efficient performance; other contrivances will suggest themselves where stones are not procurable. Although it would seem that alcohol is consumed to a disadvantage without a wick, yet practically the "Etna" boils water with a smaller consumption of spirit than any contrivance yet tried, a good argand lamp requiring at least half an ounce to do the same work as the Etna. The Russian blast lamp is still more wasteful, consuming nearly 2 ounces. The superior economy of the Etna is attributed to the low temperature of the wickless flame and the manner in which the boiler is wrapped in the fire, no more heat being supplied than can be taken up by so bad a conductor as water. The defect of all lamps giving an intense flame being that heat is wasted by being supplied too quickly, so that the apparently feeble fire in the gutter of the Etna is more efficient than the heat of powerful lamps, as well as more economical; the latter quality is very important to the pedestrian, to whom every ounce of weight is a consideration. P. Lewald, referring to the phenomenon first observed by Dr. Fritsche, says it is not at all a correct statement that the blocks of tin exposed to a cold of -35° should alter their state of aggregation from that cause; the real cause is that the blocks of tin usually of 250 cubic inches capacity are cast in iron moulds, and as a consequence thereof the tin contracts unequally, and so as to leave in the inside of the blocks cavities often so large as to occupy 40 cubic inches. These hollows are lined by a crystallized metal at a high degree of tension. The tin at St. Petersburgh was laying heaped block upon block, and the effect of the cold was simply a remote cause to what took place, the weight of the blocks of metal placed on each other being such as to produce necessarily a pressure too great to be borne by the undermost blocks. The author says, if tin is molten and allowed to cool, so as to shrink uniformly, no cold, even of -40° or less, will have the effect observed in the locality alluded to. L. Cailletet has studied the variation of compression of air and hydrogen between 1 and 800 atmospheres. Up to 80 atmospheres' pressure, air is more compressed than it should be if it followed the law of Mariotte; and at 680 atmospheres' pressure it only occupies two-thirds of the space which it ought to do theoretically. The method by which the author is enabled to measure the volumes occupied by a gas in an opaque apparatus is very simple. The glass tube is enclosed in an iron one; the former, containing the gas, is lightly gilt. The mercury which serves for the transmission of pressure, whitens the gold, leaving a well-defined mark on it after the pressure ceases. ELECTRICITY. In a letter to M. Dumas, Professor de la Rive states that he has just finished a series of experiments on the mag netic rotatory power of liquids, the results of which will be shortly published. The first portion of this work is devoted to the description of the apparatus and processes of experimentation; the second part contains the results of the determination of the magnetic rotatory power of some liquids. As a curious anomaly the author mentions that taking water as unit, the coefficient of the magnetic rotatory power of monohydrated sulphuric acid is 0 750, and that coefficient is, for liquid anhydrous sulphurous acid, equal to 1 240 at a temperature of 12. The third part of this work is devoted to the study of the influence of the temperature on the magnetic rotatory power. In the fourth part, the author gives the results of his investigations of the magnetic rotatory power of a mixture of two liquids as compared with that each of these liquids possesses separately. The fifth part contains the results obtained by experimenting with two isomeric liquids. In some experimental researches on the length of duration of the electric spark, MM. Lucas and Cazin employ two transparent discs placed upon the same axis. One of these discs is a fixture, while a more or less rapid rotatory motion can be imparted to the other. Upon both discs are painted the same number of opaque stripes in the direction of the radius. When, therefore, an electric spark is observed through these discs, a certain amount of speed having been imparted to the movable one (the apparatus being placed in a darkened room), it is clear that by the light emitted by the spark a certain number of coincidences of the movable and fixed stripes may be observed, and these coincidences may serve to calculate the period of duration of the spark. Dr. Demayes describes at length an apparatus constructed by him, which appears to be an improvement