THE INDIGENOUS TANS AND VEGETABLE DYESTUFFS OF NEW ZEALAND.

New Zealand Journal of Agriculture, Volume XV, Issue 3, 20 September 1917, Page 117

THE INDIGENOUS TANS AND VEGETABLE DYESTUFFS OF NEW ZEALAND.

PART I— continued.

B. C. ASTON,

F.1.C., Chemist to the Department.

DYEING is the art of applying to a material another substance which results in the alteration of the colour of the material in such a way that it is more or less permanent under the

conditions to which it is to be exposed. The essential difference between dyes and paints is that the latter do not penetrate below the surface of the material to be coloured. Dyes sink below the surface, and hence must be capable of entering the tissue of the material in solution.

Tans must also be capable of penetrating the substance to be treated, but they have the property of enabling the material to resist putrefaction. Hence the function of dyes is most largely ornamental, that of paints ornamental and protective, and that of tans used as such most largely preservative, although to some extent effecting a change of colour. . A subsidiary use of tans is as mordants in fixing a dye in a form in 'which it cannot . easily be removed from

the fabric treated. Tans can also be differentiated as a class by their astringent taste and chemical reactions, all giving black, green, or blue-black colours with iron salts. , . •

MODERN EXPERIENCE AND RESEARCH IN NEW ZEALAND TANNINS AND DYES.

It will now be more convenient to adopt for the statements made a different arrangement, in which the sources of the tans and dyestuffs are considered with some regard to their botanical relationship. That adopted is the order followed in Cheeseman's “ Manual of the New Zealand Flora,” which, although unhappily out of print, is the systematic work which is most readily available to the student.

Aristotelia racemosa (Makomako or Wineberry). (1868) suggests. that the bark of this plant , might be used for dyeing a blue-black.

Ela&ocavpus dentatus (Hinau) Skeyf (1886) states, in a table containing the percentages of, tannin in barks as received, analysed in the Colonial Laboratory and compiled for Messrs. Lightband and Co., and “ which may be found useful to tanners,” that the hinau-bark contained 19-12 per cent, of tannin. KirkJ (1889) states that the bark is ; of. great value for tanning purposes, as it contains over 20 per cent, of tannin. Cheeseman§ (1906) states that the bark is still used by a few inland Maori tribes for dyeing flax cloths.

Elaeocarpus Hookerianus (Pokaka). Skeyf mentions 3-92 as the percentage of tannin in the bark. Kirk J states that the bark has been tested by Mr. Kingsland, of Invercargill, for tanning purposes and found to produce good firm leather. It contains 10 per cent, of tannin.

Coviaria ruscifolia (syn. C. sarmentosa) (Tutu or Tupakihi). Lauder Lindsay (1868) quotes Skey in the jurors’ report of the- New Zealand Exhibition, 1865, . that tannin abounds in the leaf, root, calyx, seeds, flower-stalk, old wood, and pith of the plant, being in order of richness as follows : (1) young leaves, from 0-3 to 2-08 per cent. , (2) old shoots ; (3) root ; (4) old wood. The percentage is much higher in the dry than in the fresh state, varying from 2-14 to 8-32 in the former. There is .no perceptible loss of tannin by drying the plant at 130-150° F., whence it is inferred that the small branches could

be dried and stacked like oak-bark without losing any of the tanning properties. The plant is strongly recommended by Lindsay to the notice of the local tanners on account of its abundance. Kirk* states that the bark of C. ruscifolia contains 16-8 per cent, of tannin, and strongly recommends the use of the whole plant for this purpose. Skeyf (1895) once, however, analysed a sample (6929) of bark forwarded by the Hon. Mr. Ward, and found only 6-6 per cent, of tannin in the material dried at 212 0 F.

