though these animals often sunk, the water still in their absence retained its peculiar colour. On further examination he found the cause of this to be a vast abundance of Diatoms, chiefly of one moniliform species, the name of which does not appear to have been determined. The Medusæ and other animals were found to feed on these plants, and, as is well known, are themselves the food of the whale, hence the presence of those vast cetaceans in the "black water." The same Diatom (with others) is the cause of the brown "rotten ice" of explorers; but this fact has been previously noticed by Dr. Sutherland.

A paper by Dr. C. Collingwood on the same subject, read at the Microscopical Society in March, appears in the 'Microscopical Journal.' In this the cause of the coloured water in the Indian ocean and China sea is investigated; as in the former case, it is due to a minute Alga, not a Diatom, but referable to Trichodesmium, a genus of Oscillatoriæ. The appearance produced on the water is that of a yellowish-brown scum, the sailors call it "sea-dust." The plant consists of short filaments, composed of a single line of cells, combined into a cylindrical unbranched fibre. A good many of these are aggregated into little bundles, having the appearance either of a "sheaf" or a "wedge," according as they are in close contact either at the middle or at one end. A species of Oscillatoria (?) occurs with it. Dr. Collingwood has never seen any red discoloration of the sea, such as is said to have been observed by many persons in the Red Sea and Persian Gulf, and also in the North Pacific, and which is caused by one or more closely allied species of Trichodesmium.

Hederaceæ.-Dr. Seemann gives another instalment of his revision of this order in the May number of the Journal of Botany.' Kissodendron, Didymopanax, Aralia, and other genera are passed in review; and the characters of two new genera Dipanax and Triplasandra are defined. The author however appears to have a tendency to create genera in this order on somewhat slender grounds.

British Botany.-The curators (Mr. Baker and Dr. Trimen) of the London Botanical Exchange Club have published their annual Report for 1867. Three new plants are described: Rosa Hailstoni, Baker (a variety of R. canina), from Yorkshire; the true Allium carinatum, Linn., from Nottinghamshire; and Salix Grahami, Borrer, from Sutherland. The Report includes notes on the numerous interesting or rare species, native and introduced, which have been communicated to the Club during the year.

The recently discovered Viola Arenaria, D.C., is recorded by Mr. James Backhouse from a new locality "several miles distant from the only previously known one in Teesdale, Durham.

A Carduus, said to be new to Britain, has been gathered in Ross

shire; from the description given it appears to be one of the many hybrid thistles already known. Specimens were shown at a late meeting of the Edinburgh Botanical Society.

M. Mitten adds to our Flora a new Moss, Trichostomum flavo-virens, Bruch and Müller. It was found on Shoreham beach, Sussex. A figure and description will be found in the Journal of Botany' for April.

New Books.-The Ray Society has published the second and concluding volume of Robert Brown's works, edited by Mr. Bennett.

'The Chinchona species of New Granada,' by Clement R. Markham, with notes by J. E. Howard, has been published by the India Office. It contains the hitherto unpublished descriptions of the species distinguished by Mutis, the celebrated Spanish botanist, which have been since 1807 kept at the Botanic Gardens, Madrid; and also those of Dr. Karsten, originally published in German.

The long-expected 'Flora of Northumberland and Durham' by Mr. Baker and Dr. Tate, is printed and forms vol. ii. of the ‘Natural History Transactions of Northumberland and Durham.'

'Refugium Botanicum' is the title of a new periodical, edited by W. W. Saunders. It consists of figures and descriptions of little known or new plants of botanical interest. The plates are drawn by Fitch from living specimens in Mr. Saunders' collection, and the descriptions are by Mr. Baker of Kew. This first part contains 24 plates, chiefly of succulent and bulbous plants, many being South African. The smaller orchids are promised, and Professor Reichenbach of Hamburgh will describe them.

