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BECK, Ltd., 68 Cornhill, London, E.C.. APR 6 1901 SCLENCE-GOSSTP. BUTTERFLY-COLLECTING IN 2 to = CORSICA. BY DHE Riv. H.C: Lance, M.D: 7AN STS having had some successful weeks of # Digne, St. Martin Vesubie, and other places in the South of France, and butterfly-collecting at finding myself at Nice, I determined to visit Corsica, Having succeeded with Papzlio alexanor at Digne, I thought I might as well try to take P. hospzton also. Corsica had always been to my imagination a sort of From Photo | [4y Drv. Lang. Forest OF VIZzAVONA. enchanted island, with a certain air of mystery hang- ing over it apart from brigands and vendettas and things of that kind. I knew there were certain butter- flies which one could only see there alive, unless So I started from Nice in the very best of spirits on Saturday one chose to go further on to Sardinia. evening, the 8th of last July. hittle steamer of the lightful, as much as a summer night on the Mediter- ranean could make it. When we anchored off Calvi at 4 A.M., and the sun in rising began to light up the mountains in the centre of the island, I felt that my eyes were resting on a fairer scene than had ever before delighted them. April 1g00. No 71. The trip on board the Fraissinet Line was most de- Vol. VI. Going ashore in a small boat, I had to! wait at Calvi some two hours before my train started for Vi nation. zavona, Which place I had selected as my desti- I had ample opportunity of admiring the effect of the increasing light upon the marvellous scene of land and sea; but closer attention revealed the fact that vegetation was much dried up on the coast, and there was very little to be seen in the way of verdure, except ‘some thick bushes climbing up the rock on which the citadel is built. My ‘‘ Gerz” glass resolved these into dense masses of the prickly pear cactus, which seems to grow everywhere round the coast, and is used for making hedges and fences. Very striking was the strong aroma that literally filled From Photo.) [6y Dr. Lan Granp HOreEt DE VizzaAvona. the air. This [had noticed on board some miles away from land, just as one smells the scent of gorse when oft the Cornish this occasion I could certainly smell Corsica 1 coast at a distance out at sea. On before it could be seen. The fascinating and powerful Ai scent is caused chiefly by an aromatic | chrysum angustifolium, which clothes the ‘} 322 and extends up into the forest region. Myrtle, bay, mountain pines, and thyme are also probable com- ponents of this natural incense. A railway runs right through the island, and carries with it its civilising power. in Corsica now, though it is said one or two ex- members of that profession are still to be interviewed by the curious in such people or by students of There are no brigands criminology. who would wish it to be faster that sees Corsica for the first time on a July morning? For a period the route is near the coast; and the glimpses of quaint The train moves very slowly; but towns with cupola-topped church towers, of rocky headlands jutting out into the sparkling sea, make one forget the time that is passing and the heat that is increasing as the sun mounts up towards noon- tide. Soon we get on to the ‘‘ Makis,” the wilder- ness that lies between the sea and the forest zone, sloping gradually upwards. It is as wild as Dartmoor, but softened with the balmy breath of southern breezes ; and luxuriant are the plants already alluded to, with many others. Here and there we passed a road whose milestones reminded one that we are ina department of France. Once there was seen a cyclist, to show that Corsica is up to date. On we went, slowly but pleasantly upwards, until we reached Corte, on the verge of the forests and backed by lofty mountains. It is a strongly built and fortified place, bristling with romantic episodes in the former days of Corsica’s history. After passing this town the scenery increased in grandeur as we continued up- wards through rocky gorges and steep mountain slopes covered with magnificent pine forests. We reached the sub-Alpine pine zone at Vivario, and by the time the train stopped at Vizzavona were in the very heart of the best entomological collecting-ground, and in almost the exact centre of the island. Vizzavona itself consists of a few scattered peasants’ eottages, a railway station, and a large hotel, ‘¢ The Grand Hotel de Vizzavona.** This building looks strangely out of place, and one is at first inclined to view its presence with feelings of the deepest resent- ment; but a further acquaintance with its convenience and comfort compels an alteration of opinion, It is in the forest of Vizzavona, on the upper verge of the pine region, consequently much better situated for butterfly-collecting than the less pretentious and more picturesque ‘‘ Hétel de Monte d’Oro,” which is higher up the road to Ajaccio. On the right-hand side-going up the pass is Monte d’Oro, about 8,000 ft. high, and on the left Monte Renoso, about the same alti- tude. Vizzavona itself is at an elevation of 4,000 ft., consequently with a climate much cooler than that of the coast or the ‘* Makis.” Above the pine zone there is an extensive forest of beech-trees, such as one sees on the hills in Buckinghamshire, and above this rocky slopes leading up to the mountain sum- mits ; but these are not the best regions for butterflies. The mountain lepidoptera of Corsica are sub-Alpine, and no Alpine forms occur. There are no Parnassii, Erebiae, Alpine Argynnides, Coliades, or Lycaenids, SCIENCE-GOSS/P. such as one would certainly meet with on the main- land at elevations equal to that of these mountains. The best collecting-ground is on the descent from Vizzavona to Tattone, and on this route most, if not all, of the special Corsican forms of butterflies may be met with. Judging from the ‘‘sugar’’ marks on the tree-trunks by the roadside, this is also a good locality for moths. These special forms of butterflies, some of them peculiar to Corsica and Sardinia, are Papilio hospiton, Anthocharis tagis var. wesularis, Vanessa tchnusa, Argynnis elisa, Satyrus neomiris, S. semele var. artstaeus, Pararge tigelius, Coenonympha cortnna, and Syrichthus sao var. therapne. On ar- riving at Vizzavona, at about 2 p.M., I almost at once started out to look for butterflies, the afternoon being bright and sunny. Just outside the hotel Coezo- nynipha corinna was in great abundance ; but whilst I was busy with these, there came on a very heavy thunderstorm with drenching rain which compelled me to seek shelter. The rain lasted for the rest of the afternoon and evening. The next day being fine with a cloudless sky, the following species were ob- served: Papilio