The genus Coriaria, to which the tutu belongs, is a very widely spread one, consisting of closely allied species which are found in southern Europe, Central and South America, Japan, India, and New -Zealand. The European C. myrtifolia is known as Geberstrauch . (dyers’ bush)' in Germany, and as redoul in - France. It has been used for dyeing and tanning, being then worth £9 10s. per ton. In Russia the root is largely used for tanning. Experiments upon the dyeing properties of C. myrtifolia carried out in the dyeing laboratory of the Yorkshire College, Leeds, have shown that the leaves of this species contain about 16 per cent, of tanning-matter. The colour of leather tanned with the extract was practically equal to that produced by sumach. The percentage of tanning-matter in sumach is, however, considerably higher than in the two species of Coriaria. C. thymifolia is in South America known as the “ inkplant,” and the juice of the. fleshy petals is used as ink under the name “ chauchi.” Jameson J (1863), writing from Quito, is quoted by Dr. Hooker that this ink is preferred to the commercial inks in use. It . does not corrode the steel pen, and it is said to resist the action of sea-water. When newly written the colour is reddish, becoming black after a few hours. Coriaria thymifolia is one of the commonest hillside plants in many parts of New Zealand. From it Easterfield and Aston§ (1900) isolated a quantity of gallic acid and the dye quercitin (C 15 H 10 0 7 2H 2 0), which is a glucoside, a lemonyellow crystalline powder having marked dyeing properties. It has been found by A. G. Perkin]| (1900) in Coriaria myrtifolia,' and iswidely distributed in the vegetable kingdom, . occurring in berberry, onion-skin, Cape sumach, and Gambier- catechu.

. Ackama rosaefolia (Makamaka). — suggests that .it might be found useful in tanning. . .Kirk* states that the bark has been utilized for tanning, and is probably of similar value to that of the closely allied tawhero. ' - /

1 W einmannia sylvicola (Tawhero or Towai).—Kirk* states that this tree has long been famous for its bark, which contains from •10 to 13 per cent, of tannin, and was formerly used to a large extent in the Auckland tanneries. The supply was, however, obtained in a most wasteful manner, the bark being peeled as high as a man could reach, the branches and upper portions being left untouched, so that the supply in the immediate vicinity of the settlements soon became exhausted. Cheeseman f- also states that the bark is largely used in tanning. ' 7

Weinmannia racemosa (Towai or Tawhero in the North, Kamahi in the South Island).This tree is closely allied to the preceding species, which only occurs in the North Island. - Buchananj (1868) states that the bark is valuable in tanning. • Skey§ (1868) gives an analysis of extract of towai-bark furnished by Mr. Grayling, of Taranaki, as follows : Water, 21-5 per cent. catechuic acid, 42-5 per cent. 7 tannic acid, 31-1 per cent. ; lignin, i-8 per cent. ; gum and undetermined, 3-1 per cent. Kirk|| (1886) states that Grayling was awarded a certificate of merit for this extract at the United States International Exhibition, Philadelphia, 1876-79. Kirk* states that the bark is of great value for tanning, as it contains 13 per . cent, of tannin. He suggests that it might be made into an extract, as it can be obtained in vast quantities. (1899), reporting •on sample 8049 of kamahi-bark from Rataville, Ratanui, reports that as received it contained 5-6 per cent, of tannin and 9-2 per cent, of extractive matter, and was much inferior to oak or wattle bark as a tanning-material. Mr. Kingsland** (1916), managing director of a large firm of tanners in the South Island, made an exhaustive trial of this and other native barks for years, but in the end discarded them altogether in favour of Australian and Tasmanian wattle, finding that even at a greater cost wattle was better and cheaper for their purpose. It- is now thirty years since this firm manufactured any of these barks grown in New Zealand, and it has used only wattlebark since. The tanning with 'native barks was slow compared with wattle but one of the worst features of the native barks was the large proportion •of dye and acid they • —substances detrimental to the colour and appearance of the leather when manu-

facture'd for sale to the' boot-factories, although the durability of the .leathers produced from these barks was very good, especially so for “ sole ” leather. Owing to the existence of the deleterious substances mentioned, “ upper ” leather manufactured from these barks suffered to some extent in appearance, &c. ; and where fine, clear, brightgrained leathers were required say, for saddlers’ work in brown harness, leggings, and bridle-hide —it was out of the question to produce a satisfactory and saleable article. “ Mr. Kingsland, who has so ‘kindly placed his valuable experience at the author’s disposal, points out that chrome (mineral)’ tannage is largely replacing organic (vegetable) tannage, perhaps one-half of the leather now made in' New Zealand being produced by the former method. , He also points out that the climatic conditions for harvesting, bark may not be suitable in wet districts of New Zealand, nor the lowland soil conditions so suitable for growing it. He. hints that should some method be found of combating the injurious effects of the substances called by .him acids and dyes in the New Zealand barks they may yet be found to be satisfactory. The Woolston Tanneries (Limited), of Christchurch* (1916), who pay some £13,000 per annum for imported wattle-bark and other extracts, came to the conclusion that kamahibark. was the most suitable to’ experiment with in the attempt to utilize native barks in tanning. Another firm, who wish ■ the source of their information kept confidential, express the opinion that owing to the small percentage of tannin in New Zealand barks there is no possibility of utilizing them unless concentrated to the form of an extract. ' .

