AT the Royal Institution, Professor Langley, of the Alleghany University, Penn., recently delivered a lecture on "Sunlight and its Absorption by the Earth's Atmosphere." From a notice of it in the "English Mechanic" it appears that he ascended one of the peaks of the Alleghany Mountains in California, and measured the heating effects of the different parts of the spectrum at the bottom and at the top of the mountain. At the top he found the ultra-red end greatly elongated. The heating effects were presumably observed by means of the bolometre, an instrument which Professor Langley invented, finding that the thermopile was not sufficiently sensitive. In the bolometer, an exceedingly fine wire of platinum or iron (he made one wire from a leaf of iron 15th of an inch in thickness), has its temperature and hence its electrical conductivity changed in different parts of the spectrum, the result being shown on a very sensitive galvanometer. By means of a Rowland's grating, the effect of twenty or thirty prisms can be obtained without the squeezing together of the red rays which is the result of using glass prisms.

MICROSCOPY.

COLE'S "MICROSCOPICAL STUDIES."-Four slides, illustrative of this series, are to hand, viz. Jaws of Epeira Diadema ; Batrachospermum; Lung, alveolar pneumonia, 3rd stage; and a transverse section of the organ of Bojanus from an Anodon.

LIVERPOOL MICROSCOPICAL SOCIETY. The ordinary monthly meeting was held on Friday at the Royal Institution, the President, Mr. Chas. Botterill, F.R.M.S., in the chair, when there was a large attendance. Mr. I. C. Thompson referred to the loss sustained to microscopical science through the death of Mr. Charles Vance Smith, who, though paralysed for many years, bad attained a high position amongst microscopists through his delineation of the microscopical structure of plants. Mr. A. Norman Tate, F.I.C., read the paper of the evening, on "The Microscopical Examination of Potable Water." After alluding to the impossibility of always determining by chemical means alone, whether a water is or is not fit for dietetic purposes, he proceeded to speak of the importance of microscopical investigation in relation to water supply, pointing out that it afforded better opportunity of determining the character of organic impurities, and that it might frequently assist in ascertaining the character of the mineral constituents. He described different modes of collecting and examining waters microscopically, and urged the importance of further investigation, so as to ascertain how far the organised matters present in water are capable of developing disease, and how such organisms may be destroyed. In conclusion he mentioned impurities found in natural ice, and also two methods of examination of rain and air. A discussion followed, and a conversazione was then held at which a number of interesting objects were exhibited.

BORO-GLYCERIDE FOR MOUNTING MICRO-OBJECTS.

DRY MOUNTING.-In mounting objects by the dry process, a vapour condenses on the under side of the thin glass cover, which, on evaporating, leaves a series of small dots; thus entirely spoiling the appearance of the object under high powers. I may as well state that my method of mounting is taken from Martin's well-known manual, with the only difference of using a thin layer of gum before I apply the goldsize. I shall be much obliged if any of your numerous readers could give me any information on the subject. -F. Cresswell Du Bois.

STAINING NERVE AND MUSCLE.-I would refer E. B. L. for directions for staining the above, and the best modes of application, to read "Methods of Research as used in the Zoological Station of Naples," in vol. ii. of the "Postal Microscopical Journal," and also "How to Work the Microscope," by Dr. Beale, p. 299 (1868 ed.), &c., in which full details are given for demonstration of finest fibres, &c.-V. A. Latham.

on this substance, and with, at present, such good results, that it seems very worthy of extended trial. Boro-glyceride is an antiseptic manufactured under Professor Barff's Patent by the Kreochyle Company. It is non-poisonous and non-corrosive. Its two great uses are for preserving food and for antiseptic dressing for wounds. For mounting micro-objects, I use a saturated solution, made by dissolving the substance in warm water-using about one part to twelve of water and allowing the surplus to crystallise out and settle. When it is known that this solution will

preserve white of egg without coagulating the albumen, it will be seen to be very different in its chemical action from such powerful antiseptics as corrosive sublimate and carbolic acid. As far as my observation goes, boro-glyceride solution is excellent for vegetable tissues. It does not act on them in any way, grains of chlorophyll even remain unchanged. It does not destroy the aniline colours used for staining sections, although the delicate colours of flower petals appear to bleach in the solution. It answers for mounting insects whole and without pressure. Gold size or brown cement does for fixing the upper glass of the cell. The boro-glyceride, which is nearly a new substance, having proved useful and easy of

manipulation in my hands, it is desirable that competent mounters should try it and report results. To draw attention to it is my object in writing.-A. P. Wire.

