the Llyn Cwm Orthin has cut a narrow channel in the rock, some fifteen feet deep, I should judge. It then falls about twenty feet down a nearly vertical joint plane. The peculiarity that attracts attention is the extraordinarily small influence the water has had in eating away the surface down which it falls, and the great effect it has had upon its more horizontal bed. This is a characteristic that may be observed elsewhere, at the Rhiadr Ddu, or Maentwrog falls, for instance. It seems to point to the grinding action of stones, sand, and gravel, as the effective cause in the sawing down of a stream-bed, in hard rock, in a mountain district. These materials propelled along the bed of the stream would be always in contact with the rock, whereas at the fall they would be shot over, often without touching the vertical face. This subject of waterfall denudation, is one that requires exploration. I am not aware of any geologist having specially investigated the subject.

We have now returned to the point we commenced to ascend, having made a circular tour on Moelwyn. We may return to Ffestiniog by another route, by following the road towards Blaenau. I would recommend two excursions to be made of this, which I have described as one. A drive to Tan-y-Grisiau to commence with, will leave quite enough work to be done on Moelwyn. The geologist will then commence his work fresh, and will experience no difficulty on the return journey in walking back to Ffestiniog.

(To be continued.)

SCIENCE-GOSSIP.

THE first balloon ascent ever made in our army in presence of the enemy, took place near Suakin on the 25th of March. The balloon used was made of goldbeaters' skin, contained 7000 cubic feet of gas, measured 23 feet in diameter, and weighed 90 lbs. It was inflated from compressed reservoirs with gas made at Chatham, and was guided by means of a rope attached to a wagon below. Communication was kept up by means of pieces of paper attached by a loop to a rope. The balloon remained up nine hours, and the results were apparently considered successful.

WE have received a pamphlet by Mr. G. A. Rowell, entitled, "Electric Meteorology. What is Gas? How the Theory was worked up. An Appendix, 1884."

IN "Science" for February, is an account by Lieut. Greeley of the geographical work of the late Arctic expedition, illustrated by a large map. The discoveries made to the westward of his winter quarters into Grinnell Land and Arthur Land led Lieut. Greeley to the opinion that the western shores of these regions will be found at no great distance.

THE "Annales Industrielles" give an account, says "Science," of the making of cork bricks, now being employed for coating steam-boilers, ice-cellars, &c. The cork is winnowed from impurities, ground in a mill, kneaded up with a suitable cement, and pressed into bricks; then dried, first in the air, and afterwards by artificial heat. They are not hard, and not liable to decomposition; they keep out moisture, heat, cold, and sound.

IN its bearing on the question of hereditary transmission of peculiarities, the following case, recently reported to the "Lancet" from Bridgewater, is interesting. The abnormal number of six digits occurred in the case of a man, his son, his grandchild, and two grandchildren (not all in linear descent), and in all cases it was the left foot which possessed the extra feature.

IN a paper lately read at a meeting of the Chemical Society, Mr. H. Brereton Baker, F.C.S., described some experiments he had made with reference to the effect of moisture upon combustion. He heated both amorphous phosphorus and carbon in dried oxygen and in oxygen saturated with moisture. In both tubes containing moist gas, combustion took place, but in the dry gas, the phosphorus slowly distilled, forming a red and yellow deposit on the cooler part of the tube, while in the case of the carbon in dry gas, no apparent combustion took place. Dr. Armstrong said he had some time ago come to the conclusion that probably chemical action did not take place between two substances, and that he had even ventured to affirm that some day it would be found that a mixture of pure oxygen with pure hydrogen was not explosive.

IN the Annals and Mag. Nat. Hist. for last month is a description by Mr. C. V. Riley, of a new insect injurious to wheat, to which the name of Isosoma grandis has been given.

THE strict political economists will have in future to make allowance for new motives and new courses of action. It deserves to be placed on record that the workmen in the employ of Messrs. William Cooke & Co., of the Tinsley Iron, Steel and Wire Works recently offered a week's work without wages, which was accepted by their employers. The men, being desirous of assisting their employers in some way during the present depression in trade, and being unable to accept reduced wages, in consequence of their being controlled by a board in this matter, decided to make this generous offer, one probably without precedent in English trade, and which has naturally attracted considerable notice.

SIR WILLIAM DAWSON, principal of M'Gill College, Montreal, has been nominated president at the meeting of the British Association at Birmingham next year, 1886.