• Tetragonia trigyna (New Zealand —Colensof states that on the Maoris learning to write they used the fluid of this plant, which yields a purple juice,' for ink. The fruit of Scheffler a digitata and the.juice of the root of Phormium were also used by them for a similar purpose.

Metrosideros spp.—SkeyJ gives the tannin-content of rata ” as 15-2 per cent. Kirk§ states that the bark of Metrosideros robusta (rata) contains 18-56 per cent, of tannin. .

Coprosma spp.—lt is somewhat remarkable that the possibilities of the Coprosma genus, which is restricted in habitat to Australasia, Pacific islands, New Guinea, and Borneo, should mot have been chemically .examined as a source of dyes, seeing that the genus is included in the family Rubiaceae, which contains the madder, of commerce. Of all the New Zealand plants,' theory would point to this

genus as the one most likely to realize economic expectations in the matter of dyestuffs, owing to its relationship to the madder, its abundance, size, and the coloured inner bark of some of the species. The madder-plant (Rubia tinctorum), according to Pliny, was used in the ancient civilizations. Some authorities assert that it was used in dyeing long before it was employed in painting. Its cultivation was much encouraged in the reign of Charlemagne, but it met with varying fortunes in Europe until the first half of the nineteenth century, when in France under Louis Philippe its culture was increased in consequence of its use in dyeing military material. This prosperity continued until the synthesis (artificial manufacture) of alizarin, the chief dye in madder, was accomplished in 1869. This discovery by chemists in Germany was patented in England on the 25th June, 1869. On the following day Perkin applied for a provisional patent which he had discovered independently. The two investigators then collaborated with the Badische Anilin und Sodafabrik. This was the first natural vegetable dyestuff to be artificially produced, and it and its derivatives now rival those of indigo in importance. The yellow root of madder, which becomes red on drying, contains a much larger proportion of the colour-making substances than other parts of the plant, a fact which bids fair to find a parallel in the case of the coprosmas, judging by the increased thickness and colour of the root-bark compared with the above-ground parts. It is to be noted that the artificial dyestuff has almost entirely replaced the natural madder-root except for dyeing military material and making fine pigments. The present author, finding that the bark of certain New Zealand species of C opr osmo yielded with alkalis a brilliant purple-red solution, looked into the matter. Although the bark of Coprosma grandifolia was examined for alkaloids with a negative result by Skeyf (1869), and he noted that the inner surface of the bark was a bright-yellow colour, the chemical examination of the colouring-matters of this species and the genus generally does not seem to have received the attention which its close relationship to the madder-plant (Rubio tinctorum) of commerce would warrant.

There are at least three New Zealand species of the genus Coprosma* —representatives of which are among the commonest and most widely distributed native shrubs—the bark of which (especially that of the root) is of considerable tinctorial power —viz., Coprosma grandifolia, C.. linariifolia, and C. areolata. The first has an orange-yellow, the

second a bright-yellow, and the third a deep-brown inner bark. The colour is more deep the nearer it is to the root, and less deep towards the ends of the branches. The Maoris are said to have used both Coprosma grandifolia and C. robusta or C. lucida for producing shades of yellow in their phormium cloths, but the author can find no reference to a red or a blue dye obtained by the Natives from these plants.