machaon var. aurantiaca, Pieris brassicae, P. rapae, L. sinapis, C. hyale, C. edusa, Polyommatus phleas (with a dark form approaching var. elews) on Helichrysum at Tattone. Lycaena aegon is a small dark form at Vizzavona, L. zcarus has there an underside much resembling that of L. sephyrus, but with intra-discoidal spots on fore- wings. ZL. argéolus is common at Vizzavona by the roadside, with underside nearly white and with very small spots. This was ‘chiefly found flying round bramble bushes. Z. avgzs was also taken. Whilst referring to the roadside I may mention that on the road between Vizzavona and Tattone nearly all the butterflies that are found in Corsica may be taken ; and we can strike right and left into the pine woods at the foot of Monte Renoso on the one side, and Monte d’Oro on the other. It is in this district that Papzlio hospiton can be taken at the proper time, though I, being too late for it, did not see any. For the opposite reason, because too early, I did not see any Vavessa tchnusa, which appears about July 20th. The Vanessae I found were J. c-album, V. egea, V. to, V. atalanta, and V. carduz. Fritillaries were tolerably common, the species being Argynnts pandora (a fine fresh specimen of which I took in the hotel garden at 8 A.M.), drgynnis paphia var. anargyra, and A. eltsa, which may be taken commonly in open places in the pine woods when the sun is out. It is very conspicuous on account of the small size of the black spots on the bright fulvous wings. Among the Satyridae I saw no species of Melanargia nox of Erebza. Satyrus semele is repre- sented by the var. avrzstaews, which was not un- common. The only other Satyrzs was S. neomiris, a pretty insect which is very abundant at Vizzavona. I believe it is quite distinct, and not an insular form of any other species. Pararge egervéa in the usual southern form was not uncommon; P. megera var. tigelius Was common at Tattone and at Bastia, where SCIENCE-GOSSTP. I also found 2 pinephele tithonus, and more fre- quently 2. zda. 2. jantva occurs commonly in its var. hzspulla, which does not differ from that form found. in the South of France. Coenonynipha corinna was the commonest butterfly at Vizzavona, a very pretty and distinct little Satyrid. It was to be seen everywhere and in great numbers. C. pamphilus, though found there, is not nearly so common ; I did not take the var. /y//us. I found no Hesperidae during my stay in Corsica, though I sought diligently for Syricthus therabne, which I had hoped to find. On Friday, July 14th, I began my return, going by train to Bastia, which I reached at noon. ‘There it was intensely hot, but very enjoyable. The old town, with its picturesque church and_ buildings mingled with southern vegetation and sloping down to the blue Mediterranean, formed a picture worthy of Ruskin’s words or Stanfield’s brush. After lunch I braved the fierce heat, and went collecting in some orchards on the hillsides behind the town. My takings were principally Satyridae, including Sa/yrws 23 ios) aristaeus, S. tithonus, S. tda, and \S. tigelius. Everything was so dried up that it was difficult to- find a verdant spot, so I had to trespass on private grounds. No one interfered ; probably my net was a sign that I was like the manin ‘* The Runaway Girl” ‘searching for the rarer lepidoptera,’’ and so I was left alone. This evening Bastia was ev fée; and sucha Jcte\—a “ festa duplex major,” as ecclesiastical language would express it. So we left the harbour, on board the steamer, amid the firing of guns from the citadel, fireworks, and illuminations—-for it was the ‘‘ Féte Nationale.”” One was glad, in spite of the vivacity of the scene, to get out into the stillness of night upon the sea, and steam back to Nice in peace and quietness. Though Papilio hospiton was not in my collecting- box, I had a fair collection of Corsican butterflies — made during my five days’ visit—and, more than that, I had seen and also scented this wonderful island. I left Corsica with the hope of some day paying it another visit. All Saints’ Vicarage, Southend-on-Sea: March 3rd, 1900. REARING SNAILS IN CAPTIVITY. By ELEONORA ARMITAGE. HE remarks on homing of snails and other matters connected with the living animal in SCIENCE-GossiP (ane, p. 243) have interested me, and I feel tempted to transcribe some of my notes and observations on the subject. I am not a col- lector of shells nor a student of conchology, neither do I possess any literature on the subject ; therefore anything I can say is only a record of my own ob- servations. In the summer of 1895 I was given two individuals of the ‘* Roman” or ‘‘ apple” snail (Hed?v pomatia), which is not found in this neighbourhood. I kept them under a large bell-glass in a shady part of the garden, sometimes on turf and.sometimes on a flower- border, where they could burrow at their ease and keep themselves moist and cool. T fed them on cab- bage and lettuce leaves, with a strawberry now and then. Occasionally they were allowed to take exer- cise, being tethered to a stake on the grass by means of a long piece of fine string, one end of which was tied round the shell. them crawl to the end of their tether and strain to get beyond, pulling more than I ever saw before of a They spent most It was interesting to watch living snail’s body out of its shell. of the daytime sleeping, nestled in the grass or under the shade of a cabbage leaf, awakening in the evening to crawl over the interior of the bell-glass and to feed, which they: did mostly at might. Often they roosted on the glass. I had to keep them prisoners, as I did not want them to devour my choicest flowers, which is what snails and slugs always do ; but I have known them escape, probably by burrowing beneath the Fell-glass and eventually emerging on the other I have frequently recaptured them ; they do not stray very far, and are conspicuous by their size and the light tints of the shell and the pale colour of side. the foot. They did not display any homing instinct ; I have never known one to return to the bell-glass or its neighbourhood. Both these individuals in July burrowed about two to three inches in the soil and deposited eggs. and opaque, and about the size of a garden pea. The egg is white, round, glistenin:, Unfortunately none of these eggs hatched out: the weather was very hot, and probably some dried up and some were devoured by slugs and insects. Towards the end of October they retired under- ground, and when I dug them up a few days after I found that they each had made a very neat, smooth white porcelain door to the mouth of the shell and gone to sleep for the winter. They were safely re- interred about three inches below ground. The larger of the two snails weighed