over the States in early days, but has since been supplanted, as in England, by the brown rat (M. decumanus). Forty years ago the black rat was the only rat in South-west Ohio. About thirty years ago the brown rat drove him out. Some years later the same occurred in Illinois. I have been informed by one of my students living in Minnesota, that neither rat is known in and about the town of St. Cloud in that state, only one having ever been seen there, and that was killed on landing from a I have seen it stated that the black rat is still to be found in some localities in England, among them the Whitechapel Docks. E. W. CLAYPOLE

steamer.

66

Antioch College, Ohio, April 7

Did Flowers Exist during the Carboniferous Epoch? I CANNOT accept Mr. McLachlan's reference of the interesting Breyeria borinensis to the Ephemeride, even though he has examined the fossil," and "has no doubt" about it. The photograph which I possess is so beautifully sharp that it brings out the minutest details, and a careful examination and comparison of it with specimens and drawings leads me to the conclusion, that in the general character of the wing-neuration it is strictly lepidopterous and of the Bombycine type, having the costal, subcostal, and median nervures, with their branches and bifurcations, arranged precisely as in that group, but differing in the much greater length of the wing and the increased number of the branches of the subcostal vein-seven instead of four. In some of the Chalcosiidæ, however, there are often six branches to this vein, but crowded together and sometimes anastomosing, owing to the much shorter apical portion of the wing. In this family also we often have an intermediate false vein, which is distinctly visible in the fossil. Until, therefore, I am referred to some group of insects with which it more nearly agrees, I must believe it to be an ancestral moth, even though, according to Prof. Haeckel and Mr. Scudder, moths ought not to have existed in the carboniferous epoch.

After a careful comparison of the photograph with specimens and figures of Ephemeridæ, I can see no resemblance whatever to the neuration of the family with which Mr. McLachlan so confidently associates it; while the "dense transverse reticulation" to which he refers seems to me to be merely due to crumpling of the membrane, and certainly bears no close resemblance to the strong reticulation of the veining of the Ephemeridæ, and it is, moreover, only visible at all at the base of the wing. The general form of the wing and arrangement of the veins are, however, so different, as, to me, to be conclusive against this view. ALFRED R. WALLACE

Blue Flame from Common Salt

At the present time any spectroscopic observations of coloured flames are peculiarly interesting, and I am glad to see the origin of the blue or violet flame produced by common salt and other chlorides again discussed in your pages.

66

In the letter of Mr. Percy Smith (NATURE, vol. xix. p. 483), he considers the only feasible explanation to be "that it is due simply to hydrochloric acid," but he gives no proof, and admits that a spark between carbon points in a bottle of this gas does not give the violet bands. In a short paper on the subject in the Philosophical Magazine of December, 1862, I considered this supposition is negatived by the fact that anhydrous chloride of copper emits these rays equally whether it be placed in a flame of hydrogen or of pure bisulphide of carbon." Neither does this characteristic flame seem due to any carbon compound, inasmuch as several chlorides will give it in a hydrogen flame. I also found that "a stream of chlorine or hydrochloric acid passed into a flame never gives the violet light, nor does Dutch liquid, muriatic ether, or chloroform mixed with alcohol and burnt in a spirit lamp," though chloride of platinum or gold give a flash of it at that temperature.

Would Mr. Smith favour us with any details of his experiments which may support his conclusion? 17, Pembridge Square, April 10

J. H. GLADSTONE

to be a diamond, and which was indeed admitted to be a Cape diamond.

Judgment was given for the plaintiff, because several diamond dealers gave evidence which, the judge stated, clearly showed that what were described as 66 Cape diamonds were not at all to be regarded as ordinary diamonds, and the receipt showed that the ring was sold as a diamond ring. The "several diamond dealers" stated that so-called Cape diamonds were comparatively valueless and lacked the essential qualities of the Brazilian stones, viz., lustre, hardness, and colour.

