and green calyx), is a great favourite in our cottage garders, and goes by the name of "King Charles in the Oak." It is a very showy plant. With respect to the form of primula intermediate between the primrose and the cowslip, when first I began botanizing, I, of course, labelled it "Primula elatior," but I learned after awhile that it was not the true oxlip (which plant, however, I have never had the good fortune to see), and for a long time I have looked upon the cowslip (Primula veris), the primrose (P. vulgaris), and the spurious oxlip (P. intermedia, if I may so call it), as varieties of one species, but I feel quite convinced now that what I venture to name intermedia is a true hybrid between the other two species. My reasons for arriving at this conclusion are that I have found it in every imaginable stage of development between the cowslip and the primrose. Amongst cowslips, which, however, are not very common with us, I have sometimes found individual plants having the flowers cup-shaped like a cowslip, deep yellow, with an orange centre; cowslip-scented, sometimes drooping, but sometimes erect, and considerably larger than ordinary cowslip flowers. These, certainly, may be a development of the cowslip, and not hybrids at all; but then the development goes on, and I find oxlips with the flowers still deepyellow in colour, but flat like a primrose (sometimes slightly cupped), and almost as large as a shilling. And, again, I find oxlips having the flowers quite like a primrose in colour, shape, and size; but a specimen of this kind now before me has the unmistakable cowslip odour very strongly, while a yellow one, also before me, has very little perfume at all, and what it has is more like primrose than cowslip. I have no particular notes on the subject, but I am under the impression that I have frequently seen oxlips amongst cowslips where the latter were plentiful, and I fancy that Professor Buckman will remember and corroborate the fact that we found oxlips amongst cowslips in a small wood at Ewen, near Cirencester, many years ago, and that there were sometimes on the same root oxlips and cowslips, sometimes oxlips and primroses, but not primroses and cowslips. I take it that the hybrid will most resemble the cowslip when a cowslip has produced the seed, and that such a plant will occasionally send up umbels of both oxlips and cowslips, but that the hybrid will be most like a primrose when the primrose has been the female parent, and that it will then have a tendency to send up umbels of oxlip and single-flowered scapes from the same root. What I have written does not prove anything, but the subject seems worthy of investigation, and I hope during the next few days to begin some experiments by impregnating cowslips with primrose pollen, and primroses with cowslip pollen, and saving the seed, and if others would do the same, when

opportunity occurs (it will be too late this year when this is read), I fancy we should arrive at some valuable and certainly interesting results.-Robert Holland.

THE OXLIP.-The view entertained by your correspondent "B." in reference to the consanguinity of this plant with the primrose, rather than with the cowslip, requires confirmation, and his observation of the facts on which that view is based assuredly does not agree with my own. In this district of East Sussex, where the soil is cloggy, the primrose flourishes most luxuriantly, but I have never once met with the oxlip here, nor even the cowslip; and I have heard aged labourers say they have never seen the oxlip growing here, but it is common enough on the calcareous soil of the South Downs. In Dorsetshire the cowslip is very abundant, and I have often found the oxlip growing with them. The primrose does not grow so luxuriantly there as it does in this soil. Some years ago I sowed some garden polyanthus seed which produced cowslips, oxlips, and polyanthuses, but no primroses.-S.

RUST AND SMUT IN INDIA.-At our request, Dr. Stewart, Officiating Conservator of Forests at Lahore, has just forwarded to us specimens of rust and smut on Indian Graminacea. These include the common smut (Ustilago segetum) upon Cymbopogon Iwaruncusa, upon wheat, and upon a species of Saccharum and of Eragrostis, in the latter mixed with a kind of Macrosporium, with a singularly hard compact form on barley from the Jhelum district; also the glume rust, Trichobasis glumarum, on wheat. Together with these was a species of Tulostoma from Montgomery District. It is allied to Tulostoma mammosum, but appears to differ in the depression around the stipe at its junction with the globose head, at which point the head easily separates from the stem. Undoubtedly the common red rust and the corn mildew occur on grain in Northern India, but of this we have at present no evidence. We wish that some of our Indian correspondents would send us the ergot on rice which is said to occur in Bengal.

