exposing the mass freely to the
air by repeated stirring, and adding lime, salt, alum, or
argillaceous and other substances, either to heighten the color or
impart consistence. To such an extent did this custom at one time
prevail, that, in several of our northern counties each farm and
cottage had its tank or barrel of putrefying urine, a homely but
perfectly efficient mode of generating the necessary amount of
ammonia. In the county of Aberdeen, in particular, every homestead
had its reservoir of "Graith,"[53] and the "Lit-pig,"[54] which
stood by every fireside, was as familiar an article of furniture in
the cots of the peasantry, as the "cuttie-stool," or the "meal
girnel." So lately as 1841 (and I presume the practice continues to
the present day), Mr. Edmonston stated that, of four or five native
dyes, used by the Shetlanders to color cloth and yarns, two at least
were furnished by lichens, viz., a _brown dye_ from _Parmelia
saxatilis_, under the name of "Scrottyie," and a _red_ one from
_Lecanora tartarea_, under that of "Korkalett." It is very probable,
however, that steam and free trade have gradually dispelled this
good old custom, even in the remoter corners of our island;
machinery-made articles being now readily supplied, at a rate so
extraordinarily cheap, as to render it absolutely expensive (as to
time, if not also as to money) to prepare colors, even by a process
so simple and inexpensive as that just mentioned."

Under the third head, he examined, in a general way, the chemistry
of the colorific and coloring matters of the lichens and the results
to which it has led, avoiding as much as possible the technicalities
inseparable from such a subject, and giving a short _vise_ of the
researches of Heeren, Kane, Rochleder, and Heldt, Stenhouse,
Schunck, Laurent, and Gerhardt, and others. "Our untaught senses
should undoubtedly lead us to expect the lichens, whose thallus
exhibits the brightest tints, to yield the finest dyes, and these,
too, of a color similar to that of the thallus, but experience
teaches us that the beautiful reddish or purplish coloring-matters
are producible in the greatest abundance by the very species from
which we should least expect to derive any, viz., in those most
devoid of external color. This, though at first sight very
remarkable, is easily explicable, when we remember that, in most of
the so-called dye-lichens, colorific principles exist in a colorless
form, and only become converted into colored substances under a
peculiar combination of circumstances.

"Some lichens contain coloring matters, ready formed, and these
exhibit themselves in the tint of the thallus of the plants, _e.g._
chrysophanic [or parietinic] acid in _Parmelia parietina_, and
vulpinic acid in _Evernia vulpina_. In other species we find
principles, which, while in the plant, and unacted on by chemical
re-agents, are colorless, but which, when the lichens are exposed to
the combined influence of atmospheric air, water, and ammonia, yield
colored substances. This series of colored products is usually
comprehended more for convenience sake than on account of chemical
identity, under the generic term orceine."

The whole subject of the chemistry of these bodies is at present in
a most unsatisfactory condition, demanding fresh investigation and
research, in illustration of which, the author exhibited tables of
the colorific and coloring principles, so far as they are at present
known, showing their chemical formulæ and the authority therefor,
and various relative information. "It is highly probable that when
the chemistry of the lichens has been more fully studied, and the
whole subject of their color-educts and products better understood,
we shall begin to reduce the present confused mass of complex
substances, and find the same principles more extensively diffused
through different lichen species." Dr. L. entered somewhat minutely
on the chemical reactions of the better known colorific and coloring
principles, and their derivatives, so far at least as these throw
any light on the production and transmutation of the red or purple
colors extracted from what may be termed _par excellence_, the
_dye-lichens_. After a few remarks on the chemical constitution of
orchil and litmus, as given by Kane, Gelis, Pereira, and others, he
discussed the subject of decolorisation of weak infusions of orchil
and litmus by exclusion of atmospheric air, and by various
deoxidising agents, and the different theories as to the causation
of this phenomenon. "I have repeatedly had occasion to notice that,
when weak infusions of these substances are excluded for some time
from atmospheric air, in a bottle, with a tightly fitting cork, they
gradually lose color, but rapidly regain it on re-exposure. It is
curious that both orchil and litmus are what are called transient or
false colors, _i.e._, they slowly lose their bloom and tint by long
exposure to the atmosphere; the coloring matter, therefore, appears
to be decolorised both by exposure to, and exclusion from the air,
phenomena apparently of very opposite characters. The cause of the
latter phenomenon has never, so far as I am aware, been quite
satisfactorily explained; but it has been variously supposed to be
due:--

1. To the mere negation of oxygen.

2. To the development, in the liquids, of various substances,
capable of exerting a decolorising influence on the coloring matter.

