do it in the hope that it may perhaps ultimately assist in removing some of them. It is obviously desirable that the charts, which are intended to show the distribution of pressure and temperature, should be derived from observations made at the same hour. Germany observes at eight o'clock of central European time, and France observes simultaneously (or nearly so) by choosing seven o'clock Paris time for its readings. We observe at eight o'clock Greenwich time, which is an hour later. It is the great desire of Continental meteorologists that our standard hour should be seven o'clock; and what prevents it from being so? Chiefly and absolutely the additional cost which the Post Office must claim for the transmission of telegrams; because messages transmitted before eight o'clock are subject to an additional charge of one shilling, which may be claimed by the postmaster, the claim being possibly increased to two shillings when the postmaster and telegraphist are different persons. This is prohibitive, but it does not exhaust the inconvenience of the additional charge. For the purpose of weather forecasting it is clearly necessary that telegrams should be received as early as possible by the Meteorological Office. But the eight o'clock rule delays telegrams from some Irish stations, because eight o'clock by Dublin time is 8.25 by Greenwich time, and therefore Irish telegrams may have to wait until nearly half-past eight if they are to be transmitted without extra charge.

While the international organisation of meteorology is well on its way, though difficulties such as those I have mentioned may temporarily retard it, another question not altogether disconnected with it has been raised by Sir John Eliot. This is the establishment of an institution devoted to the collective study of meteorological problems affecting all parts of the British Dominions. It is true, not only in this, but also in other matters, that in order to take our proper position in international work it is necessary that we should set our own house in order, and we must give Sir John Eliot's proposals our hearty support. If I do not enter further into this question it is because I am to-day dealing more especially with problems which go beyond the limits of the Empire. I assume the existence of a national organisation, but lay stress on the insufficiency of this limitation.

We

The importance of the subject, however, may be my justification if I direct your attention for a moment to the meteorological question as it presents itself in India. all know and realise the vital importance of the rainy season, and the benefit which the native population would derive if it were possible to predict, even if only imperfectly, the setting in of the monsoon. It appears that Dr. Walker, the present director of observatories in India, recently obtained very encouraging results in this respect. According to his investigations, a forecast of the monsoon may be derived from a knowledge of the weather during preceding months in different parts of the world. Thus a heavy rainfall in Zanzibar in May is followed by a weak monsoon, while a pressure deficiency in Siberia during the month of March indicates a probable deficiency of rain in India during the following August. I need not insist on the importance of these results, which at present are purely empirical, and require further confirmation; but it is quite clear that for the successful prosecution of these inquiries political boundaries must be disregarded, and a system of intercommunication organised between countries chiefly concerned. Dr. Walker informs me that he has successfully arranged for telegraphic reports to be sent to him at the beginning of June from six different stations in Siberia. It is hoped that this cooperation, which was unavoidably discontinued during the late war, may now be re-established.

the

The course of international organisations does not always run smoothly. The efforts made toward cooperation in earthquake records have unfortunately led to differences of opinion, which have hitherto prevented a truly international system being formed; and if I give a short historical account of the circumstances which have led up to these differences it is only in the hope that this may help to remove them. The scientific investigation of earthquakes may be said to have begun when British professors of physics, engineering, and geology were appointed at the

Imperial College of Engineering in Tokio. Some of them, on returning home, succeeded in interesting the British Association in the subject. Ever since 1880 that association has been an active supporter of seismic investigations. The much disturbed region of the Japanese island was naturally the first to be studied; but in 1895 Prof. Milne, as one of the secretaries of the committee, issued a circular directing attention to the desirability of observing waves which have travelled great distances, and some months later, Dr. E. v. Rebeur-Paschwitz, of Strassburg, drew up suggestions for the establishment of an international system of earthquake stations. To this scheme Prof. Milne and other members of the British Association committee gave their approval. The cooperation which thus seemed so happily inaugurated was broken by the unfortunate death of its originator. Circumstances then arose which compelled the British Association committee to go its own way. Under its direction a system was established which now includes about forty stations distributed all over the world. But the needs of different countries are not, and were not meant to be, completely satisfied by this organisation.

