Imagens das páginas

other food-products of the deep is of paramount importance in regulating and bettering the fisheries around our


A few years ago the scientific aspects of this industry received but scant attention. Many outcries have indeed been always heard as to injurious methods of fishing, the wilful destruction of fish suitable for food, and the general depletion of certain fisheries, but in spite of Royal Commissions and Courts of Inquiry, we have been slow to grasp the truth that for want of proper knowledge with which to control our laws and regulations we have been timidly procrastinating, and allowing our chance of ready resuscitation to diminish. We have about 400,000 men dependent on our fisheries, and yet are at the present day lagging behind other and younger countries in our State Aid. In Scotland the proportion between fishermen and the rest of the population is I in every 76; in Ireland I in every 216; in England and Wales i in every 612. In a recent report of the Board of Trade it is also stated that "the sea fisheries of the United Kingdom appear to be of greater value than those of any other country in which fishery records are kept." The value of the fish landed annually in the United Kingdom is about six million pounds, and yet a large proportion of our fishermen eke out a miserable existence, and see the industry in which they are engaged becoming more and more unremunerative every year. In Scotland, where most is done for our fisheries, there is a Government Board where appeal can at all times be made by any persons desiring alterations in the existing state of circumstances. A Board which not only collects all statistics, but which has power and capabilities to inquire into all methods of fishing, whether from a biological or commercial standpoint, as well as to construct by-laws if necessary. In England the absence of such a body is much felt. Conference after conference is held, but although promoted under the most favourable auspices, the resolutions agreed upon can hardly be made to impress the House of Commons, because of this want of a proper channel. It would be quite out of place in an article such as the present to speculate as to the constitution of a Fishery Board for England, but without any doubt it should have not only a representative of biology, but a small staff of investigators.

The unfortunate antithesis which at present exists between so-called practical people and men of science results largely from the unknown altitude from which the latter choose somewhat exclusively to illuminate the world. Without desiring in any way to discount the pursuit of knowledge for its own sake, it seems apparent that the benefits to be derived for our fisheries are not to be obtained from the lovers of pure science, but rather from those who, having had the proper scientific training, are willing to occupy a position in which they will be intimately acquainted with the requirements of practice as their object, and yet be able to focus the theoretic rays of the specialists on the different sections of their work.

The history of the various Royal Commissions has thrown considerable light on the particular nature of the information needed. It has also shown how widely the investigations yet to be carried on must extend.

Take, for example, the old vexed question of beam trawling in Scotland. Fishermen practising the timehonoured art of long-lineing appeared as witnesses before the Commission of 1883, and being keenly antagonistic to the trawler, described how this species of robber descended upon their old haunts, scraped and harrowed the bottom to the utter destruction of all spawn and fry, scooped up tons of fish (which should have lived to have been caught by hook and line in the proper manner), and glutted the market with what was quite unfit for human, food.

It is often extremely difficult to separate political interests from fishery reports, but the fact remains that

evidence of this kind, being inserted in the public press, led to much misunderstanding, and inclined people to support the line fishermen at the expense of the trawler. But the late Lord Dalhousie, as chairman of the Commission, was fortunate in having as one of his colleagues a naturalist who had for many years given special attention to fisheries. The statements, therefore, as to destruction of spawn and young fish were tried and found wanting. The evidence as to the natural history of fishes being most wild and conjectural, though given by men who had spent their lives at sea and were masters of their craft, was met by scientific accuracy and fell to the ground. We find in the official report of the Commission, published in 1886, very decided statements indicating that in the opinion of the Commissioners the injury done by the use of the beam-trawl is insignificant.

Much information has now been gained as to the eggs and embryology of sea fishes, and important observations published on such matters; for instance, as to the proportional numbers and sizes of the sexes, and the sizes at which the various food fishes become sexually mature.

Observations made on the last-named inquiry show that on different coasts where the conditions of life vary as to temperature, food, or ocean currents, the sizes at which any individual members of a species of fish spawn are distinctly different, and that the rate of growth is different. This is a matter of some importance to those who would prevent capture of fish till after some progeny has been allowed to remain. Fulton's experiments on the proportional numbers of the sexes show that out of 12,666 fish of twenty-one species examined, 3,858 were males and 8,808 were females-a ratio of 228 females to 100 males.