3. To deoxidation of the coloring matter by substances, which have a
great tendency to become oxidised or peroxised; _e.g._ hydrogen, in
the case of decolorisation by sulphuretted hydrogen, nascent
hydrogen, and the protoxides of iron and tin, &c.

4. To the fixation of an additional amount of hydrogen in a new
colorless body, formed by the union of the sulphuretted hydrogen or
other substances with the coloring matter of the liquid. This view
is chiefly supported by Kane, who says, "that precisely as the
coloring matters combine with water, to form different shades of
red-colored bodies--with ammonia to produce a series of bodies,
which are blue and purple--so they combined with sulphuretted
hydrogen to form colorless compounds in solution, which, if solid,
very probably would be white." He supposes, in a word, that for
every colored substance existing in orchil and litmus, there is a
corresponding white one, producible by the action of sulphuretted
hydrogen, &c.; and, in proof of this theory, he mentions having
obtained from Azolitmine and Betaorceine colorless bodies, to which
he gave the respective names of Leuco-litmine and Leuco-orceine.

The author then gave a short summary of Dr. Westring's experiments
on the dyeing powers of the Swedish lichens, which he found might be
conveniently divided into four classes, according to the degree of
heat employed in their maceration, viz.:--

1. Lichens, whose coloring matter was easily extractable by _cold_
water alone.

2. Those which required for the elimination of their coloring
matter, maceration in _tepid_ water (_i.e._ below 258 degs. Swedish
thermometer).

3. Those which required maceration in _warm_ water (_i.e._between 50
and 60 degs. Swedish thermometer).

4. Those requiring _boiling_ water alone, or with the aid of
solvents.

"It must be admitted that our knowledge of the true nature of the
colorofic and coloring principles of the lichens is, as yet, very
imperfect and confused, and one great cause of the dubity and
obscurity overhanging the subject, is the fact that different
analysts have arrived at most opposite results, even in the
examination of the same species. For instance, in _Rocella
tinctoria_, which has, of all the dye-Lichens, been most frequently
selected for analytical investigation, on account of its important
product orchil, the discrepancies between the results obtained are
very striking. In it Heeren discovered his _Erythrine_; Kane his
_Erythriline_; Schunk his _Erythric acid_; and Stenhouse three
different substances in as many varieties of the plant; all of these
bodies differing more or less from each other in composition and
properties (at least, if we are to assume, as correct, the
descriptions given of them by their respective discoverers").

"I have already hinted that there is no ratio between the external
and internal color or structure of a lichen, and the kind or amount
of coloring matter it will be found to yield. It is exceedingly
natural to suppose that such a ratio should exist; but, proceeding
for some time on this supposition, I was frequently disappointed in
my results--the most showy and brilliantly colored lichens often
furnishing the dullest and most worthless colors. For instance, the
bright yellow thallus of _Parmelia parietina_, and the beautiful
scarlet apothecia of _Scyphophorus cocciferus_, instead of producing
a rich yellow in the one case, and a deep crimson in the other,
yielded, respectively, only dirty greenish-yellow and brownish
colors. As a general rule I should almost be inclined to say that
the finer the color of the thallus of any given lichen, the more is
that lichen to be suspected of poverty in valuable coloring matters;
and that, on the other hand, the palest pulverulent or crustaceous
species, especially such as are saxicolous, may be expected to yield
the most beautiful and valuable pigments (_e.g._ the Rocellas and
Lecanoras). In such circumstances it is necessary to have some test,
of easy applicability, of the kind and amount of colorific
properties of any lichen, and this fortunately is readily
attainable."

The fourth section of the paper was devoted to the consideration of
the various tests of colorific power, which have been recommended by
different authors. "Of these, the greater number proceed on the
principle of developing the coloring matter by some alkali, in
conjunction with the decomposing action of atmospheric oxygen and
water; others are founded on the reaction between colorific
principles of certain of the dye lichens and some of our ordinary
chemical re-agents." The author noticed in particular--

1. Helot's test, }
2. Westring's tests, }qualitative.
3. Stenhouse's test, }
4. " quantitative.

Helot's test consists in digesting the dried and powdered lichen or
a few hours, at a temperature of 130 degs., in a weak solution of
ammonia, sufficiently strong, however, to be tolerably pungent. One
that is fit for the dyer will yield a rich violet red liquor.