WINGED SEEDS.-In the seed of Lophospermum erubescens, in which the thin membranous wing surrounds the entire circumference of the seed, the cells, with their spiral fibres, are well shown. The most remarkable specimen of wing, however, and one in which this tissue is largely developed, occurs in a plant from the East Indies (Calosanthes Indica), the wing being more than an inch in length on each side of the seed.-Quekett's "Lectures on Histology."

BITTER-VETCH CLUSTER CUPS (Ecidium Orobi, D. C.). A correspondent has sent us this rare parasite from Sheffield.

GEOLOGY.

TOOME BRIDGE EARTH AND FLINT FLAKES.Toome Bridge is a small village on a branch of the Northern Counties Railway, between Randalstown and Castle Dawson-about five miles from Randalstown, and three from Castle Dawson. It is situated in the county Antrim, but is close to the boundary of the county Londonderry. The bridge from which the locality takes its name was a curious old nine-arch structure that formerly crossed the river Bann, which at this spot divides the counties. The bridge was removed some time ago, and the County Road deviated; and now the County Road crosses the river by an iron bridge at a short distance from the site of the former old stone bridge. The river thus crossed is called the Lower Bann, to distinguish it from the Upper Bann, which, after rising in the Mourne Mountain of the county Down, falls into Lough Neagh at its south end, near the town of Lurgan. The Lower Bann leaves the Lough again at Toome Bridge, and falls into the sea a little to the north of Coleraine. Some fifteen years ago extensive works were carried on at Toome with the view of improving the navigation of the Lower Bann. During the progress of those works, a large number of stone and bronze implements were found, the majority of which are now in the Museum of the Royal Irish Academy, in Dublin. At this time also a bed of earth was cut into, which is now known as Toome Bridge earth, and mounted specimens of it are to be found in the cabinets of most microscopists, few of whom know anything of its whereabouts. The land at both sides of the river, particularly at the western side, is very low for hundreds of acres, and doubtless at one time was covered by the water of Lough Neagh; indeed, previous to the alteration of the bed of the river, the adjoining lands, and even the County Road, used to be frequently submerged during winter. From indications given in several directions, it is probable that the diatomaceous earth occurs over the whole of the extensive flat country, and when it has been cut through it shows a thickness of from three to five feet. All the hedgerows along the roads, and dividing the fields, are built of it; and even bricks have been manufactured from it, and it is so often turned up in the fields that the farmers returning from their work look as white all over as if they had been working in lime all day. An excellent section is exposed all along the river banks. This white earth is well marked, and it seems to rest upon a sunken peat moss. At low water during the summer the peat is exposed, and trunks of trees project from the peat up into the diatomaceous earth, so that the earth itself is newer than the peat. The latter forms in some places the bed of the river. A second iron bridge carries the railway across the river between the above County Road bridge and the

Lough, and the peat forms the bed of the river between the railway bridge and the Lough. On this peat there occurs a bed of gravel, and in this gravel there are vast quantities of flint flakes similar to those found in the valley of the Somme, and the ossiferous caverns of England and the Continent. The boys in the locality wade out into the water in the summer, and collect the flakes, many of them very well formed, although mere flakes, there being no chippings upon them. With these flakes, however, there are some arrow-heads and stone celts found, and in some of the adjoining bogs inland flakes, arrow-heads, and celts have been found, similar in every respect to those found in the bed of the Bann.-W. Gray.