Now all this is beside the question, which was not as to the value of Cape diamonds, nor yet what they lacked of the qualities of the Brazilian stone, but simply whether this stone was a diamond or not, not even whether it was or was not an ordinary diamond, and I am surprised that any judge could be thus led away from the legal point.

I see that notice of appeal has been given, and it is to be hoped for the credit of elementary science that the court above will require some scientific evidence, such as specific gravity or chemical composition, about Cape diamonds. If, for instance, it can be shown that they are a form of carbon, the point is settled.

It would be just as absurd for a person to object to Derby coal as not coal because it lacked the good qualities of Wallsend. The ring was sold as a diamond ring; the question is: Is the stone a diamond?

YOUR correspondent J. T. B. asks for further instances of the cultivation of the sense of temperature. None can be more striking than that of the caste of egg-hatchers in Egypt, whe determine the temperature in their ovens entirely without the aid of instruments, and maintain it at 100° to 103° Fahr. during the requisite three weeks. How successful they are is shown by the official return for 1831, given by Lane ("Modern Egyptians, London, 1842, vol. 2, p. 5, et seq.) from whom I take these particulars. Out of a total of 26,204,500 eggs artificially incubated, 17,418,973 were successfully hatched. April 19 ALFRED H. HUTH

Tides at Chepstow

THE highest tides in the Wye and in the Severn for the present year were on Tuesday, April 8. On that day, up the Wye, at Llandogo, the tidal rise was 13 feet; at Tintern Abbey, 21 feet 5 inches; at Chepstow Railway Bridge, 44 feet. Up the Severn, at Newnham, the tidal rise was 20 feet; at Portskewitt, 46 feet 6 inches; at Cardiff, 44 feet; at Clevedon Pier, 52 feet.

Reference to Coxe's "Historical Tour in Monmouthshire," 4to Edition, 1801, p. 358, containing his own soundings at high tide, on September 4, proves that there has been no perceptible change in the depth of the Wye at high tide this century.

The Severn has been confined within narrower limits by the South Wales Railway embankment, on the Monmouthshire side, since 1850, and by Lord Fitzhardinge's breast-works on the Gloucestershire side, from about same date, but the height of the tide and the depth of the river have not been sensibly affected by these slight alterations. One fact further may be worth mention, however a gun-boat or armed sloop, commanded by Capt. White, came up the "Pill," below St. Pierre, in 1827, on a surveying expedition, remained at anchor some days, and re-entered the Severn without difficulty, piloted by W. Wheeler, a thing that would now be impossible on account of the embankments. The Pill is a mere creek-the 'anchorage," dry ground. JOHN YEATS

Cape Diamonds

of the eighty-first degree of north latitude, on or near the shore of Lady Franklin Bay, for the purpose of scientific observation and exploration, and to develop or discover new whaling grounds; such officers as may be necessary to be detailed to take part in the same, and with permission to use any public vessel or vessels in connection therewith. This is essentially Capt. Howgate's plan, and probably introduced by his request.

THE last number of the Indian Antiquary contains a note by Major J. S. F. Mackenzie on some curious customs current among the Komti caste in regard to marriage, &c. "A Folklore Parallel," by Prof. C. H. Tawney, of Calcutta, is also worthy of notice.

MGR. LAVIGERIE, Archbishop of Algiers, communicates to Les Missions Catholiques intelligence respecting the portion of the French missionary expedition in East Africa, which, under the leadership of Père Livinhac, was gradually making its way towards Lake Victoria. At the date of the letter (December) the five Europeans were all in good health, and were then in Mirambo's country, on the way to Uganda. Père Livinhac writes that they had been three months in Unyanyembe, and that they were then twenty or thirty days' march from the lake. In the same number of Les Missions Catholiques Mgr. Ridel continues the account of his recent captivity in Corea, in which he gives a terrible picture of the prisons of the country.