Dr. Westring recommended simply macerating three or four drachms of
the lichen in cool spring water, assisting, perhaps, the solvent
action of the water by minute quantities of common salt, nitre,
quicklime, sulphate of copper or iron, or similar re-agents. If
these means failed, after a sufficient length of time had been
allowed for the development of color, he digested a fresh portion of
the pulverised lichen in water, containing small quantities of
sal-ammoniac and quicklime [in the proportion of 25 parts of water,
1-10th lime, and 1-20th sal-ammoniac for every part of lichen], for
a period varying from eight to fourteen days, and by this process,
he says, he never failed to develop all the color which the plant
was capable of yielding.

Dr. Stenhouse, of London, one of our latest and best authorities on
the chemistry of the lichens, adds to an alcoholic infusion of the
lichen, a solution of common bleaching powder (chloride of lime),
whereby, if it contain certain colorific principles capable of
developing, under the joint action of air, water, and ammonia, red
coloring matters, a fugitive but distinct _blood-red color_ will be
exhibited. The amount of this colorific matter may be estimated
quantitatively by noting the quantity of the chloride of lime
solution required to destroy this blood-red color in different
cases: or the same result may be obtained by macerating for a short
period in milk of lime--filtering--precipitating the filtered liquor
by acetic or muriatic acid--collecting this precipitate on a weighed
filter--drying at ordinary temperatures and again weighing.

The author entered into a full analysis of these tests and
processes--pointing out their respective advantages and
disadvantages--and showing their practical value and applications.
He stated that he had made use of these, and various other tests, in
upwards of 300 experiments, and the one which he employed to the
greatest extent, because most uniformly applicable, was Helot's
ammonia test. The following combination is that most favorable for
the development of the coloring matter of the lichens--viz., the
presence

1. Of _water_ as a solvent menstruum.
2. Of atmospheric _oxygen_.
3. Of _ammonia_, in the state of vapor or in solution, and
4. Of a moderate degree of _heat_;

And according as the proportion of these combining elements varies,
so do the kind and amount of color educed by them. This combination
is the foundation of all the processes for the manufacture of the
lichen dyes throughout the world, however different these may appear
to be in detail or results.

I believe it may come to be a matter of great commercial importance
to discover, at home or abroad, some cheap and easily-procurable
substitute for the _Roccellas_, which are gradually becoming scarce,
and consequently valuable in European commerce, having sometimes
fetched, in times of scarcity, no less than £1,000 per ton. No
plants can be so easily collected and preserved as
lichens--requiring merely to be cleaned, dried, pulverised, and
packed; and if their bulk be an objection to transport, their whole
colorific matter may be collected in the way I have already
mentioned. Ascending to the verge of eternal snows, and descending
to the ocean level--with a geographical diffusion that is
co-extensive with the surface of our earth, it is difficult to say
where lichens shall not be found. There are myriads of small rocky
islets in the boundless ocean, and there are thousands of miles of
barren rocky coast and sterile mountain range in every part of the
world, which, though at present unfit to bear any of the higher
members of the vegetable kingdom, are yet carpeted and adorned with
a rich covering of lichens, and of those very species too, which I
have already spoken of as prolific in colorific materials. I
sincerely believe, therefore, that a more general attention to the
very simple tests just enumerated, would ultimately result in a
greatly extended use of the lichens as dye agents. What renders it
very probable that efforts in this direction are likely to meet with
success is the great similarity of species found all over the world.
It has been repeatedly noticed that the European species, which, of
course, are best known, differ little from those of North America.
Dr. Robert Brown remarked the same fact with regard to New Holland
species, and Humboldt also recognised the similarity in natives of
the South American Andes. Of a large collection made by Professor
Royle, in the Himalayas, Don pronounced almost every one to be
identical with European species. From examining the raw vegetable
products, sent by different countries to the Great Exhibition of
1851, I am satisfied that, even now, there are many fields open for
the establishment of an export trade in _Roccellas_ and other
so-called orchella weeds." I there saw specimens of good dye lichens
from almost every part of the world, including our own young
colonies; and as a single instance of their probable value, I may
introduce here the copy of a note appended to a specimen of orchella
weed from the island of Socotra, contained in the Indian collection
of that exhibition, "_abundant_, but _unknown_ as an article of use
or commerce. Also abundant on the hills around (Aden) and _might_ be
made an article of trade." Roccellas from this source are estimated
as worth £190 to £380 per ton. I believe that a similar statement
might be made with regard to the countless islands of the broad
Atlantic and Pacific, which may, at some future period, perhaps not
far distant, be found to be rich depots of orchella weeds, just as
some of them are, at present, rich fields of guano, and may, as
such, become new nuclei of British commerce and enterprise. Even at
home, in the immediate vicinity of Edinburgh, or, to restrict our
limits still more narrowly, within the compass of Arthur's Seat,
there are not a few very good dye-lichens, which require merely to
be scraped with an old knife or similar instrument, from the rocks
to which they adhere, and subjected to the ammonia process already
mentioned. Of twelve specimens thus collected at random one morning,
I found no less than three yielded beautiful purple-red colors,
apparently as fine as orchil or cudbear, while the others furnished
rich and dark tints of brownish-red, brown and olive-green.