AFTER a colliery explosion at Unsworth in March last, Mr. C. S. Lindsay showed great endurance and heroism in endeavouring to save the lives of two fellow explorers who were overcome by choke-damp. Mr. Lindsay is said to have carried iron nails in his mouth, which he sucked, and was thus enabled to resist the effects of the choke-damp longer than his companions. The explanation given was that the carbonic acid gas coming into contact with oxide of iron formed insoluble carbonate of iron and so was rendered innocuous. F. R. S., writing to the "Times," with reference to this explosion, says that the quantity of carbonic acid absorbed by this means is inappreciable, as might indeed be expected, and suggests a respirator filled with cotton-wool and slaked lime or caustic soda, to absorb the carbonic acid gas or choke-damp; "or, better still, a cylinder filled with the same material carried on the back with a flexible breathing tube and mouthpiece will enable an explorer to remain for some time in an atmosphere charged with choke-damp which would be at once fatal if inspired directly."

THOUGH rather late, it may not be amiss to warn those of our readers who are experimental chemists against phosphorus trichloride. Dr. Edward Divers, principal of the Imperial Engineering College, Japan, has had a severe accident through the bursting of a bottle containing the trichloride. It had been used for years as a lecture specimen, but while Dr. Divers was warming the neck in order to extract the stopper the bottle burst, and the injury caused was so serious that it was feared the sight of one eye would be destroyed.

A USEFUL means of cultivating among its readers that desirable faculty, observation, is afforded by the "Natural History Journal and School Reporter," in the form of a list of flowers with dates of opening, the average of three years, appended, so that early appearances may be noted, and a Floral Calendar formed. This Journal which is conducted by the Society of Friends' Schools, and is published by William Sessions, York, is in many respects a good example of a school magazine, and the amount of attention to Natural Science which it reveals is highly commendable.

MR. ADAM SEDGWICK has in preparation a new book, to be entitled "The Elements of Animal Biology," which is intended to serve as an introduction to the study of Animal Morphology and Physiology. Messrs. Swan Sonnenschein & Co. are to be the publishers.

WE have received a report of a lecture by Mr. E. Lovett, delivered before the Croydon Microscopical and Natural History Club. The subject of the paper was the evolution of the fish-hook from prehistoric times.

for a

WE must have systematic names in science, we cannot communicate our knowledge satisfactorily without them, but they are not science. What do our readers think of " Amblystoma tigrinum mavortium hallowelli suspectum maculatissimum systematic name? But this is the sort of thing held out in "Nature," as an example of what trinomialism may lead to. It is said that a shortening process has been devised, whereby the above may be written "(Ca) Amblystoma tigrinum." This looks as if scientific knowledge, instead of being open to common folk, as it ought to be, were to be the exclusive property of the favoured few, and to be hedged round with mystery as it was in the middle

ages.

JAPAN seems at present to be the headquarters of earthquake study, and we have fortunately so few earthquakes in this country that no such systematic attention has been given to them. Meantime the one which occurred in the East of England in April last year has been turned to good account after the event. In the February number of the "Proceedings of the Geologists' Association," is a paper with map by Mr. R. Meldola, F.R.A.S., on some of its Geological aspects. The author, discussing the position of the paleozoic and other rocks below the surface, regards the older rocks as not being necessarily concerned with the origin of the earthquake. The disturbance originating below later formations was first spread by the harder sub-cretaceous rocks, and at the extreme limits the shock was propagated along the paleozoic rocks which acted as mechanical conductors of the wave, and thus, as it were, exaggerated the westward extension of the effects.

STAINING NERVE AND MUSCLE.-As to the most perfect mode of demonstrating the distribution of nervous structures microscopists differ. Klein and Cohnheim consider that preparation stained with chloride of gold will show the ultimate ramifications of nerve fibres; whilst Beale ("Microscope in Medicine") says he has never been able to demonstrate the final distribution of nerve fibres by the chloride of gold stain, but did so by specially preparing the specimens and then acting on it with acetic acid. Soak the specimen in glycerine for some days, beginning with a weak watery solution, and gradually increasing the density of the fluid, finishing with Price's glycerine, sp. gr. 1240. Now wash the tissue with glycerine containing 5 drops of acetic acid to the ounce. Put a drop of glycerine, containing 2 drops of acetic acid to the ounce, on a clean slide, place the tissue in it, and apply a thin cover glass. Examine with a high power. The prolonged action of the acid causes the nerve fibres to become slightly granular, and thus to be easily distinguished from the tissues in which they ramify. The muscular structures of the specimen will also be shown by this mode of preparation.-Dunley Owen, B.Sc.

