worthy of notice is shown by the experiments of Cloez. This chemist obtained from the seeds of Aleurites cordata, by means of carbon bisulphide, 41 per cent. of a fixed oil, forming a solid crystalline mass below 32° C. When on the contrary the seeds were treated with ether an oil was obtained that did not solidify even at -18° C. But what is most surprising is that when prepared either by pressure or by one of the solvents mentioned, and heated in the air to 200° C., it changes suddenly into a solid transparent jelly, which is no longer soluble in ether or carbon bisulphide.* This change takes place also after a few days, when excluded from the air, under the influence of light alone. The oil dries more rapidly than linseed oil. The principal acid in it was obtained in crystals that melted at 44°, but very rapidly resinified, and therefore did not consist of linoleic acid. In many respects this Chinese wood oil recalls the singular "axin" or "age" of Mexico, examined by Hoppe-Seyler, in 1860. The Nin fat of Yucatan, described by Dondé, might also be mentioned here. All these oils appear to correspond in yielding a peculiar body, which Mulder described as linoxyn. NOTES ON INDIAN DRUGS. correspond to the description given by Adanson and others to that of Guibourt (confer. Guibourt, vol. iii., p. 644). The shell is hard, woody and light, clothed with a dull green, felt-like down, composed of simple hairs; it is made up of regularly arranged wood cells, intersected here and there by vascular bundles. The fruit is full of a subacid pulp, which is divided by fibrous bands into a number of compartments. The pulp dries up into a starch-like powder, which adheres together in polyhedral masses, a seed forming the centre of each. The seeds are enclosed in a horny shell, with a rusty red rough exterior; they are kidney shaped, and half an inch in length. The structure of the bark is very confused: it consists of a mixture of pitted and wood cells, without any regular arrangement; the epidermis is scabrous, and appears to consist of the desquamating cells of the bark. When fresh the bark is about five-eighths of an inch in thickness; a section shows a mottled yellowish green and reddish brown surface; internally it is intimately united with the woody fibre of the trunk; it does not taste bitter, but is said by Duchassaing to be a useful substitute for cinchona. The pulp is very mucilaginous, and has a pleasant cool subacid taste, which it retains when dry. It may probably be a useful demulcent acid refrigerant. No part of the tree appears to be used medicinally in Bombay. The fruit makes floats for fishing nets and bottles for holding water. (Continued from Vol. VI., page 1003.) EMBELIA RIFES.—Local name, WAiwarung, Common in the neighbourhood of Bombay, has a nearly SALMALIA MALABARICA.-Local name, SAUR. globular red fruit, rather smaller than a peppercorn, The astringent exudation Muchurrus, or Supari che which grows in large bunches. The drug has the phool. A red fungus like mass, changing to a dark five partite calyx and stalk often attached; the outer mahogany colour when old; it is brittle and flaky. shell is striated from the base to the apex, where The larger tears are hollow in the centre, and the there is a small beak; its colour is reddish-brown, cavity is of a cinnamon colour, and has a cellular marked with dark spots. Inside the outer shell is appearance. Muchurrus is not a simple juice but the the seed, enveloped in a delicate membrane, on reproduct of a diseased action, being a proliferation of moving which a cup-like hollow is seen opposite the the cells of the suberous tissue of the bark. Upon insertion of the stalk. The seed is horny, of a red-making a section of the diseased part a number of dish colour, and its external surface appears to be small cavities are seen which contain a semitranscovered with spots of white mildew; this appearance, parent jelly-like substance, consisting of oblong however, with the aid of a lens, is seen to be due to cells with botryoidal nuclei. At the margin of the a delicate crystalline efflorescence. If kept for any cavity the columns of healthy cells are seen breaking time the outer shell of the fruit becomes nearly up and the cells separating to join the jelly-like black, hence the statements that two kinds are met mass; this gradually increases in size, and finds its with in the shops. From the rapidity with which way to the surface to be extruded as muchurrus. this change takes place I should suppose the quality Upon its first appearance it is of an opaque yellowish of the drug to be not affected by it. Waiwarung is white colour, firm externally, but semi-fluid inheld