THE PETRIFIED FOREST.-This celebrated forest, or rather plain of prostrate trees, is about an hour's ride from Cairo. The fragments are scattered about in all directions as far as the eye can reach; the hills all round and the valleys of the desert are strewed with them. There you see branches in one place, trunks in another, roots in another. Some of the pieces are split up, as if they had cracked from age or the heat of the sun. Many of the pieces are evidently of the palm tree. All the fragments are as hard as the hardest flint. Petrifactions of this kind are found in other parts of Egypt, but not to the same extent. Many speculations and suggestions have been offered as to the cause of these petrifactions, but it is beyond doubt that the trees were at one time under water. It cannot now be known whether they grew where they lie or whether they were brought there by a flood (or rather the flood) from a distance. The place, though now a howling wilderness, might have been in the earlier ages of the world a land of great and luxuriant vegetation. There is no doubt, however, that these trees date from the time of the deluge. They may indeed have been uprooted in some distant land, brought by the advancing flood, and deposited where they now lie. Many of these trees measure from 40 to 60 feet in length, and several are above 3 feet in diameter. The small fragments may be counted by millions, and thousands lie buried under the sand. They are capable of a high polish, and might be used as ornaments of various kinds.-E. St. John Fair

man.

ROCKS OF THE AQUEOUS DEPOSIT BEHIND THE CITADEL, CAIRO.-Immediately behind the citadel at Cairo there is a small range of mountains called the Mokattam mountains, which is almost entirely composed of shells, roots of various vegetable substances, and small branches and roots of trees, all petrified and forming a solid rock. Besides these, sharks' teeth and crabs have been found in these mountains. There is no doubt that these rocks have been deposited by water, and, taking into consideration the evidence of other phenomena equally

strange to be met with in various parts of Lower Egypt-as, for instance, the existence of sea-water shells in different portions of the desert, and above all the petrified desert-it is evident that the whole of this part of the country was at one time covered by the sea. The Mokattam mountains are of a light yellow colour; the summits are quite free of any sort of vegetation, and various parts are covered with loose blocks of stones of the calcium species. There is in these mountains a very remarkable rock of a reddish colour, called by the Arabs Ghebel Achmar, which means literally red mountain. It is of a very soft nature, and closely resembles red ochre. In this range there are also immense caves, in each of which a regiment of soldiers might easily be quartered. The whole of Upper Egypt might be said to be a vast mass of granite, but Lower Egypt, at all events the Delta, having been probably formed by the clay and sand brought down by the Nile, shows no visible traces of this rock. The centre of the earth is a vast crucible in which materials of which we have no precise knowledge are fused or melted together, and then forced up to the surface, either by the intense heat or by a sort of centrifugal force. The composition called granite is formed and forced upwards in this manner, and as it cools and hardens bursts its way through the softer strata until it appears above the surface, assuming in many places the forms of stupendous mountains. Sometimes the force is only sufficient to raise the strata above to a certain height, while the granite itself remains concealed underneath. This may account for aqueous deposits being found in the shape of mountains, as in the instance of the Mokattam mountains in question. They once probably formed the bed of the ocean, and in the course of ages were raised to their present height by the upheaving of igneous rocks from below.-E. St. John Fairman.

and

AGE OF NIAGARA. Many eminent geologists affirm that the eroding power of the swift rolling waters of the Columbia, Potomac, and Missouri could not, on an average, effect the stupendous erosions alluded to in less than 40,000 years; Sir Charles Lyell asserts, after personal study, and close searching and accurate observation of the nature and properties of the Silurian rocks of the Niagara bed, and of the average annual rate of the erosion at present, that the strength of the eroding power, great though it be, could not possibly have effected the retreat of the cataract to its modern site in less than 35,000 years.-The Twin Records of Creation.

FOSSIL DORMOUSE.-At the meeting of the Zoological Society of London, 9th May, Dr. A. Leith Adams read a communication respecting a new fossil Dormouse from the quarternary formations of Malta, proposed to be called Myoxus melitensis.

MICROSCOPY.

FEATHERS FOR MOUNTING.-The feathers from the drake's head form a very interesting object under the microscope. Under a power of 80 diameters they appear to be divided into rectangular cells. Their colour, when viewed opaque, is beautiful. Can any one tell me if there is mention of them in any work on the microscope? The cells are best shown when mounted in balsam.-A. W. Cooper.