_ Extracts from Coprosma grandifolia dye cotton a delicate pink or red, and wool shades of purple, and the brown inner bark of C. areolata stains the hands a persistent brown. The following experiment seems to show that both alizarin and purpurin or nearly allied compounds are present in the bark of C. grandifolia. Seventy- grams of the fresh bark of C. grandifolia from the above-ground portions of the plant ' gathered in August were allowed to lie for forty-eight hours, and were then steeped in water for twenty-four hours and the water separated. The bark was then steeped in alcohol for twentyfour hours and the alcohol removed by distillation.. A . small . portion of the alcoholic extract gave on mixing with caustic soda perCent. solution) a brilliant purple coloration, becoming yellow with dilute hydrochloric acid. The acid alcoholic extract was shaken with ether six times; which removed all the colouring-matter. . On evaporating the ether a crust of orange-coloured crystals was deposited : these under the microscope were , seen to consist of a mixture of bright-red and yellowish clumps of acicular crystals. After drying in a desiccator over sulphuric acid the weight was 0-05 gram (= 0-068 per cent, of the wet bark). These crystals, which sublimed on the walls of a test-tube immersed in hot sulphuric acid, by the action of a boiling saturated solution of potash alum were separated into a yellowish-red fluorescent solution and a brown insoluble substance which gave an intense purple coloration with alkalis. Tannic acid did not precipitate the colouring-matter from either the acid or alkaline solution. ' ’ .

The present desire to utilize New Zealand vegetable dyes in connection with the home spinning of woollen goods and the dyeing of military material, and the abundance of the forty New Zealand species of Coprosma and the large size of their roots compared with madderroots used in commerce, have suggested to the author that the economic as well as the scientific aspect should be investigated. Preliminary tests show that there is reason to believe that closely similar if not identical dyes to those of madder are to be obtained from Coprosma, and the matter is accordingly being made the subject of research.

Eugenia maive (Whakou or Whawhakou or “ Riwaka ”). —Kirk* (1886) states that the bark contains 16-7 per cent, of tannin. Blockleyf (1902) found in E. Smithii, the New South Wales “ Lillypilly,” 10-7 per cent, of tannin.

Fuchsia excorticata (Kotukutuku). —Buchanan J notes that the wood is astringent, forming shades of purple to black with iron. Kirk§ states that the wood contains 5-3 per cent, of tannin, according to an analysis made in the Colonial Museum.

Vitex lucens (syn. V. littoralis) (Puriri). —A. G. Perkin|| (1898), working in the Clothworkers’. Research Laboratory of the Yorkshire College Dyeing Department, isolated and studied two yellow dyestuffs from puriri wood obtained from Auckland, which he named vitexin and homovitexin. - He reports on the dyeing properties of the wood as follows: - ' - ,

In studying the dyeing properties of this material, woollen, cloth mordanted with aluminium, iron, chromiuin, and tin was employed. The results are. embodied in the table below, in which have also been placed for comparison the shades given by old fustic (Mor us tinctoria) and weld (Reseda luteola), for these among the commercial natural dyestuffs most nearly approximate in shade to the Vitex littoralis. The most striking property of this dyestuff is the very yellow tones it produces with chromium and aluminium mordants, these being free from any admixture of red, and possess, if anything, a faint greenish tint. Exposed to light for three months, the chromium and iron mordanted patterns showed no'great alteration, whereas the aluminium and tin shades had very perceptibly faded. ' The results with mordanted calico were similar, although the colours thus obtained had a slightly brighter character. Three samples of the wood were examined, with the result that there was some variation in colour-strength; the-sample last received was the strongest, and this was employed-for the above dyeing experiments. On account of the;pure-yellow tones it. produces, some hope exists that, where these are necessary, this dyestuff may be of some commercial utility for this purpose. A well-known Leeds firm who have examined a sample consider that it should have a limited sale at £4 per ton, a value somewhat below that, of old fustic, which is at present £4 10s' During the -examination of apigenin and vitexin it has been shown that these colouring-matters are not perceptibly oxidized on passing air through their alkaline solutions, and it 'seemed of interest to'ascertain if this-property was in any way connected' with their behaviour on exposure to light: . Experiments, however, seem to negative this view, for the shades given by aluminium and tin mordants are not fast, and those with chromium and iron possess no great

superiority over those obtained from colouring-matters which suffer decomposition when oxidized in a similar manner.