one ounce, its diameter was 1} in. x I$in., girth 5in. x q2in. ; >In. ; the smaller one weighed ? ounce, diameter 12 in. I} in. ; girth 4} in. x 3? in. In the spring of 1896 the larger snail emerged on April 24th, while the smaller one didnot appear ull May 23rd. During the summer the larger snail laid a batch of eggs and the smaller one two batches. Early in July the larger snail died. I was deter- mined, if possible, to rear some young snails; so I put some damp moss in a biscuit tin, and placed the M 2 324 eggs among it, and some young dandelion plants to act as food for the baby snails on emerging. Of course the lid was kept on the tin, with air-holes punched in it. After four or five weeks’ the little snails hatched out at the end of July. They were tiny white transparent things, but lively and hungry. After feeding, the greenstuff could plainly be seen in the alimentary canal. In two months they had about doubled in size, and were getting some pigment on They settled down to dandelion diet at once. ‘the shell, which was extremely delicate and brittle. In the autumn they, too, made doors to their shells -and went to sleep ; and the tin containing them was buried in the ground. At the beginning of April 1897 they were dug up, and I found that most of them were already awake and beginning to feed. in diameter, They were now about 2 in. and grew during this summer to about % in., but varied slightly both in size and colouring. On March 17th, 1898, two of the young ones awoke and appeared above ground ; this was rather an early date. They summer. In 1899 I had one original snail and a dozen young ones. grew considerably during that The latter grew as large as the old one ; and now that they have hibernated I cannot distinguish that one from the others, but I believe it to be alive still. None of the young ones have laid eggs as far as I know, and they are now three and a half years old ; therefore the old one, which was full grown when I had it in 1895, should be nowat least eight years old. I have often asked, and have never been able to ob- tain, the information as to how long is the lifetime of a snail; but some one once suggested two years. To obtain an answer was one of the reasons why I took to keeping snails. I weighed and measured these snails after they had hibernated, the differences be- tween them being small. The average is :—Weight, height, T expect they will grow larger next year. 2 02.3; size, length 14in., width 12 in. ; 1} in. The Roman snails have not developed any tame- ness in captivity, but continue to draw in their horns and bodies at the approach of a human being. Snails can, however, be interesting pets and become quite tame. In May, 1896, I obtained four specimens in Barbados, W.1., ofa very large handsome land snail, Bulinius (Borus) oblongus, and brought them back to England in June. I could not bring their own food for the voyage, but they fed on lettuces supplied by the steward. They lived in a large biscuit tin, and took exercise on deck in fine weather and on the saloon tables when it was cold. When they reached their home they were put under a large bell-glass in a shady spot. They did not care for cabbage, but would .eat Icttuce and preferred dandelion leaves to anything else. They liked bur- They have a handsome long conical shell, selfcoloured pink with a dark border ; the body is a very dark slaty-black colour, with a broad Ilunt head, fringed lips, and a large rowing in the moist earth. SCIENCE-GOSSTP. mouth-opening. The following measurements will give an idea of the size of these fine molluscs. No. 1 : length of shell, 37 in.; length of foot, 5$in.; weight, 40z.; No. 2: shell, 33 in. ; foot, 5in.; weight, 43 oz. They looked very fine, crawling about in a dignified manner, five inches of dark foot carrying the large pink shell. Fearing the rigours of an English winter for tropi- cal snails, I sent them to the kind care of the Superintendent of the Zoological Gardens, London, where they spent the winter in a glass box in the Three of the four survived to return to me at the end of May in the following year. They fed well, and crawled about and burrowed as usual; but after the middle of July they faltered, and one after the other died in a few weeks, first ceasing to feed and becoming almost inactive. I could not discover the cause of death, but they may have reached the limit of their existence. They did not breed in England. I found it was quite unnecessary to tether these snails, as they had a strong homing instinct. I took them out daily from the bell-glass, and put them some little distance away on a piece of turf, where they liked crawling about and feeding ; and after they had had enough of it they always turned homewards, and went back to the bell-glass. Here they used often to begin burrowing in the soil just outside the glass, so as to get back inside. I have found them in various stages —some partly, and some quite, underground. They used to meet the Roman snails occasionally, and even crawl over each other, but they never showed any inclina- Phey were not at all Insect House, eating lettuces. tion for acquaintanceship. afraid of me, and did not shut up in their shells when I took them up; but they liked to sit on the back of my hand. I think they enjoyed the warmth, and they always came fully out of the shell; then I would give the snail a tender young dandelion leaf, poking the apex of it to the mouth, which at once opened and closed on it. I held the other end, and in a marvellously short time the whole leaf would dis- appear down to the stalk ; while the chewing of the tooth-ribbon made quite a loud rasping noise. The mouth was so wide that a small leaf could enter flat. I much regretted the loss of these interesting pets. Dadnor, Ross, Herefordshire : Sanuary 1909. THE Common BirreRN.—This rare and interest- ing bird has been recorded from several parts of both England and Ireland during the past winter. Weight 16 oz. Printer, Projector, Keverser, fitted with high-class Lenses. SEDAN) eS SEED Price complete, £6 10s. REDUCED TO £5 10s. Sensitive Films, positive and negative, 25 [t., 3s. 6d. each. EXTRAORDINARY VALUE. Wo complications. So simple a child can use it. HUGHES’ PETITE AMATEUR PROJECTOR. 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WEST, 26 Woodville Terrace, BRADFORD. Send Stamp for detailed List of 76 different Series. SEND FOR OUR ~——— Mlustrated Catalogue or MICROSCOPES AND APPARATUS Post Free to Readers of Science-Gossip. MOUNTED SPECIMENS. Specially prepared for Teaching purposes.