CENTERING OBJECTS.-As hardly any hint in microscopic manipulation is too trifling to be of use, at least to beginners, I venture to send the following device, which I have used for some years, as from the excentric position which objects sometimes occupy on the slide it is evident that some mounters trust (vain confidence!) to the eye alone. Cut a piece of card the exact size of a slide, draw two lines diagonally from corner to corner, the point of intersection will show the centre, where a small hole should be punched or cut out. To use the contrivance, place it carefully on a slide, and with a pen put a dot of ink on the glass through the hole; the object is of course to be mounted on the other side of the slide, and the ink-spot is easily scraped off afterwards. The dot on the glass is preferable to any loose mark placed underneath while mounting, as it cannot possibly shift its position.-George Guyon.

MOUNTING OBJECTS.-As I continually see in SCIENCE-GOSSIP discussions on the relative merits of various fluids for mounting microscopic objects, I would say a word on behalf of a very simple one, viz., distilled water. I have now lying before me on my table two specimens which were among my earliest attempts at mounting, and which were mounted at least eighteen years ago. Out of these eighteen years they have passed more than fourteen with me in the tropics, and yet they are as green and as fresh, and as perfect for microscopic examination as they were on the day they were mounted. The objects are Nostoc vulgare and Jungermannia tomentella. They are both mounted on slips of glass of the usual size, viz., 3 inches by 1. In one case the cell in which the object lies was built up of red sealing-wax dissolved in spirits of wine, and the thin glass cover cemented with the same. As the sealing-wax was laid on in a broad band (nearly three-tenths of an inch) no air at all has got in, and the specimen is in every respect as perfect as it was eighteen years ago. This is the more surprising as sticks of the very same sealing-wax brought out to this country, and laid in a drawer, in consequence of the heat, soon ran together, and flowed out into a flat circular cake. The effect of dissolving it in spirits of wine seems to have been to enable the wax

to preserve its hardness and brittleness, for that on the specimen in question is extremely hard, and as sharp at the edges as at first. In the other case the object was mounted in a cell ground out of the glass, and the thin glass cover cemented with black asphalte cement, which also has stood remarkably well, though, as it was laid on in a very narrow band, a large globule of air has got in, which spoils the appearance of the slide as a mounted specimen, but has not affected the object in the least degree. Distilled water, having thus stood the test of eighteen years, is, I think, shown to be a suitable fluid for, at least, vegetable tissues.

While on the subject of fluids and cements, I may take the opportunity of stating that marine glue (which answers so admirably for fastening glass rings to slides) when kept in the lump, loses its properties after two or three years in a hot country. When strips of it are laid on a slide and held over a spirit lamp, or if a piece of it be held in the flame, instead of melting, it burns and smoulders away into a dry ash, and is therefore useless. It is the same, also, with ordinary English sealing-wax, so that it is impossible to seal a letter with it.— C. S. P. P., Moulmein.

FATTY ACIDS.-E. Histed speaks of spermaceti as a good polariscopic object: I, to the same effect, recommend the fatty acids, either by E. H.'s process or otherwise in the ordinary way.-S. D.

MOVEMENTS OF DIATOMS. -SCIENCE-GOSSIP is, I apprehend, a publication in which I may quietly buttonhole your own proper person, and relate what I have seen recently in our instrument of instruments, the microscope. Now, although I possess a few books relating more or less to all subjects which come under the said instrument's glass eyes, I am not aware of any which clear up the question of "How do the navicula force their way through the water?" Neither do I for one moment suppose that a humble individual like myself is going at once to solve it. I shall, however, relate (if you will kindly lend your ear) what I have lately seen. After a trip last Saturday, May 11th, to Swanscombe, which somehow or other is not now what Swanscombe was formerly (speaking from a microscopic point of view), I found that I had got Surirella, P. angulata, Nitzschia, R. elongata, P. fasciola, P. quadrata, Amphiplura, &c., &c., not to mention any quantity of ciliated and non-ciliated animalcules. With regard to the means of viewing them, I considered my Ross compressorium the best, and consequently transferred from my soup-plate (into which all the gatherings had been as usual turned) a drop from the surface. For the first time in my life I found a quadratum on edge-not having, as in ninetynine cases out of a hundred, screwed down the top

