1 Jan. 12, 1912 The Fundamental Principles of Chemistry. An net 7 6 32 By Wilhelm Ostwald. ΙΟ 60 906 6 6 2 6 6 2 21 A Short Manual of Inorganic Chemistry. By A. 96 net Practical Methods of Inorganic Chemistry. By F. Mollwo Perkin Practical Electro-chemistry. By B. Blount. net 15 net 4 6 Electro-metallurgy. By J. B. C. Kershaw.. net 6 London: Printed and Published for the Proprietor by EDWIN JOHN DAVEY, at the Office, 16, Newcastle Street, Farringdon Street, E.C. January 12, 1912 56 600 66 6 ...... net 6 0 net 2 6 600 Edited by AND JOURNAL OF PHYSICAL SCIENCE Establish Sixty-eight Years. Sir Wm. Crookes, O.M., F.R.S. (WITH WHICH IS INCORPORATED THE "CHEMICAL GAZETTE"). BROTHERTON & CO., Ltd. FOR SCIENTIFIC AND RESEARCH WORK IN LABORATORIES. Works: BIRMINGHAM, GLASGOW. AMMONIA Offices: City Chambers, LEEDS. ENQUIRIES SOLICITED, PLATINUM Utensils. We supply all forms and sizes of Platinum Utensils and Apparatus for Chemical and Physical purposes. All our utensils are hammered to shape, tested, LONDON REFINING & METALLURGICAL WORKS, and finished in the best manner. All kinds of Platinum scrap bought for cash or taken in exchange for new.-DERBY and CO., Ltd., 44, Clerkenwell Road, London, E.C. OZONE APPARATUS MICA. Telephone "INSTITUTE of BREWING JOURNAL" No. 2248 P. WIGGINS & SONS, 102/3/4, Minories, London, E. Manufacturers of Mica Goods for Electrical and ALL purposes. PURE CULTIVATION OF YEAST. Courses for beginners, as well as for Advanced Students in Physiology and Technology of Fermentations. Biological Analysis of Yeast. The Laboratory possesses a numerous collection of Yeasts (Brewers', Distillers', Wine, Disease Yeasts), Moulds, and Bacteria. Manuals: ALFRED JÖRGENSEN, "Micro-organisms and Fermentation," 4th edition (Charles Griffin and Co., London), and "The Practical Management of Pure Yeast" (London, "The Brewing Trade Review"). The Laboratory supplies for direct use Pure Cultures of Yeast for Breweries, Distilleries, Wine Manufactories, &c., and performs Analyses of Yeasts, &c. Further particulars on application to the Director Alfred JörgENSEN, The Laboratory, -COLLECTIVE INDEX, 1887-1910. This publication, consisting of 550 pages, forms a very exhaustive Book of Reference to Scientific Work carried out in connection with Brewing, Malting, Dis tilling, and Allied Industries in all parte of the world during the past twenty-three years. Price 10s. 6d. post free.-Apply, Institute of Brewing, Brewers' Hall, Addle Street, London, E.C. TO DISTILLERS, Manufacturing chemISTS, and OTHERS. including 3 Copper Rectifying Stills (544, 587, and 2905 gallons respectively); Copper Worm Condensers; 5 Gun-metal Spirit Safes; pair Gun-metal Spirit Pumps; 63 Oak Vats up to 4335 gallons capacity; numerous Casks, Butts, and Pipes; Pitch-pine Stillage; 2 Wine Presses; Copper and Iron Boiling Pans; Copper Piping and Fittings; 9 Liquor and other Pumps; a 50,000-gallon Cast-iron Water Tank; Iron and Slate Tanks; 2 Iron Hot-water Boilers; Copper Feed-water Heater; 2 Lancashire Boilers; Beam and other Engines; Shafting and Gearing; Belting; Warehouse Cranes; Weighing Machines; Copper Measures and Utensils; Office Furniture; 6 Pair- and Singlehorse Vans, and numerous other effects. May be Viewed by Orders, and CATALOGUES had of Messrs. LAYTONS, Solicitors, 29, Budge Row, E.C.; or of Messrs. FULLER, HORSEY, SONS, and CASSELL, 11, Billiter Square, London, E.C., and 100, King Street, Manchester. LE RADIUM. COVERS FOR BINDING. PUBLIE TOUT CE QUI CONCERNE LES DES SUBSTANCES RADIOACTIVES. Cloth, Gilt-lettered Covers for Binding the Half-yearly CHEMICAL NEWS may now be obtained. Price 1/6 each (post free 1/8). Volumes Bourd in Cloth Cases, Lettered and Numbered at 2s. 6d. per volume CHEMICAL NEWS office. 16, NEWCASTLE ST., FARRINGDON ST., E.C SULPHUROUS ACID and SULPHITES. Liquid SO, in Syphons, for Lectures, &c. PHOSPHORIC ACID and PHOSPHATES. CARAMELS & COLORINGS for all purposes. A. BOAKE, ROBERTS, & CO. (LIMITED), Stratford, London, E. substance. 