EXAMINATION OF FIBRES, &C.-The "American Monthly Microscopical Journal" for March contains a translation, from "Etudes sur les Fibres," by M. Vétillart, in which flax, hemp, nettle, cotton, jute, phormium, and other fibres are classified and their appearance, dimensions, &c., described. The preliminary directions given, however, scarcely seem full enough, but the translation is not stated to be a continuation.

CRYSTALS FOR THE POLARISCOPE.-It is most vexatious that some of these attractive preparations should be so fleeting. From my own experience this applies to some only, for others appear to be just as enduring. I once had a somewhat large collection of objects of this class, but as they deteriorated I took them to pieces until only a few now remain. All crystals containing sulphate of copper lost their sharpness in a few weeks, and were almost useless in a few months. Sulphate of iron also lost its sharpness, but afterwards appeared to get no worse, while crystals of oxalurate of ammonia, hippuric acid, and salicine are in every respect as beautiful and perfect as when prepared some seven or eight years ago. That dampness will destroy these objects I have had abundant proof; for, once wishing to finish off two slides in a hurry, and my browncement being dried up, I ran a ring of gum-water round the cover-glasses and afterwards finished them. Shortly, the crystals could be distinctly seen dissolving from the outer edge, their gradual dissolution towards the centre being very interesting under the microscope. A friend who devoted much time to this branch of microscopy once told me that

pure balsam would preserve crystals, that would gradually dissolve if the balsam contained turpentine. Perhaps some readers can say whether this is so, or whether gum dammar or copal would be a better preservative, for any method of micro preparation that is not permanent must be very unsatisfactory.— J. W. Neville, Handsworth.

I VENTURE to ask you to give me space for an appeal to brother microscopists in various parts of the world. I am desirous of obtaining samples of mud from abroad, especially from tropical and sub-tropical countries in South America and elsewhere, with a view of cultivating them here. I hope, by so doing, to bring to light many new forms, both of infusoria and rotifera, as the power which these creatures have of protecting themselves against changes in external conditions is so great. The mud should be taken from the surface of the bed of a pond or lake, or some similar body of water, preferably from the surface of the part which dried up last, and should be labelled with the name of the locality. A few ounces will be amply sufficient from each spot, and I shall be glad to refund any expense incurred in forwarding, and to communicate results to the senders.-Edward C. Bousfield, 363, Old Kent Road, London, S.E.

ZOOLOGY.

ASTARTE BOREALIS.-I have received amongst other shore-shells from the beach at Warkworth, Northumberland, a valve of this shell with a very fresh epidermis. Its condition resembles that of specimens taken from a fish's stomach.-R. D. Darbishire, in "The Journal of Conchology."

THE PROCEEDINGS OF THE HOLMESDALE NATURAL HISTORY CLUB for 1881-2-3, recently published, contains an interesting paper by Mr. H. M. Wallis, of Reading, on "Character, as one of the Causes of the Rarity or Abundance of Different Species of Birds." In it the author points out how the different qualities of brute courage, "coolness," teachableness, and adaptiveness, operate in different cases for or against their possessors in the struggle for existence. Sparrows drive martins from their nests and pigeons from their food, and in the winter during stress of weather such boldness would serve the sparrow in good stead. The amount of disturbance birds will tolerate during nesting varies with different species, and the more timid a bird is the less will be its chance of bringing up its young. The Great Auk has been exterminated through its clinging to its traditional breeding sites while the Greater Shearwater escapes in consequence of its solitary habits, so that nothing is known of its nest or eggs. Other instances of the adaptive faculties of birds are given by Mr. Wallis, whose paper is most readable

and interesting. The Proceedings contain also reports of many other papers or addresses, together with other matter botanical, geological and microscopical, and accounts of numerous excursions. The Holmesdale Club, most of whose members hail from Redhill and Reigate, appears to be in a very flourishing condition.