A TELEGRAM from Malmö states that the steamer Nordenskjöld, built for M. Sibiriakoff, to go to the assistance of Prof. Nordenskjöld's expedition, was launched on the 17th inst.

A VERY interesting narrative of travel has just been commenced in the Tour du Monde, entitled "Voyage en Nouvelle Guinée," by M. Achille Raffray. The first instalment deals with the Moluccas, which M. Raffray visited en route, but in the second he commences his work in New Guinea. The illustrations are unusually good.

BIOLOGICAL NOTES

THE EARLY TYPES OF INSECTS.-Samuel H. Scudder has published a memoir on the early types of insects (Memoirs of the Boston Society of Natural History, vol. iii. Part i. No. 11, March, 1879). He concludes that the hexapods, arachnids, and myriapods appeared together in the carboniferous strata. That the hexapod insects may be divided into a higher group (Metabola), and a lower group (Heterometabola), that the latter are Devonian and carboniferous, the former just appearing in the Jurassic period. The Devonian forms were in the early stages of their life, undoubtedly aquatic. Nearly all the paleozoic orthoptera belong to the lower Saltatorial families. It would seem that the earlier types were of inferior organisation, and that the general type of wing structure in insects has remained unaltered from the

earliest times.

HALOSPHÆRA, A NEW GENUS OF UNICELLULAR ALGE.-Under this name Dr. F. Schmitz describes, in the first "Heft" of the first volume of the Mittheilungen aus der zoologischen Station zu Neapel, an organism which is found abundantly between the middle of January and the middle of April, floating on the surface of the water in the Bay of Naples.. Hitherto known to collectors simply as punti verdi, Dr. Schmitz gives it the name Halosphæra viridis. It presents to the naked eye the appearance of minute just visible pale green globules, the largest having a diameter of from 0.5 to 0.6 mm., but with no independent power of motion like that of Volvox. Each globule consists of a tolerably thick perfectly smooth and colourless cell-wall, coated on the inside with a thin layer of pale green protoplasm, which incloses a single very large central vacuole filled with a colourless cell-sap.

The

The green colour of the protoplasm is due to its being .interspersed with a small number of minute grains of chlorophyll; and there is also, at an early stage, a single globular nucleus with a somewhat darker nucleolus. As the cell increases somewhat slowly in size, the process of cell-division commences. The single nucleus divides into two nuclei, which gradually separate from one another; and this process is repeated time after time, until a very large number of nuclei, which the author reckons to average from 200 to 300, come to be tolerably regularly distributed through the parietal protoplasm of the mothercell, which has by this time attained its full size. layer of protoplasm then breaks up into a number of primordial daughter-cells, each surrounding one of the nuclei, and having the form of a hemispherical ball, the flat surface of which is in contact with the cell-wall of the mother-cell. They are of a uniform bright green colour, without apparently containing any distinct grains of chlorophyll. The external cell-wall of the mother-cell has now become differentiated into two distinct layers, the outer one of which bursts into two nearly equal halves, and becomes completely detached from the inner one, which now itself consists distinctly of two layers. The hemispherical green daughter-cells then become transformed into zoospores of a very peculiar shape. They begin gradually to detach themselves from the outer cell-wall, and to take up positions in the interior of the cell. In most cases each of them contracts in the centre into somewhat the shape of an hour-glass, but pointed at the two ends, ultimately dividing in the middle into two zoospores of conical shape, with a nearly flat base, but toothed at the edges, and a pointed apex. To a colourless protuberance in the centre of the nearly flat base are attached two very long vibratile cilia. Sometimes only a single zoospore is formed from each of the primordial cells, and occasionally more than two. The remaining cell-wall of the mother-cell has, in the meantime, been gradually swelling up and deliquescing, and has now become completely converted into mucilage, so that the zoospores escape free into the surrounding water. After moving about for some time with a rather slow swarming motion, they fall to the bottom; but their further development has not been followed up. Until its complete life-history is known, it is impossible to assign a systematic position to Halosphæra. It may possibly come near Eremosphæra, a genus of Conjugate; its resemblance to Volvox is clearly only superficial.

