Imágenes de páginas


nodes looked for, because the distances between them remained side of such a point the throw changed sign. It was sometimes nnaffected on changing the rate of alternation. The distances found that there was a decided tendency for the position of no from node to node also were found to measure different amounts throw to occur between two telephone nodes, the throw changing (though on the whole there was a decided tendency towards sign on either side of these points. But further experiments. regularity). The average distance apart of the nodes in the showed that this arrangement of the permanent magnetism was different rings tried lay between 10 and 18 inches.

probably accidental, and due to the very currents employed in The occurrence of the nodes might have been very well making the telephone observations. For when only very feeble attributed to the ring being locally irregular in its susceptibility currents had been used on a ring, these consequent poles were to induction, but for the irreconcilable fact that the effects on absent. either side of a node were found to be of opposite phase, just It is possible, as one would expect, to artificially make a as it would be, were the phenomenon due to stationary inter. minimum intensity position, at any point on a ring, by winding ference waves.

on a few turns of thick copper wire. But the fact that the phases This was ascertained by means of two coils connected in the on either side of such a point (found as before by means of two same sense in series with the telephone. When these coils coils in circuit with a telephone) are the same, precludes the were arranged at places of equal intensity, one on each side of idea that the nodes can be due to Foucault currents. a node, no sound was to be heard in the telephone, the effects Obviously, however, the phenomenon depends on neutralizing one another. A commutator, to throw in the coils permanent peculiarity round the ring which happens to occur singly or together as desired, is convenient for making this fairly regularly. What this peculiarity is, or how it is brought experiment.

about, I have not yet been able to discover. From this, one would naturally assume that the currents

Fred, T. TROUTON. induced on either side of a node must be of opposite sign, seeing that they neutralize each other in the telephone ; but experi. ments with the galvanometer show it not to be the case. To test this, the galvanometer is connected up through a com

OYSTERS AT THE ANTIPODES. mutator arrangement fixed to the originator of the primary current in such a way as only to admit of the currents induced so much attention has been given in England to the various

questions connected with oyster-fisheries that it may be of in one direction passing. Tried in this way, no difference in interest to note some facts relating to the oyster-fisheries of our the direction of the current on either side of a telephone node was Australian kinsfolk. The subject was admirably dealt with in found, or, indeed, any trace of a minimum effect at these points.

a lecture delivered by Mr. Saville-Kent before the Christchurch The thing can also be tested by means of a ballistic galvano-meeting of the Australasian Association for the Advancement meter, and a reversing key with battery, for, with a reversing of Science. This lecture is entitled “Oysters and Oysterkey and telephone, the nodes, which are quite independent of Culture in Australasia,” and has been published separately. the speed, are to be found, as well as the opposite phase effect. Mr. Saville-Kent devotes attention chiefly to Australia and The ballistic galvanometer gives no indication of there being Tasmania, as, at the time when his lecture was prepared, he any difference at the nodes from elsewhere, and the deflection

had not had an opportunity of personally studying the question everywhere is in the same direction.

in New Zealand. Beginning with Tasmania, where for five It was thought that perhaps the telephone effect was in some

years he was officially connected with the oyster-fisheries, he way connected with the fact that the form of the alternating cur- points out that the oyster of Tasmania corresponds closely with rent was not a simple wave or sign curve, owing to the method em

the type Ostrea edulis, produced and cultivated in British waters. ployed in producing it. This consisted of a rotating commutator, whích threw in circuit alternately two cells connected up singly and

Formerly, this oyster was so abundant in Tasmanian waters,

that, according to the report of a Royal Commission of Fisheries in opposite directions. For this reason, the effect, when using a in 1882, about lwenty years previously a quantity representing small alternating machine with about 40 alternations per second, at current prices a retail value of no less than £90,000 had was compared, and was found to be in no way different. Also

been exported in a single year to Victoria and New South what must have been a very regular variable current of the Wales. "At that time, oysters were so plentiful that it was a simple harmonic type was procured by means of a microphone common practice to burn i hem in large quantities for the purpose and an organ-pipe. This gave like results.

of making lime. The strain was, of course, too severe, and One is thus left apparently to suppose the sound in the by and by the Tasmanians found that, although there was still telephone to be due to a peculiarity in the character of the a demand for oysters, there was no longer a home-supply, and curve representing the rise and fall of the current, probably that it was necessary for them to go elsewhere for the commodity something of the nature of a subsidiary oscillation ; ibis sub.

which they had so recklessly wasted. In 1884, when Mr. Savillesidiary oscillation being absent at the nodes, and of opposite Kent reached the colony, the oyster-fisheries of Tasmania had sign on either side.