Dr. Lindley's communication was illustrated with specimens of
coloring matters yielded by various lichens collected in the
neighbourhood of Edinburgh, &c.

BARKS FOR TANNING.

Let us now take a brief review of the sources from whence tanning materials may be obtained, which will also enable us to form a fair estimate of the prospect of future supplies. Only one medal was awarded, at the Great Exhibition, for tanning substances, viz., to Messrs. Curtis, Brothers (United Kingdom, No. 126), but honorable mention was made of the following competitors:--One from Tunis, one from Van Diemen's Land, one from New Zealand, one from Belgium, one from the Cape of Good Hope, one from Canada, and one from the United Kingdom.

The substance from which pure tannin is most frequently obtained for chemical purposes is nutgalls, for tannin constitutes above 40 per cent, of their weight. It may be procured also from several other sources, such as oak, horse chestnut, sumach, and cinchona barks, catechu, kino, &c.

The basis of the skins of animals is composed of a substance to which the name of gelatine is given. One of the properties of this substance is, that when combined with tannin, it forms the compound of tannate of gelatine, or leather, a substance which is so useful to mankind. From time immemorial, the substance employed to furnish the tannin to the hides of animals, in order to convert them into leather, has been oak bark. But as the purpose for which oaks are grown is their timber, and not their bark, the supply of oak bark cannot be calculated upon, and this is, perhaps, one of the causes why tanning as an art is in such a backward state.

The consumption of tannin required in the leather manufacture may be estimated from the fact that more than 672,000 cwts. of raw hides were imported in 1851, besides the hides of the cattle, &c., consumed in the United Kingdom. On the Continent and in the United States the consumption of bark for this purpose is also considerable.

The imports of bark for the use of tanners and dyers has amounted yearly to the very large quantity of 380,674 cwt., besides what we obtain at home. Oak bark contains usually the largest proportion of tannin, and according to Davy's experiments eight-and-a-half pounds of oak bark are equivalent for tanning purposes to two-and-a-quarter of galls, three of sumach, seven-and-a-half of Leicester willow, eleven of Spanish chesnut, eighteen of elm, and twenty-one of common willow bark. Tannin obtained from these sources, however, differs materially in some of its characters. The tannin of nutgalls, which is that generally employed for chemical purposes, is sometimes called gallo-tannic acid, to distinguish it from other species.

Notwithstanding the number of different substances which have from time to time been introduced for the use of tanners, it is, nevertheless, pretty generally acknowledged that there is nothing superior, or even equal, to good oak bark, and that all attempts to hurry the process beyond a certain point by the use of concentrated solutions of tan, &c., are for the most part failures, as the manufacture of good leather, to a great extent, depends on the process being conducted in a slow and gradual, but--at the same time--thorough and complete matter.

Oak bark is, however, by no means the only astringent bark well suited to the use of the tanner, and in various parts of the world other similar substances are used with very great success. All these tanning materials, though they may not be considered by the English tanner equal to the best oak bark, are, nevertheless, of great value to him; they may be employed in conjunction with oak bark, or even as a substitute in times of scarcity, or when the price of oak bark is high; in fact the very existence of such substances tends to keep down and equalise the price of bark, and to prevent it from undergoing those great fluctuations in value which would necessarily occur were it the only tanning material available to our manufacture--("Prof. Solly in Jury Reports of Great Exhibition.")

There are a vast number of bark and other substances useful for tanning purposes, which are found in the tropics, that are comparatively unknown or little regarded in Europe; but which might be readily obtained in large quantities and at a trifling cost. The bark of many species of _Acacia_ furnishes the tanning principle in a great degree, particularly that of _A. arabica_, which, under the name of Babul wood, is largely used about Scinde, Biliary, Gruzerat, and other parts of India; where it is regarded as a powerful tonic. The fruit of _A. vera_, termed Egyptian and Senegal "bablah," has been employed in tanning and dyeing. Numerous species of this tribe are found abundant in New South Wales and the Cape Colony, and these, particularly the wattle bark of Australia, are in common use for tanning, from their astringent properties. The bark and rind of the fruit of the pomegranate (_Pumica Granata_) have similar properties.