There is always a certain number of earthquakes having purely local importance and requiring discussion from a purely local point of view. For the purpose of such discussion relating to the disturbances which chiefly affect Central Europe, the Union (so-called Kartell) of the Academies of Vienna, Munich, Leipzig, and Göttingen formed a committee and did excellent work. In the meantime Prof. Gerland, who had succeeded Dr. RebeurPaschwitz at Strassburg, had personally invited a number of friends interested in the subject to a conference at Strassburg with the object of forming an international association. This was followed in 1903 by a formal conference called by the German Government, at which Great Britain was represented by Sir George Darwin and Prof. Milne. This conference drew up a scheme for an international association, and a large number of countries, including Russia and Japan, joined. Strassburg was selected as the seat of the Central Bureau. The matter came up for discussion at the meeting of the International Association of Academies, which was held in London in the year 1904, and a committee was appointed for the purpose of suggesting such modifications in the constitution of the seismic organisation as might bring it into harmony with the views of the associated academies. This committee, over which I had the honour to preside, met at Frankfort, and recommended a number of important changes, which were unanimously accepted by the second seismic conference held last summer in Berlin. In consequence of this acceptance it appears that Italy and the United States joined the seismic association, while England declared its willingness to join under certain conditions, of which the simultaneous adhesion of France was one. The following summary of the States which have joined, and their population, is copied from the official report of the last meeting at Berlin:—

It was decided at the Berlin meeting that Prof. Kövesligethy, of Budapest, should be secretary, and Prof. Palazzo, of Rome, the vice-president, of the International Seismic Association. Prof. Gerland had already previously been designated as director of the Central Bureau. The office of president of the association was left vacant until the final decision of Great Britain as to its adhesion had been settled. There the matter stands for the present.

The disastrous results of recent earthquakes and volcanic eruptions have directed increased attention to the subject. Its thorough investigation is indeed likely to yield important information on the interior constitution of the earth. A hearty cooperation to obtain and circulate the material for a detailed discussion cannot fail to bear fruit, and, even though there may be legitimate grounds for dissatisfaction at the manner in which a particular scheme has been organised, I must express my own opinion that at the present moment the permanent interests of this country would be best secured by our joining the association and helping to direct its work in a manner which would assis rather than hamper the present organisation of the British Association.

Although time is running short, I am perhaps in private duty bound not altogether to pass over in silence an organisation which has its central bureau in my own laboratory at the University of Manchester. This is a union for the observation of solar phenomena. Called into being chiefly by the energy of Prof. Hale, this association is perhaps unique in two respects. It aims more directly at conducting research work than is the case with other unions, and in so far may run the danger of hampering private efforts. This danger has, I believe, been well guarded against by the constitution adopted at the first meeting of the conference held last September at Oxford. The second peculiarity referred to is that it works a central bureau, a computing bureau (under the direction of Prof. Turner), and is going to publish Transactions without any funds beyond those doled out to it by charity. Its vitality will, I hope, help it to overcome its initial troubles. Its ambitious programme includes a definite agreement on the standard of wave-length and investigations on the permanence or variability of solar radiation.

This latter question is of considerable interest to meteorologists, and comes, therefore, within the purview of the directors of meteorological observatories, who have also, under the presidency of Sir Norman Lockyer, established a commission charged with its discussion. An arrangement has been made securing cooperation between the two bodies, the Solar Union leaving out of its programme the difficult question of the relationship between sun-spot variability and meteorological phenomena.

Although an unnecessary overlapping of two separate enterprises has in this instance been avoided, such overlapping constitutes a certain danger for the future, as the problems of geo-physics-for the investigation of which international associations are specially marked out-are so intimately connected with each other that a homogeneous treatment would seem to require a central body supervising to some extent the separate associations. Such a central body may be found in the International Association of Academies, which promises to play so important a part in scientific history that a short account of its early history may be of interest. The Kartell of some of the German academies and that of Vienna has already been referred to. In discussing the utility of its deliberations, Prof. Felix Klein, of Göttingen, first mentioned to me the idea that an association of a similar nature would be likely to prove of still greater value, if formed between the scientific and literary academies all over the world. In consequence of this conversation I tried to interest the Royal Society in the subject; and in order to obtain further information Prof. Armstrong and myself attended privately, though with the knowledge and consent of the council of the Royal Society, the meeting of the Kartell which was held at Leipzig in the year 1897. In the following year the two secretaries of the Royal Society, Sir Michael Foster and Sir Arthur Rücker, together with Prof. Armstrong and myself, attended the Kartell which then met at Göttingen.

