volume. This fills thirteen pages in double columns, and is an almost exhaustive enumeration of the works and scattered papers which relate to this group of plants.

Distribution of Potassa and Soda in Plants.—In a recent number of the 66 Comptes Rendus," M. E. Peligot has endeavoured to determine whether a plant, watered during the entire period of its growth with water holding in solution common salt and nitrate of soda, absorbs a certain quantity of soda; and whether it takes from the soil other elements from plants of the same species cultivated under identical circumstances, but watered, some with common water and others with potassic and magnesian solutions. The tabulated observations show that the common salt and the nitrate of soda have been totally left by the plants; none of the ashes contained soda. Nitrate of soda acts only in consequence of the acid it contains, which probably combines by double decomposition with potassa or lime.

Pith of the Balsam Fir.-According to Dr. Dawson's researches, the pith of the balsam fir (Abies balsamea) has the same curious structure of pith that he years since found in Sternbergia, the pith of a Devonian conifer. It is well seen in young twigs one or two years old, and closely resembles that of Dadoxylon Materiarium of the upper coal formation of Nova Scotia. The structure is in each case an "organic partitioning of the pith by diaphragms of denser cells opposite the nodes."

Concealed Chlorophyll in Plants.-M. Prillieux ("Comptes Rendus," June 26th), discusses the structure of the bird's-nest orchis (Neottia nidusavis), which is generally considered a non-parasitic plant not containing chlorophyll. He observed that if a plant is placed in alcohol it turns green, and then imparts that colour to the alcohol. Under the microscope it is seen that the brown colour of the petals is due to small elongated brown bodies scattered without order through the cells and grouped round the nucleus in each cell. These bodies have the power of swelling, and are what he regards as proteinaceous analogues of crystals. The application of alkalies or acids, or even of heat, immediately turns them green, and any re-agent which dissolves chlorophyll itself in like manner becomes green. M. Prillieux ("Academy," August 1st) believes, however, that chlorophyll does not exist as such in the living plant, the most careful experiments showing no disengagement of oxygen, but rather of carbonic acid; the chlorophyll is probably rather a product of the action of the re-agents applied. The tissues contain abundance of starch, which they probably. absorb in that state.

CHEMISTRY.

The direct Synthesis of Ammonia.-An interesting experimental manufacture of ammonia by mixing dry hydrogen and nitrogen, and sending the electric spark through them, has been recorded by Mr. W. F. Donkin, who has lately read a paper on the subject, which has appeared in abstract in the "Proceedings of the Royal Society." He says, that "The action of induced

electricity on mixtures of certain gases has been lately shown by Sir Benjamin Brodie (P. R. S. April 3, 1873), to yield very interesting results. An obvious application of his method was to treat a mixture of dry hydrogen and nitrogen in a similar manner as those referred to above, with the view of effecting the synthesis of ammonia; and Sir B. Brodie kindly allowed me the use of his apparatus for the purpose of the experiment, which was conducted as follows:-A mixture of about three volumes of hydrogen with one of nitrogen in a bell-jar over water, was passed through two tubes containing pumice moistened with alkaline pyrogallate and sulphuric acid respectively, then through a Siemen's induction-tube, and into a bulb containing dilute hydrochloric acid. The whole apparatus being first filled with pure hydrogen, about half a litre of the mixed gases was sent through the apparatus, the induction coil not being in action; the bulb containing the acid was then removed and another substituted, containing an equal volume of the same acid. About half a litre of the mixed gases was now passed through the apparatus, submitting them to the action of the electricity. The contents of the two bulbs were next transferred to two testtubes; and after adding excess of potash to each, Nessler's test was applied. The first solution gave a faint yellow coloration, the second a rather thick reddish-brown precipitate. No attempt was made to estimate the quantity of ammonia formed, as it would vary with many of the conditions of the experiment."

Activity of Chlorine in Darkness.—This is an interesting subject, especially as chlorine is supposed to act almost exclusively in the light. However, M. Melsens has observed that carbon in the form of coke, purified by repeated washings and ignitions in a current of dry chlorine, can absorb nearly its own weight of this gas. If now a current of hydrogen, previously dried over phosphoric oxide, be passed over this chlorinated carbon, even cold and in absolute darkness, notable quantities of hydrochloric acid gas are disengaged. A true combustion of hydrogen in chlorine takes place, the temperature being actually lowered by the return of the chlorine to the gaseous state. Vide "Comptes Rendus," lxxvi. p. 92.