in high repute as an anthelmintic among the ternally, and there is no central cavity. The dry country people, especially in cases of tape-worm, a exudation when soaked in water swells up and disorder not uncommon among the native Christians communicates a red colour and slight astringency to of the western coast. The dose is a teaspoonful of it; a section can then be made to show its cellular the powder twice a day for a child, and a dessert structure. I have not been able to satisfy myself spoonful for an adult; it is not purgative; the taste as to the cause of the disease in the bark which is rather pleasant, slightly astringent, and not un-produces this substance, but traces of insects are like that of tea leaves. The worm is expelled dead. A purgative should be given to prepare the patient for the drug. ADANSONIA DIGITATA.-Local name, GoWIK CHENTZ, with one kind in the market. or CHUREE CHENTZ. This remarkable tree is not uncommon upon this part of the western coast. The fruit varies much, both in shape and size; some specimens *Comptes Rendus, Sept. 1875, p. 469, and 1876, p. 501. always to be seen at the site of exudation. Incisions in the healthy bark yield nothing. Muchurrus has a purely astringent taste like tannin, for which it probably is an efficient substitute. I have only met ODINA WODIER.-Local name, SHIMPTEE, or MOOI. The gum, Shimptee, or Mooi cha goud. This gum is partly in tears of a yellowish tinge, and partly in colourless angular fragments, which are full of fissures like gum arabic; it has a disagreeable taste, and is not astringent; about one half of it is com ERGOTINE. The researches of Professor Salkowski and other German chemists on the active principle in the preparation of ergotine were recently referred to. Professor Buchheim now writes to the Klinische Wochenschrift confessing that he also has not succeeded in isolating completely that principle, though he worked on it for several months; and he states his reasons why he thinks that such isolation might be impossible, and that for practical medical purposes the infusion of ergot, or the freshly prepared extract, will alone remain available. The organization of the ergot fungus seems to him so low that its mycelium cannot build up organic matter, so as to constitute an alkaloid or glucoside substance from water, carbonic acid and ammonia, but feeds, so to speak, more directly on the vegetable material of the mother plant. He believes that less elementary compouds are taken up by it from the rye grain, and thinks the gluten the most likely material from which to form the gelatine-like substance which he isolated partly from ergotine. On this modified albuminous constituent of the rye, at a certain stage of its metamorphosis, he infers, depends the peculiar action of the fresh infusion or extract. Any further complex chemical processes and reactions for the isolation of the active substance must necessarily have changed it so much in its natural course of decomposition that it has lost its efficacy, in the same manner, for instance, as the decomposing albuminous substances of putrid blood lose their poisonous effects when decomposition has reached to a certain point. The freshly prepared ergotine seems therefore to give alone a guarantee of success. For subcutaneous application it ought to be carefully neutralized by carbonate of soda, as it contains much acid, especially lactic acid, as Buchheim found, besides quantities of leucine. MATÉ, OR PARAGUAYAN TEA. Some interesting paragraphs respecting this substance are quoted in the Revista Farmacéutica, the organ of the Argentine Pharmaceutical Society, from an unpublished work by Dr. Bialet, entitled 'Compendio de Anatomia, Fiscologia é Higiene humana.' Of these the following is an abstract: The Matéor Paraguay Tea tree (Ilex mate paraguayensis), is a small tree belonging to the family of the Celastrineæ,* which reaches at the most a height of seven metres; ordinarily it does not exceed four or five. Its trunk is about twenty centimetres in circumference, and is covered, by a whitish bark. The leaves are oblong, cuneiform, *Not to the Ilicies, as stated by some authors. obtuse and finely dentate. It has axillary multipartite peduncles; calyx tetrasepalous; the corolla with four petals in the form of a crown; stile none; stigma 4-fid; fruit a 4-seeded berry. The plant grows very abundantly in Paraguay, North Corrientes, Chaco, and South Brazil, where it forms woods called "yerbales." Paraguay in the following way:-The entire trees are cut According to Dr. Mantegazza, maté is prepared in down, and the small branches and shoots are taken with the leaves and placed in the tatacúa, a plot