The secretaries were impressed by the great possibilities of the scheme, and the council then took the initiative and approached the academies of Paris and St. Petersburg, which both returned favourable answers.

In consequence of the correspondence between these learned societies, the Royal Academy of Berlin, in conjunction with the Royal Society of London, issued invitations for a general conference to be held at Wiesbaden on October 9 and 10, in the year 1899.

The following were represented at this meeting, at which the statutes of the new association were agreed upon :—

The Royal Prussian Academy of Sciences of Berlin.
The Royal Academy of Sciences of Göttingen.
The Royal Saxon Academy of Sciences of Leipzig.
The Royal Society of London.

The Royal Bavarian Academy of Science of Munich.
The Academy of Sciences of Paris.

The Imperial Academy of Science of St. Petersburg.
The National Academy of Science of Washington.
The Imperial Academy of Sciences of Vienna.

The unanimity of the meeting may be judged from the fact that a working constitution, which subsequent experience proved to be eminently effective, was finally arrived at on the second day. Many distinguished men took part in the discussions; amongst them Prof. Simon Newcomb and the late Prof. Virchow may be specially mentioned.

Although the Berlin Academy had never joined the German Kartell, the first idea of a wider association seems to be due to a distinguished member of that body, the historian Mommsen, who, though of advanced age, was able to be present at the first regular meeting of the associ ation, which was held at Paris on April 16-20, 1901. In addition to the societies which took part in its foundation, the following form part of the association, and were TPpresented at Paris :

The Royal Academy of Sciences of Amsterdam.
The Royal Belgian Academy of Sciences, Arts
Letters.

The Hungarian Academy of Sciences.
The Academy of Sciences of Christiania.
The Academy of Sciences of Copenhagen.

and

The Academy "des Inscriptions et Belles Lettres " of the Institut de France.

This meeting is not likely to pass out of the memory of those who took part in it. Its importance was enhanced by the social functions which were held in connection with it, and which included a luncheon given by President Loubet at the Elysée, a banquet given by the Conseil Municipal, and a special performance at the Théâtre Français. The subsequent triennial meeting of the academy, which was held in London in 1904, passed off not less brilliantly. The representatives of the learned societies were received by their Majesties at Windsor, and the Lord Mayor invited them to dinner at the Mansion House. Social entertainments, though welcome as marking the importance of the occasion, are not allowed to interfere with the very substantial work which is being done at these meetings. The list of subjects which were included in the discussion of the London assembly may give an idea of the range of activity of the association. A permanent committee is charged with the investigation of the functions of the brain, others deal with questions of atmospheric electricity, and of the measurement of magnetic elements at sea. An important proposal to carry out an exact magnetic survey along a complete circle of latitude is under discussion. The section of letters dealt with the mutual arrangements between libraries regarding the interchange of manuscripts, approved the intended edition of the Mahabharata, and considered a proposal to construct a new Thesaurus of Ancient Greek. The association also took cognisance of and received reports on independent

international undertakings, such as the Catalogue of Scientific Literature, the Geodetic Association, and the Geological Congress.

The association meets every three years. To these meetings each constituent academy may send as many delegates as may be found convenient. For the discussion of special questions the assembly divides itself into a scientific section and a literary section.

In each of these sections, as well as in the plenary meetings comprising both sections, each academy has only one vote. At each triennial assembly the next meeting place is chosen. In the intervals between the meetings the affairs of the association are placed in the hands of a council on which each academy is represented by two members or one, according as it comprises both a literary and scientific section or only one of them. The resolutions passed by the association are not binding on the constituent academies, who maintain their liberty of adopting or rejecting them.