The bark of _Avicenna tomentosa_ is in great use in the Brazils for tanning. So are the curved pods of _Cæsalpinia Coriari_, in the East and West Indies, under the name of Divi-divi. _Coriaria myrtifolia_ is not only used in tanning leather, but also for staining black. It is worth £9 to £10 per ton. _Pterocarpus marsupium_ furnishes about Tellicherry the concrete exudation called kino, a powerful astringent used for tanning.

The plants of the mangrove tribe, _Rhizophora Mangle_, and other allied species, have frequently an astringent bark, which is in many cases used for tanning and dyeing black. This tree is very common in most tropical countries, where it forms dense thickets on the muddy banks of rivers and the sea shores. The bark of _Bauhinia variegata_, is made use of in Scinde and other parts of Asia. The bitter astringent bark and the galls of several of the Tamarisk tribe are also well suited for the purpose.

_Mesembryanthemum nodiflorum_, one of the numerous indigenous species of the Cape, is used in making morocco leather.

The extract procured from the bark of the _Butea_, that of the _Buchanania latifolia_, the _Scyzgium_ (_Calyptranthes_), _Jambolana_, &c., are likely to be of consequence to the tanners, and could be produced in India in large quantities. Specimens of these, and of the bark of the Saul tree, of _Nychanthes arbortrista, Terminalia angustifolia_, and of the gaub fruit (_Diospyros glutinosa_), were shown by the East India Company. The bark of the hemlock tree is extensively employed for tanning in New Brunswick.

The bark of yellow hercules (_Xanthoxylum ochroxylon_), and the pods of _Acacia tortuosa_ are used for tanning in the West Indies.

In the instructions given by the Admiralty to Sir James Boss, when proceeding on his Antarctic Expedition, his attention was particularly called to the astringent substances adapted for tanning, and to the various extracts of barks, &c., imported into England from our Australian settlements, and which are employed by the tanner. Little sterling information has as yet been obtained as to the qualities of the astringent gums, barks, and dyes, yielded in such abundance by the trees of those colonies, and the proportion of tannin they contained.

In 1846, 563 tons of bark for tanning were exported from Port Phillip.

A large quantity of tannin is extracted from various species of Eucalyptus, the gigantic gum trees in Australia and Van Diemen's Land (of which quarter all the species are natives), and sent to the English market; it is said to be twice as powerful in its operations as oak bark. Some of these trees attain a height of 200 feet. Their bark separates remarkably into layers. A sort of kino gum, an astringent resinous-like substance, is also extracted from _E. resinifera_, the brown gum-tree of New Holland, which is sold in the medicine bazaars of India. It exudes in the form of red juice from incisions in the bark. A single tree will often yield 60 gallons. In Brazil they use the bark of _Luhea panicata_, an evergreen climber, for tanning leather; and in Peru the bark of some species of _Weinmaunia_ serve the same purpose. Among other powerful astringents I may notice the root of a species of Sea Lavender (_Statice Caroliniana_), _Myrica cerifera_, and _Heuchera Americana_, all natives of North America. Also the petals of _Hibiscus Rosa-sinensis_, a native of Asia.

The sea-side grape (_Coccolaba uvifera_) yields an astringent substance, known as Jamaica kino.

The bark of the _Cassia auriculata_, and the milky juice of the _Asclepias gigantea_, are used for tanning in India.

The red astringent gum obtained from _Butea frondosa_, a middling size tree, common in Bengal and the mountainous parts of India, is used by the natives for tanning. English tanners, however, object to its use on account of the color which it communicates to the leather.

The barks of the _Mora excelsa_, Benth; Courida (_Avicenna nutida_), cashew (_Anicardium occidentale_), guava and hog-plum (_Spondius lutea_, Linn.), have all been successfully used for tanning in Demerara and the West India Islands, where they are very abundant. Specimens were sent from British Guiana.

The root of the Palmetto palm (_Chaemaerops Palmetto_) is stated to be valuable for the purposes of tanning. The leaves of _Nerium Oleander_ contain tannic acid. The bark of a species of Malphigia is much used by the Brazilians.