25 THE CHEMICAL NEWS. tannic derivative of pyrogallol exists in any normal part of VOL. CV., No. 2721. NOTES ON PLANT CHEMISTRY. The Origin of the Lichen Acids. THE quite distinctive chemical specialty of lichens is the presence of what are called lichen acids, some of which afford the chromogen of well known domestic dyes. These acids are chiefly developed or excreted in the outermost cortical cells and on the upper surface of the reproductive organs (apothecia), i.e., in such parts as are well exposed to the air. The acids are not contained in the cells them selves, but only appear on the cell walls and in certain small irregular corpuscles called granulations or gonimia, when these occur in the epithallus. It is important to notice that those lichens which produce relatively large quantities of oxalate of calcium have a proportionally small content of lichen acids. Some ninety-four of the latter belong to the aromatic series, while forty-nine belong to the fatty series. The special faculty of lichens to produce these very peculiar and elusive compounds is, according to Zopf, founded in all probability on a special chemical cooperation corresponding to the consortium character; i.e., to the fact that these plants are a symbiotic association of an alga and a fungus living by a kind of mild parasitismthe fungus borrowing from the alga its carbohydrates, while the alga in return borrows its water, proteids, and salts from the fungus. In the many cases where the lichen acid is an ester," one may, perhaps," says Zopf, "so imagine this co-operation that the alga yields the alcohol (e.g., in the form of erythrite), the fungus the acid (in the form of lecanoric acid)," the result being represented by erythrin; the species of Rocella which produce this substance carry algae of the genus Trentepohlia which in fact form erythrite. Now, no doubt the acids are the result of the peculiar symbiotic association of alga and fungus, and the latter is the sole seat of the production-actual appearance of the acids (it does not produce these by itself); but the important fact that when the quantity of the albumenoids decreases the quantity of the acid increases points to a more specific origin. The co-operation, in fact, seems clearly to consist in this, that as the alga borrows its albumenoids from the fungus, a powerful process of deassimilation is inevitable in the latter. The alga would imperatively require the nitrogenous groups of the albumenoid molecule, the aromatic groups thereof would not be needed, and would be left behind in the fungus. The acids therefore originate by a mechanism of deassimilation, provoked by a penury of nitrogen in the neighbouring cells of the alga, whose cells, moreover, seem to exist in a kind of juvenile condition as compared with those of the fungus, which are naturally highly nitrogenous with a great reserve of force. This latter circumstance may be connected with the peculiar phenolic chromogens evolved by lichens, viz., orcinol, quinones of the anthracene series. The methylation points to a more extensive abandonment of the carbon groups than is usual in similar processes (production of floral pigment, &c.) taking place in the higher plants. Gallotannin. Many of the old analysts seemed to detect this form of tannin and its acid (gallic acid) in a great number of plants; e.g., in nettle, tea, Euphorbia, Coriaria, various species of geraniums, arnica, plumbago, yellow water-lily, The leaves, bark, &c., of various trees and shrubs were also said to contain gallotannin, such as oak, poplar, birch, hazel, dogwood, &c., and even lately Trimble asserts that the tannin of the Spanish chestnut tree is the same &c. It may, however, be safely asserted that no the plants mentioned. Among British herbaceous plants I have found it only in members of the orders Onagracea and Lythracea. The detection of gallotannin in a plant may be illustrated by the behaviour of the aqueous solution of an alcoholic extract (after benzene) of the overground parts of a willow-herb (Epilobium), viz., with iron salts a blue-black precipitate, with ammonia a yellow colour with scarlet streaks to a brown-yellow liquid, with limewater yellow, green, and brown precipitates, with acetate of uranium a brown precipitate; precipitates also with gelatin and tartar emetic plus NH,CI, but none with bromine water; when a drop of sulphate of potash solution followed by a few drops iodine solution are added an instantaneous transient red coloration is immediately produced; finally, no phlobaphene was yielded by boiling HCl. It is hardly necessary to say that no other kind of tannin or tannoid extracted from plants yields a series of reactions comparable to the above. There are, however, certain tannins which are partially similar thereto in some respects; for instance, those of sedum, bistort, various Rosacea, dogwood, Spanish chestnut; but all these precipitate bromine water and yield phlobaphenes, and do not give the icdine reaction. All these, moreover, contain catechol and phloroglucin nuclei, and it