The Association of Academies suffers unavoidably from a certain want of homogeneity, owing to differences in the constitution of its component bodies. Most Continental academies contain both literary and scientific sections, and at the organising meeting held at Wiesbaden, marked attention was directed to the fact that there was no body in England that could be considered as representative of literary studies. If matters had been left as they stood then, this country would have been altogether unrepresented as regards half the activity of the association. Efforts were made in consequence to take a more liberal view of the branches of knowledge coming within the range of the Royal Society, and to include literary subjects. Very unfortunately, in my opinion, these efforts failed, and a charter was granted to the British Academy, which has now been included as a separate body among the list of academies forming part of the association. While in this respect we have been at a certain disadvantage, the constiTution of the Royal Society has the great advantage of being truly representative of the Empire. In France, on the other hand, no one can belong to the Academy of Sciences who is not domiciled in Paris. Similarly, although Germany possesses four Royal academies (Berlin, Gottingen, Leipzig, Munich), each of them is confined, as regards ordinary members, to its own locality, so that a professor of the Universities of Bonn or Heidelberg, however eminent he may be, could not become a member of any of these academies. Neither in France nor in Germany can the academy therefore be called truly representative. The disadvantages which may arise from this defect have been minimised by adopting a rule that the International Association of Academies may appoint committees for the discussion of special questions, and that members of these committees need not be members of any of the constituent academies. This to a large degree obviates what would otherwise be a considerable difficulty. Nevertheless, I believe that the circumstances to which I have directed attention form the only impediment in the way of handing over to the Association of Academies the ultimate control of every new international undertaking, and even the charge of some of those already established. It is highly desirable that we should work towards this end. An energetic enthusiast may easily start a new enterprise, and Governments are appealed to from different sides for help and support. There ought to be some authoritative body to whom the Governments could apply for advice. Overlapping and waste would thus be avoided.

It is not my desire to disguise the difficulties which have sometimes been encountered in providing for joint undertakings on a large scale. Whether national or international, combined work between men of different temperaments always requires some suppression of personality. Even stronger feelings may be involved when a central office or bureau has to be selected which specially distinguishes one locality. The advantage gained by the locality is often one of appearance rather than of reality, for these central offices should be the servants rather than the masters of the undertaking. In order to prevent national feeling being aroused by any preference given to one nation, it has been customary in some cases to have a. president who belongs to a different country from that of

the director of the Central Bureau; there are also a vicepresident and a secretary, all belonging to different nations. It is thought that such a distribution of office may assist in preserving harmony. I believe that this is the case, but sometimes at the risk of impaired efficiency. It cannot be denied, however, that the seat of the central office of an important undertaking confers a certain dignity, and it is quite natural that a country should feel some pride in the distinction.

England on the whole has not done so badly. We should not forget that in a great portion of the world all clocks strike the same minutes and seconds. Before long all civilised countries (except Ireland) will have adopted the Greenwich meridian for their standard of time, and we may rightly, therefore, call Greenwich the central bureau of universal time.

The offices of the International Catalogue and both the central and computing bureaux of the Solar Union are situated in this country, and if we have not secured an even larger share of the onerous but honourable duties incumbent on such offices the fault is our own. The questions which at the present moment more especially require combined treatment are those of geo-physics, a subject for which very inadequate provision has been made in England. Our earthquake observations almost entirely depend on the self-devotion of one man, and the Meteorological Office, which might reasonably be expected to take charge of certain portions of the work, such as atmospheric electricity, is kept in a state of chronic poverty, and has to restrict itself to work of the most pressing necessity.

Fermat is having of the number of well-equipped

stations for geodetic, magnetic, and aeronautic work, naturally reaps the reward when the offices of an international undertaking have to be chosen which shall be attached to flourishing institutions in charge of men possessing the leisure and qualifications for the work.