The flounder and the brill were, however, found to be exceptions, while the greatest inequality was found in the case of the long rough dab (Hippoglossoides limandoides), where the ratio was 842 females to 100 males, or nearly seventeen females to every two males. As regards the proportional size, the observations show that "Among all the flat fishes without exception, the female is longer than the male, the ratio varying with the species."

Mr. Holt, who has worked most extensively at the sexual maturation of fishes, in order to determine if possible a method of protecting fishes which have never spawned, discards the male sex altogether, and considers only the sizes of the females, since the males, being both smaller and less numerous, would be more highly protected than the females by any measures drawn up with a view to prohibiting the capture or sale of flat fishes under certain sizes. Others who have worked at the same subject pursue the same course.

Take the

These inquiries have been instituted not for their own sakes, but because, from studying the fisheries of the country, it has become obvious that knowledge of this kind is essential. The constant clamour kept up by fishermen who daily see their returns becoming smaller does not reach the ears of those who are busily occupied in commerce, or in science; it is appreciated only when special attention is paid to the history and present condition of some of the most important areas. great industry of the Dogger Banks, which for other reasons has come before the notice of the public of late years. In 1828 the North Sea was practically an unknown fishing region. Boats of no very great size were in that year just beginning operations from Harwich. Before this date trawling was confined to the south coast, having commenced at Brixham about the year 1764. The Dogger Bank was found to be teeming with fish; there was plenty for every one, and an almost endless scope for fresh ventures. The "Silver Pits" were discovered in 1837, the name being significant of the value to the discoverer and his followers. So things went on, more and larger boats were built, heavier gear used, boats banded

together in fleets, and remained out on the grounds for weeks at a time, steam was introduced, and the east-side of the North Sea visited. It was a "roaring trade," and many were made wealthy by it. Now things are changed, and every one cries out that the balance has been overturned, that the fish are being caught faster than the stock is being kept up: this, in spite of what was once said as to the amount of fish which could be taken from one acre of sea-bottom. It is possible to fix close times during which salmon and trout must not be taken from certain rivers, and to hatch fry which will remain in the one district. It is another matter to apply close seasons, or fix standard sizes for areas of the open sea. From what we know of life at the sea-bottom it is pretty certain that if one of the conditions necessary for keeping up a true balance of nature is removed or greatly lessened, the proportional arrangement of the remaining fauna is also interfered with, for since marine animals prey largely upon each other it follows that if one class of devourers is removed, the devoured become more numerous, which again seriously affects other classes.

For this reason an over-fished oyster or mussel bed if left to itself, or not properly regulated, will probably never regain its former condition, a fact brought out with great clearness in the course of the evidence taken before Lord Balfour of Burleigh, at the Board of Trade Conference last June. With free swimming round fish the condition is somewhat analogous, although more knowledge is required concerning their migratory movements. If the natural balance is interfered with, the result, although at first it may be only to increase certain other forms which are also of advantage to man, will eventually appear when useless or unprofitable fishes remain in the majority, or when the appearance of a once common and useful species is no longer present in the market.

If human interference can so alter the marketable productivity of the sea, and materially lessen the incomes of a large portion of a nation, surely it becomes a duty to study the application of such sciences as deal directly with the animals concerned. If by continual fishing the only available grounds became depleted, it is by a thorough study of the actual cause and effect, and the application of the principles of natural history involved, that the only true remedy is to be found.




THE HE friends of science throughout the country may be congratulated upon the fact that work in the laboratories of the Royal College of Science and of the City and Guilds Institute is not to be rendered impossi ble by the building of a railway along Exhibition Road. Sir John Kennaway, the chairman, and the members of the House of Commons Committee deserve the best thanks of the community for their unanimous rejection of the scheme even if only partly on scientific grounds. When the evidence given before the committee comes to be published there will be some curious reading. Lord Kelvin, the President of the Royal Society, informed the committee of what was at stake, and gave his opinion as to the question both of mechanical and electrical disturbance. The paid "scientific experts" in their pleading on the side of the company promoters may be said to have almost eclipsed the usual "emphasis" of statement. We may refer to this evidence later, but in the meantime the following quotation from a leader in the Times indicates the general opinion as to the importance of the

result which has been achieved:

"What makes the history of this Bill novel and interesting is the second line of attack adopted by its opponents. On either side of Exhibition Road stand two of the most important scientific institutions in London. One of these-the Royal