ARION ATER, VAR. BICOLOR.-This variety which I noted in a late number of SCIENCE-GOSSIP, as being found near Stroud, and referring to which Mr. T. D. A. Cockerell in his note last month mentions that I do not give any description of the slug, is upon the authority of Mr. Roebuck, the recorder for the Conchological Society, to whom I sent some specimens, not having noticed it before or having means to identify it. He wrote me, that though he had it previously sent to him from Ireland, this was the first time he had seen it from an English locality. Not taking any notes at the time, nor able at present to visit the place where I found them, I cannot venture upon any accurate description, but, if Mr. Cockerell will send me his address, I shall be happy to forward him some specimens of this interesting variety when I can procure them. I may mention here, that the chosen locality of this variety seems to be damp marsh spots. Have any readers of SCIENCE-GOSSIP, who take an interest in these matters, met with a variety of Arion ater, which has the wrinkles of the skin and the mantle of a unicolorous ash colour, and the interstices of a much lighter colour, almost white, so that when the animal is extended it appears much lighter. This I have found in company with the common black kind, but have not noticed any of an intermediate character.--E. J. Elliot, Stroud, Glos.

NOTES ON MOLLUSCA, MIDDLeSex and Kent.— Limax lævis. On March 29 I found this species in a damp spot near the Thames at Twickenham, associated with H. pulchella, Z. crystallinus, C. lubrica, and Carychium minimum. The river here is very prolific in freshwater shells. I have seen the bed at low water covered with countless specimens of Unio pictorum and Anodonta anatina, dotted here and there with Lim. peregra, L. auricularia, Ancylus fluviatilis, Paludina vivipara, and Neritina fluviatilis; while the grassy banks abound in L. palustris, L. truncatula, and Succinea elegans. On April 5, I again met with Limax lævis living under very similar conditions on the banks of the Cray, at St. Mary Cray in Kent, this time with Zonites nitidus, H. concinna, Succinea elegans, and S. virescens, as well as Z. crystallinus and Car. minimum. The river contains Sph. corneum, B. tentaculata, V. piscinalis, V. cristata, Plan. vortex, P. contortus, P. complanatus, Lim. peregra, and L. palustris. I may here mention that L. lævis is the ninth species of slug recorded for Middlesex, the others being

Arion ater, A. hortensis, Amalia gagates, A. marginata, Limax flavus, L. agrestis, L. maximus, and, last, but not least, Testacella haliotidea, v. scutulum, which has been found in gardens in various parts of the country, including Bedford Park.-Sydney C Cockerell.

BOTANY.

SWISS PLANTS.-Your notice in SCIENCE-GOSSIP (January) called my attention to your observation about the double dahlia. I have watched the enclosed Cyclamen Europæum, apprehending by the slowness in its full flower that it would be overpowered by the first flower. It has succeded. This plant is cultivated and the second year with me, first with the double flower, originally brought to a nursery here found only at one place; up the mountain two miles off there I have found it. I have now collected over 1000 wild flowers, &c., and having duplicates I offered exchange. After five or six years search in the four cantons by a celebrated botanist here, the result did not exceed 1415; a few new ones I have found, he has added to the work he had published, and is pleased with my searchings.1. H. C. Russell.

HELLEBORUS VIRIDIS.-Dr. FitzGerald observes of this plant: "I was struck with the curious form of the stem immediately beneath the flower. It has a wrinkled appearance for about half-an-inch." Having a number of recently gathered specimens before me, March 30, I would remark that while the stems immediately beneath the flower have uniformly this wrinkled appearance of various length, it is also to be observed on the petioles, in one instance I find it nearly three inches long. The cuticle of this plant seems to be of unusual tenuity, which may account for the circumstance mentioned. I am not acquainted with the growth of this hellebore at a later stage, but hope to note it further on.-F. H. Arnold.

WATSON BOTANICAL EXCHANGE CLUB.-We have received a Report of this recently formed club, the object of which is "to promote more intercourse, help, and exchange, between working botanists, and particularly with regard to critical species." The club already numbers over thirty members, and the report contains a long list of desiderata which should give them plenty of work during the coming season. The hon. sec. is Mr. A. R. Waller, Low Ousegate, York.

A BEAUTIFUL specimen of the osprey (Pandion haliaetus) visited Copmere in October 1882, and remained a week on its southern migration.-W. Wells Braden.

GEOLOGY, & C.