Barger* (1906) has subsequently found vitexin in the products ,of the ■ hydrolysis of saponarin . from Saponaria officinalis, and with Perkin's collaboration compared the tinctorial properties. of vitexin from both sources. Barger also studied the constitution of vitexin, which he says seems to belong to a new class Of colouring-matters closely allied to the flavone group. The present economic importance of the puriri is that it has been suggested by Professor Easterfield, of Wellington, as a source of khaki dye for.military material, in place of old fustic. -

Avicennia officinalis (New Zealand Mangrove).Mr. E. Phillips Turner, of Wellington, sent the author' 10 lb. of the'bark of this, tree in November, 1915, but no trace, of tannin could be found, a result which was in accordance with its lack of astringent taste. The author consulted Sir D. Prain (Kew), Mr. Maiden (Sydney), and Mr. Baker (Technological Museum, Sydney) regarding this somewhat remarkable absence of tannin, considering the statements which have been made regarding the tannin-content of Avicennia, and even of A. officinalis in other countries. Bakerf (1915), who gives a list of these references, finds that the bark on the Australian plant is so thin, the quantity of bark and the percentage of . tannin so small, that it would never pay to use it for tanning purposes. All three of these authorities- suggest that there is considerable confusion in the references to mangroves in literature, and one suggests that the New Zealand plant may yet have to be classified under a name distinct from A. officinalis. Avicennia from Southern Nigeria has been found to contain from 12-5 to 19-8 per cent, of tannin. No mention of. Avicennia as a source of tannin is made by such authorities as Allen§ (1901), Thorpe|| (1913), or Philippine Islands (1911), who, however, mention other genera of mangroves as being

valuable tannin sourcesviz., Rhizophora, Gerlofs, Bruguiera, Xylocar us, Kandelia, and Sanner alia. .

Fagus (syn. .Nothofagus) (Beech, or “ Birch ” of the Settler).— great deal of confusion exists in the popular naming of this genus, the species of which are all large forest-trees, and have, according-to Cheeseman* and Kirk,J the following settlers’ names : Fagus Menziesii is tawhai, tawai, white, silver, brown, dr red birch ; F. fusca is tawai, tawai-raunui, black-birch, bull-birch, or red-birch ; F. Solandri is tawhai, tawhai-rauriki, black, red, or brown birch F. cliffortioides is tawhai-rauriki, black, white, .or mountain birch. Kirk (1886) .states that a Mr. Godsif, or Goodhue, of Havelock, recently produced from F. fusca (the bark of which is used for tanning) by a simple method a tannin-extract which contained 22-51 per cent, of tannin. SkeyJ states that the bark of the “ black-birch ” (1872) contained 6-9 per cent., the red-birch (March, 1885) 6-i per cent., the black-birch (March, 1885) 6-2 per cent.,, and the brown-birch 7-02 per cent, of tannin. Kirk quotes the red-birch as containing 7-6 per cent, of tannin.

Mr. Kingsland§ states he found from experience that a birch-bark produced from the Nelson District of New Zealand, and put on the market by a Mr. Lightband,' contained' the highest percentage of tannin of any New Zealand barks he had ground. Mr. C. C. Empson, Stock Inspector at Nelson, kindly made inquiry and reported that the Mr. Lightband referred to did at one time' carry on a business at Wakefield, crushing birch-bark for tanning purposes, using mostly brown-birch bark, but. the venture was not a success financially. Mr. Greenslade, tanner, of Nelson, claims that with one exception he is the only tanner who has stuck to birch-bark, which he has been using for many yearsprincipally brown-birch, but he mixes blackbirch with it. The latter is not so easily obtained, and is much lighter than the brown-birch bark, but the mixed bark makes good tan. Birch-bark, Mr.. Greenslade claims, is as good as the English oak-bark and just as slow, but makes the very best quality of leather. Four tons of mixed birch-bark are equal to i. ton of wattle-bark, but the wattle-bark , can be used a second time. This tans in •' half the time that birch-bark does. The cost of obtaining the birch-bark is now becoming .prohibitive, and taken altogether the wattle is cheaper. Birch-bark which . formerly cost £2 now costs £3, whereas wattle costs £g; mixed birch-bark gives a tan liquor of 12 0 density, whereas wattle gives 33 0 . Leather tanned by" wattle is inferior in quality to that tanned by birch tan.

Podocarpus spicata (Matai oi' Black-pine).—Kirk states that the bark is occasionally used by the tanners, but only to a small extent.

Dacrydium cupressinum (Red-pine or Rimu). —Skey* (1886) states that rimu-bark as received contained 3-8 per cent, of tannin. Kirkf states that rimu-bark is often used by the tanner, and is valued for certain qualities of leather, although it imparts a red colour to the skin. Its percentage of tannin is low, being only 4-3 per cent., and he suggests that an extract should be made.