College of Science-is supported by the State; the ev founded by the City and Guilds of London for the prom advanced technical education The former of these mer. and the great collection of scientific instruments which r formed at South Kensington, make an organised whole collection, which includes the earlier and the latest tre is invaluable both historically and practically, close proximity to the lecture-halls and laboratone wa use can be made of the instruments. The collection laboratories are used not only by many other students, the large number of national scholars and exhitetitze v after the annual May examination of the Science E Department, are brought up from all parts of the country at the public expense. These students, and the deserv who work at the City and Guilds Institute, form at element in the situation; for to them the advent of an e railway was a serious peril. It was shown, and adm the magnetic disturbances in the neighbourhood of the London Railway are so great that no accurate magis can be done within some hundreds of yards of it. Now th posed Paddington and Clapham Railway would ren, se hundreds of yards from the South Kensington laterates, a within forty feet of some of them; and there was a on the part of the Professors that at such smail da would be impossible not only to accurately neatrals the flicting forces, but to prevent the astronomical instrume affected by the earth-tremors caused by the passage This view was urged by Lord Kelvin, perhaps the living authority on such matters, and by Pr·f! Lockyer, Ayrton, Rucker, and Boys; and after a contes lasted three days their view prevailed, and the committe the preamble of the Bill Not proved.' The men of are to be congratulated on the result. A year or mig successfully defended their South Kensington preserve the invasion of Art; and it would be pitiful indeed if were now to be put in jeopardy by a practical appl herself. It appears that electricity cannot be studied neighbourhood of an electric railway; naturally, then, not have an electric railway close to the great central where electrical science is taught at the public expen."


THE annual general meeting of the Institution o. Architects is being held this week in the rooms of the S of Arts, which have been lent for the purpose. The v ings began yesterday (Wednesday) morning, and will. to-morrow evening. The meeting is one of more any importance in the history of the Institution from the a the president, the Earl of Ravensworth, is resigning the tion which he has so well filled for a period of forme Lord Ravensworth is the second president the Insist had, he having succeeded to the chair on the death Hampton, who first occupied the position. The new is Lord Brassey, whose great interest in all maritime well qualifies him for the post. Lord Ravensworth ▾ sever his connection with the Institution, as he will

position of a vice-president. The following is the proje of the present meeting :-Wednesday, March 21-M meeting, at twelve o'clock: Annual report of Conne"; • by the president (the Earl of Ravensworth; on e position of the cruiser in warfare, by Rear-Admiral S on approximate curves of stability, by W Hok. Th March 23.-Morning meeting, at twelve o'clock: Soďte 20 tions relating to the strength of bulkheads, by Dr. }on the measurement of wake currents, by George A. Cr on the new Afonasieff's formulæ for solving app various problems connected with the propulsion Captain E. E. Goulaeff. Evening meeting, at eres Some experiments on the transmission of heal 'Inv plates, by A. J. Durston; some notes on the testing (` by J. T. Milton. Friday, March 24-Morning twelve o'clock: On an apparatus for measuring 2012 – the vibrations of steamers, by Herr E. Olto Schik A

[ocr errors][merged small]

Sharpe, four lectures on the geographical distribution of birds; Mr. James Swinburne, three lectures on some applications of electricity to chemistry (the Tyndall lectures). The Friday

airs of injuries to the hulls of vessels by collisions, stranding, | Dewar, five lectures on the atmosphere; Mr. R. Bowdler nd explosions, by Captain J. Kiddle. Evening meeting, at even o'clock: Some experiments with the engines of the s.s. 'veagh, by John Inglis ; on the cyclogram, or clock-face diagram, of the sequence of pressures in multi-cylinder engines, by F. Edwards; presentation of an address from the Institution to the Right Hon. the Earl of Ravensworth, on his retirement from the office of president. In addition to the above there is a paper by Lord Brassey on merchant ships as cruisers. The annual linner was held at the Holborn Restaurant yesterday evening. In summer the Institution will meet at Cardiff.

Ox Friday a deputation will wait upon Mr. Campbell Bannerman to make some representations as to the position of those Woolwich cadets who have taken up science at the entrance examination. The existing system at the Royal Military Academy, as we have repeatedly taken occasion to point out, is very unfavourable to cadets of the scientific type, and it is hoped that the approaching interview may lead to the adoption of more reasonable methods. Among the members of the deputation will be Sir Henry Roscoe, Sir Henry Howorth, and the head masters of Rugby, Cheltenham, and Clifton.