for some years been an obsolete industry. Profiting by the As mentioned before, it is necessary for the alternating coil to information which had been made accessible through the Interbe placed at definite positions, in order that the system of national Fisheries Exhibition and associated Conferences in podes and internodes should occur. These positions of the London in 1883, and by Prof. Hubrecht's testimony as to the alternating coil are at about the same average distance apart, oyster-fisheries of the Schelde, Mr. Saville-Kent recommended and are of very much the same character with respect to regu- the establishment, in suitable localities, of efficiently-protected larity as the nodes of the telephone coil. In fact, if the alter

Government reserves, upon which breeding-stocks of oysters of nating coil and the telephone coil change places round the ring, the best quality should be carefully cultivated and permanently the best position for the alternating coil will always be between retained. These reserves were to fulfil the double purpose of two nodes, and the nodes will be found situated between iwo old breeding.centres, from whence the surrounding waters might be positions of the alternating coil. If the alternating coil be restocked, and also of model oyster-farms, around which private placed at a point where a node was found in some other position beds might be established on similar lines. The scheme recomof the alternating coil, the system of nodes and internodes mended being approved, sites formerly associated with the most generally completely disappears, and now on moving the tele- prolific oyster production were selected. The operations were phone coil round the ring the intensity uniformly diminishes necessarily conducted on a very modest scale. Oyster stock, until the diameter is reached, and then increases round the other suitable for laying on the reserves, could be accumulated only half of the ring. This gives the phenomenon a distinctly by slow and laborious processes, and some 20,000 to 50,000 resonant character. The induced current, as observed by a

oysters represented the approximate numbers that were gradugalvanometer, is always of the latter character, that is to say, ally collected and placed under cultivation. In order that the a uniform fall, and then a rise on going round the ring.

largest possible amount of spat produced by the oyster stocks As a rule the permanent magnetism of these large rings is laid down might be caught, various methods were adopted, the irregular, and apparently apt to change frequently. A determi.

principle being that which has been followed with so much dation of the permanent magnetism was easily made by means

success by M. Coste on the west coast of France. In addition to of one of the coils connected with a ballistic galvanometer. By

dead oyster-shells, or “cultch,” which has, from the earliest days moving this through a given amount at a time, say an inch, and

of oyster-culture, been recognized as representing a most natural noting the throw of the needle, one was able to plot out a re- and prolific catchment material for the adhesion of the spat, presentation of the state of the permanent magnetism. In this

artificial collectors of various descriptions were introduced. In way, places where no throw occurs were found, while to either

France, tiles cemented on their lower surfaces have been found

to constitute the most productive and economic collectors. In to the bottom, where they assume their permanently fixed conTasmania, as in all the other Australasian colonies, tiles being dition. Such is the fecundity of this oyster that the rocks and much too expensive for such a purpose, a cheap and efficient every available hiding-place in the bays, estuaries, and inlets of substitute for them was effectually improvised out of the thin the districts it affects become literally plastered with the embryo roughly-cleft boards known as "split palings,” which can be brood ; and until quite recently, artificial culture in the scientific produced in timber-producing districts at a cost of from 8s. to sense has in New South Wales been usually regarded as an unros. per 1000. These paling collectors are coated on their profitable and unnecessary superfluity. Lately, however, the under surface with cement, a brick or stone is fastened under- oyster-fisheries of the colony have been seriously damaged by neath at each end to give them stability, and a wire loop secured a disease which either destroys the oyster or makes it unfit for through the centre of their upper surface forms a convenient food. Mr. Saville-Kent attributes this disease to the pollution handle by which they can be manipulated on shore or raised of rivers. If he is right in this view, in support of which he with a boat-hook from beneath the water.

has much to say, the oyster-growers of New South Wales will, The results have been most satisfactory. Last year oysters as he says, have to make the most of the water area lest to them had become so plentiful at Spring Bay that the Hobart market where the water is pure. They may also have to turn their atwas glutted, and the sale price was reduced 50 per cent. Thus tention to the cultivation of the New South Wales variety of the an important industry has been revived, and there can be little mud oyster. doubt that by the due maintenance of the breeding-reserves the In Queensland, as in New South Wales, the only oyster used in oyster-fisheries of Tasmania will be restored to more than their commerce is the rock variety, which may be said to attain its former prosperity. In accordance with Mr. Saville-Kent's re- maximum development in both quantity and quality in the commendations, all holders of private oyster-beds in Tasmania Moreton and Wide Bay districts. In these areas the species is are bound by the terms of their leases to retain a certain amount so abundant that large consignments, above those required for of breeding-stock-not less than 10,000 mature oysters to the home consumption, are exported to New South Wales and acre-permanently on their oyster-beds. This regulation con- Victoria. The disease which has so seriously depleted the tributes materially towards the distribution of spat throughout fisheries of New South Wales has not yet affected the the surrounding water, and to the re-establishment of the oyster. Queensland beds. Mr. Saville-Kent thinks that this immunity fisheries upon a durable basis.