glass until all underneath must be flat-which gave it a curious appearance. In the ordinary mode of seeing these minute objects, there appears when alive, as every one has seen, a central spot, and a minute ring at either extremity. Our friend viewed sideways, gave me apparently the idea that the two rings might be the orifices of two tubes, and it struck me that the Ruthven propeller, in which water is sucked in at one end of the vessel and ejected at the other, might really be the principle upon which our Pleurosigma get along. If this is anything very old, let your humble servant down as lightly as possible. I mention it purely as gossip. I saw no motion, but I think my specimen was defunct. Does the central ring exercise any influence upon the two tubes in contracting and expelling the fluid, or otherwise? The powers used were a good and . The would not go through the thickness of glass and water necessary to keep the object in position. I bring this forward simply because it is likely some of your readers may have seen the same sort of thing, and at the same time, with that feeling of diffidence that makes those who work long at the microscope not always to believe their own eyes.-John Bockett.

GLENSHIRA SAND.-In answer to J. W. W.'s inquiry respecting the method employed by the late Dr. Gregory with Glenshira sand, I have pleasure in informing him that, in a letter written by the Professor to an acquaintance of mine, he directed him to have four or six glasses, each about twelve inches high; into the first, nearly filled with water, to pour some of the sand, and to allow it one minute to settle, the fluid to be then carefully poured into the second glass, and two minutes to be allowed previous to the fluid being decanted from the deposit into the third glass, and here four or five minutes were to be allowed; the process to be thus repeated, doubling the time for the sediment to settle in each glass; the deposit will consist almost entirely of sand in the first glass, in the next of sand and the larger diatoms, the finest kinds being found in the last glasses.

If J. W. W. is desirous of exchanging Glenshira sand for other diatomaceous material, the writer will be glad to hear from him.-Joseph B. Bodman, Castor, Peterborough.

MOUNTING DIATOMS.-How must I proceed in order to make diatoms stick on the slides after they are arranged? I have succeeded in arranging small groups, but all trials to make them stick have been in vain; the diatoms float away as soon as the balsam is put on them, and yet it is possible to fix them, as is proved by the beautiful preparations which are sold in England.-E. W. Schoenebeck, Prussia.

NOTES AND QUERIES.

AQUARIUM PEST.-I last year collected from my aquarium several pieces of the Valisneria spiralis, on which were deposited the ova of the Planorbis corneus, and put them in a small glass jar containing water, which I placed in a window with a south aspect, and let it remain there several weeks, when on examining its contents I found upwards of one hundred minute molluscs, some of which I now have in an aquarium; they vary in size from threesixteenths to seven-sixteenths of an inch in diameter. If your correspondent L. H. F. will adopt the same course, and keep the jar where the sun can act upon it, I have no doubt he will be satisfied that the 'nests" he names are the eggs of the snail, and that "something will come from them."-H. M., Sheffield.

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EGGS OF THE LACKEY MотH.-Mr. H. H. O'Farrell inquires if any of the readers of SCIENCEGOSSIP have met with the eggs of the Lackey Moth laid in a patch, and not a ring. I believe it is a very common occurrence, as I myself have frequently found them so.-E. F.

SKELETON LEAVES.-Your correspondent J. S. S. will have no difficulty with her skeleton leaves if she removes them from the water on blotting paper, and she may detach them from it with dry blotting paper and a careful use of her fingers. The same paper may be dried and used several times.-A. S.

PRIMROSES.-In SCIENCE-GOSSIP for May 1st, your correspondent B. mentions having found Oxlips amongst Primroses, but never among Cowslips; it may therefore be interesting to state that here, on the Mendip Hills, in fields which are almost covered with Cowslips, we frequently find very fine specimens of the Primula elatior growing amongst them.-J.

[Is our correspondent certain of its being Primula elatior?-ED.]