of earth about six feet square surrounded by a fire, where the plant undergoes its first roasting. From thence it is taken to the barbacúa, which is a grating supported by a strong arch, underneath which burns a large fire; here it is submitted to a particular torrefaction, determined by experience, which develops the aromatic principle. Then it is reduced to a coarse powder in mortars formed of pits dug in the earth and well rammed. It is next put into fresh The packages (tercois) thus obtained, which weigh 90 to bullock skins, well pressed and placed in the sun to dry. 100 kilograms, are very compact; and have an average value in commerce of one to two dollars the kilo, according to quality, those of Paraguay and Missiones being the better, or least hurtful, those of Oran and Paranaguá being much more prejudicial to health. Dr. Bialet considers not one, up to the present time, Of all the analyses of maté that have appeared in books, deserves much credit. Senor Arata, however, who has devoted much time and skill to the subject has placed the following data at his service :Maté contains in 100 parts: Organic combustible substances Ash. The ash contains- Calcium Oxide Sand, Silica, Carbon, and Loss 91.685 8.315 Among the soluble principles is an average of 1.300 of caffeine. The quantity, however, was found to be very variable in different plants analysed; the Paraguay and Missiones plants contained the most and the Paranaguá careful search for caffeic acid and the caffeates that some and Argentine the least. Senor Arata has made a say they have found in maté, but hitherto always with negative results; the same remark applies to the examination for a volatile acid. and requires a special method for its estimation; the average amount obtained by the ordinary method is not The tannin of maté is peculiar; it does not tan hides, more than 12 per cent. ; but the whole quantity present amounts to about 16 per cent. matters. salts. The plants, after being collected, were most thoroughly freed from all animal life, mud, and foreign organic and inorganic substances, and dried in an airy place (granary) on grain-sifters of split tubing. In cleansing the plants, innumerable water and swamp-animals were found, among which I will mention the following; Large numbers of four species of fresh-water Polyps (Hydra), chiefly II. rulgaris and H. fusca, H. grisea and H. viridis being less abundant. Also an innumerable quantity of water-snails (Limophila), often replaced by several species of Limnæa, such as L. vulgaris, palustris, ovata, stagnalis, peregra, truncatula, auricularia, and numbers of Planorbis (Ger. "Tellerschnecken"); e. g., P. hispidis, vortex, spirorbis, marginatus, charteus, leucostoma, contortus, complanatus, and nitidus. Maté contains also a large quantity of a peculiar fatty matter, not entirely saponifiable by potash, besides pectic Comparing maté with the other caffeic substances it ranks between coffee and tea for the proportion of caffeine it contains, and has the largest proportion of mineral The action of maté, like that of all other caffeic substances, is upon the nervous system; but though it contains a large quantity of caffeine it does not exalt the peripheric nerves like tea, nor the cerebric like coffee; but rather contributes in a high degree to the indolence and drowsiness of the ordinary drinkers of maté, whose mental faculties become at length disarranged and im- Among the most prominent insects present, both in the poverished to a lamentable degree. It accelerates the larva and perfect state, were the large water beetlecardiac contractions, producing many more affections of Dytiscus latissimus; also, Gyrinus natator, Nepa cinerea, the heart than tea or coffee. Upon the digestive organs and Notonecta glauca; two specimens of Nepa and Noto' it acts variously; no other beverage disturbs them so necta making themselves felt by their penetrating stings. much, though there are persons who can tolerate its use. The larvae of the Sialidee were rarely to be found; those It accelerates the peristaltic movements and produces an of the Ephemerinæ more frequently. irritation of the organs generally. These effects are produced in whatever way the maté may be taken, but the most injurious effects are produced upon the mucous membrane when the maté is taken hot and is sucked through a "bombilla," as it then passes into the stomach uncooled by previous contact with the mouth. When the use of maté is prolonged it becomes an imperious necessity, such a gloominess following abstention from it, that habitual drinkers would rather go without food than without maté. The moderate use of two or three doses a day during the