A NEW ALGA.-In the first Heft of the Ist vol. of the Mittheilungen aus der zool. Station zu Neapel, Dr. Falkenberg describes a new genus of Phæosporeæ under the name Discosporangium, with the following characters:-Thallus, an irregularly branched filament, consisting of a single row of cells, and growing by an apical cell. Reproduction by zoospores, which are formed singly in the compartments of multilocular zoosporangia. The zoosporangia are placed singly near the middle of the cells of the thallus, forming a square unilamellar plate, the compartments of which open separately when ripe on the upper side of the sporangium.

berg gives a complete list of the marine Algae of the Bay IN the second Heft of the same publication Dr. Falkenof Naples.

MARINE FLOWERING PLANTS.-Dr. I. B. Balfour has just published (Transactions Bot. Soc. Edinburgh, Session 1877-78) a most valuable and interesting memoir on two species of the genus Halophila, found very abundantly in widely extended patches on the reefs surrounding the island of Rodriguez. The island was visited in 1874 by Dr. I. Balfour as naturalist accompanying the "Transit of Venus" expedition. Of the two species one, H. ovalis, grows on spots which are just uncovered at low tides. The other, H. stipulacea, grows in places where it is always submerged.

Specimens

its

gra

།

200

collected both in flower and fruit were preserved in alcohol, and were most painstakingly investigated at 19 Prof. de Bary's botanical laboratory at Strassburg. The only portion of the life-history of these plants left for future investigators is the germination of their seeds, which, probably, does not take place until the first quarter of the year. The stem structure is simple. Of the presence of sieve-tubes in the bundles there appears to be no doubt. The mode of the tissue formation at the tips of the roots is peculiar; from an initial group of cells underneath the root-cap, there issues three distinct tissues. This corresponds to the third type of Janczewski, who, among the monocotyledons, found it only in Elodea. The scale and foliage leaves are described in detail. The epidermal layer is peculiar; stomates are to be found in neither of the species. The floral axis is short and axillary; there is a double-leaved spathe. The author is inclined with Ascherson to consider the plants dioecious. The anther cavities are filled with a mass of confervoid pollen. These pollen cells are found to be united in long strings, each string apparently continuous through the greater part of the length of the cylinder. The partition walls between adjacent cells in a string are transverse. The ovary is inferior and contains many ovules. The author suggests the morphological identity of the stamens and carpels, "the same phyllomes (or the phyllomes from the same nodal regions), which, in the male form stamens, in the female form carpels." A technical and emended character to the genus and of the two species concludes this paper.

AMERICAN APHIDES.-Dr. Riley gives a detailed account of the life-history of some species of gall-making Pemphigina (Art. 1, vol. v. Bulletin of the United States Geological and Geographical Survey of the Territories, 1879). The facts concerning these Aphides have a special interest on account of the close relationship between the insects of this group and the now notorious grape vine Phylloxera. The special history of Schizoneura americana, n. sp., is given. It is to be found curling and gnarling the leaves of the White Elm (Ulmus americana), and passes from the egg state through no less than seven stages, in some winged, in some wingless, but in all agamic until the seventh, when, as the result of fertilisation, the true egg state is again reached. Another very common gall described is that formed by Colopha ulmicola, and the diagnoses of five new species of Pemphigus are given. In a second part of this paper Mr. Monell describes several new species, and gives detailed synonymy of several already described. Two excellent plates accompany Dr. Riley's notes on the gall-making forms.