is probably due to the circumstance that the Queensland oysterReferring next to Victoria, Mr. Saville-Kent says that the fisheries are chiefly located in bays and channels in close specific form of oyster indigenous to the Victorian coast-line is a proximity to the open sea, from whence, even after heavy floods so-called mud oyster, identical with that produced in Tasmanian from the tributary rivers, they are speedily revived by an inflow waters, and to all outward appearance indistinguishable from of sea-water. He urges the Queensland authorities to preserve the British native, Ostrea edulis. In sormer years vast quanti- these tributary streams as far as possible from pollution by ties of this oyster were obtained from Western Port Bay, Port chemical or other noxious works, which if allowed to increase to Albert, and Corner Inlet. Over-dredging, however, has re- any considerable extent cannot fail to exert a very deleterious duced these prolific natural beds to the very verge of extinction, effect upon both the oyster and all other fisheries of the bays so that Victoria has for many years been dependent upon New into which the rivers flow. Artificial oyster-culture, with the South Wales, Queensland, South Australia, and New Zealand, exception of one or two small experiments, has been so far for her oyster supplies. Some time ago Mr. Saville-Kent was carried out in Queensland waters on the simple lines only of invited by the Government of Victoria to make a tour of and transporting the young brood or ware, locally known as report upon the fisheries of the colony, giving special attention "cultivation,” from one locality and laying it down on ground to the practicability of reviving the oyster-fisheries. As a result where it will develop more speedily to maturity. Mr. Savilleof that tour of inspection, he strongly recommended the adoption, Kent believes, however, that it would be profitable to use split at Western Pori and Port Albert more particularly, of the palings as spat collectors. One advantage possessed by this methods which had proved so effective in Tasmania. One such form of collector is the shelter from the sun's heat afforded reserve with a very small stock of oysters was formed at Port to the young brood when left high and dry by the receding Albert. Unfortunately, however, the Government omitted to

tide. Millions of the Australian rock oyster are destroyed make provision for periodical skilled supervision, and the reserve annually through exposure to the overpowering heat of the subdwindled away. As Mr. Saville-Kent says, unless such reserves tropical sun in the early days of their attachment to exposed can be maintained in efficient working order, and the operations

rocks near high-water mark. The overhanging ledges of larger periodically required thereon be supervised by a practical ostre- rocks and the shady sides of stone jetties or embankments are culturist, the money expended on iheir establishment is simply invariably found to attract and support the greatest amount of wasted.

nyster brood, and this shelter, which is naturally sought, plainly At various parts of the Victorian coast-line, Mr. Saville-Kent indicates the lines that may be most profitably followed in observed considerable numbers of oyster-she!Is, evidently derived operations connected with the artificial cultivation of the species. from deep water, that had recently been cast upon the shore by We may note that since Mr. Saville-Kent's lecture was pubstorms. He consequently predicted that more or less extensive lished a report by him. on “Oysters and Oyster-fisheries of heds would be found off the coast; and off-shore beds have in Queensland” has been issued by the Queensland Government. fact been since discovered. Mr. Saville-Kent points out that a In this report, which is carefully illustrated, full details are given most favourable opportunity is thus afforded for the restocking as to the conditions which must be specially taken into account of the in-shore fisheries.

by all persons connected with Queensland oyster-fisheries. In New South Wales a separate species of oyster has to be Referring to the split paling collectors, Mr. Savilletaken into consideration. The commercial species of this colony Kent emphatically repeats what he says in their favour in his is the rock oyster, Ostrea glomerata. At the same time a mud lecture. After considerable experience he expresses his conoyster, identical with or most closely allied to the Victorian and viction that they are the most convenient and economic form for Tasmanian type, Ostrea edulis, occurs in some numbers upon use in Australian waters, and that they may be characterized as the coast, but in consequence of the hitherto profuse abundance an essentially Australian product. About half-tide mark repreof the rock variety it has not been considered worthy of com

sents the zine within which-at all times of the year, but inercial attention. In form and general aspect the New South especially in the months of February and August—they gather Wales rock oyster somewhat resembles the Portuguese oyster, the most abundant harvest of spat. On their first attachment to Ostrea angulata, and also the American Ostrea virgineana. the cemented collectors, the young oysters adhere to the cement With these two species it further corresponds in its breeding by the entire surface of the attached shell. After attaining to habits, which are essentially distinct from those of the English, about half an inch in diameter, the free edges of the shells Victorian, and Tasmanian mud oyster, Ostrea edulis. In the begin to grow outwards, and this direction of their growth is case of the Australian rock oyster there is no nursing of the continued until at an age of about six months they project an young brood, which is turned out to shift for itself, not only in inch and a half or two inches from the collector. Ai this stage a shell-less but even in an unfertilized condition. Like the spawn the young oysters may be easily detached with or without the of many fishes, these ova are fertilized in the water. They can cement, and be laid on the banks as ordinary "cultivation." be readily fertilized artificially, and Mr. Saville-Kent has found The collectors may then be re-cemented and re-laid for the that four days after fertilization the shells, which make their ap