The panke (_Gunnera scabra_) is a fine plant, growing in Chili, on the sandstone cliffs, which somewhat resembles the rhubarb on a gigantic scale. The inhabitants eat the stalks, which are subacid, tan leather with the roots, and also prepare a black dye from them. The leaf is nearly circular, but deeply indented on its margin. Mr. Darwin measured one which was nearly eight feet in diameter, and therefore no less than twenty-four in circumference. The stalk is rather more than a yard high, and each plant sends out four or five of these enormous leaves, presenting together a very noble appearance.

The barks replete with the tanning principle should be stripped with hatchets and bills from the trunk and branches of trees in spring, when their sap flows most freely. The average quantity of oak bark obtained from our forests is estimated at 150,000 tons annually, of which Ireland and Scotland furnish but a very small quantity.

The following table, given by Dr. Ure, shows the quantity of extractive matter and tannin yielded by different substances:--

In 480 parts In 100 parts
by Davy. by Cadet.
Sicilian sumach 78 --
Malaga ditto 79 --
Souchong tea 48 --
Green tea 41 --
Bombay catechu 261 --
Bengal ditto 231 --
Nutgalls 127 46
Bark of pomegranate -- 32
" Virginian sumach -- 10
" Carolina ditto -- 5

Catechu and Gambier are very valuable for tanning, and are alluded to under the heads GAMBIER and ARECA PALM.

CATECHU is obtained from the _Acacia Catechu_, an arboreous tree growing from fifteen to twenty feet high, with a brown and scabrous bark. The interior wood is brown, dark red or blackish, and the exterior white, one or two inches thick. It inhabits various parts of the East Indies, of which it is a native, and is also now common in Jamaica. It bears whitish or pale yellow flowers.

The catechu obtained from this tree in Pegu, is celebrated throughout India, and fetches £4 to £5 more per ton than gambier and other astringent extracts. When of good quality, catechu is more powerful as an astringent than kino. Of all the astringent substances we know, catechu appears to contain the largest proportion of tannin, and Mr. Purkis found that one pound was equivalent to seven or eight of oak bark for tanning leather.

The term catechu, observes Dr. Pereira, is applied to various astringent extracts imported from India and the neighbouring countries. A few years ago the terms catechu, terra japonica, and cutch were employed synonymously; they are now, however, for the most part used in trade somewhat distinctively, though not uniformly in the same sense. The manufacture of catechu from the _Acacia catechu_ as practised in Canara and Behar, has been described by Mr. Kerr ("Med. Obs. and Inquiries," vol. v.), and Dr. Hamilton ("Journey through Mysore," &c., vol. iii.), while Professor Royle has explained the process followed in Northern India. According to the last-mentioned gentleman, "the kutt manufacturers move to different parts of the country in different seasons, erect temporary huts in the jungles, and selecting trees fit for their purpose, cut the inner wood into small chips. These they put into small earthen pots, which are arranged in a double row, along a fireplace built of mud; water is then poured in until the whole are covered; after a considerable portion has boiled away, the clear liquor is strained into one of the neighbouring pots, and a fresh supply of the material is put into the first, and the operation repeated until the extract in the general receiver is of sufficient consistence to be poured into clay moulds, which, in the Kheree Pass and Doon, where I have seen the process, are generally of a quadrangular form. This catechu is usually of a pale red color, and is considered there to be of the best quality. By the manufacturers it is conveyed to Saharunpore and Moradabad, whence it follows the course of commerce down the Ganges, and meets that from Nepaul, so that both may be exported from Calcutta."

GAMBIER.

The Gambier plant (_Uncaria Gambler_, Roxburgh, _Nauclea Gambir_, Hunter), has been described by Rumphius under the name of _Funis uncatus_. It is a stout, scandent, evergreen shrub, which strongly resembles the myrtle. It is generally cultivated in the same plantation with pepper, as the leaves and shoots, after undergoing the process by which their juice is extracted, to furnish a kind of catechu, are found to be an excellent manure for the pepper vines. The leaves and young shoots of the gambier plant are collected as soon as they have attained a sufficient size, and boiled in iron pans until the juice acquires the consistence of treacle. The decoction is poured out into narrow troughs, dried, and afterwards cut up into small cakes, and packed in baskets for exportation. The gambier extract, which is of a yellowish brown color, and has the consistence of hard cheese, is much esteemed by the Malays for mixing with the preparation of betel, which they are in the habit of chewing; and considerable quantities have lately been imported to this country, where it is used for dyeing colors, and for tanning leather. The demand for gambier here is on the increase; and when better known to our chemists, it will probably be found applicable to many other purposes than those to which it is at present applied.