MR. W. L. CALDERWOOD has resigned the post of director of the Laboratory of the Marine Biological Association at Plymouth. He vacates the residence early in April.

We are privately informed of the death, on the 7th instant, of Dr. G. Vasey, the chief of the botanical section of the United States Department of Agriculture at Washington. He was a native of Yorkshire, we believe, and emigrated to America many years ago. The grasses of North America were his special study, and he published several important works on this family. The "Grasses of the Pacific Slope" and the "Grasses of the South-west," fully illustrated, are his latest works; but the former is not yet completed. Dr. Vasey wrote also on the agricultural value of the grasses of the United States. Last year he visited England, and made many friends through his amiable disposition.

WE learn with regret, from the daily papers, that the Rev. W. Woolls, of Burwood, near Sydney, New South Wales, bas lately died. It is stated that he emigrated from England as long ago as 1831, and he certainly did much to promote science in the country of his adoption. Botany was his favourite study, | and he made several important contributions to botanical literature, chiefly on the botany of New South Wales. He was president of the "Cumberland Mutual Improvement Society," and in that capacity delivered a number of carefully compiled instructive lectures on the vegetable products and resources of the colony, and other branches of botany. One of the most interesting of his published lectures is on the progress of botanical discovery in Australia, which is indeed a concise and correct history of the subject. It was he who wrote the appreciative reviews of the volumes of Bentham's "Flora Australiensis "that appeared in the Sydney Morning Herald, and he himself published separate accounts of the plants of the neighbourhood of Sydney, of the Paramatta district, and of the colony of New South Wales.

THE Botanisches Centralblatt announces the death of Dr. Karl Prantl, Professor of Botany in the University of Breslau, and director of the Botanic Garden there. For some years past Dr. Prantl has edited Hedwigia, a journal devoted to cryptogamic botany; but it was chiefly as a teacher that he was known. An English edition of his " Lehrbuch der Botanik" was edited by Dr. S. H. Vines in 1880.

THE following are among the lecture arrangements at the Royal Institution after Easter :-Mr. John Macdonell, three lectures on symbolism in ceremonies, customs, and art; Prof.

evening meetings will be resumed on April 14, when a discourse will be given by Sir William H. Flower, on seals; succeeding discourses will probably be given by Prof. A. B. W. Kennedy, Prof. Francis Gotch, Mr. Shelford Bidwell, the Right Hon. Lord Kelvin, Mr. Alfred Austin, Mr. Beerbohm Tree, Prof. Osborne Reynolds, Prof. T. E. Thorpe, and other gentlemen.

DR. H. WOODWARD, F. R.S., is the president of the Malacological Society which was founded lately at a meeting held at 67, Chancery Lane. The Society will meet at the same place on Friday, April 14, at 8 p.m., and again on the second Fridays in May and June, after which there will be no meeting till November.

ANY one who may desire to learn all that is best worth knowing about the progress and prospects of technical education should read an admirable lecture on the subject delivered by Sir Philip Magnus last week before the Society of Arts, and printed in the current number of the Society's Journal. Sir Philip is of opinion that what is now wanted is the co-ordination of our resources and the simplification of our machinery. The Technical Instruction Committees, with the help of their able secretaries, are doing good and useful work, although much of it is necessarily impeded by the restrictions of the Acts of Parlia ment under which they work. Between these bodies and the School Boards, Sir Philip urges, there should be earnest cooperation. To them, acting together, and strengthened by the representatives of other educational interests, should be ultimately submitted the duty of making that further provision for secondary education, the need of which is generally admitted.

A MEETING was held at the First Avenue Hotel on Saturday last for the purpose of forming a Cage-bird Club. Dr. Martin, chairman of the Norton Ornithological Society, and vice-president of the London Cage-bird Association, occupied the chair; and a paper was read by Mr. W. H. Betts, who explained that the object of the club was the enrolment among its members of ladies and gentlemen who, from the fact that the majority of cage-bird clubs were held at public-houses, were debarred from membership thereof. He said the club would endeavour to train novices in the management of cage-birds, would give encouragement and assistance to ornithological societies generally, would circulate literature with the object of improving the moral tone of the cage-bird fancy, and would endeavour to prevent cheating at shows and to put an end to brutality. On the motion of the Rev. W. K. Suart, president of the Cage-Bird Association, seconded by Mr. George Crabb, president of the London and Provincial Ornithological Society,

Mr. Betts

it was determined that the club should be founded. was appointed honorary treasurer, and Miss E. A. Darbyshire honorary secretary.