—A Speciality. SERIES I. Illustrating Elementary Botany. SERIES II. 5 the Life Histories of Plants. Bither Set, 72 Slides, £3 3 O, Special Set illustrating the Anatomy of the Frog. C BAKER, May 6 7 Aquar ds* a, 22.28 5, Bosse To he lvoked for just ‘before sunrise. CONJUNCTIONS OF PLANETS WITH THE Moon. oO: Apr. 3 2 Venus} Iam. planet 0.46 N. pp) oats) Jupite Oot 2G) jefe. on ay vucey UNI an 3) Saturn Si pamen vei 5 eye! 35 7} Mercury“ Ty pamigewnr. ni Ss. 2, 27 Mars*} a6 p.m. Se 7 on ” s Daylight. + Below English horizon. OccuLTATIONS AND NEAR APPROACHES. Dis- Angle Re- Angle Magni- appears. from appears. from Apr. S¢far. tude. ht. Vertex. h.m. Vertex, ° ° fi o Tauri 9-30 P.M. .. 29 -. 10.22 p.m... 263 -v Geminorum 1.6 am... 157 .. Near approach Soen Cancri + 11.46 p.m. .. 53 12.45 p.m. 277 17..8 Scorpti Io.45pm.. 224 .. Near appreach 21..¢° i 2.27a.m... 110 .. 3.42a.m.... 267 24--c' Capricorni 3-23 a.m. Ora sercy/ cous on eey/ THE SUN has again been exerting considerable energy. On March goth two fine spots were seen advancing towards the limb. No trace of them was seen four days previously. MERCURY is a morning star all the month, in Pisces, reaching its greatest western elongation, 27° 19’, at 3.a.m. on April 22nd, but badly placed for observation, rising only about half an hour before the sun. VENUS is an evening star, in good position all. the month, It is in Taurus, and at midnight on April 28th reaches its greatest elongation, 45° 30’ east. The planet cannot well be better placed, not setting until about four and a half hours after the sun. MARS is too close to the sun for observation. JUPITER rises nearly a quarter of an hour before midnight on the Ist, and two hours earlier on April 30th. SATURN rises about two hours later than Jupiter. Both are too far south for very successful observation. URANUS is very near to Jupiter, coming to the meridian only a few minutes later than that planet. and situated just over a degree farther to the south. NEPTUNE at the end of the month will be found about four and a half degrees to the south of Venus. GIACOBINI’S COMET (a 1900) is estimated Ly M. Javelle to be equal to 13th magnitude, and therefore is out of the reach of small instruments. On the afternoon of April 28th it will be in perihelion. THe Isaac Newron STUDENTSHIP, at Cam- bridge University, of the annual value of £200, for ibis years, has been awarded to J. Hopwood Jeans, B.A., of Trinity College. APPARENT ENLARGEMENT OF CELESTIAL OBJECTS NEAR THE HORIZON is a subject which from time to time causes much correspondence. A paper from Mr. J. D. Hardy and a_ note from Rev. Joseph Allen were read on the subject at the meeting of the British Astronomical Association on February 28th, and led to considerable discussion. No very definite conclusions, however, have been reached. Dr. KARL THEOpOR LUTHER has just passed away in his seventy-eighth year. So far back as 1834 he was elected an Associate of the Royal Astro- nomical Society. On April 17th, 1852, Dr. Luther discovered, at Bilk, the 17th minor planet, Thetis. This was but the first of some four-and-twenty of hese bodies; he likewise calculated the orbits of many others. For a long time he had been Director of the Diisseldorf Observatory. PROFESSOR PIAZZI SMYTH, son Admiral W. H. Smyth, has also died. Previous to his resignation in 1888, he was for many years Astronomer Royal for Scotland, and once made an expedition to Teneriffe to observe the celestial objects under more favourable atmospheric condi- tions. A popular account of this visit is given in his book on ‘* Teneriffe,” illustrated by stereoscopic views. He was well known as holding most singular views respecting the Great Pyramid, which were given to the world in ‘* Our Inheritance in the Great Pyramid” in 1864. The late R. A. Proctor, in 1884, ruthlessly shattered his contentions. of the late THE ToTAL ECLIPSE OF THE SUN.—We are sorry to hear that there is danger of the British Astronomical Association expedition to Portugal, Spain, and Algiers falling through, only two-thirds of the requisite number having booked their passage. It had been hoped that the Royal Mail Steamship Tagus would have conveyed the party to Oporto, Alicante, or Algiers, and afterwards collected \the members and brought them home. Those who remained on the Portuguese coast would have the greatest chance of disappointment. An effort will be made by Mr. Nevil Maskelyne to obtain a kine- matographic record of the eclipse from an American station. We trust that on this occasion the attempt will prove successful. SCIENCE-GOSSIP. 349 CONDUCTED BY JAMES QUICK. SEAT OF THE E.M.F. INA VoLTarc CELI This formed the subject of the presidential address recently given by Professor Oliver J. Lodge to, the Physical Society. He said : —‘* Strange that a dis- covery of this magnitude, and I may say also, in one sense, of this simplicity, should have been associated with a controversy which, arising in one form almost directly it was announced, has continued, with slight modifications and with temporary lulls, yet really without cessation, throughout the whole century. — I hardly know of another instance of a question to which every physicist in the world must necessarily at some time or another have given his attention remaining so long unsettled. What is the seat of the chief electromotive force in the voltaic pile?” Pro- fessor Iodge then discussed the controversy from the contact and the chemical sides. The opposing sides of the old controve used to be called ‘‘ contact . theorists” and ‘‘chemiical theorists.” Now the opposite sides are involved both in contact and both in chemical views. It is a question of which of several contacts is the effective one, and what kind of chemical action or affinity is the active cause. Is it the contact and chemical affinity across the metal-metal junctions or across the metal-air junctions? The opposite sides are thus metallic and dielectric. The metal-air force is of the order volts ; the metal-metal force is of the order millivolts. When a piece of zine is put in contact with a piece of copper, the oxygen atoms which surround these bodies move slightly away from the copper and approach slightly nearer to the zinc. These slight motions produce the whole Volta effect. All that is necessary for the Volta effect is the inherent film on the surface; all the rest of the gas is mere dielectric, and might be substituted by a vacuum. The safest and clearest mode of expressing the Volta effect is that it consists in an opposite charge acquired by dry zine and copper while in metallic contact—a charge which results from an E.M.F. of fixed value and is controlled solely by this E.M.F. and electro- static capacity. FLUORESCENT SCREENS. — When Rntgen-ray observations are made by means of fluorescent screens, a certain short time is found to elapse before.the X-ray picture is built up. The bones of the hand, for