There were, in 1850, 400 gambier and pepper plantations on the island of Singapore; each measures or occupies on an average an area of 500 fathoms square, and employs eight to ten hands to cultivate and manufacture the gambier and pepper. There are some pepper plantations in addition, and they have been found to answer very well without any gambier being cultivated with them. Gambier cultivation is generally a losing undertaking, but it is adopted to obtain the refuse of the leaves for manuring the pepper vines, and also to employ the people in the plantations; it besides affords the proprietors the means of getting monthly sums to carry on the cultivation of pepper, which affords two crops yearly. There were formerly 600 plantations in Singapore, but the reason already assigned, and the formation of spice plantations contiguous have caused the abandonment of all those near the town. Each plantation must have an equal extent of forest land to that cultivated with gambier and pepper, to enable the manufacture of the gambier being carried on, and each gambier plantation, of 500 fathoms square, contains about 3,500 pepper vines, which yield on an average two catties per vine, or 70 piculs of pepper, and about 170 piculs of gambier annually;--a good plantation will, however, yield sometimes as much as 120 piculs of pepper, and 200 piculs of gambier, and a bad one as little as 40 to 50 piculs of pepper, and 60 to 80 piculs of gambier. Were it not for the enormous commission charged by the agents of these plantations, from whom the cultivators get all the advances, it would prove a profitable cultivation. The rates of commission charged generally are as follows:--Per picul of gambier, fifteen to twenty-five cents; per picul of pepper, thirty to forty cents; and if the price of the former is below one-and-a-half dollars, and the latter below three-and-a-half dollars per picul, a small reduction is made in the rates of commission. On every picul of rice supplied to the planters twenty to twenty-five cents commission is charged; this includes the interest of money advanced, which is never charged. A gambier and pepper plantation is valued or estimated at about 400 dollars on an average. The following is supposed to be a correct estimate, on an average, of the yearly expenditure and returns of a gambier and pepper plantation of 500 fathoms square, viz:--

EXPENDITURE.
drs. c. men. drs. c.
Eight men at 3½ dollars and 7 Java rupees per
month, wages for headman and labourers
respectively 22.70 12 272.40
Five piculs of rice, including commission, say 6.50 12 81.60
Fish, &c. 5 12 60.0
Boat or cart hire to carry rice and produce 1¾ 12 21.0
------
435.0

PRODUCE.

170 piculs of gambier, valued at l dollar 45 cents
per picul, less 15 cents commission chargeable,
nett 221.30 -- ---
70 piculs of pepper, at 4½ dollars, less 40 cents
per picul commission, nett 287.0 -- 508.0

Yearly profit, 73 dollars, or about £15.

Several gambier and pepper plantations have been abandoned in Singapore, partly from the ground being impoverished, but more particularly from the exhaustion of the forest adjacent to their estates. The exhaustion of the trees by yearly consumption deprives the planters of the necessary fire wood which is used for the boiling down of the gambier. A gambier plantation gets exhausted in fifteen years, either from the want of firewood or the land getting impoverished.

There are about 200 plantations at Johore, and the produce of gambier for the season of 1851 was calculated at 30,000 piculs.

This shrub was, at one period, cultivated with success at Pinang and other places to the eastward, but as Java was the principal market for the produce, and the Dutch had levied a duty of twelve Java rupees per picul on it, the cultivation at the former island did not repay its cost, and it was accordingly abandoned. Prices have been lately advancing, and the Chinese are talking of trying it again. The plant is partial to hilly land or slopes at the skirts of hills. Two hundred plants are usually placed on one orlong of land, being six feet asunder. They are raised from seed, and are topped to eight or ten feet, when the gambier is to be prepared. The Chinese dry the seed slightly, and sow in rainy weather.

The seeds vegetate in forty days, and are planted out in the second or third month afterwards.

At the expiration of fourteen months, the first cutting of the branches, with the leaves on, is made. These are put into a boiler, and when the juice has been extracted, the branches and refuse are thrown away, and the boiling is continued until the liquor has obtained the proper consistence, when it is put into shallow troughs, dried, and cut into slices for sale. The second cutting takes place eight months subsequently to the first. The plant now grows strong and admits of frequent cropping, and it will endure for twenty years. No manure is used, but the plantation is kept clean.