The first part of vol. xxvi. of the 'Linnæan Society's Transactions' has been issued. In Botany it contains a monograph of the Bamboos by Colonel Munro; an account of the geographical distribution of all known ferns by Mr. Baker; and a few other papers of less interest.

Dr. Milde has published in the 'Botanische Zeitung' his Index Osmundarum, with remarks on the fructification of the genus.

Botanical News.-A paper by Mr. Darwin "On the Specific Differences between Primula veris, P. vulgaris, and P. elatior, and on the hybrid nature of the Common Oxlip, with supplementary remarks on naturally produced Hybrids in the genus Verbascum," was read at the Linnæan Society's Meeting, March 19th.

A new part of De Candolle's Prodromus' is nearly ready. It contains monographs of Salicaces by Professor Andersson of Stockholm, and of Coniferæ by Professor Parlatore of Florence.

A 'Flora of Gloucestershire,' by Dr. G. O. St. Brody, is announced as preparing for publication.

Mr. Marmaduke A. Lawson of Cambridge has been appointed lecturer on Botany at St. George's Hospital, vice Dr. Masters, resigned.

5. CHEMISTRY.

(Including the Proceedings of the Chemical Society.)

THE memoirs on subjects relating to pure and applied chemistry which have appeared during the last quarter are so numerous, that we shall be obliged to confine our notices under this heading to such discoveries as are likely to prove of commercial importance or are of especial scientific interest. Foremost amongst researches which are likely to benefit mankind we may place those which have for their object the discovery of a cheap method of preparing oxygen gas. Two processes having this object in view have lately been brought before the public. The first is by M. Gondolo, who has made some improvements in M. Boussingault's process of extracting oxygen from the air by means of baryta. M. Boussingault, in 1852, found that on passing a current of air over baryta, heated to dull redness, oxygen was subtracted from the air, and binoxide of barium formed, and that upon then raising the heat to bright redness the oxygen was set at liberty so easily that it might be first absorbed and then evolved ad infinitum. M. Gondolo has made, in carrying out the detail of the process, certain changes which admit of oxygen being prepared upon a manufacturing scale. For the porcelain tubes he substitutes iron ones, which may be made either of wrought or cast iron. Internally a coating of magnesia is applied, and externally asbestos, so as to diminish the porosity of the tube and the consumption of fuel. These tubes are arranged in a brick furnace having dampers, by means of which the temperature may be changed at will, and dull redness and bright redness easily obtained. To the baryta a mixture of lime, magnesia, and a small quantity of manganate of potash is added; this prevents fritting of the material. M. Gondolo says that he has made 122 alternate operations, and that the atmospheric oxygen and nitrogen are easily separated upon an industrial scale; the apparatus has been at work during six months, and fulfilled its purpose thoroughly.

The second method by which cheap oxygen can be procured is due to M. Mallet, who has just communicated to the Academy of Sciences an additional memoir in explanation of a process which he published last year. This depends upon the fixation of the atmospheric oxygen upon protochloride of copper forming oxychloride, which again gives out its oxygen at a higher temperature. The absorption of oxygen by protochloride of copper is spontaneous; the air being ordinarily moist, it will be complete in a few hours, if fresh surfaces be renewed. But elevation of temperature, and this is a main point, induces a much more rapid absorption: at

temperatures between 100° and 200°, as well as at higher temperatures in the presence of water, this absorption may be considered as almost instantaneous. By this process 100 kilogrammes of cupreous chloride, usually mixed with inert matter for convenience, will yield 3 to 3 cubic metres of oxygen, and as four or five operations may be made in four-and-twenty hours, this quantity, 100 kilogrammes, would yield 15 to 18 cubic metres of oxygen during the same time: the price of the chloride of copper does not exceed 1 franc the kilogramme.