DR. JAMES RORIE, writing from Westgreen House, Dundee, sends us the following note on a brilliant meteor :—“ A very brilliant meteor, or fire-ball, was seen here about 6.23 p.m. on Saturday evening, the 18th inst. When first observed it was about 70° above the horizon south-south-west from the asylum, and moving in a direction from east-south-east to west-northwest. It was visible for about five seconds, and appeared like a large pale blue ball of fire throwing off jets of red-coloured flames, and leaving behind it a pale white silvery streak, marking its course across the sky like a very thin line of vapour, but at the point near the horizon where the meteor disappeared leaving a shining electric blue colour. This streak was in all probability composed of dust particles thrown off by the meteor

during the passage in a state of ignition through the atmosphere, as it remained visible for nearly three-quarters of an hour, first as a straight line, and then, evidently caught by the westerly wind, becoming gradually contorted, and, slowly expanding and disappearing, it passed overhead like a long thin twisted cloud of pale blue smoke."

DURING the latter part of last week the high pressure over France gave way, and several shallow secondary depressions passed across our islands, accompanied by northwesterly winds, snow and hail showers. Sharp frosts occurred in places at night, the shade minima varying from 20° to 23°, while the grass temperatures were much lower, the thermometer on Saturday night falling as low as 12° to 16° in the Midland counties and in London; but during the bright intervals of the day-time the maxima reached 50° and upwards. Towards the close of the week an anti-cyclone which previously lay off our south-west coasts spread over the United Kingdom, and extended eastwards over the continent. The weather during the next few days became fine and bright generally, with the exception of fog in the neighbourhood of London and the south-east of England. The maximum day temperatures exceeded 60° at several stations, but the nights continued exceptionally cold, the ground being thickly coated with hoar frost. Such severe frosts as those experienced on several nights during the past week rarely occur so late in the season. The Weekly Weather Report for the week ending the 18th instant shows that, notwithstanding the very low minimum temperatures, the averages for the week were rather above the mean in England and the south of Ireland. Rainfall was considerably in excess of the average in the north of Scotland, but less in all other parts. The greatest amount of bright sunshine was recorded in the north-east of England, where there was 52 per cent. of the possible amount; the lowest average amount was 18 per cent, in the north of Scotland.

WITH the view of enabling masters of vessels to know what weather to expect at sea in the far East, and to choose the best routes, all the observations recorded in the archives of the Hong Kong Observatory made between o° and 45°, and between Singapore and 180° E. Gr. are being tabulated, and will serve for the construction of maps, which will ultimately make it possible to issue pilot charts for the China Seas. Dr. Doberck invites all persons having old log-books in their possession to send them to him on loan. There are log-books of our large lines which, if forwarded to the proper quarters, might help to make passages shorter, pleasanter, and safer.

THE Societies forming the Scientific Alliance of New York have held their first joint meeting, the object being to present the needs of science in that city, and the plans and purposes of the Council of the Alliance. The addresses delivered on this occasion have now been published as a pamphlet. We may note that the membership of the societies is over 650, and is said to include the names of nearly all persons in New York who are interested in pure science.

COLUMBIA COLLEGE, New York, has received from Mr. Loubat an endowment which is to be used for the encouragement of the study of (1) The history, geography, and numismatics, (2) the archæology, ethnology, and philology of North America. It will permit an award at least every five years alternately in these two groups of subjects. This year two prizes of 1000 dollars and 400 dollars will be given for the best works published in English on the subjects in question. The author need not be a citizen of the United States. The works must have been published since January 1, 1888, and must be based on original research. Copies must be sent, not later than June 1 of the present year, to the president of Columbia Col

lege, whose secretary will furnish copies of the regulations adopted.