Estimated cost of cultivating ten orlongs, about 13 acres, according to Colonel Low:--

Spanish dollars.
Value of cleared land, ten orlongs 200
Six laborers per annum 360
Quit rent 7
Boilers, firewood, and implements 20
Houses 50
Incidental 30
----
Total first year 667
Second year 397
----
1,064

The six laborers on the plantation will, after the above period, be constantly employed in cutting and preparing the gambier: the average product will be 15 piculs monthly, which, at two dollars per picul, will be 30 dollars monthly, or 360 dollars per annum. This is the account obtained by collating different Chinese statements.

The _Nauclea Gambir_ is placed by Jussieu under the natural order _Rubiaceæ_; it is a shrub attaining the height of six to eight feet, branchy; the leaves are ovate, pointed, smooth, waving, distinctly veined transversely underneath, of dark green color, and, when chewed, they have a bitter astringent taste, leaving however, afterwards, a sweetish taste in the mouth, not unlike liquorice; the flowers are aggregate, globular, composed of numerous florets, crowded on a globular naked receptacle; tubes of the corolla of a pinkish color; the upper part of the corolla fine, cleft, and of a greenish yellow color; the staminæ are five in number, and short; the pistil is longer than the corolla; the flowers are destitute of fragrance; the capsules (as correctly stated by Mr. Hunter) are stalked oblong, incrusted, and crowned with a calyx; tapering to a point below; two celled, two valved, the valves adhering at the apex, splitting at the sides; seeds very numerous, oblong, very small, compressed, furnished at both ends with a membraneous pappus.

The gambier plant is propagated either by seeds or cuttings, but the latter are preferred. It is cultivated to some extent at Singapore, but it is said that the gambier can be imported cheaper from the islands in the vicinity, more especially at the Dutch settlement at Rhio. The extract is used extensively by the natives of India, Eastern Archipelago, Cochin-China, and Cambodia, as a masticatory, wrapped up with the betel.

There are three different qualities of extract; the first and best is white, brittle, and has an earthy appearance when rubbed between the fingers (which earthy appearance gave it the name of Terra Japonica, being supposed, at first also, to come from Japan), and is formed into very small round cakes. This is the dearest sort, and most refined, but it is not unfrequently adulterated with sago; this kind is brought in the greatest quantity from the island of Sumatra. The second quality is of a brownish yellow color, is formed into oblong cakes, and, when broken, has a light brown earthy appearance; it is also made into a solid cube form; it is sold in the bazars in small packets, each containing five or six. The third quality contains more impurities than the preceding, is formed into small circular cakes, and is sold in packages of five or six in the bazar.

The method employed in preparing the extract is thus correctly related by Finlayson:--"The leaves are collected three or four times a year; they are thrown into a large cauldron, the bottom of which is formed of iron, the upper part of bark, and boiled for five or six hours, until a strong decoction is obtained; the leaves are then withdrawn, and allowed to strain over the vessel, which is kept boiling for as many hours more, until the decoction is inspissated; it is then allowed to cool, when the catechu subsides, The water is drawn off; a soft soapy substance remains, which is cut into large masses; these are further divided by a knife into small cubes, about an inch square, or into still smaller pieces, which are laid in frames to dry. This catechu has more of a granular, uniform appearance than that of Bengal; it is, perhaps, also less pure."

The younger leaves of the shrub are said to produce the whitest and best gambier; the older, a brown and inferior sort. There are other species of _Nauclea_ indigenous to Singapore, but they do not produce any extract.

Dr. Bennett has particularised four qualities of gambier:--

1. Small round cakes, about the size of a small lozenge. Color pale, purplish, yellowish, white.

2. Cubes, in which shape it is principally imported into England, and square prisms, or oblong pieces.

3. Circular discs, or short cylindrical pieces.

4. Cubical amylaceous pieces, of a darker brown than the other kinds.

Gambier is one of the most powerful of the pure astringents.

The chief places of manufacture are Saik, Malacca, Singapore, and Rhio or Bintang. Bennett, in his "Wanderings," says there are 60,000 plantations of gambier on this island. After that of Rhio, the next best gambier is that of Lingin. That used by the Malays, with the leaves of betel, in the same manner as cutch in other parts of India, is the finest and whitest; the red being stronger tasted and rank, is exported to Batavia, China, and England, for the purposes of tanning and dyeing. It is frequently adulterated with sago powder, but it may be detected by solution in water.

Large quantities of gambier are imported, under the corrupted name of cutch, into Calcutta, from Pegu. The quantity of gambier produced in Rhio, by the Chinese settlers, amounts to about 4,600 tons a year, about 2,000 of which are exported for the consumption of Java, the rest being sent to Cochin-China and other neighbouring countries.