CRYSTALS FOR THE POLARISCOPE.-If Mr. J. W. Neville uses castor oil to mount crystals in, he will not be troubled any longer by the unpleasant results described by him.-Charles F. W. T. Williams, B.A.

PARASITES OF BIRDS, &C.-Mr. C. Collins has forwarded specimens of a new series of his "special" micro-slides; a series of parasites chiefly of birds. Those sent are the parasites of heron, gull, and penguin, each slide being furnished with a label giving the classification, from sub-kingdom down to species.

ROYAL MICROSCOPICAL SOCIETY.-The Journal for April contains, besides the summary of current researches, the president's address on septic organisms, "The Lantern Microscope," by Mr. Lewis Wright; "On some unusual Forms of Lactic Ferment--Bacterium lactis," by Dr. R. L. Maddox; and a paper on a Cata-dioptric Immersion Illuminator," by Mr. J. Ware Stephenson.

66

ZOOLOGY.

IN the recent issue of the Proceedings of the Zoological Society of London is an interesting paper by Mr. H. Pryer, giving an account of a visit to the Birds'-nest Caves of British North Borneo, his object being to ascertain from what substance the edible nests, so much prized in China, are made. Large caves in Limestone rocks are inhabited both by bats and by the swifts, which build the nests in question, the nests being attached to the roof or walls of the caves. Mr. Pryer says that the material of which they are made may be found encrusting the rock in damp places, and resembling half-melted gumtragacanth. The account of the departure of the bats and the return to roost of the swifts is worth quoting. "Soon I heard a rushing sound, and, peering over the edge of the circular opening leading into Simud Itam [or the Black Cavern], I saw columns of bats wheeling round the sides in regular order. Shortly after five o'clock, although the sun had not yet set, the columns began to rise above the edge, still in a circular flight; they then rose, wheeling round a high tree growing on the opposite side, and every few minutes a large flight would break off and, after rising high in the air, disappear in the distance; each flight contained many thousands. I counted nineteen flocks go off in this way, and they continued to go off in a continual stream until it was too dark for me to see them any longer. . . . At a quarter to six the swifts began to come in to Simud Putih [the White Cave]; a few had been flying in and out all day long,

but now they began to pour in, at first in tens and then in hundreds, until the sound of their wings was like a strong gale of wind whistling through the rigging of a ship. They continued flying in until after midnight, as I could still see them flashing by over my head when I went to sleep. . . . Arising before daylight, I witnessed a reversal of the proceedings of the previous night, the swifts now going out of Simud Putih, and the bats going into Simud Itam. The latter literally 'rained' into their chasm for two hours after daylight. On looking up, the air seemed filled with small specks, which flashed down perpendicularly with great rapidity and disappeared in the darkness below." The swift has been determined to be Collocalia fuciphaga, the alga a species, probably new, of Gloeoeapsa, and the bat, Nyctinomus plicatus. There is an abundant supply of guano in these caves.

RANA ESCULENTA.-This frog, commonly considered to occur only on the continent, has been found in Norfolk. It appears that forty years ago or more, Mr. G. Berney turned some out in that county, and it is considered by Mr. G. A. Boulenger, F.Z.S., that the specimens captured are their descendants.

SUCCINEA PFEIFFERI, VAR. PARVULA.-I have recently found some Succineæ at Barnes, one of which I sent to Mrs. Fitzgerald, of Folkestone, and which she determined as belonging to the above form. I have recently taken on Barnes Common, with the Succinea, Limax lævis and Hyalina fulva, and a little way off, on a grassy bank, a specimen of Cochlicopa lubrica, which Messrs. Taylor and Roebuck have identified as var. minima, Siem.-T. D. A. Cockerell.