FLINT OR STONE IMPLEMENTS.-A considerable number of flint and stone implements has from time to time been found on the top of a ridge of fell-land lying between the East and West Allen, about twoand-a-half miles south-west of Allendale town. Although the number now known to be preserved is large, yet the probability is that it does not represent a tithe of those which are lost. Until a few years ago, the country people living in the district were in the habit of picking up these flint implements and taking them home to strike a light for their pipe. The greatest portion of the implements are composed of flint of various colours, white, red, black, &c., and consist principally of arrow heads of various forms, leaf shaped, stemmed, double and single barbed, and a very few triangular. Some of the double barbed are formed with great exactness; sharply pointed with serrated edges and chipped to a fineness almost microscopic. The serration is of great precision, showing a wonderful uniformity in size, and occur in about equal numbers on both edges. Scrapers, hatchets, saws, flukes, cores and chippings—the latter three being numerous-have also been found. A few implements of greenstone have also been found. The ground where all these articles have been found is covered with a thin deposit of peat of about a foot or 18 inches in thickness, and it is below this where they have been picked up. Similar implements have also been found on some of the adjacent Fells; for instance, Kilhope Fell, near Bent-Head, Wellhope Fell, Weardale, Langley Mill Fell, Plenmiller Fell, &c.-Dipton Burn.

THE POSITION OF PTERICHTHYS.-In the March number of the "American Naturalist," Professor E. D. Cope gives the results of an examination of numerous specimens of P. Canadensis. He points out three important peculiarities, the presence of a single opening in the middle line above, which is comparable with the "nasal pouch" of the lampreys; the absence of orbits, which condition is comparable with that of the lancelet ; and the absence of a lower jaw, in which it agrees with both these types. Professor Cope finds resemblances between Pterichthys and the tunicate Chelyosoma, and thinks that the former genus may have descended from such a type as would be represented by the larva of Chelyosoma, if that be caudate and notochordal as are other Tunicata, and especially if the larvæ possess lateral limb-like processes as in the Appendicularia. The tail has been retained in the European form of Pterichthys, but no trace was found of it in P. Canadensis. In view of the single cephalic opening being the mouth, the author considers that this family should be removed from the Craniata to the Urochorda. Among these, it differs from the Tunicata in having

the anus in the normal position, and he proposes to form a second order of the class to receive it, calling the order Antiarcha. Suspecting that P. Canadensis should belong to a genus distinct from P. Milleri, he would give it, for the present, Eichwald's name Bothriolepis.

THE GRANITE AND SCHISTOSE ROCKS OF NORTHERN DONEGAL.-Dr. Callaway, F.G.S., in a paper read before the Geological Society of London, considers the Donegal granitic rocks to be a true igneous granite, posterior in age to the associated schists. No gradation into other rocks was found; where the granite was in contact with limestone the latter contained garnets. The granite was distinctly foliated, the direction of pressure being perpendicular to the planes of foliation. The author then described the schistose rocks of the region, those of the Lough Foyle series, of most of which the semicrystalline condition was characteristic, being well seen at Londonderry and on Lough Foyle. This series he referred to the Pebidian system. The schistose rocks of the Kilmacrenan series, with intrusive granite, were described as crystalline and older than the Lough Foyle group. During the discussion which ensued, Mr. Teall and others expressed doubts as to the sufficiency of lithological composition alone for the correlation of rocks.

THE RELATION OF ULODENDRON TO LEPIDODENDRON, SIGILLARIA, &c.—At a recent meeting of the Geological Society of London, a paper by Mr. R. Kidston, F.G.S., was read, in which the author expressed the opinion, that the genus Ulodendron of Lindley and Hutton included several species and even different genera; the three species which have furnished the specimens, usually described as Ulodendron, being Lepidodendron Veltheimianum, Sternb., Sigillaria discophora, König, sp., and S. Taylori, Carruthers, sp. He was of opinion that the ulodendroid scars marked the point of attachment of caducous sessile cones. Mr. Carruthers, in the discussion which followed, considered the organs borne by these scars to be aerial roots, while Professor Boyd Dawkins and Professor Seeley agreed with the author that they probably bore seed or fruit organs.

A RECENT TERTIARY SURVIVAL?-At the same meeting, a paper by Dr. H. Woodward was read, on "Steller's Sea-cow" (Rhytina gigas = R. Stelleri) a toothless Herbivore which lived along the shore in shallow water. In 1741 it was confined to Behring's Island and Copper Island, but it was believed to have been wholly extirpated by 1780. Dr. Woodward regarded Rhytina as a last surviving species of the old Tertiary group of Sirenians, and its position as marking an "outlier" of the group now swept away.