summer heats or great fatigue is convenient, but it should be taken from a cup. It adds to the disadvantage of the "bombilla" that by indiscriminate use of the same bombilla by different persons it may become the vehicle of contagion for the most repulsive complaints. A HITHERTO NEGLECTED SOURCE OF IODINE. BY H. ZENGER, OF MUNICH. As early as 1862, Mr. Pettert examined the ashes of Cladophora glomerata for iodine, and on heating in a closed tube the palladic iodide, which he had obtained by precipitating the solution of the ashes of the plant with palladious nitrate, he detected the violet vapour of the liberated iodine. Although only a very small quantity of the plant could be obtained, from a reservoir in the garden of Professor Dr. G. C. Wittstein, he was, nevertheless, quite able to complete a qualitative analysis of the ashes and to prove the presence of iodine. My own efforts were chiefly directed, first, towards the quantitative determination of the bromine, whose presence, though not yet detected in fresh-water plants, was suspected by me as a companion of the iodine; secondly, to try some methods of precipitation for the iodine other than the palladium solution; and thirdly, to examine various fresh-water plants, not yet investigated, and to obtain the iodine and bromine from them in a pure state, even if in very small quantities. The extensive peat-bogs, as well as the canals for irrigation and drainage of the estate "Zengermoos," placed me in a position to collect great quantities of fresh-water plants with which to begin my investigations. As in the quantitative analysis of Mr. Jesslert to which I shall hereafter all attention, I had a sure basis for my operations, an my work with Cladophora glomerata. Translated n the American Chemist. tVierteljahresschrift für pract. Pharm. von Wittstein, xi, 545. Vierteljahresschrift für pract. Pharm., xii, 279, 1863. When we consider that the above named animals were present, not singly but in masses, and some of them in different varieties, we can get an idea of the population of these water plants, and understand why the water-fowl are so fond of them. I will only add that, to cleanse a quantity of C. glomerata, which only weighed 18 pounds, I was obliged to work five days, with but slight intermission, and my hands were covered with blisters, and remained swollen for a fortnight, from the attacks of the inhabitants. In spite of all my pains, the tiny skeletons of Limnea and Planorbis, which before had been invisible, could be discerned in the ashes. In a botanical point of view, I will briefly remark that Cladophora glomerata was called in the older classifications of the fresh-water Algae Conferva glomerata, L., also Chautrausia glomerata, Dec. In the newer classifications, "Conferva" (English), " Crow Silk"-French, “la conferve") forms a species of the family of the Confervacea. It consists of long, fine, dark-green threads, and, with its kindred, assists in the formation of peat. The green colour is due to chlorophyll, which is contained in the cells. Examination of Cladophora glomerata. To determine the amount of water contained in it 2000* of the air-dried plants were heated in an air-bath at 110° C., and lost thereby 8.950 per cent. For analy. sis, and for the various iodine and bromine reactions, 1000 of the plant were carefully reduced to ashes in a porcelain dish, over a charcoal fire, with frequent stirring with an iron spatula. This required considerable time, owing to the large amount of lime that was present. These 1000 gave 52:850 ash; i.e., over half the weight of the dried plants. 20 of these ashes were treated with distilled water for an half an hour in a porcelain dish, at ordinary temperature, filtered; the residue washed, and dried in an air-bath at 110° C., and weighed; the weight being 1-899. The loss in weight is the amount of soluble salts found in the ashes : 2.003 0.101-or in 100 parts=5·050. The further investigations were conducted exactly in accordance with the directions of the approved method of Dr. G. C. Wittstein, for the analysis of the ashes of plants or of organic substances in general, and gave the following result, calculated for 100 parts. I place the analysis of Jessler alongside of my own for the purpose of comparison : All these weights are expressed in grammes and fractions of the same. for 200 c. c. = 0.342 1.564 0.770 0.043 0.017 31.450 25.229 The 0.504 sodium was combined, according to Jessler, with 0.770 chlorine to form 1.274 NaCl. Iodine having Already been discovered, I began my investigation with the qualitative determination of bromine, whose presence I suspected along with the chlorine and iodine. For this