Amount of Ozone absorbed by Water.-M. L. Carius has previously shown that ozone can be absorbed by water unchanged, in quantities not inconsiderable. He now finds that at a temperature of 0°, and a pressure of 0.76 m.m., 1.346 c.c. of ozone were absorbed by 100 c.c. of water; this is independent of the amount of oxygen absorbed. The ozone used in these experiments was obtained by electric action.- "Berichte der Deutschen Chemischen Gesellschaft zu Berlin," July 14.

Improvement in Photo-lithography.-In one of the numbers of the "Chemical News" for August, M. Paul gives the following description of his process: "The paper is coated with a layer of white of egg beaten up, and mixed with a concentrated solution of bichromate. When dry it leaves a hard smooth surface. After a sufficient insolation under the negative, the paper is covered with lithographic ink, then immersed in cold water to dissolve out the unchanged albumen, which is then removed with a fine sponge."

A new Deodoriser for Prevention of Epidemics.-In "Les Mondes" (August 14) M. Chodzko declares that the phenols, the hypochlorites, and

chlorine, merely mask deleterious emanations without destroying them. He professes to have discovered a means of disinfection which neutralises all putrid effluvia. The process can be executed with rapidity, and costs only 10 centimes per cubic metre. ("Unfortunately," says the editor of the "Chemical News," who abstracts the paper, " no indication is given as to the nature of this new disinfectant.")

Waterproof Glue.--The "Chemical News" (August 29) says that bichromate of potassa has the property of rendering insoluble, under the influence of light, certain organic bodies, such as gum, glue, glycerin, &c. If a paper covered with gum mixed with bichromate is exposed to light, the coating becomes quite insoluble even in boiling water. This property is utilised in the so-called "carbon" photographic process. Strong glue becomes insoluble more rapidly than gum, and the action takes place slowly even in the dark. A concentrated solution of bichromate is prepared, which is kept in the dark, and a little of which is added to boiled gelatin. Objects glued with this, after some time, can be washed either with cold or hot water.

Mr. S. J. Mellhuish appointed Photographer to the Shah of Persia.—We learn from the "Chemical News" that Mr. Mellhuish, F.R.A.S., has received the honour of special appointment as Photographer to His Imperial Highness the Shah of Persia; the reason assigned by the Shah for conferring this honour being that he had never had portraits which pleased him so much, although he had sat to artists at St. Petersburg, Berlin, and Paris.

An Improvement in the Manufacture of Gelatin.-M. F. Heuze, who describes this method in the "Bulletin de la Société Chimique" (of Paris, August 5, 1873), says that his object is to obtain white gelatin from products of low quality. He attempted first to bleach the brown or nearly black gelatin, which is obtained as a secondary product in the manufacture of neats'-foot oil. This gelatin is applicable to very few uses on account of its dark colour, and is sold at 42 francs per 100 kilos. To prepare it, the feet-after removal of all parts useful for the turners—are digested in water or superheated steam at a pressure of 3 atmospheres. After three hours of digestion, and half-an-hour for settling, the strongly ammoniacal solution of gelatin is concentrated, the supernatant oil having been previously removed. A dark brittle gelatin is thus obtained. The author tried to bleach it with sulphurous acid, or with a sulphate in presence of hydrochloric acid, but the results were unsatisfactory. He attempted then to modify the process of manufacture itself, diminishing the duration of the action of the superheated steam. Instead of drawing off all the liquor at the expiration of three hours, it was drawn off three times from hour to hour. The solution was then mixed with wood charcoal mixed with 25 per cent. of animal charcoal, and after standing twelve hours was treated as above. The solution requires 4 per cent. of the charcoal mixture. The product is a gelatin of good quality, which only presents a yellow tint when seen in large masses. It is tasteless and scentless, and is even fit for alimentary purposes.

A new Mode of Analysis for Rocks is given by M. Fouqué, in a recent number of the "Comptes Rendus." It is briefly as follows:-One to two kilos. are reduced to a coarse powder (millimetre in diameter): the powder is divided into two portions, the one for mechanical, and the other for chemical

examination. The former is submitted to a powerful electro-magnet set in action by six to eight Bunsen elements. All the ferruginous parts are thus removed. The chemical treatment consists in the use of concentrated hydrofluoric acid for a short time. This process has been applied successfully in an examination of the lavas of Santorino.

How to Prepare Triferrous Phosphate is a question answered in a paper at one of the late meetings of the Chemical Society, by Mr. R. Schenck, who prepared this substance by pouring a solution of ferrous sulphate into a flask in which phosphoretted hydrogen was being evolved by the action of potassic hydrate on phosphorus. The precipitate of ferrous hydrate at first formed rapidly becomes grey, and finally black. After removal of the phosphorus, the iron phosphide was purified by boiling it with a solution of potassic hydrate, and subsequently with hydrochloric acid. The results of the analyses corresponded to the formula Fe,P2; the phosphorus appearing to be trivalent. The ferrous phosphide dissolves slowly in boiling acids, with evolution of gas, and in the dry state takes fire below 100°, burning to a reddish-brown powder. The author intends to apply the same method to the preparation of other phosphides.