on Siemens' electromagnetic apparatus; while making from 250 to 280 revolutions a minute, the lifting power of the magnet is 70 kilos., and under similar conditions a platinum wire, 0.8 mm. thick and 20 centim. long was rendered red-hot, and iron wire of the same thickness fused; the machine produces per second of time half a cubic centimètre of gas by the decomposition of water. In a recent instalment of his researches on electro-capillary action, which have occupied M. Becquerel for a series of years, he announces the artificial formation of the oxychloride of copper in crystalline state, and exactly similar to that found in the copper mines of Peru and Chili, and known as atacamite. This formation has taken no less than fifteen years. Mr. E. W. Blake, jun., has described a method of producing by the electric spark figures similar to those of Lichtenberg. The method consists in throwing the discharge upon the surface of a fusible non-conducting body. If the body be near its fusing-point the figure appears at once; if cold, a latent image exists, which may be developed by heat. The non-conducting surface is prepared by coating a plate of metal with an even film of pitch. Pieces of sheet tin, 3 inches square, coated with films of pitch of a thickness varying between 0.01 and 0.02 inch were used; the pitch was the ordinary article of commerce freed from sand, &c., by being melted and strained through a muslin bag. The author gives cuts of the figures as produced by frictional electricity and the induction coil. Metallic iron, as obtained by the electric current, has been examined by C. Collas. He employs a weak solution of chloride of iron, which is decomposed by the aid of a Bunsen battery; perfectly pure iron is thus obtained, which is very friable, highly oxidizable, especially when moisture is present. When this iron in the state of fine powder is poured in a bottle when the atmosphere is very moist, the iron is instantaneously oxidized, water decomposed, and the evolution of hydrogen causes the bursting of the bottle. A new method of copper extraction and its separation from other metals is published by Mr. J. Elkington. The principle consists in applying electricity for dissolving the copper contained in the crude metal obtained by the usual smelting methods, and for depositing that metal galvanically upon plates of copper, causing the other foreign metals to fall to the bottom of the vessels in which the operations take place; copper containing very small quantities of silver may be advantageously treated thus for the recovery of the last-named metal. An improvement in galvanic batteries has been devised by Mr. W. Poole Levison, of Cambridge, Mass. While making use of a small bichromate of potash battery he discovered that the addition of nitric acid to the mixture of potassic bichromate and sulphuric acid contained in its porous cups, conferred upon it the virtue of steadiness without involving the evolution of annoying fumes. For over two months during last summer the author had in almost constant action a combination of twenty-three large Bunsen cells charged with dilute sulphuric acid and the triple mixture mentioned, and "set up" openly upon the floor of the room. Not only did he work about it with perfect comfort, but left choice brass instruments in its immediate neighbourhood with impunity. Its energy never fluctuated, but after remaining for some time steady declined, precisely as if the electro-negative plates were bathed in nitric acid only. To a cooled mixture of potassic bichromate solution and sulphuric acid (perhaps preferably in atomic proportions) add nitric acid. The proportion of nitric acid may be greatly varied, as its office is merely to transfer oxygen. A research on the best methods of tinning of iron without the 2Q VOL. VII. aid of heat has been carried out by J. B. A. Daubié. The chief point of interest is that the tinning of iron in the cold cannot succeed at all, unless the bath used for that purpose contains in solution or suspended an organic substance like starch or glucose, although no precise scientific explanation of this indispensable condition has been hitherto given. The author employs the following bath: To 100 litres of water are added 3 kilos. of rye meal; this mixture is boiled for half an hour, and next filtered through cloth. To the clear but thickish liquid are added 106 kilos. of pyro-phosphate of soda, 17 kilos. of protochloride of tin, 100 to 120 grammes of sulphuric acid; this liquid is placed in well-made wooden troughs, and serves more especially for the tinning of iron and steel wire for the use of carding-machines. When instead of the two salts of tin just named cyanide of silver and cyanide of potassium are taken, the iron is perfectly silvered. 