instance, are not visible at once on the screen ; they gradually separate out from the flesh. This effect is only partially due to a change in the radiation impinging upon the screen. What is known as a ‘‘hard” X-ray vacuum tube produces radiographs with greater contrast than ‘‘soft” tubes do, and the above effect might be put down to the hardening of the tubes while in action. On the other hand, how- ever, a gradual and distinct brightening of the screen is observed, which is quite independent of any change in the radiation and is unaccompanied by any ob- servable change of colour-or chemical constitution. Some experiments made in this direction recently by Precht show that the time required for a good development of the radioscopic picture is on the whole shortest at the highest discharge potentials. It varies from a few seconds toa minute. A feasible explanation of this phenomenon lies in an allotropic modification of the substance of the screen, as sup- ported by Becquerel for radium rays. Precht, how- ever, puts forward an emission hypothesis for Réntgen! rays. Proressor D. E. Hucies.—aAt a recent meeting of the French Academy of Sciences it was announced that the late Professor Hughes had bequeathed to that institution a sum of £4,000, the income of which is to be used as a prize for the most important discovery in Physical Science, preference being given to a discovery in electricity or magnetism. A similar announcement was made by the President at a meet- ing of the Institution of Electrical Engineers a few ‘ks ago, to the effect that Professor Hughes had bequeathed the sum of £2,000 for the foundation of a ‘* David Hughes Scholarship” in connection with the Institution. ELecrric Fish oF THE N this heading a note appeared in the ‘‘ Physics” column of ScIENCE-Gossip for May 1899, p. 372, when par- ticulars were given of Professor Gotch’s lecture delivered at the Royal Institution on March 17th of that vear. Professor Gotch’s hypothesis was that the seat of the electromotive force in the fish known as the Malapterurus electricus lies in the nerve centre itself, and not in the so-called electric organ. Some recent experiments by Professor Gotch and Mr. G, J. Burch point still more conclusively to this hypothesis being the correct one. One of Mr. Burch’s capillary electrometers was used for measuring the values of the electromotive force. The fish experimented upon was first anaesthetised and then killed, and a strip of the electric organ with the nerve was carefully dis- sected out and kept at a temperature of 5° C. The time-lag between the excitation of the nerve and the record of an E.M.F. was then observed. From the various results obtained, the authors think it probable that the greater part of the time was occupied by the slow transmission of the excitatory state along the finest subdivision of the nerve within the organ near the ultimate ends. In dissecting the anaesthetised animal Professor Gotch strong shock while dividing a nerve-branch with metal scissors, the organ being grasped with metal forceps. After a comparatively few successful experiments the ex- citability of the nerve suddenly failed, and this was attended by inability of the organ to respond, whether a stimulus was applied to the nerve or to the organ substance. Measurements of the resistance of the organ were made, and it was found by taking read- ings longitudinally to the column and _ transversely, ¢.e. across and parallel to the ‘‘ discs ” respectively, that the resistance of the thin ‘‘ discs’? was consider- ably higher than that of the albuminous composition between them. If Professor Gotch’s theory is the correct one, then what is the function of the so- called electric organ ? May it not combine the duties of condenser and connection board? It may be for this rerson that the ‘‘ discs * are formed thin and are of hiz) resistance to serve as dielectrics between the conducting albuminous fluid in the compartment spaces. received a SEARCHLIGHTS.—A new portable electric search- light is reported to have been recently added to the equipment of the New York fire brigade, for use at night fires or where the smoke is very dense. The lamp takes 35 ampéres of current, and will emit a light of about 6,090 candle-power. ies) UL (e} CONDUCTED BY EDWARD A. MARTIN, F.G.S. Society oF LoNbOoN.—On the retirement of Mr. W. Whitaker, B.A., F.R.S., from the Presidency of the Geological Society of London after his two years’ term of office, Mr. J. J. H. Teall, M.A., F.R.S., was, at the annual meeting on February 16th, elected to fill the office. WoMEN AS FELLOWS. —The question of admitting to Fellowship of the Geological Society of London those geologists who are at present disqualified by reason of their sex was discussed at the anniversary meeting on February 16th last. The subject was brought up on account of the resignation from the Council of Dr. G. J. Hinde, F.R.S., as a protest against the oie of the Council to invite a lady to ‘attend in person to receive a medal which had been awarded to her by the Society. So far as the Fellows present were concerned, there seemed to be a large majority in favour of women Fellows. The subject was by mutual consent withdrawn, after being discussed by Dr. Woodward and Prof. Ifughes ; it being under- stood that the Council would further consider the matter. Dr. Woodward incidentally mentioned that forty years ago Mrs. Horner and Lady Lyell were constant visitors to the Society’s meetings. WATER-LINE IN CHALK.—In discussing the water-supply of Yorkshire, in a recent lecture before the Hull Naturalists’ Club, Mr. J. R. Mortimer states that the water-line in the chalk in no place exceeds a maximum depth of 300 feet, and makes the interesting observation that the water-line is not a horizontal plane, but rises northwards and westwards, somewhat resembling the contour of the chalk itself. Mr. H. P. Slade also found in Berkshire that the water-line has a strong tendency to follow the contour of the chalk. No explanation of this appears to have been suggested. It would be interesting to know if at other places a similarity has been noticed. GEOLOGICAL POINT OF ORIGIN OF EARTHQUAKE SHOCKS.— In a recent discussion at a meeting of the Geological Society of London the correctness of Mallet’s theory, that the point of origin of an earthquake shock may be determined by the angles at which consequent cracks in buildings appear and at which chimneys are tilted out of the perpendicular, was questioned by Professor Milne. who aptly asked what ground there was for thinking that such cracks would always appear at right angles to the direction taken by the shock. So far as he couldsee, it was a theory unsupported by facts. Professor Sollas pointed out that, owing to refraction caused by a shock passing from hard rocks into superficial rocks of a less dense character, a consider- able degree of refraction of the line taken by the shock might ensue. Consequently, the point of origin of the earthquake might really be at a far less depth than would be supposed. COLOURING OF GEOLOGICAI, Maps.