VARIETIES OF ARION ATER.-Mr. Elliot has sent me some specimens of the variety bicolor, which he finds in damp places near Stroud. It certainly is a very fine form, being rather related to the var. albo-lateralis of Roebuck. As a good deal of confusion seems to prevail concerning the varieties of A. ater, perhaps it may be well to give a brief description of the various forms, as I understand them. 1. Type form. Entirely black. 2. var. marginata. Black, with an orange or reddish foot-fringe. 3. var. nigrescens. Dark grey, with the sides usually rather lighter var. plumbea, Roebuck; lead colour, seems to be very nearly allied to this if the two can well be separated. 4. var. rufa. Reddish or brownish. 5. var. succinea. Yellow or yellowish; var. pallescens of Roebuck is light yellow. Perhaps it would be better to call both these yellow varieties succinea. 6. var. albida. White. 7. var. bicolor. Back brown, sides primrose yellow, foot-fringe orange. The brown of the back is sharply defined from the yellow of the sides. 8. var. albo-lateralis. Back black, sides white, the two colours sharply defined as in bicolor, foot-fringe orange. This variety has been found in Carnarvonshire and in West Sussex. Mr. Elliot's variety, with the inter

stices of the wrinkles light and the wrinkles darker, would seem to approach var. nigrescens, but it is probably distinct enough for a separate name. I fancy that the young of var. succinea are often alluded to in local lists as "Arion flavus.”—T. D. A. Cockerell.

BOTANY.

PROTOPLASMIC CONTINUITY.-This subject has been extended by Mr. Thomas Hick, B.A., B.Sc., into the Fucaceæ, and in a paper contributed to the "Journal of Botany," and published in separate form, he gives an account of his researches. He thinks that they conclusively establish the fact of a continuity of protoplasm through the cell walls in Fucaceæ, though of a different type from that described in many of the Florideæ. His paper is accompanied by a plate, showing figures of Ascophyllum nodosum.

TWIN PRIMROSES.—When gathering primroses a few days ago, on a hedge-bank in North Wales, I found a "twin" primrose-two flowers growing on one calyx-one of the flowers having six petals, the other five. In another place, a double primrose was found, which had nine petals, six on the outside and three in the centre. These flowers were carefully kept as good specimens of uncommon primroses, more remarkable perhaps than those mentioned in SCIENCE-GOSSIP for January and March. Several very fine single primroses with six petals were found.-M. E. Thomson.

ORCHIDS OF THE RHONE VALLEY.-In the last fortnight of April we have found the mountain slopes of the Rhone valley an admirable locality for orchidaceous plants. Evidently the character of the rock is congenial to the orchid nature, and nearly all the species here named were gathered from sloping pastures or woodlands on Lias Limestone. We must notice even the familiar Orchis mascula and Orchis morio, for beauty of the spike and strange variety in tint, and Orchis maculata for handsome spotted leaves. Orchis latifolia was abundant in the marshes, but not so fine as we have seen in the Isle of Wight. Orchis ustulata (dwarf brown wing) studded the meadows, interspersed with Ophrys arachnites (late spider), and Aceras anthropophora (green man). Ophrys muscifera was appearing here and there in woods with Neottia nidus-avis (bird's nest) and the Twayblade. Habenaria bifolia (butterfly) was in bud only, in the woods; Habenaria viridis (frog) being fully expanded. Orchis militaris we found fairly common in meadow lands. The previous year's spike of Orchis hircina (lizard) we noted, a prize seen for the first time; the prolonged though shrivelled life being quite sufficient to identify the plant; Ophrys aranifera (spider), was still in bud in the woods, apparently later in flowering in this

locality than O. arachnites. In the less accessible parts of a mountain gorge Cypripedium calceolus (lady's slipper) was putting forth strong shoots to flower later in spring. A plant, however, from the same locality was out before May in a garden at Montreux. Orchis sambricina (the elder scented orchis) was scattered in profusion over the fields of the Salvan road, with Orchis rubra (=papilionacea) a splendid crimson flower.-C. Parkinson, F.G.S.

GEOLOGY, &c.