purpose I chose the following way, which is, without doubt, the easiest: 100 ash were treated with cold water and filtered. As the filtrate gave a very slight alkaline reaction, in order to avoid the escape of iodine and bromine, I added a little sodic carbonate and concentrated the solution. In this way most of the salts separated out in crystals and could be removed by filtration, excepting the salts of the alkalies. The filtrate was then saturated with hydrochloric acid and chlorine water added, whereupon the iodine present was set free; though, nevertheless, converted into iodic acid by the excess of chlorine. At the same time the bromine was liberated, and on being caught by agitation with chloroform showed not only its characteristic colour, but also its reaction with organic substances, imparting an intense orange-yellow colour to starch. The presence of bromine was thus clearly proved. Before I speak of my method of determining the bromine quantitatively, or of my method of separating the chloride, iodide, and bromide of silver, I will mention one or two of the means I have used to precipitate the iodine. The basis of these is the precipitation of the iodine in a slightly acid solution, in the presence of chlorine and bromine, as cuprous iodide. It would, I admit, be possible to employ this method of precipitation quantitatively by using cupric sulphate alone; the result obtained would have to be doubled, however, as only half of the iodine would be precipitated as cuprous iodide, and the other half set free. By a simultaneous or previous addition of some reducing agent, such as SO, or FeSO4, the whole of the iodine may be thrown down as Cul. The precipitated Cu2I2 contains when dried at 40° C., 4 per cent. water, and is, therefore, Cu,I2Aq or Cu,O,HI. On this account I dissolved in a porcelain dish, with the necessary amount of water, five parts by weight of cupric sulphate, and eight parts of ferrous sulphate, and, as a little ferric oxide had been deposited, I added hydrochloric acid until it disappeared. With this solution the precipitation of all the iodine was effected exactly as if I had treated a very dilute solution of potassium iodide with an equal volume of the above-mentioned solution of cupric and ferrous sulphate. Nevertheless with this reagent, I was, in one experiment, unable to obtain a precipitate in a solution from the ash, although through the use of another reagent, I had been convinced that iodine was present in minute quantity. I shall return to this fact again after I have mentioned another method of determining iodine suggested by Dr. F. Mohr.* Dr. Mohr proposes the following way: In 200 c. c. of a clear solution consisting of cuprous chloride, sal ammoniac, and water, the first drop of a potassium iodide solution, which contained 1 per cent. iodine (1.308 potassium iodide) to the Mohr, Zeitschrift von Fresenius. XI1. Jahrgang, 4 heft. 3 iodine, which were detected by 2,000,000 this reagent. Therefore, for a complete precipitation of iodine from its soluble salts, we do not need either palladium or thallium. The palladious oxide test is less delicate than with cuprous chloride. A very dilute solution of potassium iodide was still further diluted with water, and poured into two glasses, side by side. To one of them was added cuprous chloride which had been clarified by ammonic chloride; to the other palladium solution. After some time the former showed a milky cloudiness, but the palladium solution none at all. These are the facts presented by Mohr. I might with certainty consider that Mohr had not regarded the difficult solubility of cuprous chloride per se in water, and that owing to a too small addition of NH Cl the Cu,Cl, came down and caused the cloudiness which he concluded was cuprous iodide. Let us consider these points more closely. The basis and starting point of Mohr's method of proceeding is, strictly speaking, identical with that by means of cuprous oxide; for in both cases we have to do with the lower state of oxidation of the copper, whether suboxide or subchloride is immaterial, as the secondary reactions taking place at the same time are only important so far as they may act to dissolve or decompose the Cu2I1⁄2 after it is formed. That this is really the case, my own observations have shown. The resulting salts of the ferrousoxide dissolve the cuprous iodine in no small quantity, a fact which Dr. Fleischer* has also noticed. The latter proposes stannous chloride as a reducing agent. The precipitation, he says, is complete and the stannous chloride does not act in the least on the cuprous iodide to dissolve it. Both facts I have found to be entirely true. From all