Silk Dyeing. Does Silk form Compounds with Acids?—M. E. Durwell, who has a paper on this question in a late number of the Paris "Bulletin de la Société Chimique," takes for the foundation of his views the hypothesis that silk forms, with acids, true compounds, capable of uniting with the coal-tar colours and with other dyes. Having ungummed silk to set the fibroine at liberty, he boiled it for a day in distilled water, to remove the last traces of the soap employed in this operation. It was then extracted with alcohol, so as to leave pure fibroine, which invariably gave an alkaline reaction. This silk was then dyed in a bath of litmus and very dilute sulphuric acid. The litmus serves here at once as reagent and as colouring matter. The colour is thus entirely fixed in the silk; but, on neutralising the bath with a trace of magnesia or of caustic soda, the blue litmus went back into solution, except a trace which was still absorbed by the silk. This experiment may be indefinitely repeated on the same colour-bath by rendering it alternately acid or neutral. It is the same with the coal-tar colours; but as these have a great tinctorial power, the experiment is less striking and decisive than with litmus. On treating two parts of fibroine with one part of sulphuric acid in the cold, combination at once takes place. Heat is developed, which must be kept down as much as possible by cooling the capsule, otherwise the silk will be completely resolved into glucose and ulmic compounds. After an hour's time, the reaction is complete. The brown liquid is filtered over asbestos, diluted with three or four times its bulk of water; the excess of acid is neutralised with baryta, filtered, and evaporated. A mass is thus obtained which, on treatment with alcohol, leaves a true compound of fibroine and of sulphuric acid. It is a white, transparent, horn-like body, soluble in water. The solution, if treated with an alkali, gives a precipitate of fibroine.

GEOLOGY AND PALEONTOLOGY.

"is

The Coal of Upper Burmah.—"This mineral," says Captain G. A. Strover, who has an important paper in the "Geological Magazine" for August, known to exist at Thingadaw, about seventy miles above Mandalay, on the western bank of the Irrawaddy; at Shuaygoo, below Bhamo; at Meimbaloung, in the Shan States east of Mandalay; to the south-west of Mandalay, in the Yaw district, at Yaignaw, east of Nat-taik. It is found at Pagan and Shimpagah, and it is probable that it exists near Meuhla and Yeynangyoung. At Thingadaw the coal has been extracted, but it is of an inferior description, and more resembles lignite than true mineral coal. An attempt was lately made here to ascertain the productiveness of the coalheds. It is nearly certain that plenty of coal exists in the locality, and a few more borings would probably prove this. The coal-bed in the Shan States at Meimbaloung contains true mineral coal, and consequently a valuable coal. It has been inspected by an experienced mining engineer, and highly approved of as equal to the best English coal. There is little doubt that the beds are extensive, but unfortunately the distance inland is great, and no easy means are available for transporting the coal to the low lands; indeed, the only method at present is by floating it down mountain streams and rapids on rafts, which entail considerable risk and loss of coal. European skill and enterprise would soon make a safe route of one description or another if really required by the Government. It remains at present, with neighbouring wealth, where nature placed it, awaiting development in times to come."

Geological Map of the United States.-This map, which is on a small scale (36 by 24 inches), presents us nevertheless with a fair notion of the geological features of this vast and well-favoured country. To the geologist, as to the public at large, the most important area to be noticed at this time is that occupied by the Carboniferous system; and if arguments were needed to favour the old-established belief that the general movement of peoples is in a westerly direction, and that the country of the future is North America, let our American cousins point with perfect confidence to their almost inexhaustible coal-fields, which are, practically speaking, unworked, so great hitherto has been the supply of surface-fuel in the clearing of boundless forests, now changing into broad fields of corn and pastures for vast herds of cattle. The older rocks, named Eozoic by the authors, comprise all the formations earlier than the Paradoxides-beds, including the oldest known metamorphic Appalachian schists. We hope to see larger maps issued in future. Why, it is not so large as our own excellent pocket map of England and Wales by Professor Ramsay.

Skull of a Dentigerous Bird from the Isle of Sheppey.-This has been described at the last meeting of the Geological Society by Professor Owen. The bird is Odontopteryx toliapicus. The specimen described by the author consisted of the brain-case, with the basal portion of both jaws. The author described in detail the structure and relations of the various bones composing this skull, which is rendered especially remarkable by the denticulation of the alveolar margins of the jaws, to which its generic appellation