Phyllocladus trichomanoides (Celery-topped Pine, Tanekaha, Toatoa). —This is a rather rare tree, of which one hears nothing but good both from the arboriculturist, the timber expert, and the barkmerchant. Of great beauty as a young tree, it is of very quick growth, under favourable conditions making about 2 ft. a year in height. The following account of its value suggests to the author that experiments might be made in planting this tree artificially, or at all events some consideration might be given to the matter. Skeyf (1883) reports as follows: —

No. 3399 is the bark of the tanekaha. It is exported to Germany in considerable quantity as a dyeing-material by Messrs. Krull and Co., who were anxious to know something of its chemical nature, and to make public such knowledge for industrial purposes. The following is the report furnished to this firm : This bark contains 25-30 per cent, of tanning-material in the state in which it was received. In this state it contained 11-33 P er cent, of water. The amount of tanning-material, therefore, upon the dry bark is 28-66 per cent. This material is principally catechuic and allied acids, tannic acid forming the remainder. The dyeing property of the bark is to be referred to this acid (the catechuic) and its allies. This substance is of considerable value in commerce, being, as Dr. Muspratt states, “ used for compound colours as black, green, brown, drab, and fawn," and is, he further states, in “ high estimation on account of its permanency." In practice I find the extract of this bark in hot water gives reddish and pink-coloured compounds with zinc, tin, and alumina ; and these seem durable, being very insoluble in water, and unchanged in the air or light.

Kirkf states that the bark contains 23 to 28 per cent, of tannin, and is therefore highly valued by the tanner. It possesses a special value as an organic mordant in the preparation of basils for kid gloves, and has realized from £3O to £5O per ton in London for this purpose ; but the demand is intermittent,' as it is dependent on the caprice of fashion with regard to particular shades of colour. Skey§ (1885) reported on another sample of reputed tanekaha-bark from Nelson (No. 3638), which contained 24-34 per cent, of tannic and catechuic acids soluble in water and precipitable therefrom by gelatine.

Phyllocladus glauca (Toatoa) and P. alpinus (Mountain Toatoa). — Kirk* suggests that the phyllodia (false leaves) of these two species probably contain large amounts of tannin, and in all probability the bark would prove of equal value to that of P. trichomanoides for tanning.

Liliaceous Plants. — Among these Colensof (1868) mentions that the root of the Phormium was used by the Maoris to produce an ink. Skey£ mentions the toi-bark as containing a large proportion of tannin. He may mean toii {Cordyline indivisa) or giant cabbage-tree.

Lichens. — With regard to the dyes extracted in Europe from lichens, Edge§ (1914) states that from cudbear were formerly made dyes in considerable quantity in Scotland, generally by : the aid of ammonia and air, on Lecanora tartarea and '.Urceolaria calcaria. Evernia prunastri, Umbilicaria vellea, U. pustulata, Parmelia perlata, Lecanora pallescens, and some other lichens of less commercial value also • give a purple colour by this method. The dyestuffs made by these British lichens are not equal to. that of Roccellae (orchil of Sweden). In the case of the crottles,, which are still largely used for dyeing browns in the homespuns of Harris, Lewis, Donegal, Shetland, &c., the dyestuff appears to be ready formed in the plant, and to be obtained by simple extraction. The best known are Parmelia saxatelis or black-crottle and P. omphalodes, while others are P. caper ata or stone-crottle, P. ceratophylla or 'dark-crottle, P. parietina, and a few species of Sticta, especially S', pulmonaria or hazel-crottle. These lichens undergo no, preparation, ' being gathered in July or August, when they are richest in colouring-matter, and simply dried ■in the sun. They dye without addition to the bath, and do not form lakes. Fine shades of brown are obtained fast to acids and alkalis,' but less fast to light than a mixture of metachrome brown B and . metachrome orange 3R, although in fading an agreeable tone is maintained. Hooker|| , (1867) states that Parmelia caper ata occurs on trees in the North and Middle Islands of New Zealand; P. saxatelis, North and Middle Islands, .on trap rocks, Otago ; P. parietina, North and Middle Islands,' common rock, wood, and bones P. perlata, common on trees, North and Middle Islands Lecanora tartarea, probably common throughout both Islands. The genera Sticta and Umbilicaria occur in New Zealand, but not • the above species ' •