is probably owing to the fact that the latter is attached to the remainder of the molecule by a single bond, or some phloroglucin hydroxyls are free, that the blue-black reaction with iron salts, which distinguishes these tannins, is obtainable. According to Trimble, the blue colour with iron salts given by oak tannins is due to a foreign substance and never to the pure tannin, but the analogy of the tannin of several Rosacea (burnet, lady's mantle, blackberry, marsh cinquefoil, common avens, &c.), which also yields blue or blueblack precipitate, would seem to show that it is really caused by some constitutional property of the tannic molecule. According to Winkel, no free phloroglucol or other phenol is ever present in plants—a statement with which I agree and this fact lends support to the view that the tannins as actually existing in the tissues are really comparatively stable substances. The Origin of Oxalate of Calcium. This subject in its physiological bearings (final cause) has proved to be the bone of considerable contention. Originally, oxalate was reckoned to be a reserve substance serving the supply of cellulose material. Some authors deny this and say that it is specially formed in those cells in which mucilaginous substances of a chalky nature or pectin compounds are very copiously accumulated. According to Duclaux, it is the result of an incomplete combustion, and this view seems to be very prevalent. Schimper's renowned theory is that the oxalate is a by-product in the formation of organic phosphates (nuclein, &c.), and its appearance is connected with the reduction of nitrate of calcium in the leaf, the nitrogen of the acid being assimilated, the oxygen thereof being cast on the sugars, and the resulting oxalic acid is deposited as a calcium salt; .e., oxalate of calcium is formed in order to eliminate oxalic acid. Amar, on the contrary, maintains that it is formed in order to eliminate calcium. It is certain, however, that the results of a comprehensive chemical analysis of plants do not warrant the formulation of any of the above hypotheses. It is certainly not true that plants which specially absorb and utilise the nitrates of the soil are always distinguished by a copious formation of oxalate, i.e., borage, foxglove; while, on the other hand, plants which contain no nitrate, e.g., several Liliacea, most native forest trees, &c., frequently produce large quantities of oxalate. Similar remarks apply even more forcibly to mucilaginous plants, several of which contain little or none of this salt; e.g., marsh marigold, lesser celandine, valerian, various grasses, &c. It seems to me that the views of MM. Maze and Ferrier on this subject (Compte Rendus, 1904, cxxxix.) are quite correct, viz., that th vegetable acids are not a product of the direct oxidation of carbohydrates by oxydases or otherwise. In fact, they are produced as a product of deassimilation, and not in connection with assimilation, as Schimper assumed. The respiratory combustion supposed to form the acids is exerted upon the living protoplasm itself as an organic process, the acids being, in certain circumstances, detached from the albumenoid molecule. In some leaves, such as elm and sycamore, for instance, where the total nitrogen as well as the sugar and mucilage do not decrease till very late, as well as in other leaves (cherry and birch) where the same constituents do decrease, there is about an equally heavy deposit of oxalate in the old organ, thuswise exhibiting, as regards its formation, an independence of carbohydrate. The Chromogen of the Gentian Blue. One would imagine that this subject would be one of entrancing interest to all students of botanical chemistry, but I am not aware of any European publication, paper, or memoir dealing specially with the chromogen of the noblest of Alpine flowers. Of fifty-nine species of Gentiana thirtyfive are blue, and there is no pink. Independently of the very favourable physiological or anatomical characters (the huge and rapid development of the corolla, the large pollen grains, the extremely numerous ovules, &c.), there must inevitably be something specially potent in the chromogen which ministers to the evolution of the intense blue coloration of the floral envelope. Unfortunately, so far as I am aware, there is no tannin, strictly so-called, produced in any of the gentians which are readily available for examination. There is, however, a tannoid which seems to be characteristic of the Gentianodes division of the order, and