No serious advance will be made in our own country in this respect until our universities pay more attention to the subject of terrestrial physics. This would involve the establishment by the universities of separate laboratories or institutions, to which their present funds could not be applied. The matter wants consideration in detail, and should be carried out according to a homogeneous scheme which would prevent wasteful repetition in different places. But I feel certain that until we have trained up a number of students who possess an adequate knowledge of questions of meteorology, geodetics, terrestrial magnetism, and seismology, the position which this country will take in international organisation cannot be a leading one, though it may be, and, indeed, owing to private efforts, is at the present moment, one of which we need not be ashamed.

Finally, I must lay stress on one aspect of the question which I hope may induce us to attach still greater importance to international undertakings. The cooperation of different nations in the joint investigation of the constitution of the terrestrial globe, of the phenomena which take place at its surface, and of the celestial bodies which shine equally upon all, directs attention to our common interests and exposes the artificial nature of political boundaries. The meetings in common discussion of earnest workers in the fields of knowledge tend to obliterate the superficial distinctions of manner and outward bearing which so often get exaggerated until they are mistaken for deepseated national characteristics.

I am afraid I have only given a very inadequate account of the serious interests which are already involved in international scientific investigations. But if I may point once more to Indian meteorology, and remind you of the vital importance of an effective study of the conditions which rule the monsoon, you will, I think. realise how impossible it is to separate scientific and national interests. The solution of this particular problem requires an intimate cooperation with Central Asia and Siberia a cooperation which has been easily secured. I do not wish to exaggerate the civilising value of scientific investigation, but the great problems of creation link all humanity together, and it may yet come to pass that when diplomacy fails-and it often comes perilously near failure— it will fall to the men of science and learning to preserve the peace of the world.

UNIVERSITY AND EDUCATIONAL INTELLIGENCE.

THE Technical High School of Prague will celebrate its hundredth anniversary in November next. Prof. Wilhelm Gint has been appointed rector for the year 1906-7.

ON July 4, the honorary degree of Sc.D. of Dublin University was conferred upon Colonel David Bruce, C.B., Mr. E. T. Whittaker, F.R.S., Astronomer Royal of Ireland, and Sir A. E. Wright, F.R.S.

PROF. C. GRAEBE has tendered his resignation of the professorship of inorganic, organic, and technical chemistry in Geneva University, to take effect from October 1, after which date Prof. Graebe will be an honorary professor of the University.

THE cost of the new metallurgical institute now being erected in connection with the Technical High School at Aachen will be met chiefly by the voluntary contributions of the Rhine and Westphalian metallurgical industries; the sum set apart for the actual buildings is 500,000 marks. At the recent laying of the foundation stone, Generaldirector Springomm, as president of the Verein deutscher Eisenhüttenleute, expressed the sympathy and best wishes of the society with the undertaking.

MR. F. C. FORTH, principal of the Municipal Technical Institute, Belfast, has sent us a copy of an interesting article on the compilation of technical students' records reprinted from the Journal of the Department of Agriculture and Technical Instruction for Ireland (vol. vi., No. 3). The system advocated of chronicling for ready reference data relative to students' attendances, marks, and successes has been devised to meet the requirements of a large technical institute, and as it has now stood the test of two years' working, the description of it should prove a valuable guide to other technical institutions.

SCARCELY a week passes without an announcement in the American papers of some handsome contribution to higher education from public-spirited citizens. In the last issue of Science received we notice that at the commencement of Brown University it was announced that 32,400l. had been subscribed for the John Hay Memorial Library, thus securing the additional gift of 30,00ol. by Mr. Andrew Carnegie. Mr. D. W. Goodspeed, secretary of the board of trustees of the University of Chicago, has announced a gift of 52,000l. from Mr. John D. Rockefeller for current expenses for the year beginning July 1. At the recent commencement of Olivet College gifts aggregating 53,000!. were announced. Of this amount 43,000l. applies toward the Carnegie endowment, leaving only 7000l. to be raised to ensure receiving Mr. Carnegie's gift of 50,000l. the will of the late Prof. George A. Wentworth, of Phillips Exeter Academy, 2000l. is bequeathed to the academy.