IMPRESSIONS OF LEAVES.-Could you inform me what is the best method of obtaining exact natureprinted copies of the leaves and impressions of leaves found in the Lower Bagshot pipe-clays? I have a great many obtained from the Lower Bagshot beds about here .R. C. C. L.

MICE AND COCKROACHES (p. 119).-It is very likely that the common mouse will feed on cockroaches: that they do feed on insects, we had positive proof down here. In the roof of this house-i.e., between the ceiling of the upper rooms and the slates-we have small apertures in the gable for ventilation, which are filled up with perforated zinc, and the larger flies all draw towards these apertures, especially on a sunshiny evening; but they cannot get out through the perforated zinc, and I was at first somewhat surprised to see mice running up the zinc and catching these flies in vast numbers. I find they eat all but the wings, which they manage to clip off as clean as if cut with a pair of scissors; but mice and rats are nearly omnivorous, according to circumstances.-W. P.

LEG LEGENDS.-Is it a recognized fact amongst naturalists that thrushes acquire new legs, and cast the old ones when about ten years old? A great many persons in this neighbourhood give what

appear well-authenticated instances of this: one of a thrush belonging to a clergyman at Stanwix, near Carlisle, which was visited and examined by many when the change was going on; another near Whitehaven, &c. The matter has been brought under my notice now on looking through the library of a deceased friend of mine who was a very close observer of nature. At the end of "Swainson's Birds" he has made the note, "A thrush kept in a cage at Lyneside (Kirklinton), said to be about ten years of age, has recently acquired a new pair of legs, the old ones drying up and dropping off. The first time I saw the bird, the new feet were protruding from the front of the knee joint, and looked soft and light-coloured. On my second visit they had lengthened considerably, but were not of any use to the bird. Afterwards I saw it when the new feet were used, and the old ones shrivelling up, soon after which the old feet dropped off." I have heard him speak of the circumstance, and express regret that he had not secured the cast-off legs as an evidence for unbelievers.-Wm. Dodgson.

[We suspect that the unbelievers are legion.ED.]

AQUARIA.-All who are in contemplation of stocking fresh-water aquaria during the ensuing summer months, will do well if they introduce a greater number of plants of a floating nature than of those which require to be set in soil, as the fish will then have greater scope and room; whilst oxygen, which is essential to their preservation, will still be supplied in sufficient quantity. The thick foliage of many subaquatic plants is calculated to considerably retard the free movements of the fish, especially when the aquarium in which they are kept is small. Of course under-water vegetation should not be entirely discarded, for if sparingly introduced it affords a grateful shelter to newts and some species of fish which are fond of seclusion. As a rule, it is advisable to have plenty of space, in order that the living objects can be more easily observed. It is by no means advantageous, for the same reason, to have too great a display of rockwork, and in fact there ought to be hardly any, unless the aquarium is of large dimension.-J. H. F., Harleston.

PERFORATING SQUIRRELS.-In the very interesting and able article on the flint-flakes of Devon, &c., by Mr. Tate, in the April number of the Popular Science Review, there is, I think, a slight error in regard to the habits of the Squirrel. At p. 173, it is stated that "perforation in the nuts demonstrates that Squirrels skipped among the branches of the trees that grew there." Now, whilst I have no doubt that Squirrels did skip among the branches at the time referred to, I do not think that they made the perforations found in the nuts, but that these were the work of the common Dormouse. I have kept both Squirrels and Dormice, and so far as my observation goes the latter always nibble a nearly circular hole in the nut, whilst the former, having first rapidly cut an irregular opening, insert the lower incisors into it, and break off one side of the shell before beginning to eat the kernel. This may be thought a trifling matter, but in natural history, as in all other departments of science, we cannot be too exact in relation to the facts on which we base the reasonings by which we advance into new fields of knowledge. I have hence deemed it well to call the attention of your readers to this point; and possibly others, with wider opportunities than I possess, may show that Squirrels do leave perforations in nuts.-Fras. Buckell, M.R.C.S.