these experiments, it follows, that the precipitation of iodine as Cul, in the presence of chlorine and bromine, could be conducted on a large scale with success, where a comparatively small loss of iodine is of no great moment, and that this method more than answers the requirements of exactness, which chemical industry on a large scale demands. But for a quantitative determination of iodine in very dilute solutions, such as we meet with in the analysis of ashes and many mineral waters, none of these methods give perfectly satisfactory results, and we are always forced back to the palladious oxide method. Dr. Mohr declares that with cuprous chloride a milky cloudiness will occur even after the palladium solution shows no more reaction. As already remarked, in a very dilute solution I obtained no precipitate of cuprous iodide, even after long standing, while the addition of palladium solution caused an immediate precipitate. That this precipitate was really palladic iodide was shown by drying and heating it in a tube closed at one end, whereby the violet iodine vapours were distinctly to be seen. Hence: In delicacy none of the hitherto discovered methods of precipitation can replace the palladious nitrate. In the investigation of other water-plants, in which I am at present engaged, I shall have opportunity to note more exactly the degree of dilution in which the palladium solution will still show a reaction. The quantitative determination of the iodine and bromine I accomplished in the following way: The dif. ference of the behaviour of the chloride, iodide, and bromide of silver to different degrees of concentration of ammonia, served as a basis for my work. For precipita Titrirmethode als selbstständige quan. analyse, § 33, Kupfer Iodbestimmung, p. 73. tion, a concentrated solution of argentic nitrate (1: 4) was employed. The washed precipitate was treated with 5 per cent. ammonia water; it dissolved the argentic chloride; on the filter remained the argentic iodide and bromide. The argentic chloride was precipitated with nitric acid, and the iodide and bromide having been washed were treated with strong (15 per cent.) ammonia. Only the argentic bromide was dissolved, which having been filtered off was likewise re-precipitated by nitric acid. In all the operations, such as digesting, precipitating, filtering, and washing, the light was excluded as much as possible. The endeavour to prepare a little iodine from the ashes of C. glomerata did not succeed, owing to the circumstance that I employed a too thin and soft glass tube, which melted on being heated, before the palladic iodide contained in it was decomposed. However, I removed the palladic iodide from the tube and heated it in a platinum crucible, whereupon the iodine escaped in a thick cloud. In this manner it could not be caught. I have therefore commenced work upon a still larger quantity of ash to obtain the iodine. Palladic iodide certainly requires quite a high temperature to decompose it into its constituents. Mr. Carl Petter remarks that in his experiments the loss in weight of C, glomerata dried at 110° C. was 8 per cent. Mr. Jessler calculated that 183 lb. of the dried algæ gave 0-23431 grm. iodine: i.e., 23-431 grms. per cwt. According to my analysis, the amount of ash in the plant was 52-850 per cent., and in 1 cwt. of ash there were 21:50 grms. iodine, and 8.50 grms. bromine. This large amount of ash consisted chiefly of lime, and had its origin in the extremely "hard" waters of Zengermoos. Without reference to an analysis by Prof. Kaiser, this fact would be proved alone by the tufa and the broad belt of that peculiar, white, calcareous earth, known as "alm," which stretches eastward towards Erding. Without doubt both the tufa and alm owe their origin to the Isar, which contained the calcic carbonate in solution and deposited it in Erdingermoos. A piece of sound wood which has lain for a short time in the Golbach, a stream which flows around Zengermoos, loses the power to float, owing to the impregnation with lime. The bed of this brook is formed, for the most part, of alm and tufa; from this fact comes the large percentage of lime in the soil and in the plants, as well as the semi-alpine flora of the district. The yellow, sweet smelling Primula auricula, with its flesh-coloured leaves and powdered stalk, flourishes here, as well as many varieties of Gentian, eg., Gentiana lutea, purpurea, pannonica, acaulis, punctata. It is readily to be seen that the lime in Cladophora glomerata existed previously as carbonate from the fact that the plants effervesce strongly with acid, which was long ago noticed. How varying the composition of one and the