* Trans N Z. Inst., Vol. i, 2nd ed. f Twentieth Col. Laboratory Report. t “ Forest Flora of New Zealand.” § “ Manual of the New Zealand Flora.” B. and F. Med. and Chir. Rev., “ On the Properties and Products of the tootplant of New Zealand.” '

* “ Forest Flora of New Zealand.” t Twenty-ninth Col. Lab. Report. J Proc. Linn. Soc. London, Vol. vii. § “ Tutu,” Pt. I, Eighth Report, Dept. Agriculture : Trans. N.Z. Inst., Vol. xxxiii ; Trans. Chem. Soc. London, Vol. Ixxix. || Trans. Chem. Soc. London, Vol. Ixxvii. Trans. N.Z. Inst., Vol. i, 2nd ed.

* “ Forest Flora of New Zealand.” f “ Manual of the New Zealand Flora.” £ “ Sketch of the Botany of Otago.” Trans. N.Z. Inst., Vol. i. ' § Trans. N.Z. Inst., Vol. i; 2nd ed. k. ' II “ New Zealand Timbers, Bark, and Secondary Forest Products.” Parliamentary Report by-T: Kirk, Chief Conservator of State Forests. C.-38. This report gives the analysis of a number of indigenous barks assayed for tannin in the Colonial Laboratory, and therefore by Skey. The discrepancy in the amount of tannin in the bark of the same tree by the same analyst may be due to the difference of the season of the year in which they were collected. *jj Thirty-second Col. Lab. Report. - ' **. Personal communication.

* Personal communication. f Trans. N.Z. Inst., Vol. i, 2nd ed.. 1 Twentieth Col. Lab. Report. § “ Forest Flora of New Zealand.” ...

* Since writing the above I have ascertained that additional species give a colour reaction with alkaliesviz., C. lucida C. rbtundifolia, C. rhamnoides, C. foetidissima, and C. microcarpa. f “ On the Examination of the Bark of Coprosma gran difolia for Alkaloids.” Trans. N.Z. Inst.,. Vol. ii.

* “ New- Zealand Timbers, Bark, and Secondary Forest Products.” Parliamentary Report by T. Kirk, Chief Conservator of State Forests. C.-38. f Jour. Soc. Chem. Industry, Feb., 1902. J “ Sketch of the Botany of Otago.” Trans. N.Z. Inst., Vol.Tv. § Forest -Flora of New Zealand.” ' || “ Colouring-matter of the New Zealand Dyewood Puriri (Vitex littoralis),” Pt. I. Trans. Chem. Soc. London, Vol. Ixxiii. .

* Saponarin : a new glucoside coloured blue with iodine. Trans. Chem. Soc. London, Vol. Ixxxix. f “ The Australian Grey Mangrove, Avicennia officinalis.” Proc. Roy. Soc. N.S.W., Vol. xlix. J Bull. Imp. Inst., 1913. § “ Commercial Organic. Analysis,” Vol. iii, Pt. I. || “ Dictionary of Applied Chemistry,” Vol. v. Y “Economic Possibilities of the Mangrove Swamps of the Philippine Islands.” P.I. Journ. Science, Vol. vi.

. * “ Manual of the New Zealand Flora.” f “ Forest Flora of New Zealand.” + Twentieth Col. Lab. Report. § Personal communication;

* Twentieth Col. Lab. Report. f “Forest Flora of New Zealand.” t Eighteenth Col. Lab. Report. § Nineteenth Col. Lab. Report.

*“ New 'Zealand'Timbers, Bark, and Secondary Forest Products.” Parliamentary • Report by T. Kirk, Chief Conservator of State Forests. C.—3B. •f Trans. N.Z. Inst., Vol. i,. 2nd ed. f Twenty-ninth Col. Lab. Report. § Journ. Soc. Dyers and Colourists, Vol. 30. Abst. in J.S.C., Vol. 33, 1914. || “ Handbook of New Zealand Flora.”

— Chromium. Aluminium. • Tin. ■ Iron. Vitex littoDull yellow, slight Dull yellow, slightly Pale lemonDull grey- ■ ralis green tint ■ pale yellow brown. Weld ' .. Full brown-yellow Bright yellow ' .. Pale yellow Deep brownolive. Old fustic Yellow olive Ditto.