GEOLOGISTS' ASSOCIATION.-At Easter a large party of the members of this Association visited Canterbury, Reculvers, and Richborough, under the direction of Mr. G. Dowker, F.C.S., and Mr. W. Whitaker, F.C.S., of the Geological Survey. Some of the members went down on Saturday and spent the day over the Tertiary country west of Canterbury. On Monday a visit was paid to Herne Bay and Reculvers, to examine the newer Tertiary beds of the cliff-section. The divisions between the Oldhaven, Woolwich and Thanet beds are less clearly marked here than near London, and hence differences of opinion exist as to the classification of the beds. These points were fully discussed on the spot. On Tuesday the party visited Pegwell Bay, where the lowest Thanet beds and their junction with the chalk were seen; then walked along the shore to Sandwich, crossing the Stour to Richborough on the way. Great changes in the coast-line have taken place, both here and at Reculvers since Roman times. These were explained by the directors. A pleasant surprise awaited the members in finding in the waiter of the Fleur-de-lis Hotel (Mr. T. B. Rosseter, F.R.M.S.) an excellent naturalist and original worker with the microscope. His instruments and preparations were placed at the disposal of the party during the evenings.

NEW SPECIES OF MAMMALS FROM FLORIDA.The Proceedings of the Academy of Natural Sciences of Philadelphia contain an account of two teeth from Florida, one of a supposed new species of Rhinoceros (R. proterus), and the other of a species of Hippotherium (Hipparion), the three-toed genus supposed to be the progenitor of our present horses, and first known in the European form of H. gracile. The latter tooth is an upper molar, and is said to indicate a small species little more than half the size of the domestic horse, or of H. gracile. To the new species thus indicated the name of Hippotherium ingenuum has been given.

CHANGES OF LEVEL IN THE SOUTH OF ENGLAND. -In the "Geological Magazine" for April, Mr. J. S. Gardner summarises these changes of level, during recent times, pointing out that there are indications of a rise having taken place at the Swale at Sheppey, the Reculvers, the coast off Richborough and off Hythe, the Dungeness Shingles, the Pevensey flats,

Kent's Hole, and to the east of the mouth of Beaulieu river; and of depression at Tilbury Docks, Selsea, Ryde, Brading harbour, Portsmouth, Bournemouth, Bourne valley, river Dart, Pentuan, Carnon, and Torbay; besides changes of some kind at Pagham Harbour, the Solent, the Isle of Wight and Poole.

NOTES AND QUERIES.

THE WATEROUSEL IN NORTHUMBERLAND.—This is perhaps one of the most common of the waterfrequenting birds (wren and wagtail excepted). It is perhaps more common in Northumberland than in any other county in England, and is to be found in almost all the valleys of the small unfrequented streams of that county. There, in the summer, you may, if you sit by the banks of the river, catch sight of it diving into the water in search of insects. It has been said by a great authority, that the ousel has the power of walking on the bed of the river, but I am very much inclined to doubt that, though there is no doubt that its food consists of insects that cling to the bottom of the stones, as well as of small fish, and you would almost wonder at its power in getting to these insects. It is capable of staying a long space of time under the water, and it also swims well on the surface. It is most interesting to stand and watch this bird obtain its food. It will dive headlong into the water, rise up again after capturing its prey, and proceed to devour it, and if you go to the spot you will generally find it strewn with fragments of the shell, or cases of the water-insects. It builds its nests in the banks of the stream which it frequents, and prefers to be in the solitudes of the woods, rather than near the haunts of men, though I have known one case where one, or rather a pair, of these birds built their nest in close proximity to a large town. In winter especially, it seems to draw near to the towns and villages on the banks of the streams. It is then that its low sweet song may be heard to perfection. These birds are very early builders, a pair, to my knowledge, having commenced to build their nest early in the month of February, 1883. It was then beautiful mild weather, but early in the following month, before they had finished their building operations, a severe frost set in, followed by a heavy fall of snow. This did not at all hinder the process of building, but it seemed to be an incentive to make them work harder, for one morning, while the ground was covered with snow, I stood and watched them for about an hour, and I saw them fly into the tunnel (in the wall of which they were building their nest), every two or three minutes, with roots and leaves in their bills, and on March 15 it laid the first egg; this day was probably the coldest day we had that winter. But, soon after, I think when it had got its fourth egg, it was robbed by some idle boys. Strange to say, it shifted its residence to a new spot, not many yards from the old spot, and built a new nest, and succeeded in hatching its full complement of eggs, six in number. The eggs are of a beautiful white. The song of this bird is low and sweet, and, strange to say, when you hear it singing, you would think that you were listening to a chorus of birds instead of one. Its song may be heard at its best in winter.-J. Bowman, Newcastleon-Tyne, Northumberland.