—Many geo- logists have felt the necessity of adopting a aon colouring for the maps w hich they prepare, and will gladly welcome the latest suggestion, which indeed SCIENCE-GOSSZP. has been carned into execution, of adopting the prismatic colours in successive order. In such a hypsometric map the violet end of the spectrum is used for the older rocks, the newer formations being coloured in succession with tints approaching the red end of the spectrum. The effect’ of such a map is very striking, and we recommiend a trial of the system in making geological maps. MALVERN AND. ABBERLEY _ITILLS.—Professor Groom has been continuing his studies ‘On the Geological Structure of Portions of the Malvern and Abberley Hills,” and has communicated his observa- tions to the Geological Society. In his paper he gave descriptions of the exposed rocks of the Malvern Range from Swinyard Hill to North Hill, the dis- trict of Cowleigh Park, Martley, Woodbury, Walls- grove, and the neighbouring tract of Coal Measures. The Silurian rocks west of the hills are almost in- variably inverted, and the Malvernian rock frequently can be found to be overthrust on to them, In several cases there is reason to suspect that slips of Silurian rocks are caught in infolds amongst the Malvernian rocks. The author concludes that the whole of this district, May Hill, the Old Red Sandstone tract to the west, the coalfields of the Forest of Dean, S. Wales, and Bristol, and the Tortworth district, are traversed by a series of related folds, whose axes run in two chief directions intersecting at a considerable angle : the axial planes of one set tend to dip east, and of the other in a southerly direction. Overfold- ing has taken place frequently from the east, less frequently from the south ; and this inversion affects the southern as well as the middle and north of the Malvern range. The Archaean rocks are thrust into various members of the Carverian System in the south and of the Silurian System in the north. The intensity of the folding diminished west of the old ranges. The chief movement appears to have progressed in sections from north to south, and the western fronts of different sections show some tendency towards convexity in the direction of movement. COLOURING MATTER OF FLUORSPAR AND CAL- CITE.—The question as to whether the beautiful coloration which these minerals sometimes exhibit is of organic or inorganic origin has been much dis- cussed. Ina paper in the annual report for 1897 of the Naturalists’ Society of Brunswick, Herr Frome publishes the results of some chemical experiments undertaken with the view of settling the matter. Analysing a specimen of chestnut-brown translucent calcite, he found that it contained no iron or man- ganese or other inorganic substance calculated to impart the dark colour. The mineral completely dissolved in HCl with a wine-yellow colour and sepa- ration of brown flocks. The latter was found to be identical with Berzelius’s apocrenic acid. The amount of this was about 0:2 per cent., and o-o1 per cent. of another blackish acid was also obtained from the yellow filtrate. Herr Frome concludes that these acids exist in combination in the calcite, and from an ammoniacal solution of apocrenic acid containing some bicarbonate of calcium he obtained artificial crystals of brownish calcite exactly similar to those of the natural mineral. I may add that the apocrenic acid aforesaid is com- monly found as a constituent of vegetable mould and humus matters, and is doubtless of organic origin. It results from the decomposition of the benzene deriva- tives contained in decaying leaves and rootlets, and perhaps some of the cellulosic-proteid combinations of the plant may also contribute to its production. — DD pS IPL O), Keegan, Patterdale, Westmoreland. SCIENCE-GOSSIP. CORRESPONDENCE. We have pleasure in inviting any readers who desire to raise discussions on scientific subjects, to address their letters to the Editor, at 110 Strand, London, W.C. Our only restriction will be, i case the correspondence exceeds the bounds of courtesy ; which we trust is a matter of great improbability. These letters may be anonymous. In that case they must be accompanied by the full name and address of the writer, not for publication, but as an earnest of good faith, The Editor does not hold himself responsible for the opinions of the corre- spondents,—£a. S.-G. OBSERVATIONS ON VARIABLE STARS To the Editor of SCUUNCE-GosstP. Str,—It has occurred to me that the fullest advan- tage has not been taken of all the data which observation of variable stars has given to us. I pro- pose to show, taking the well-known variable Algol as an example, that several more interesting facts may be determined. The following is a summary of what we already know about this star. Algol and his satellite revolve in circular or approximately circular orbits, for the variations of speed indicated by the spectroscope are precisely those which would be shown by a body revolving at a uniform rate ; these orbits are of course in the same plane. The line of sight from the earth to Algol also lies in this plane, for Professor Pickering has found that the method of diminution of light during eclipse is exactly such as would be caused by a spherical body passing in front of Algol. The eclipse is therefore annular, not partial, and the conclusion just given follows at once. The complete period of revolution of either Algol or his satellite is very approximately 4,089 minutes, that of greatest eclipse is 20 m., and the total period of eclipse is 560m. Algol varies from the second magnitude at maximum to the fourth at minimum ; 7.c. at the time of greatest eclipse we receive from it (2-512)2 of the light we receive nor- mally. Now it follows from the ‘‘law of inverse squares ” that when an opaque sphere passes in front of a large luminous one, that s, being surface of luminous sphere, s, that of opaque one, D, distance of former, D, that of latter, 1, light of former un- eclipsed, L, when at greatest eclipse, then (i= tp) ee -. if A and B& represent the diameters of Algol and his satellite respectively But the difference between the distances of Algol ard his satellite is so minute, compared with that of either from the earth, that the ratio of D, to D, may, with- out any appreciable error, be taken equal to unity. 