By

THE new Code of regulations for public elementary schools marks a great advance on similar publications of a few years ago. The detailed schedules of former years, with their minute instructions as to the work of separate standards, are discontinued. Great prominence is given to a few broad educational principles, on which all successful school practice must be based. The new code, in fact, supplemented by the recently published excellent suggestions for teachers, provides just that necessary official guidance which should suffice to enable properly trained teachers to adapt their procedure and curriculum to local conditions and requirements. The tendency exhibited by the central authority to give efficient teachers a freer hand is satisfactory, and we welcome it. A new scheme of arithmetic is included in the Code, and it reflects the movement started by the British Association to eliminate from school arithmetic all fanciful problems of little everyday use, and to introduce practical measurements at an early stage. The scheme in the new Code puts such measurements in the Fifth Standard work, but omits to state definitely in the same section that such practical work with a scale of inches and tenths, or centimetres and millimetres, is the most satisfactory and natural introduction to decimals.

Decimals are, of course, included in the scheme, but the apparent omission referred to makes it appear that the study of decimals is to be postponed until vulgar fractions and mensuration have been mastered. Though the formal study of decimals may be deferred until the Sixth Standard is reached, the use of a decimally-divided scale for measurements should certainly form part of the work in the Fifth Standard at least, if not at an earlier stage. Mensuration without decimals is an anachronism; and the Board of Education ought to state, through its inspectors or otherwise, that use should be made of scales divided into tenths, in the measurements of rectangles and rectangular solids, and of triangles, included in the course prescribed.

SOCIETIES AND ACADEMIES. LONDON.

Royal Society, December 14, 1905.-" An Investigation into the Structure of the Lumbo-sacral-coccygeal Cord of the Macaque Monkey (Macacus sinicus).' By Mabel Purefoy FitzGerald. Communicated by Prof. Francis Gotch, F.R.S.

From the examination of the cross-sections of the lumbosacral-coccygeal cord of the Macaque monkey (Macacus sinicus), it is seen that :

(1) The maximum section area of the cord, of the white substance as a whole, as well as of the dorsal and the ventro-lateral columns, is found in the fourth lumbar region.

(2) The maximum section area of the grey substance as a whole, and of the dorsal and the ventral horns, is found in the fifth lumbar region.

(3) Reckoning the cross-sectional area of the cord as 100, the maximum percentage of the white substance as a whole, and of the dorsal and the ventro-lateral columns, is found in the first lumbar region.

(4) The maximum percentage of the grey substance is reached in the first coccygeal region.

(5) Reckoning the total area of the grey substance in each cross-section of the cord as 100, the maximum percentage of the dorsal horns is found in the third coccygeal region, and that of the ventral horns in the fifth lumbar region.

January 18.-" Observations on the Life-history of Leucocytes." By C. E. Walker. Communicated by Prof. C. S. Sherrington, F.R.S.

January 25.-" On the Origin of the Sertoli, or Footcells of the Testis." By C. E. Walker and Miss Alice L. Embleton. Communicated by Prof. C. S. Sherrington, F.R.S.

In animals, those cells set aside to produce definite sexual elements go through two divisions, the first and second maiotic (heterotype and homotype) divisions, and are then, without any further division, converted directly into spermatozoa. The same thing happens in the maturation of the ovum. No post-maiotic (post-homotype) divisions have hitherto been recorded.

In plants, on the other hand, after the second maiotic division has occurred, an apparently unlimited number of generations may be produced of cells that have gone through the maiotic phase, and consequently possess only half the somatic number of chromosomes. In the first of the above papers, the occurrence of maiotic phenomena is recorded among the leucocytes and the cells which are their immediate ancestors. According to these observ ations, after the first and second maiotic divisions have occurred, they are followed by an indefinite number of generations of cells possessing only half the somatic complement of chromosomes. The first maiotic division is preceded by amitosis and mitosis of the somatic character, just as happens in the testes of many animals, if not in all. It must be remembered that in certain plants only a few of the cells which have gone through the maiotic phase ever become sex cells. The others may form tissues having somatic characters and functions. This parallel between certain vegetable cells and ieucocytes is carried further by the observations recorded in the second of the above papers. Here it is stated that at an early stage in the develop

ment of the testis, before the tubules or pockets are formed, it is impossible to discriminate between the cells destined to become foot-cells and the leucocytes or their immediate ancestors in the same animal.