catchment of a second crop. pearance on the second day, become so dense that the embryo Of the oyster-fisheries of South and West Australia Mr. Saville. oysters can no longer support themselves in the water, but sink Kent is not able, in his lecture, to give precise details. He says, however, that excellent oysters of fine quality and magnificent party did not proceed further, and from Yamil-kul they returned proportions, allied to Ostrea edulis, are exported from Spencer's to Mandalyk, and thence began their journey to Lob-nor, which Gulf in South Australia to the Victorian markets, and more journey took no less than one month. From Lob.nor the especially to Ballarat. Some of these South Australian oysters | Expedition went up the Yarkend-daria, visiting on the way the are of such Brobdingnagian dimensions that it is customary to great settlement of Kurla (4000 inhabitants), the fort of cut them in four pieces for sale at the oyster saloons, the quarters Karasbar (10,800 inbabitants in the sort and the oasis), and the thus divided being severally allotted to separate shells of ordinary town Uruntchi, situated at the foot of the Tian-shan, and resisize and sold as single oysters.

dence of the Governor-General of West China. On their way Mr. Saville-Kent congratulates New Zealand upon her to the Russian frontier the travellers visited also the oasis of abundant stores of oysters of various kinds. The days for the Sa-tsan, peopled by Chinese, and crossed the Malas River as well systematic artificial cultivation of the oyster in that colony have as the desert Khatyn-ula. On January 15, 1891, they entered not yet arrived, and if she carefully husbands her natural the Russian post of Zaisan. resources they may, he thinks, be long delayed.



INTELLIGENCE. AT an extraordinary meeting of the Russian Geographical

Society on October 14, General Pevtsoff made his report OXFORD.—The Rev. Andrew Clark, M.A., Fellow of Lincoln about the Tibet Expedition, of which he was the commander College, has been elected by Congregation a Curator of the after the death of Przewalsky. Having crossed the main Tian. Bodleian Library, in place of Prof. Max Müller, whose term of shan ridge by the Bedel Pass, the Expedition went southwards, office had expired. through an extremely narrow gorge of the Kara-leke ridge. In The Provost of Oriel College has been re-elected a Delegate some places the gorge has only the width of 30 to 35 feet, while of the University Museum. its walls are 700 feet high. The first Kashgarian village reached Mr. F. Liddell, B.A. Christ Church, has been elected to a was Kalpyn, whence the travellers went to Yarkend. From Fellowship at All Souls' College. Mr. Liddell, who is a son of Yarkend they moved on the great Khotan high-road into the the Dean of Christ Church, was placed in the first class by the northern spurs of the Kuen-lun. There they stayed for some examiners in the Final Classical Schools. Mr. A. H. Hardinge, forty days, at a height of 10,000 feet above the sea, at Tokhta- M.A., formerly Fellow of All Souls' College, has been elected hon, collecting many interesting plants and birds, while the to a Fellowship under Statute 3, Clause 10, of the College geologist of the expedition, M. Bogdanovitch, made a long ex- Statutes. cursion into the region between the Yarkend-daria and the There was no candidate for election to the Burdelt-Coutts Tyznan Rivers. On September 13 they left the highlands, and Scholarships. The scholarships are of the annual value after a three weeks' journey arrived at the Khotan oasis, the of about £115, tenable for two years, for the promotion population of which (120,000) are skilful in the manufacture of of the study of geology, and of natural science bearing on carpets, felts, silks, and so on. From Khotan they went to geology. This is the fifth occasion since the foundation of Keria, and next to Niya, where they left their superfluous luggage, the scholarships that there has been either no candidate or no and whence they started to explore the Kuen-Jun, in order to election. try to find a good pass to Tibet. The pass was found at the In consequence of the requirements of the Civil Service Comsources of the Tillan-hadji stream, not far from the Minjilin- missioners for the limited competition for assistantships in the khanom monastery. It proved to be quite available both for Royal Observatory, Greenwich, the Savilian Professor of Astrohorses and camels. The winter was spent at Niya. On May 7, nomy has offered a short course of lectures on Newton's the work of exploration was resumed, and next week the Expe- Principia." The study of Newton has been practically abodition reached ihe Kara-sai village. Followed by two men only, lished from the requirements of the Oxford Mathematical Schools M. Roborovsky went up the Saryk-tuz Pass (discovered during for some time past. the preceding autumn), and attained the sources of the Keriya- A studentship, provided out of the funds of the Newton Testidaria on the Tibet plateau. Its altitude proved to be theremonial Fund, having been offered to the University by the 16,500 feet, and its surface was an absolute desert. The want Managing Committee of the British School at Athens, the of food for the horses compelled M. Roborovsky soon to return Craven Committee will proceed to make the appointment in the to Kara-sai. He soon made a second attempt at further explora. course of the present term. The studentship is of the value of tion, but, after having marched some 50 miles southwards on £50, and is tenable for one year. The holder will be required to the plateau, he was again compelled to return. During the reside at Athens for not less than three months during the same time, M. Kozloff went across the border-ridge, follow. ensuing winter and spring. Candidates should apply to the ing for some 100 miles the Bastan-tigrak River. He passed by Secretary of the Board of Faculties, Clarendon Buildings. Lake Dashi-kul and went up the river which flows into the lake