12. ZOOLOGY AND MORPHOLOGY. The Zoological Position of the Brachiopoda.-Leuckart, Haeckel, and Gegenbauer do not include the Polyzoa among the Mollusca, as is done by Huxley, but class them as also the Tunicata among the great heterogeneous group of Vermes. Mr. Morse, an American naturalist, who has devoted much study to the Molluscoida, proposes to turn over the Brachiopoda into the same position. In doing so he unconsciously meets an argument advanced in favour of the retention of the Polyzoa among Mollusca by Professor Rolleston, viz. that they present close affinities to the Brachiopoda, especially to the larval Brachiopod described by Fritz Müller. Mr. Morse has by perseverance obtained the great advantage of studying living specimens of Lingula, a species of which he obtained in quantity on the North Carolina coast. He compares the setæ which fringe the mouth of Lingula to those of Annelids (in this he is probably misled), the lophophor with its cirrhi to the cephalic appendages of tubicolous worms, the oviducts with their trumpetshaped openings to the funnel-like oviducts of many worms; the embryo of Thecidium, with its four segments and eye-spots, is adduced, as also the embryo of Discina, which, according to Fritz Müller, has projecting bristles like the temporary bristles of some Annelid-larvæ. Mr. Morse says it is a startling discovery that the vascular fluid of Lingula is red, and seems to think that this colour gives this Brachiopod some affinity to worms. It is, however, not at all surprising, though Lingula is an interesting addition to the category of invertebrata with red blood, including as it does already the molluscs Planorbis and Arca. Probably the coloration is due to Hæmoglobin as in the cases of Molluscs, Insects, Crustacea, and Vermes with red blood, investigated by Mr. Ray Lankester. Mr. Morse's proposition to classify Brachiopoda with Vermes deserves full consideration, but we shall look for some solid reasons in the memoir which he promises on the subject. New Sponges.-Sponges continue to occupy a great deal the attention of naturalists. Dr. Perceval Wright, Mr. Carter, Mr. Charles Stewart, and others, have lately described new genera and species. Mr. W. S. Kent, of the British Museum, who two months since made an expedition to the coasts of Portugal in the yacht of Mr. Marshall Hall, has described three new species (two belonging to new genera) of that very important and interesting group, the silicious sponges or Vitrea of Professor Wyville Thomson. The Vitrea are represented by the notorious Hyalonema, or glass-rope sponge; by Euplectella, the beautiful lace-sponge; and by Professor Thomson's new genus, Holtenia. Mr. Kent would recognize Dr. J. E. Gray's division of the Corallispongia in preference to that of Vitrea proposed by Professor Wyville Thomson. In describing a new species allied to that author's Holtenia Carpenteri, he points out that the genus Holtenia must give place to Pheronema, previously proposed by that most distinguished of American naturalists, Dr. Leidy, of Philadelphia. There appears to be no doubt that the sponge described under this name by Dr. Leidy is generically identical with Wyville Thomson's subsequently described Holtenia. Mr. Kent's new species is called Pheronema Grayi, and was obtained by him in the deep sea off the coast of Portugal. Two other interesting vitreous sponges were also detected, and have been fully described by Mr. Kent. The Royal Society assisted Mr. Kent in the outlay necessary for dredging apparatus, &c., and these new sponges are among the first of the fruits of his Voyage which he has made known. The Society has done well to entrust some of its funds to this promising naturalist; and zoological science is much indebted to Mr. Marshall Hall for using his yacht for its advancement. Bathybius and the Coccoliths.-The organism which Professor Huxley described two years ago as being so widely spread in the ooze of the ocean bottom, consisting of a simple ramified network of protoplasm, has been recognized and fully established by no less an authority than Professor Haeckel, of Jena. Professor Haeckel gives figures of the protoplasmic network, and then discusses the propriety of associating with this organism the Coccoliths and Coccospheres, as Huxley has done. He does not arrive at definite conclusions on this point; but re-figures all the various forms of Coccoliths, Cyatholiths, and Discoliths described by Huxley. Haeckel would at present definitely establish Bathybius on the |