NEW BIRDS FROM THE PORTUGUESE POSSESSIONS IN WESTERN AFRICA.-Prof. Barboza du Bocage publishes Journ.de Scien. Math. Phys. Natur., Nos. xxiii. and xxiv., Lisboa, 1878) his sixteenth and seventeenth lists of birds from Angola. A new genus and species (Hylypsornis salvadori) is established for a creeper, and a pretty sun-bird is called after M. d'Anchieta, who has added so much to our knowledge of the birds of Angola (Nectarinia anchieta). Several other new species are described in the sixteenth list. In the seventeenth list a new genus and many additional new species are also established, the more remarkable being a sun-bird (Nectarinia oustaleti) and a unique bird from Caconda (Sharpia angolensis), called after Mr. Sharpe, of the British Museum, and having affinities with Hyphantornis.

A UNIVERSAL CATALOGUE THE HE Council of the Society of Arts, probably the most practically useful body in the kingdom, has taken a positive step towards the accomplishment of a task which certainly deserves to be called gigantic. We need not

moralise once more on the extent to which the making of books has been carried; many a modern Solomon has no doubt been appalled into silence in the effort even to realise, far less to express, the extent of this manufacture. To attempt to begin ab initio to catalogue the works published during the past century, or even since the beginning of the present century, would be a task which to us would seem to be hopelessly endless. Any one whose business it is to work with books, and even the most thoroughgoing scientific worker must refer to them occasionally, must recognise the immense advantage, however, of having in one properly arranged catalogue, as complete a list as possible of printed books, and the farther back it went, the more valuable it would be. It is, then, certainly a fortunate thing that there exists ready to hand, though unprinted, a catalogue which for all practical purposes may be regarded as a universal catalogue of printed books, and that not only for the past century, but the past four centuries and more; for the British Museum Catalogue begins as far back as 1450. Some time ago the Society of Arts considered the advisability and practicability of constructing a catalogue coming down to the year 1600. The Council addressed a series of questions to them likely to give useful answers, and afterwards met to hear evidence on the subject. Mr. Bullen and other authorities were thus examined, and it seems to have been Mr. Bullen who happily suggested that the best and only sure method of laying a solid foundation for the Universal Catalogue of English printed literature would be to print the Catalogue of the Printed Books in the British Museum, from A.D. 1450 to the present time, say, the end of the year 1878, representing about 1,250,000 vols., and comprising between 2,000,000 and 3,000,000 entries, i.e., main titles and cross references. He con"in a rough sidered the work might be ready for printing, and ready way," in two years, and in less time if more force were employed, and that it would take five years to print. All the witnesses agreed that the printing of the British Museum Catalogue would be highly desirable, and the Committee are of the same opinion.

As we have had occasion to point out in these pages, the British Museum Catalogue is by no means perfect, and it is specially difficult for a man in search of a scientific serial or paper to get at it without much roundabout hunting from one cross reference to another, much waste of time, and loss of temper. Still considering all the difficulties in the way of constructing a perfectly new catalogue, we do not think a better course could be followed than that suggested by the Society of Arts' Council. It might be possible to introduce some improvement in arrangement during the process of printing, and especially with reference to the arrangement of the publications of scientific societies, also be borne in mind that the Catalogue is only one of which at present is so completely unscientific. It must authors, and that for many purposes of research such a catalogue is of little use without an equally complete one of subjects. Still the want of the latter is no argument against the publication of the former, though we should hope that the one would be followed by the other. costly undertaking could hardly be accomplished by any Of course such a stupendous, and, at its cheapest, private body, and it is natural that the Society of Arts scheme has the approval of the President of the Society, should look to government for help in the matter. As the the Prince of Wales, we should think that the Government is not likely to hesitate in granting such aid as might be required. Of course the printing and paper need not be luxurious nor expensive, and the specimenpage issued by the Society seems to us satisfactory. It is calculated that the British Museum Catalogue would thus occupy about forty-five volumes of 1,000 pages each, and could be issued through the Stationery Office at about 16s. per vol., and even less if the edition were of 2,000 copies. No doubt a fair sale would be obtained for such a publica

tion both at home and abroad, for take it all in all, as Mr. Bullen says, "no catalogue in the world, whether in print or in manuscript, is equal to that of the British Museum." We hope, therefore, that the proposal of the Society will speedily meet with a favourable response from Govern

M.