MR. THOMAS STEEL, of Victoria, has been visiting severa zoological gardens in Great Britain and America; and in the February number of the Victorian Naturalist he gives an i teresting account of some of his experiences. In the London Zoological Gardens he was naturally attracted especially b animals and birds from Australia. The kangaroos seemed him to have very small quarters compared with those set apar for kangaroos in the Melbourne gardens. Nevertheless, i thought them "fairly healthy and sleek." Mr. Steel was math pleased with a pair of Australian brush turkeys, who were evidently "quite at home in their enclosure." The laughi jackass, however, was the animal which interested him mo strongly. He had "quite a thrill of pleasure" when he reorg "well-remembered voice." Of the collection of animals in the Central Park, New York, Mr. Steel formed very high opinion. He was much surprised that so mighty. city should be "so far behind in a matter of this kind." Of th dejected-looking lions" in the Central Park he says that they were greatly to be pitied. They were "cooped up in the smallest of cages, with no proper shelter and no exercising yard."

nised its

[ocr errors]

THE Kew Bulletin, appendix ii. 1893, consists of a list 3 the new garden plants of the year 1892. The list includes only plants brought into cultivation for the first time dari 1892, but the most noteworthy of those which have been res troduced after being lost from cultivation. Other plants cluded in the list have been in gardens for several year but either were not described or their names had not bee authenticated until recently. These annual lists, as the Be points out, are indispensable to the maintenance of a corre nomenclature, especially in the smaller botanical establishmen in correspondence with Kew, which are, as a rule, only scantily provided with horticultural periodicals. The lists also affi information respecting new plants under cultivation at Kes many of which will be distributed from the Royal Gardens the regular course of exchange with other botanic establis


PROF. P. H. SCHOUTE and some other Dutch mathema ticians have undertaken to edit, under the auspices of the Mathematical Society of Amsterdam, a "Revue Semestriel des Publications Mathematiques." The first part of the volume has just been issued by W. Versluys, Amsterdam. Th "Revue" appears likely to be of service to mathematicians ar beyond the limits of Holland.

THE Smithsonian Institution has published a collection translations of some of the best recent memoirs issued in Ear pean countries on "The Mechanics of the Earth's Atmosphere. The work has been prepared by Mr. Cleveland Abbe, who e presses his conviction that "meteorology can be advanced beyʊr. its present stage only by the devotion to it of the highest tale in mathematical and experimental physics.

THE geological department of Colby University, US has published a useful "Summary of Progress in Me eralogy and Petrography in 1892," by W. S. Bayley. Th volume consists of monthly notes contributed to the A Naturalist.

MR. ELLIOT STOCK has issued a little volume, by "Medic showing how the height and chest measurement may increased by systematic exercise. The title of the volume "How to Improve the Physique."

IN the current number of the Comptes Rendus there are papers on the use of the electric current in producing bigb

ratures. In one MM. Moissan and Violle describe two forms electric furnace which they have used in their experiments. le substance to be heated is contained in a small crucible ide of carbon having two holes pierced through its side to ow the carbon rods, between which the arc is formed, to 55. This crucible is surrounded by blocks of lime to rece the loss of heat on account of radiation. In one form furnace there is an arrangement by which a piece of graphite, er being heated in the arc, is allowed to fall into a caloriter, and by this means they have found that a temperature of 0° can be reached. In the other paper MM. Lagrange and pho have investigated the fact, observed by Planté and others, it when you pass a sufficiently strong current through an ctrolyte, using as negative electrode a fine wire, and as posie electrode a conductor of considerable surface, a kind of ninous sheath is formed round the negative electrode. The thors find that the heat developed in this sheath is very great, d that by its means a very intense heat can be applied at any int of a body while, on account of the rapidity with which the at is disengaged, the rest of the body remains cold. As an plication of this method they have heated to a bright red the Iside of a bar of steel, while the inside remained comparaely cool, then by merely stopping the current the cold liquid 5 come in contact with the hot steel. In this way they have dened the outside of bars of steel, while the inside has nained soft and therefore tough.

PROF. L. WEBER, of Kiel, has recently constructed a rcury barometer which can be filled without boiling, and ose vacuum can be freed from residual air at any time in a ¡ seconds. It consists, according to the Zeitschrift für strumentenkunde, of a vertical tube with two bulbs, one on ch side. One of these bulbs ends in a tube to which an arubber tube can be attached. The other is connected by hort tube with a capillary constriction. A narrow tube concts the lower end of the bulb with the top of the main tube, s forming a kind of double barometer. To fill it mercury is red into the first bulb and allowed to enter the main tube. doing so it forces the air down through the narrow tube and by the second bulb. Some mercury also enters the latter the capillary constriction. On placing the instrument in a tical position a vacuum is formed at the top of the two comnicating tubes, which is slightly longer in the narrow one ing to capillary depression. Barometric readings are then en in the usual way by means of a scale fixed to the main e. The vacuum can be tested and easily restored in the owing way: The indiarubber tube attached to the first bulb is in an elastic ball with a small hole in it. This hole is sed by the thumb and the ball is compressed. Mercury is s forced up the main tube and over into the capillary tube. here is any residual air it will form a bubble between the two umns, which will on further compression be driven out ough the second bulb. On releasing the pressure the vacuum e-established, and the slight difference of level in the two bs is gradually obliterated by the passage of mercury through capillary contraction. The latter can be replaced by a glass with a conically ground end, by means of which the comnication between the two bulbs can be temporarily interted.