CAMBRIDGE.-The first award of the Isaac Newton Student. from the east, through a wild desert, 14,000 feet above the sea.

ship in Astronomy and Physical Optics has been made to He also was soon compelled to return to Kara-sai. The next attempt was made by all three explorers together, accompanied Ralph Allen Sampson, B.A., Fellow of St. John's College, by four Russians and a few natives. They went up the Aksu

Prof. Thomson, F.R.S., has been elected Chairman of River, and soon were on a plateau, 15,000 feet high and almost

Examiners for Part II. of tbe Mathematical Tripos. quite devoid of vegetation. Terrible snow-storms were raging in the first days of July. The only mammals seen were two ante.

The vacancy of the office of Superintendent of the Museum

of Zoology will take place on January 1, 1892. The stipend is lopes, and the only bird met with was a lark. Finding no food for the horses, the Expedition had nothing to do but to return to

£,200. Applications are to be sent to Prof. Newton before

November 19. Kara-sai. Thence they started for Tchertchen, and at Atchan

The State Medicine Syndicate report that this year there were they were rejoined by M. Bogdanovitch, who had explored in the meantime the geological structure of the two passes of Saryk64 candidates for the Diploma in Public Health, of whom 45

were successful. They propose, on account of the large number After a short stay at Mandalyk, where good of candidates, to hold a second examination in the first week of grazing-grounds were found, and the horses recovered, the Expe. April 1892. The Syndicate have resolved to transfer to the dition crossed again the Kuen-lun viđ the Muzluk Pass (15,500 University a sum of £150 from their accumulated funds. feet high), and after having crossed it they divided into two parties, one of which, under M. Roborovsky, went south-east, and the other, under General Pevtsoff, moved southwards, up the little River Uluk-su, which is the source of the Tchertchen-daria.

SCIENTIFIC SERIALS. They soon came to an immense chalky mountain ridge, which American Journal of Mathematics, vol. xiv. No. 1 (Baltimore, rose to about 20,000 feet in the south, while a wide valley Johns Hopkins Press). —This number, which contains an ex. stretched south-westwards between that ridge and the Kuen-lun. cellent likeness and autograph of Prof. Klein, opens with articles The party stopped at the foot of this ridge, at a small lake, by Goursat, “Sur une probleme relatif à la désormation des Yamil-kul. From some natives who were engaged in gold surfaces," and by Appell, “Sur une expression nouvelle des mining in a gorge of the ridge, they learned that its

name is Akka- fonctions elliptiques par le quotient de deux séries.”—Major tai, and that its summits are covered with perpetual snow. The MacMahon, F.R.S., contributes a fourth memoir

a new

theory of symmetric functions. The author has extended the species of Diptera, unnamed. He said they had been submitted subject of these memoirs in a paper with the title “Memoir on to Mr. R. H. Meade, but were unknown to him, and are probsymmetric functions of the roots of systems of equations" inably new to the British list.-Mr. R. Adkin exhibited two the Philosophical Transactions, A. (1890).- The next paper, by specimens of a supposed new species of Tortrix (Tortrix doneC. P. Steinmetz, was read before the New York Mathematical lana, Carpenter), bred from larvæ found on pine-trees at Tuam. Society, and is entitled “Multivalent and univalent involutory Mr. C. G. Barrett said he examined the specimens with great correspondences in a plane determined by a net of curves of nth care, but he did not consider that they belonged to a new order.”—The following note, also read before the same Society, species. He was unable to distinguish them from Tortrix is on the algebraic proof of a certain series. It supplies a viburnana.-M. A. Wailly exhibited preserved larvæ, in “ temporary lack,” which was regretted by the author, E. various stages, of Citheronia regalis, which he had bred from McClintock, in a memoir which will be found in vol. ii. p. 108. ova received from Iowa, United States. He said that the The same writer furnishes another addition to the memoir just natives called this larva the Hickory Horned Devil, and that the referred to (vol. ii.), on independent definitions of the func- specimens exhibited were the first that had been bred in this tions log x and e*.-H. B. Newson writes on a pair of curves country. M. Wailly further exhibited three female specimens of the fourth degree, and their application in the theory of of Antheræa yama-mai bred from cocoons received from Japan; quadrics ; and H. P. Manning finishes this instalment with a also a nest of cocoons of Bombyx radama, received from the note on linear transformation, which was suggested by a method west coast of Madagascar. Prof. J. B. Smith, of the United States, employed by Prof. Cayley, F.R.S., in vol. v. of the Amer. and Colonel Swinhoe took part in a discussion on the habits Journal.