4 14 (Ly — Ls) B L,—L.s Taking L, : 1, = (2°512)?, this gives that, corrected to six places of decimals, the diameter of Algol is I°O9QOI00 times that of his satellite. There is, how- ever, another entirely different method of finding this ratio which I will now explain. A little con- sideration will! show that the distance across the “line of sight ” from the Earth to Algol which he Soil and his satellite traverse during the total period of eclipse is A + B, and similarly that passed over during the 20 m. of greatest eclipse is A — B; also, since they are moving uniformly in similar orbits, the distances which either separately passes over in these two periods are in the ratio of A+ Bto A —B. The distance across the line of sight which either of them traverses during one of these periods is the chord of its orbit on which stands the are described during the time. Tor, taking the mean line of sight to be that from the earth to Algol at exactly the middle of the eclipse, the arc described by either the latter or his companion during eclipse is symmetrical with regard to this line, and therefore the chord on which it stands is perpendicular to it. Let the chord described by either Algol or his satellite (it makes no difference which we take) during the whole eclipse be C,, during time of maximum eclipse c,. Let the angles subtended at the centre of motion by these chords be @, and @, respectively. Then c, : C, 3: sin 4, ¢ sin @,. But 6, in degrees is 360° x arc described during eclipse circumference of orbit _ 360° x period of eclipse _ 360° « 560 _ 49° 18°9!. period of revolution 4089 60° x 20° Similarly 4, =, SIRE EAN Fel nico y 4089 45°05 .A+B_C,_sin 8, _ sin 49° 18:9! _ 7583 “A=B) G, | sin 0, sin 1% 45°65’ 308 = 1:084674 corrected to six places of decimals. n> This result agrees very well with that arrived at by the previous perfectly independent process. It will be seen that the whole difference is only 005426, which, if Algol’s diameter was 1,000,000 miles, or considerably greater than that of our sun, would only make the comparatively very small difference of 4,681 miles in estimating that of his satellite. If the line of sight was slightly tilted out of the plane of Algol’s orbit, not sufficient to make the eclipse partial, but causing it to be unsymmetrically annular as seen from the earth, the distances across the line of sight passed over during the whole eclipse and maximum eclipse would then be less than A+B and A—B8; consequently the result arrived at by the second method would be rather too large. Since, however, the latter is actually slightly the smaller of the two, what difference there is cannot be accounted for in this manner, and hence the orbit is not tilted. Thus we reach the rather important conclusion that Algol’s orbital velocity, as shown by the spectroscope, of 26°5 miles per second, is his true velocity ; for if the orbit was tilted the latter would have a component perpendicular to the line of sight which would not affect the spectroscope. I think the small dis crepancy can be best accounted for by the very likely supposition that the true variation during eclipse is not really precisely two theoretical mag- nitudes ; or, again, the orbits may not be exactly circular. If the fluctuations in light of a large number of variable stars were compared with their periods of eclipse in the above manner, some interesting results might be obtained. When the two results were approximately equal, we should know that the star in question revolved in a circular orbit in a common plane with the line of sight. When they were greatly different, it would show that either the orbit 352 was elliptical or very much tilted. By examining the light with the photometer, so asto see if the varia- tion was such as would be produced by a dark sphere, we could determine which of these two hypotheses was correct. Some stars would need exceptional methods of examination; for instance, 6 Cephei, which is much longer passing from maximum to minimum than ace verséd. This would be ex- plained if the star revolved in an elliptical orbit whose minor axis was parallel, or nearly parallel, to the line of sight, the focus round which it and its satellite revolved being the one which the former approached nearest to im the half period after eclipse. It would thus describe this part of its orbit more rapidly than the other. Again, B Lyrae with a double period has probably two satellites of unequal size, which would account for the fact that, though the maxima of this star are equal, the minima are unequal. R. J. HuGuHeEs. Norman Court, Southsea: Feb. 16th, 1900. EDITORIAL NOTICE. I have to sincerely thank the very large number of our readers who have so kindly inquired, and ex- pressed their sympathy, during my past serious illness. It was occasioned by an acute attack of pneumonia, resulting from a chill on December 14th last. The consequent after-effects so frequently attending a seizure of this kind are rapidly passing away. I have to thank my colleague, Miss Flora Winstone, for having, unaided, conducted the editorial duties of SCIENCE-GOssIP numbers for January, February, and March. I greatly regret, however, to have to say that this lady has had to undergo a severe surgical operation, entailing the removal of a portion of the skull. I am happy to report that it was successfully accomplished, and she is progressing towards re- covery. JOHN 1T. CARRINGTON, Editor SCYENCE-GossI?. NOTICES OF SOCIETIES. Ordinary mectings are marked t, excursions *; nanies af persons following excursions are of Conductors. § Lantern Lllustrations. Roya Institution oF GREAT BRITAIN, April 3.—+Fishes. Professor E. Ray Lankester, F.R.S. +> 5:—tHighest Andes. E. A. Fitzgerald, F.L.S. », 6,—+tSolid Hydrogen. Professor Dewar, F.R.S. sy 7-—TPolarised Light. Lord Rayleigh, F.R.S. SourH Lonpon EnTomoxtocicaLt anD Natura History Sociery. April 12.—-;Paper by J. W. Tutt, F.E.S. 3» 26.—+$Wild Flowers at Home. E. Step, F.L.S. sy» 26.—t$Ornithology. Norru Lonpon Naturat Hisrory Society. April 5.—}Some Birds of Norfolk Broads P. J. Hanson. +) 19.—}Fruits and Seeds on their Travels. H. W. S. Worsley-Berrison, F.L.S. 5, 28.—*Visit Mammals Section B.M. J. A. Simes. Lambetn Frerp CLun anD SCIENTIFIC SOCIETY. April 2.—+How the Earth is Weighed and Measured. J. J. Hall, F.R.A.S. 1) 7-7 Visit Odontological Society’s Museum, Leicester Square, W.C. 4, 16,—' Bookham and Ranmore. G. Masters, +, 28.—*Kew Gardens. E. J. Davies. np Norwoop Brancu SELBORNE SOCIETY. H. G. Bradley. THE Sipcup LireraRyY AND SCIENTIFIC SOCIETY. April 3.—Sound, Light, and Heat. Rey. 1). Ross, B.Sc. May 1.——}Microscopical and Wild Flower Evening. Messrs. Hembry and Tappolet. HampsTEaD ASTRONOMICAL AND SclENTIFIC Society. April 6.—+Paper. Frederick Womack, M.B.. B.Sc. May 4.