A new method of preparing magnesium has been devised by M. Reichert. He takes 1,000 grammes of the anhydrous double chloride of magnésium and potassium, pulverizes it, and mixes it with 100 grammes of finely powdered fluor spar; this mixture is fused with 100 grammes of sodium. The compound proposed for use occurs in the mineral kingdom in tolerable abundance as carnallite. White pieces of this mineral are available, and require no previous treatment; coloured fragments must be dissolved in water, the impurities allowed to settle, and the lixivium evaporated.

Professor Gamgee, President of the Albert Veterinary College, author of several works upon the cattle plague, and a recognized authority in such matters, has discovered a new process for preserving meat, which is simple and inexpensive. The animal is caused to inhale carbonic oxide gas. Before it is quite insensible it is bled in the usual way. When dressed the carcase is suspended in an air-tight receiver, the air exhausted, and the receiver filled with carbonic oxide gas; a small quantity of sulphurous acid gas is also added. After remaining here for from 24 to 48 hours, meat may be removed, and hung in a dry atmosphere; it will keep for one, two, or three months, or longer, with no perceptible change in taste or appearance. The tests of the method thus far applied have been attended with success. Beef killed in London in March last year was sent to New York in June, and as late as the middle of July was shown to a prominent butcher in Fulton market, who did not discover that it was other than ordinary beef, and expressed the opinion that it had probably been killed about two days. Mutton killed in London last July, and sent to New York soon after, arrived perfectly fresh; and one piece of beef kept for ten days in a can surrounded by water at a temperature of 90° to 100°, came out perfectly fresh. The process, in the opinion of eminent chemists, does not injure the meat in the least; this is an advantage very difficult of attainment, even in the case of transportation of live stock, which is liable to the bad effects of confinement and the length of the journey. Among the beneficial results of the adoption of this scheme would be a better supply in our markets of wholesome meat and at a desirably cheaper rate.

The extraction of oils by means of bisulphide of carbon is now carried on at Moabit, near Berlin, upon a very large scale. In the manufactory of M. Heyl, 2,570 kilos. of oil, of sufficiently good quality to be employed in lubricating machinery, are manufactured daily. Colza and linseed are the materials chiefly operated upon; the residues serve very well to feed cattle with. The seeds are first crushed and dried by heating. For the daily fabrication of 2,570 kilos. of oil only six men are required. Analysis has shown the residues to contain only 2 per cent. of oil and 7 per cent. of water, while the residues of the ordinary pressure process contain 9 per cent. of oil and 15 per cent. of water. In the extraction of the oil, 7,000 kilos. of bisulphide of carbon are used daily, and the amount lost is 28 kilos.

M. Rakowitsch proposes a method of examining flour by means of chloroform. The following are the results which he says may be gathered from an experiment capable of being made in a few minutes:-The amounts of bran, the moisture between 10 and 25 per cent., the damaged flour, the mineral matters, the ergot of rye, and other impurities. The whole of these are determined by the relative specific gravities of the different substances in chloroform. The flour is simply placed in a tube and mixed with chloroform; the chloroform is enabled to hold in very thorough suspension the pure flour, while the other materials are not thus suspended. By adding spirits of wine of 95°, the flour is precipitated to the bottom of the tube. The more humid the flour, the more spirits of wine must be added, and thus the amount of humidity in the flour is arrived at.

The employment of charcoal filters has long been advocated, on account of the known property of this substance to absorb and oxidize organic matter. Mr. W. Skey, of New Zealand, has now shown that charcoal will remove arsenic from water. If a few drops of a solution of a salt of arsenic, or arsenious acid, be put into a few ounces of dilute sulphuric acid, and the mixed solution agitated at intervals with recently ignited charcoal for an hour or two, the clear liquid obtained by filtration does not manifest any reaction of arsenic when tested by Marsh's process. Tungstic acid also is removed from acid solutions by charcoal applied in like manner, and is given up to a solution of caustic alkali.

The subject of water analysis still occupies the attention of this society to an extent entirely out of proportion to the merits of the inquiry. At the meeting on March 5th, Messrs. Wanklyn and Chapman read a long paper "On the Action of Oxidizing Agents on