AN interesting communication concerning metallic osmium is tributed to the current number of the Comptes Rendus by 1. Joly and Vezes. Metallic osmium, as usually prepared by method of Berzelius, which consists in calcining the sulphide carbon crucible, takes the form of a powder or a spongy 5 of a blue colour. As thus obtained it is rapidly attacked the oxygen of the air with production of the volatile and gerously poisonous tetroxide Os¤; hence the metal conatly exhales a strong odour due to the vapour of the tetroxide.

Sainte-Claire Deville and Debray some time ago succeeded in obtaining metallic osmium in the form of beautiful little greyish blue crystals, by passing the vapour of the tetroxide through a strongly heated carbon tube. The density of these crystals, 22 48, was the highest which has been observed for the metal. All the efforts, however, of Sainte-Claire Deville and Debray to fuse osmium in the flame of the oxyhydrogen blowpipe were unavailing. If enclosed in a crucible of carbon surrounded by another of lime, the metal simply remained unchanged, but if heated directly in the flame itself it rapidly disappeared, owing to its conversion into the volatile tetroxide, but no trace of fusion was ever observed. It is now shown that osmium does melt at the temperature of a very powerful electric arc, in a manner analogous to ruthenium. It is, of course, essential that special precautions should be taken in order to prevent loss of the extremely expensive metal by oxidation, and consequently volatility, particularly as the volatile product of the oxidation, the tetroxide, is so injurious to the experimenter. The operation was therefore performed in the electric furnace devised by Ducretet and Lejeune, which enabled the metal to be heated in a carbon crucible placed in a closed chamber traversed by a stream of carbon dioxide. Under these conditions when osmium is rapidly raised to the highest temperature of the electric arc it melts without sensible loss by volatilisation. After fusion osmium presents a very brilliant metallic surface of a beautiful blue colour slightly tinged with grey. It breaks with a crystalline fracture, and is distinguished by its remarkable hardness, being harder than both ruthenium and iridium, readily cutting glass and scratching quartz. Moreover, after fusion osmium appears to be no longer attacked by the atmospheric oxygen, its surface remaining bright greyish-blue.

THE whole of the refractory metals of the platinum family have now been obtained in the liquid form. Of them all osmium has been found the most refractory, its melting point being considerably higher than that of ruthenium. It resembles the latter metal very much in many of its properties, particularly as regards the ready formation of a volatile tetroxide. It differs entirely, however, from ruthenium in aspect, exhibiting as above described a remarkable blue metallic lustre, while ruthenium is more white than platinum, resembling in fact burnished silver. The six metals of the platinum group would appear to more particularly resemble each other in pairs, ruthenium and osmium having many physical and chemical attributes in common, rhodium and iridium being similarly very nearly allied, and palladium and platinum forming the third pair. In many respects, however, osmium exhibits a peculiar and somewhat isolated character, more akin to that of the metalloidal elements; indeed, so marked is this that Deville and Debray termed it the metalloid of the platinum group, Berzelius compared it to arsenic, and Dumas to tellurium.

NOTES from the Marine Biological Station, Plymouth Little change has been observed in the floating fauna since last week. Sarsia prolifera and medusæ of Clytia Johnstoni have again been taken; and Obelia medusæ have been plentiful, although for the most part very small and immature. A few Polydora larvæ have been taken. Evadne Nordmanni, which at times is abundant in the surface waters, has made its first appearance for the year; the few individuals noticed were carrying embryos in the brood pouch. The Nemertine Cephalothrix lineare and the crabs Portunus depurator and holsatus have begun to breed.

THE additions to the Zoological Society's Gardens during the past week include eleven Orbicular Horned Lizards (Phrynosoma orbiculare) from California, presented by Mr. William Chamberlain; a Stanley Parrakeet (Platycercus icterotis) from Australia, deposited; a wandering Albatross (Diomedea exulans) captured

« AnteriorContinuar »