—tHypnotism. A. E. Tebb, M.D., B.S., D.P.H. ~ SCIENCE-GOSSTP. NOTICE. SUBSCRIPTIONS (6s. 6d. per annum) may be paid at any time. The postage of SCIENCE-GossI?P is really one penny, but only half that rate is charged to subscribers. NOTICES TO CORRESPONDENTS. To CorRRESPONDENTS £ND EXCHANGERS. —SCIENCE-GossiP is published on the 25th of each month. All notes or other communications should reach us not later than the 18th of the month for insertion in the following number. No com- munications can be inserted or noticed without full name and address of writer. Notices of changes of address admitted free. Bustness Communications.—All Business communications relating to Sc1eNCE-GossiP must be addressed to the Proprietor of ScreNcE-GossiP, 110 Strand, London. EpirortaL ComMMUuUNICATIONS, articles, books for review, instruments for notice, specimens for identification, &c., to be addressed to JoHN T. CarrINGTON, 110 Strand, London, W.C. SunscrieTions.—The volumes of Science Gossip begin with the June numbers, but Subscriptions may commence with any number, at the rate of 6s. 6d. for twelve months (including postage), and should be remitted to the Office, 110 Strand, London, W.C. Norice.—Contributors are requested to strictly observe the following rules. All contributions must be c/earZy written on one side of the paper only. Words intended to be printed in italics should be marked under with a single line. Generic names must be given in full, excepting where used immediately before. Capitals may only be used for generic, and not specific names. Scientific names and names of places to be written in round hand. Tue Editor will be pleased to answer questions and name specimens through the Correspondence column of the mag: Specimens, in good condition, of not more than three species to be sent at one time, carriage paid. Duplicates only to be sent, which will not be returned. The srecimens must have id ntifying numbers attached, together with locality, date, and particulars of capture. Tue Editor is not responsible for unused MSS., neither can he undertake to return them unless accompanied with stamps for return postage. ANSWERS TO CORRESPONDENTS. O. H. E. (Walton-on-Thames).— The vivid green colour sometimes found on decaying wood is, we believe, caused by some species of bacteria. It is certainly not chlorophyll. Several kinds of bacteria produce brilliant colours in the substance occupied by them. EXCHANGES. Norice.—Exchanges extending to thirty words (including name and address) admitted free, but additional words must be prepaid at the rate of threepence for every seven words or less. Fosstts. Ordovician, Silurian. Devenian, Rhaetic, and Jurassic, will exchange for Chalk, Thanet, Woolwich, Old- haven, London Clay, Crag or Drift species.—Dr. Brendon Gubbin, 15 Redland Grove, Bristol. WANTED to exchange (or to borrow for examination) Shells used as Money, singly or strung together by their users. Other Shells and Natural History specimens offered in return.— Wilfred Mark Webb, F.L.S., 2 The Broadway, Hammer- smith, W. OFFERED. 100 Nos. of ‘! Nature,” 1880 to 1883, contain numerous articles by Darwin, Spencer, Romanes, etc. Want Standard Works ; Scientific. preferred. —W. MacKie, Newport Street, Werneth, Oldham. OrrereD. ‘Type Slide of Foraminifera, by Hailes, with Catalogue, 50 Species, and 79 Selected Specimens. Cannot be sent on approval, but may be seen at address as under. Wanted, a good Type Slide of Diatoms with names, late editions of Microscopical or Scientific books, two-thirds or half-inch Objective, or offers.—J. C. Sigsworth, 16 Santos Road, West Hill, Wandsworth, S.W. OrrerED. ‘Tropical and European Butterflies, Moths, Dragonflies, and other insects, British marine shells, too books and periodicals. Wanted, cowries, cones, mitres, &c., or offers. W. 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Cement for replacing Antenne, 6d. per bottle. Forceps for removing insects, 15, 6d., 2s., 2s. 6d. per pair. Cabinet Cork, 7 by 34, best quality, 1s. 4d. per dozen sheets. Pupa Diggers, in leather sheath, 1s. gd. Insect Lens, 1s. to 8s. Glass ‘Top and Glass Bottomed Boxes, from 1s. 4d. per dozen. Label Lists of British Butterflies, 2d. Ditto Land and Fresh-Water Shells, 2d. Egg Drills, 2d., 3d., 1s. ; Metal Blow Pipe, 4d. and 6d. Our new Label List of British Macro-Lepidoptera, with Latin and English Names, 1s. 6d. Our new Catalogue of British Lepidop- tera, every species numbered, rs. ; or on one side for Labels, 2s. All articles enumerated are kept in stock, and can be sent immediately on receipt of order. The ‘“‘DIXON” LAMP NET (invaluable for taking Moths off Street Lamps without elimbing the lamp posts), 2s. 6d. CABINETS. Special Show Room. The following are the prices of a few of the smaller sizes ; for measurements and larger sizes see catalogue. Minerals and Dried Plants, Fossils, &c. tos. 6d, 15s. od. Eggs. 12s. od. 16s. 6d. Insect. 4 Drawers ...... 13s. 6d... 6 Drawers Minerals and Dried Insect. Eggs. Plants, Fossils, &c. § Drawers .......+ Seep oocnacies Z0Sn cone eane 255. 10 Drawers .....+.. AS State isisate atts Goss Sosanace 455. A LARGE STOCK OF INSECTS’ AND BIRDS’ EGGs. Birds, Mammals, &c., Preserved and Mounted by First-class Workmen, 36 STRAND, W.C. (Five Doors from Charing Cross). W. LONGLEY, ENTOMOLOGICAL CABINET and APPARATUS MAKER, 12 WHITE HART STREET, Catherine Street, Strand, London, W.C. Nets, Breeding Cages, and Apparatus of every descrip- tion; Cabinets for Insects, Birds’ Eggs, Minerals, Shells, Coins, etc., etc. ; Pocket Boxes, Store Boxes, and Book Boxes. Sheets of Cork any size to order. NATURAL HISTORY AGENT AND BOOKSELLER. TRAIN- ING. Pel- Scientific Development of the Natural Memory. Mind-Wandering Cured. Success at Exams. tm A quick, sure and easy method of learning all Branches of Science, Mathematics, Languages, &c. Lessons in “‘ the System" conducted in English, French, German, Italian and Dutch, ‘“Tcan confidently recommend the system in every instance where much memory work is necessary.” G. W. Connor, M.R.C.S.; L.D.S. (Lond.). “ Pelman’s system exceptionally effective."—Ep. Science-Gossip. Correspondence Lessons and Personal Tuition. Prospectus post free on application to the Secretary, SCHOOL OF MEMORY TRAINING, 70w, BERNERS ST., LONDON, W. Telegrams : ‘*‘ AUKS,” LONDON. Telephone: 1824 GERRARD. ESTABLISHED 1760. «Je Cc. STE VZEn Ss, (HENRY STEVENS. D. PELL-SMITH.) AUCTIONEER AND YALUER, 38 KING STREET, COVENT GARDEN, LONDON, W.C. This Old-established and widely known Business is now being conducted under new partnership arrangement. Every Friday at 12.30 Sales are held at the Rooms of Microscopes and all Accessories by best makers. 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