of the larvæ of Citheronia regalis, and as to the period at which The articles in the numbers of the Journal of Botany for they dropped their spines prior to pupating. - Dr. Sharp exOctober and November are mostly of interest to specialists in

hibited several specimens of a weevil, Ectopsis ferrugalis, the local foras. Mr. A. Fryer describes and figures a new Eng.

ends of the elytra of which bore a close resemblance to the section lish Potamogeton (or, rather, hybrid). Mr. T. H. Buffham

of a twig cut with a sharp knife. He said he had received the describes and figures the hitherto unknown plurilocular sporanges specimens from Mr. G. V. Hudson, of Wellington, New Zealand, in two sea-weeds, Asperococcus bullosus and Myriotrichia clava

who stated that they were found resting in large numbers on formis. Mr. F. N. Williams contributes a synopsis of the

dead trunks and branches of Panax arborea in the forests,—Mr. primary characters in the species of Rheum.

G. C. Champion stated that the species of Forficulida, captured

by Mr. J. J. Walker, R.N., in Tasmania, and exhibited by The last number received of the Botanical Magazine published himself at ihe meeting of the Society in April last, was, he at Tokyo, Japan (for June), contains an interesting article,

believed, referable to Anisolabis tasmanica, Bormans, described illustrated, on a new Japanese Prasiola, P. japonica, by Dr. R. in the Comptes rendus of the Ent. Soc. Belgique, 1880.—The Yatabe, which, the author states, is collected in large quantities Rev. A. E. Eaton made some remarks on the synonymy of the in the districts where it grows, and is sold as an article of food

Psychodidæ, and stated that, since August 1890, he had identiunder different names in different localities. It is eaten either

fied all of the British species in Mr. Verrall’s list, except slightly broiled or with vinegar, the mode of preparation being Sycorax silacea.-Mr. Gervase F. Mathew, R.N., communicated very similar to that of the ordinary purple and green lavers. a paper entitled “The Effect of Change of Climate upon the Other articles in the same number are on the reproduction of

emergence of certain species of Lepidoptera.” A discussion Laminaria japonica ; on a recent problem in vegetable physio- followed, in which Mr. Stainton, F.R.S., Mr. Barrett, Dr. logy (apparently the greatly discussed question of the direct

Sharp, F.R.S., and Mr. McLachlan, F.R.S., took part. absorption of nitrogen from the air by plants); and on the colours and scents of flowers; but as all these are unfortunately

Royal Microscopical Society, October 21.-Dr. R. in Japanese, they are inaccessible to the English reader.

Braithwaite, President, in the chair.—The President said that

the pleasure with which he met the Fellows after the vacation The number of the Nuovo Giornale Botanico Italiano for

was very sadly marred by the death of one of their Secretaries, October is chiefly occupied with the Proceedings of the Italian

Mr. John Mayall, Jun. The loss they had sustained was one Botanical Society. The attention of Italian botanists is still

which the Society could hardly hope to replace, because perdirected to the interesting phenomena connected with the pol- haps there was no living person who knew more about the lination of the Aroideæ : Signor Caleri has a paper on the

microscope and its applications than their deceased friend Mr. flowering of Arum Dioscoridis, and Prof. Arcangeli one on the

Mayall. The difficulty in which they were placed had, however, fertilizers of Helicodiceros muscivorus. He is unable to discover

for the present been met by the kindness of Dr. Dallinger, who any evidence that the latter plant is really carnivorous.—Signor had undertaken to fill up the vacant place until the end of the Martelli discusses a vine-disease which has lately appeared in

current session.—Mr. A. D. Michael proposed, and Mr. T. H. the neighbourhood of Florence, and which he identifies with

Powell seconded, that a special vote of thanks be given to Dr. the “ black rot” of the American grape, caused by a Pyreno. Dallinger for his kindness in accepting the office of Secretary. mycetous fungus, Physalospora Bidwelli.

The vote of thanks was carried by acclamation.-Mr. F.
Chapman read his paper on the Foraminifera of the Gault.-

Sir Walter J. Sendall exhibited and described a new apparatus

which he had devised for making accurate measurements with

the camera lucida, the inherent faults of which were explained LONDON.