RANUNCULUS FICARIA.-Not only is R. ficaria usually classed as the "pile-wort," but it is equally

commonly described as Lesser celandine. The following authors so name it: Sir J. D. Hooker, in the "Student's Flora of the British Islands"; Anne Pratt, Spencer Thompson, in "British Wild Flowers, where to find, and how to know them;" J. T. Burgess, in his little book on "Old English Wild Flowers." It is not wise to place any reliance on the popular or trivial name of a plant when seeking its genus, for such trivial name will often vary with locality. It would take a student a long time to find the evening primrose among the Primulaceæ.-F. J. George.

GOLDEN EAGLE'S EGGS.-The fact of the eagle mentioned by A. F. being kept in captivity would not, I think, have any effect on the colour of the eggs. They are to be found from pure white to those of a rich dark brown, and I have a pair in my collection of the former colour taken in Scotland. It is, I think, more remarkable that it should lay at all, as, although it is said to be more easily domesticated than the white-tailed eagle, it is a species that does not readily lay in confinement.-J. M. Campbell.

TREE STANDING AFTER A FALL OF MANY FEET.In the description in White's "Selborne" of a landslip at Hawkley, mention is made of several oaks, which slipped thirty or forty feet, but still remained standing and in a state of vegetation. Several years ago, a similar occurrence took place in Hubbard's Valley, near Louth, when a beech (Fagus sylvatica) growing near the top of a steep bank, from the side of which much chalk had been excavated, slipped down, together with the earth at its roots, for a distance more than equal to its own height. This tree, which is still standing, produces every year an ordinary supply of foliage, and seems to have been but little affected by its fall.-H. Wallis Kew, Louth.

A CORRESPONDENT sends from Kent a specimen of an abnormal bluebell (Scilla nutans) in which the bracts are greatly developed, attaining a length between two and three inches, or even more. The bracts are yellowish and green, instead of being blue, as in the normal flower, and their great length gives the raceme a tasselled appearance as in a sprouting ear of grass.

CHARA AND NITELLA.-Can any one kindly inform me where chara and nitella can be found near Tonbridge?-C. J. Bohnso.

PURPLE WOOD SORREL.-Can any reader kindly tell me if this is a distinct species? I have found it several times in North Wales. In some places the flowers were a deep purple, in others a pinkish purple. In both plants, the under side of the leaves was very dark, those of the deep purple flowers being darkest.-M. E. Thomson.

THE COLOUR OF THE RED SEA.-I shall be glad to add a few remarks to Dr. Stonham's in your March number, on the minute weed seen by him in the Red Sea. I have had many opportunities of observing it, and have found it in both Atlantic Oceans, both Pacific Oceans, and the Bay of Bengal, so it seems to be pretty largely distributed. I am of the opinion

that it is often noted as volcanic dust when seen in calm weather floating on the surface, and also that it frequently escapes notice altogether. Sometimes I have seen it, and even when I have called attention to it floating in the sea, yet till I got some water in a bucket, other people could not distinguish it. In addition to the little bundles Dr. Stonham figures, little balls may frequently be seen very similar to the

little seeds one collects when walking through bushes, but which can all be pulled out with a needle into the separate fibres. The separate bundles are generally of a light brown colour, but when in great quantities it appears sometimes brown, and at other times almost black. In calm weather it collects principally on the surface, but when the sea is agitated, it then sinks to a small depth.-D. Wilson Barker, jun., F.R.Met. Soc.; Chief Officer, s.s. "International."