same plant may be, according to its location, can be seen from the analysis of Mr. Jessler and my own. He obtained the plants out of pure spring water; I, out of very hard water. It would be impossible to detect iodine in this water, no matter how concentrated, but the plants have the property of absorbing the iodine and bromine, and thus concentrating and storing them up. I think that after my experience with Cladophora and other water plants, I am justified in believing that iodine and bromine occur in water plants to an extent as yet hardly dreamed of, and that also in land plants these bodies can be recognized with certainty. Karl Sprengel, whose worth has been wrongly underralued, to whom with better right than to Liebig we should ascribe the foundation of the new scientific agriculture (for Liebig only built upon the foundation laid by Sprengel, and more than ignored him whose too great modesty and lack of self-conceit-faults no one ever accused Liebig of-were his only mistakes), says: "Very probably iodine is contained in all earths which are rich in sodic chloride. I have found it in small quantities in the subsoil of the marshes on the coast of the North Sea. Whether or not the iodine belongs to the nourishing materials absorbed by the plant, which is probable, it is at any rate present, and we will therefore, etc." That the manganese was present as manganous oxide in the ashes is proved by the evolution of chlorine on treating the ash with hydrochloric acid. Alumina, almost completely ignored by Liebig, I found in every analysis of the ash. The same result has been very often obtained in Wittstein's laboratory, and by scientists such as Sprengel, Boussingault, and others, who have done so much for agriculture. All these have found alumina constantly present and often in comparatively large quantities in the ashes of plants, and hence we are obliged to set it down among the prominent constituents of plants. On account of the great number of fresh-water plants existing everywhere, it is quite possible that the manufacture of iodine from them may grow to be a branch of chemical industry. I shall direct my attention to the examination for bromine and iodine, of as many land and water plants as possible. At present I am engaged upon another water plant, Lemna minor. This plant surpasses Cladophora glomerata in the large amount of salts soluble in water it contains. Iodine, in considerable quantity, and bromine are present. The exact quantitative results will be given later. Nevertheless we can already say with certainty that iodine and bromine occur much more extensively in the vegetable kingdom than has hitherto been supposed. A METHOD OF ESTIMATING BISMUTH BY M. M. PATTINSON MUIR, F.R.S.E., Löwe (J. prakt. Chemie, lxvii., 288 and 463), has described two salts produced by the action of potassium chromate and potassium dichromate respectively upon warm, nearly neutral solutions of bismuth nitrate. To the first of these salts he assigns the formula 3 BiO. 2CrO3, and to the second the formula BigOg. 2CrO,. The same author has described a process for estimating bismuth gravimetrically, based upon the formation of these salts (ibid., 464). Pearson has described a process for the estimation of bismuth, nearly identical with that of Löwe, and in addition a process based upon the same reaction, for the volumetric examination of the same metal (Phil. Mag. [4], xi, 204). In Pearson's volumetric process potassium dichromate solution is run into the solution of bismuth until the whole of that metal is precipitated, the termination of the reaction being determined by noting the point at which the supernatant liquid acquires a permanent yellow tint. The process described by the author of the present paper depends upon the facts concerning the formation of chromate of bismuth made known by Löwe and referred to above. Potassium chromate or potassium dichromate solution is run into a nearly neutral solution of bismuth nitrate until the whole of the metal is precipitated in the form of chromate. The final point of the reaction is determined by bringing a drop of the supernatant yellow liquid into contact with a drop of the silver nitrate solution upon a white slab, when red silver chromate is produced. On account of the uncertainty which still exists in reference to the exact composition of the chromates of bismuth, and also on occount of the fact that a slight excess of either of the potassium chromates appears Karl Sprengel. Chemie für Landwirthe, Forstmänner und Cameralisten. 1 Theil, p. 334. Gottingen, bei Vander. hæck und Ruprecht, 1831. From a paper read before the Chemical Society (Journ. Chem. Soc., April, 1876.) |