by drawings on the blackboard. Mr. E. M. Nelson said there Entomological Society, October 7.-Dr. D. Sharp, F.R.S., could be no doubt that camera lucida measurements when Vice-President, in the chair. - The Chairman referred to made in the ordinary way as described were grossly incorrect, the death, on September 14 last, of Mr. E. W. Janson, who and that the apparatus that had been devised was most ingenious had been a member of the Society since 1843, and who had and thoroughly scientific in principle. He thought, however, formerly filled the offices of secretary and librarian respectively. that there was a much simpler method of obtaining measure-The "Rev. Dr. Walker exhibited a long series of several ments by projecting the image for a distance of 5 feet; the curve species of Erebia, and of Argynnis pales, which he had recently would with so large a radius be practically reduced to a straight captured near Roldal, in Norway.--Mr. W. L. Distant ex- line. The camera lucida and neutral tint reflector were hibited specimens of Danais chrysippus, with its two varietal only rough-and-ready means, and useful only for ready reference ; forms, alcippus, Cram., and dorippus, Klug., all which he found where correctness was of importance, the eye-piece micrometer together in the Pretoria district of the Transvaal. Mr. Jenner would best meet the requirements; the ruling of eye-piece Weir and Colonel Swinhoe took part in the discussion which micrometers was now done so perfectly that it was possible to ensued as to these forms and their distribution.—The Rev. W. arrive at measurements even as small as 1/500,000 of an inch F. Johnson sent for exhibition specimens of Velia currens from with far greater accuracy than could be attained with any stagnant water near Armagh ; also a specimen of Nabis limbatus, machine. Dr. W. H. Dallinger thought there could be no killed whilst holding on to its prey, a very hard species of doubt of the value of the apparatus within certain limits, but it Ichneumon. Mr. Saunders thought that, from the nature of the would require great care for use with high powers, partly on Ichneumon, the only chance the Nabis had of reaching its in- account of its weight if made in brass, as the specimen before 1crnal juices would be through the anal opening, as recorded by them ; perhaps it might be made in aluminium or some other Mr. E. A. Butler in a similar case, in the Entomologist's Monthly light material. The discussion was continued by Messrs. A. D. Magazine, October 1891.-Mr. F. P. Pascoe exhibited two British lichael, C. and Sir Walter J. Sendall.-Mr. W. I.

Chadwick described the Leach lantern microscope as follows. The alum trough is of large size, and is used in the ordinary The microscope can be applied to any oxy-hydrogen lantern. slide stage of the lantern. At the conclusion of the paper, t is screwed on the front in place of the ordinary lantern ob- Messrs. Chadwick and Leach gave a demonstration with common ective, the size of Aange required being 24 inches ; when the and polarized light. antern objective flange is larger than this, an adaptor must

CAMBRIDGE. le provided ; and when the of the lantern is *ricketty," a rigid lengthening tube may be adapted. The President, in the chair. --The officers for the ensuing session

Philosophical Society, October 26.-Prof. G. H. Darwin, antern condenser should be about 4 inches or 43 inches in iameter, and of the triple form. The stage of the microscope is

were elected as follows :-President: Prof. G. H. Darwin.

Vice-Presidents : Prof. Hughes, Prof. Thomson, Mr. J. W. pen at both sides, and at the top also, and serves for all classes Fobjects, whether ordinary microscopic slides or polariscope J. Larmor, Mr. S. F. Harmer, Mr. E. W. Hobson. New

Clark. Treasurer: Mr. R. T. Glazebrook. Secretaries : Mr. rystals, shown with either narrow angle rays or by the convergent Members of Council : Mr. H. F. Newall, Mr. C. T. Heycock, ystem of lenses. The stage being so constructed, it is extremely

Mr. A. E. H. Love.—The following communications were ccessible for the introduction of sub-condensers, with which the nstrument is provided. The object-holder is quite a novel idea, the secondary of a transformer, by Prof. Thomson.-On an experi

made to the Society :-On the absorption of energy by the principal mechanism of it is placed under the stage (to be out of

ment of Sir Humphry Davy's, by Mr. G. F. C. Searle. Two he way) ; two arms passing through slots in the bottom of the itage, actuated by a spring and manipulated by a milled head,

copper wires are passed up through holes about 5 centimetres serve to hold the objects fat against the inside surface of the the surface of the trough. Mercury is then poured into the

apart in the bottom of a flat trough, their ends being level with ront of the stage. The diaphragm, or compound wheel of liaphragms, is rotative on a pivot attached to the plate arm in trough to a depth of about 4 millimetres. On sending a powerful uch a manner that the whole may be raised out of the field

current through the mercury by means of the two wires the Lltogether, and dropped into it again, in an instant ; when the mercury in the immediate neighbourhood of the electrodes was

elevated into a small cone 2 or 3 millimetres in height. --Some wheel is raised, a spring catch holds it in position. When in

notes on Clark's cells, by Mr. R. T. Glazebrook and Mr. S. his position the whole field of the microscope can be utilized or showing objects up to it inches in diameter. When,

Skinner. In addition to the causes of variation indicated by is in using polarized light, it is desired not to be incom

Lord Rayleigh, the authors find that the state of amalgamation

of the zinc pole may cause a fall in force if the zinc does not inoded with the diaphragms, the detachable plate carrying the compound wheel can be instantly removed from the stage, and

show a bright surface. This is worked out by means of a testing when again required it can be as quickly restored. The arms

cell into which the faulty zincs are transplanted. The result is of the object-holder projecting through the bottom of the stage sulphate solution. To correct ihis fault previous amalgamation

confirmed by Swinburne's experiments on zinc rods in zinc have sufficient lateral movement to admit any zoophyte trough or in the presence of dilute sulphuric acid is recommended, or vooden frame or combination of wooden frames up to 1 inch in immersion of the zinc in the paste. Dr. Hopkinson's method hickness. Thus the advantages of this arrangement are clearly nanifest. The two sub-condensers with which the instrument of testing cells by tapping was shown. - Illustrations of_a s provided are found to give satisfaction with all objectives of Whetham.-On gold-tin alloys, by Mr. A. P. Laurie.