THE PIED FLY-CATCHER.-On the 25th and 26th of April, I observed near here, a bird very rare in this part of the country, the pied flycatcher (Muscicapa luctuosa) ; a remarkable bird, owing to its strongly contrasted black and white plumage, and its great activity. I can find only two cases recorded of the appearance of this bird in Somerset or Gloucestershire, and both of these were many years ago. Morris, in his "British Birds" states that he had never seen this bird alive. I should be glad to learn whether this species has been observed elsewhere this spring.-Alfred C. Pass.

HOLLY LEAVES.-The old holly-trees about here (Epping Forest) invariably show this tendency, the leaves of the upper part of the tree usually having only the terminal spine, with sometimes one or two additional spines. I have never seen a holly leaf in the forest without the terminal spine. It is a question whether the phenomenon is to be accounted for on the cattle theory, since those long upper branches of old trees which hang down within reach of the larger animals, frequently bear many leaves with only the one spine. Again, why should this one spine always remain? Is it known that cattle will eat holly leaves, if the upper ones are given to them? There seems to be an analogy between the upper leaves of an old holly and those of an old ivy, as in both the characteristic shape is lost. What is the explanation in the case of the ivy?-F. W. Elliott.

FLINT IMPLEMENTS.-Are any flint implements found in the neighbourhood of Bagshot, and if so where is the best place to look for them?-Charles Noble.

NOTICES TO CORRESPONDENTS.

we now

To CORRESPONDENTS AND EXCHANGERS.-As publish SCIENCE-GOSSIP earlier than formerly, we cannot undertake to insert in the following number any communications which reach us later than the 8th of the previous month.

TO ANONYMOUS QUERISTS.-We receive so many queries which do not bear the writers' names that we are forced to adhere to our rule of not noticing them.

TO DEALERS AND OTHERS.-We are always glad to treat dealers in natural history objects on the same fair and general ground as amateurs, in so far as the "exchanges" offered are fair exchanges. But it is evident that, when their offers are simply disguised advertisements, for the purpose of evading the cost of advertising, an advantage is taken of our gratuitous insertion of "exchanges" which cannot be tolerated."

WE request that all exchanges may be signed with name (or initials) and full address at the end.

A. S. MACKIE.-1. Limnæa peregra, but rather doubtful. 2. Sphærium lacustre. 3 and 4. We do not undertake to name foreign species. 5. Cypræa Europaa, if British. 6. The socalled "seal's egg" is the shell or "test" of a sea-urchin, an Echinoderm. A somewhat larger one with spines adhering was recently pointed out as a humming-bird's nest ! HERBERT 5. ALEXANDER.-Your objects are the so-called pseudo-podia of the moss Aulacomnium androgynum." The stalked heads "consist of little gemmæ which in this moss often replace the spores (capsules bearing spores are rarely found on it)."

S. J. H.-An answer next month if possible.

D. BRADLEY.-See "Engineering" for 1877 for articles on the Aneroid Barometer, which may answer your purpose. There should be numbers of the series also in some preceding year. Negretti and Zambra's "Treatise on Meteorological Instruments is said not to be so thorough.

V. A. LATHAM.-Thanks for your suggestion. But a reviewer may not always know the price of a book reviewed. Ewart's book on the "Dissection of the Frog" is published at 1s. 6d. (London: Simpkin.) McAlpine's work is at present withdrawn from publication.

G. E. E. JUN.-Write for specimens of "The Naturalist," 6d. Editors, Park Row, Leeds; "The Midland Naturalist," bd., (London, Bogue); "The Natural History Journal and School Reporter, 4d., (William Sessions, York); (2) Lyell's "Student's Manual of Geology" gives a good many.

C. D. JUN.-Your criticisms are too violent and "unparliamentary." Reconsider them and write again.

S. CHADWICK.-Where and in what formation was the fossil spine found?

THIESK.-Several of your mosses either had no fructification or it became spoiled.

INITIALS LOST.-The lesser celandine is Ranunculus ficaria, a flower of the buttercup order. The celandine, or greater celandine, is Chelidonium majus, also a yellow flower, but belonging to the poppy order. The two plants are very unlike one another, though the name is similar.