is named gentisin, C14H10O5, is a member of the xanthone group of natural dye-stuffs, and contains the quinol and phloroglucol nuclei or residues. It would seem that it is to the quinol nucleus or complex that the blue coloration of the gentian corolla is mainly attributable, and this statement will seem justified by the following facts:-On an analysis of the leaves of a plant, the bogbean (Menyanthes trifoliata) belonging to the order Gentianacea, I was extremely interested to find (the fact had never been recorded before, I believe) that they contained caffeetannin, and I forthwith concluded, rightly I hope, that this was the actual tannic chromogen of the gentian blue. It may be mentioned that all the allied orders (Oleacea, Apocynacea, Asclepiadea, Aquifoliacea) contain a quinol tannin, and all exhibit blue flowers in many of their species, and these blues, be it observed, are true blues, and not purples or violets as in Leguminosa, Geraniacea, &c., Caffeetannin is a substance that has proved a puzzle. Some chemists hold that it is a sugary diether of caffeic acid, and others say that it is not a glucoside, and yet one or two affirm that it is a mere mixture of acids and other substances. What is certainly true is that it yields protocatechuic acid on fusion with potass, and that its reactions are not similar to the ordinary catechol tannins, the latter fact being a conclusive proof that it contains in its molecule a nucleus other than that of catechol or phloroglucol. This other nucleus is evidently quinol, although caffeic acid is considered to be a derivative of styrene, which is a side-chain derivative of benzene. In fact, free cinnamic acid has been found in various labiates, figwort, &c., which contain caffeetannin or ferulic acid, and, as is known, Salvia patens is one of the most distinct and beautiful deep blue flowers in cultivation. All tannins possess a chromogenic nucleus of a phenolic nature upon which an aldehyde in a favourable acid medium reacts to produce a coloration, and it is very important to notice that caffeetannin is the only tannin known, besides gallotannin, which yields oxidative blue compounds with bases. Moreover, these tannins contain more HO groups in their molecule than any other. According to Liebermann the entrance of HO groups (both as to number and position) into a colouring matter changes the tint from yellow up to blue, and finally black. The state of the question here AMERICAN turpentine, pinene prepared from American turpentine, Russian turpentine, and sylvestrene prepared from Russian turpentine, were respectively mixed with their own volume of water and oxidised by a current of air at 65° C. for twenty-four hours. The aqueous solutions were then examined, and gave the following results:American Turpentine.-Formic acid, 0017 per cent; acetic acid, o'038 per cent; formaldehyde, indications; acetaldehyde, none. Pinene. Formic acid, o 14 per cent; acetic acid, 0·057 per cent; formaldehyde, indications; acetaldehyde, none. sylvestrene were dried over ignited calcium chloride, and American turpentine, pinene, Russian turpentine, and then oxidised with a current of dry air at 65° to 69° C. during a perion of some weeks, when the oils had the following specific gravities:-American turpentine, 931; pinene, 962; Russian turpentine, 940; and sylvestrene, 958. The oxidised oils were shaken up with half their volumes of water, and the aqueous solutions examined, with the following results : American Turpentine.-Formic acid, o'055 per cent; acetic acid, o'024 per cent; formaldehyde, none; peroxide of hydrogen, o'71 vol. Pinene. Formic acid, o 054 per cent; acetic acid, o'186 per cent; formaldehyde, indications; peroxide of hydrogen, o'348 vol. Russian Turpentine.-Formic acid, o'13 per cent; acetic acid, o'08 per cent; formaldehyde none; peroxide of hydrogen, I'06 vol. Sylvestrene.-Formic acid, o'059 per cent; acetic acid, 0 264 per cent; formaldehyde, indications; peroxide of hydrogen, o‘532 vol. passing through the turpentine was washed in a flask of water. With respect to the two samples of turpentine, the air after This water was found to contain considerable quantities of formic and acetic acids, also peroxide of hydrogen, but only indications of formaldehyde. Peroxide of hydrogen when added to American and Russian turpentine produces some formic and acetic acids, but the action is slow. A Communication from the Laboratories of the "Sanitas" Co., Ltd. Read before the Society of Chemical Industry, January 8, 1912. |