method of measuring ionic velocities, by Mr. W. C. D. rom 2} to ir inch focus. When the light has been properly concentrated, high powers can be used. It should also be

PARIS. observed that when high powers are used the front lens of the objective is open to the view of the manipulator, a great con- Academy of Sciences, November 2.-M. Duchartre in the venience when inserting the object, by enabling it to be imme- chair.-On aberration, by M. Mascart.-Note on Mont Blanc diately adjusted within the area of the lens. When polarized light Observatory, by M. J. Janssen. This is a brief report of the is to be used, the polarizing prism must be pushed into the rotating attempt to reach the rock through the snow on the summit of tube of the instrument by removing the concave lens at the back, Mont Blanc, in order to obtain a foundation for a proposed and after inserting the prism this concave lens may be replaced Observatory. In spite of circumstances which rendered the proin an instant. The rotating tube is an advantage over fixed posed building impossible, M. Janssen believed that an edifice tubes, as the polarizing prism can by this arrangement be placed of some kind resting on the snow would permit the necessary in any desired azimuth which best suits the object. The con- observations to be carried on, and had one constructed accordvergent system of lenses for use with polarized light in transmit. ing to his ideas. No displacement of the erection occurred ting rays through biaxial crystals was worked out by Mr. Leach. during the twenty days previous to M. Janssen's departure from It gives powerful illuminations, and includes an angle of 170°. the summit of the mountain. The construction of a similar The front focussing arrangement was introduced by Mr. Leach | but more important building is therefore contemplated for next in 1883. Before that time several supplementary lenses had to year. ---Note by M. Armand Gautier, accompanying the presentabe kept in readiness for use, as different classes of crystals were tion of his work on “ Biological Chemistry."-On the Arago placed in the polariscope. Mr. Leach discovered how these Laboratory, by M. de Lacaze-Duthiers.-Contribution to the supplementary lenses might be dispensed with, and fitted up his natural history of the truftle: parallelism between the Terfaz or system accordingly; and now all makers of first-class polariscopes Kama (Terfezia, Tirmania) of Africa and Asia and the truffles attach to their instruments this great improvement. The con. of Europe, by M. A. Chatin. In the comparison the points cave field lens, with which the instrument is provided, is abso- considered are geographical distribution, climate, soil, nutritious lutely necessary when the polarizing prism is in use. With plants, periods of ripening, depth in soil, and numerous other all powers it enlarges the field, and equalizes the distribution of characteristics. -An excursion in the Rocky Mountains, by M. illumination. The three objective adaptors with which the instru- Albert Gaudry. At the end of the recent Geological Congress ment is provided admit of any microscope power with the at Washington a party was organized to visit the Rocky Moun. standard screw; they are made to slide in the front tube of the tains. An account is given of some of the objects of geological microscope, which is provided with a rack and pinion, and also interest observed by the excursionists. — Note on the storm that with a fine screw movement. Thus, by having the various powers visited Martinique on August 18, 1891 (an extract from the already screwed into the adaptors, one may be changed for American Journal of Meteorology), by M. Faye. - Researches another almost instantaneously. And into the front or tube on butylene monobromides, by M. E. Reboul. There are three portion of these adaptors the tube of the amplifier is made to butylene monobromides known besides the isobutylene of slide. The amplifier which is provided is a Barlow lens, and Boutlerow. The author describes the preparation and properbeing achromatic, it enhances the aplanatic qualities of the ties of one of these, to which he assigns the constitution CH,objective. It has been asserted "that high power cannot be CH-CBr=CH2. He proposes to term it ethyl-acetylene used in the lantern microscope ; that it is unable to exhibit fine a-hydrobromide. - Observations of two new asteroids discovered detail upon the screen, and that no alum trough is required." at Nice Observatory on September 24 and October 8, 1891, by No doubt this is all true so far as applied to inefficient instru. M. Charlois. Observations of position are given.-On the ments. But the Leach microscope does require an alum trough, dimensions and form of the section of a stream (veine) of gas because where great light is concentrated from the oxy-hydrogen under limited counter-pressure during a limited delivery, by M. luminant, great heat must, from the very nature of the means Parenty.-On a model of a luminous fountain, by M. G. employed, be concentrated with it, and the alum trough is the Trouvé.-On the direct combinations of metals with chlorine only practical thing which can be used to absorb the heat rays. and bromine, by MM. Henri Gautier and Georges Charpy,

« AnteriorContinuar »