EXCHANGES.

GOOD botanical, histological, crystals, polariscopic, diatoms, fish scales and miscellaneous, microscopic slides for others as good of bacilli, entozoa, algæ, desmids, zoophytes, rocks, fossil woods.-B. Wells, Dalmain Road, Forest Hill.

WANTED, British and foreign Arionidæ and Limacidæ, also foreign Unioida and Physæ. Offered, shells, minerals, and specimens of Cinomorium coccineum.-Cajetan Platania Platania, Via S. Giuseppe, No. 14, Acireale, Sicily.

LEPIDOPTERA.-Duplicates: Cardamine, Corydon, Io, Atalanta, S. populi, Ligustri, Z. Trifolit, Betularia, Piniaria, Rhomboidaria, Defoliaria, Rubiginata, Dubitata, Pyraliata, Perla, Lutosa (fair), Suffusa, Lota, Spadicea, Ferruginea (fair), Oxyacanthæ, Cerella. Desiderata numerous. Accepted offers answered within a week.-George Balding, Ruby Street, Wisbech.

LANG'S "Butterflies of Europe," value £3 15s. Wanted, Lindsay's "Lichens," Journal of Microscopy," vols. i., ii., and iii. Offers solicited. Martin J. Harding, Old Bank, Shrewsbury.

WANTED, an aquarium, with slate bottom and plate-glass front, back, and sides, size about 2 ft. X 10 in. X 10 in. Will give in exchange complete set of Cassell's "Technical Educator," unbound, or "Building News" for 1878 and 1880, bound in half-yearly volumes.-W. H. Pratt, 15 Gill Street, Nottingham.

WANTED, any or all London University Calendars, 1879-1884, inclusive. Offered, Darwin's "Cross and Self Fertilis. of Plants," Weale's "Integ. Diff. Calc.,” Sybil" (by Disraeli), Swainson's "Insects,' or other mathl. or scient. works.W. G. Woollcombe, The Close, Exeter.

WANTED, SCIENCE-GOSSIP, Jan. to May (or complete year), for 1870, also 1871, 1872, and 1873. Miscellaneous books in exchange.-W. Greener, 38 Black Lion Lane, Hammersmith, W. WANTED, "Hogg on the Microscope;" Clarke's "Objects for the Microscope," and other microscopical books; also SCIENCE-GOSSIP complete for 1881, and "Common British SeaWeeds," by L. Lane. Will give in exchange well-mounted micro slides.-W. S. Anderson, 7 Granby Street, Ilkeston.

LARGE number of British marine shells to exchange. Will collectors in all parts of the kingdom send lists of duplicates and receive mine?-J., 15 Warren Street, Tenby.

WANTED, a good microscope. Can offer in exchange a double-barrelled air-pump and accessories; electrical, chemical, and other apparatus; books; stamps; dried plants, &c., to full value.--Mr. Edwards, 34 Ling Street, Liverpool.

WANTED, "Journal of Naturalist during Voyage round the World," by the late Charles Darwin; and the first two vols. of the "Journal of the Postal Microscopical Society," unbound. Stand condenser for microscope, and also turntable.-L. Francis, 1 Elm Villa, Elm Grove, Rye Lane, Peckham, S. E. SPECIMENS of the new British plant, Potentilla Norvegica (see Hooker's "Student's Flora," last ed.), for new varieties of land and freshwater shells or antiquarian objects. Plant not in flower till June.-G. Roberts, Lofthouse, near Wakefield.

WANTED, vols. xi., xii., and xiii. of Maund's "Botanic Garden," or odd numbers.-Miss Higgins, 93 Wellington Street, Luton, Beds.

Good specimens of Canadian insects, reptiles, birds, and minerals for English specimens of the same; also a few Canadian land and freshwater shells for exchange. Correspondence solicited with parties desiring specimens of zoology, botany, and geology from Canada.-W. D. Shaw, Sect. Treas. Montreal Agassiz Association, 34 St. Peter Street, Montreal, Canada. • 4 in., † in., and in. objectives by Ross; exchange good binocular stand.-S., 20 Montpelier Road, N.W.