A MIRROR BAROMETER LÉON TEISSERENC DE BORT has invented an aneroid mirror barometer, which is described in a recent number of La Nature. It is based on a method analogous to that well-known since the researches of Gauss for the reading of small rotations. M. Teisserenc de Bort has sought to obtain an aneroid barometer which will give precise observations at sea, especially in rough weather, when it is impossible to read the mercury barometer. The principle of this barometer is very simple. The elastic tub or box B carries, as in most aneroids, a metallic point, which follows its movements. In the

ment, and that should it be decided to print the British Museum Catalogue, some plan will be formed by which proofs may be revised not only by qualified bibliographers, but that the various departments of literature, science, and art will be represented on the staff of revisers.

ordinary aneroid the transformation of the vertical movement into a rotating movement necessitates either a chain or a curb, or a sort of fork which works in a spiral furrow cut in the axis which supports the needle. These various systems have the inconvenience of producing frictions; some of them are liable to dust and rust. In the mirror barometer, the transformation of the movement is obtained by the simple contact of a small palette supported on the axis of the mirror and of the point spoken of above. As the angle which the plane of the mirror may describe does not exceed 12° on each side of the vertical, it follows that the contact of the point in the palette is always precise.

As to the amplification of the movements necessary to enable us to appreciate millimetres and their fractions, this is obtained by reading with the aid of a small reticled telescope, L, the image of a graduated scale E which is reflected in the mirror M. By combining the enlargement of the telescope with the distance of the scale from the mirror, we succeed in giving to the apparatus a length of less than 20 cm. by 12, which renders it quite portable. It is important to remark that the amplification of the movements of the box, which, in ordinary barometers, is obtained by means of several levers, is obtained here by an optical process; it follows that the numerous frictions and the time lost in contacts are mostly

BUTTERFLIES WITH DISSIMILAR SEXES

ΝΑ ATURALISTS have long been familiar with the fact that the two sexes of certain species of lepidoptera often differed from each other in colour and marking, and sometimes in form and size to a very considerable extent. For this phenomenon the convenient term Antigeny" " has been proposed by Mr. S. H. Scudder. In accordance with Darwin's theory of sexual selection we find that when the sexes of a butterfly differ to any marked extent in colour, it is generally the male which is the more gaudily coloured, although there are certain genera in which the reverse obtains; but, as I pointed out in NATURE (vol. iii. p. 508), there is reason to believe that in these exceptional cases the males may be

* Proc. Amer. Acad., xii. 150.

eliminated. There remains only a single movement, that of the axis which bears the mirror; in the barometer figured the pivots are of steel and the cap of platinum, and in order to avoid rust, the whole is nickel-plated.

M. Teisserenc de Bort proposes to construct others, in which the axis will be mounted on rubies. This garniture will not sensibly increase the price of the apparatus. This instrument is too new to allow us to appreciate the full degree of precision which it can attain. In a trial in a captive balloon by Capt. Perrier of several aneroids as compared with the mirror, the latter showed a great sensibility, and it quickly resumed its original position on landing.

the selecting sex. Mr. Charles Darwin having recently called my attention to a paper on this subject in Kosmos,1 by that most philosophical entomologist, Fritz Müller, I have thought that an abstract might interest readers of NATURE.

The species of which the author treats, Epicalia acontius, has such very dissimilar sexes that Fabricius described them as distinct species, calling the male Antiochus and the female Medea, while in Doubleday and Westwood's "Genera of Diurnal Lepidoptera" the two sexes are placed in different genera, the male in Epicalia and the female in Myscelia. It is not known with certainty who first pointed out that Antiochus and Medea were the sexes of the same species; but this fact is now I" Epicalia acontius. Ein ungleiches Ehepaar," Kosmos, January, 1879, P. 285.