Among these cells, also, divisions are seen where the chromosome number is half what is found in the somatic cells. The conclusion drawn from this is that the undifferentiated cells which surround the male ova, and which eventually form both the foot-cells and the walls of the pockets or tubules of the testis, are derived from leucocytes or have immediately common ancestors. If these observations be correct, we have, therefore, animal cells which, though reduced, form tissues possessing somatic characters and functions known to happen in plants.

The bearing of these observations upon the cancer problem is obvious when the fusion between leucocytes and tissue cells recorded elsewhere is borne in mind.

May 17. Some Physical Constants of Ammonia: a Study of the Effect of Change of Temperature and Pressure on an Easily Condensible Gas." By Dr. E. P. Perman and J. H. Davies. Communicated by Principal E. H. Griffiths, F.R.S.

(1) The vapour density of ammonia at o° has been found to be 0-77085 (mass of 1 litre in grams at latitude 45°), previous results being 0-7708 by Guye and 0.7719 by Le Duc.

(2) When the ammonia and the glass vessel were thoroughly dried no appreciable adsorption of ammonia by glass, or condensation of ammonia on the surface of glass, was found to take place.

(3) From density determinations at different temperatures, the coefficient of expansion of ammonia has been deduced as 0.003914 between o° and -20°, and 0.003847 between 0° and 100°.

(4) From Rayleigh's determination of the compressibility of ammonia and our own value for the density, the molecular weight of ammonia has been calculated as 17-030, and the atomic weight of nitrogen as 14.007.

(5) Incidentally, the density of air free from water vapour and carbon dioxide has been determined as 1-2920 (lat. 45°).

(6) The deviation from Dalton's law for a mixture of approximately equal volumes of air and ammonia has been found to be about 1 part in 1000.

(7) The pressure-coefficient of ammonia has been determined, the pressure being atmospheric at 15°. Between 0° and -20° the coefficient was 0.004003, and between o° and 98° it was 0.003802.

The determination of the vapour pressure of liquid ammonia was repeated at some of the lower temperatures, using pure ammonia, in order to obtain an accurate value for its boiling point. From the results, the boiling point of liquid ammonia at 760 mm. pressure was found to be -33°5 C.

June 7. On the Osmotic Pressures of some Concentrated Aqueous Solutions." By the Earl of Berkeley and E. G. J. Hartley. Communicated by W. C. D. Whetham, F.R.S.

This communication gives an account of measurements of osmotic pressures of aqueous solutions of cane sugar, dextrose, galactose, and mannite. The method adopted is that briefly outlined by us in vol. 1xxiii., Roy. Soc. Proc. A gradually increasing pressure is placed upon the solution (which is separated from the solvent by a semipermeable membrane) until the solvent, which at first flows into the solution, reverses its direction, and is squeezed out. The pressure, when there is no movement of the solvent, is considered to be the osmotic pressure. Owing to the difficulty of determining the exact point at which no movement takes place, and for other reasons, the experiments are carried out so as to enable an observation to be made of the rate of movement of the solvent, both when the pressure on the solution is just below and when just above the turning-point pressure. The osmotic pressure is deduced from these rates. The range of pressures covered by the experiments is from 12 to 135 atmospheres.

A description is also given of the methods adopted for

making the copper ferrocyanide membranes, and it is pointed out that with the best membranes, in most cases, a small quantity of solution comes through during the experiment. It is shown that even a small leak causes a considerable lowering of the observed pressure, hence the final results accepted are those where the leak was least.

Attention is directed to the fact that the osmotic pressures of cane-sugar solutions, when measured directly and when calculated from their vapour pressures, agree to within 3 per cent.

Zoological Society, June 19.-Sir Edmund G. Loder, Bart., vice-president, in the chair.-The nudibranchs of southern India and Ceylon, with special reference to the collections and drawings preserved in the Hancock Museum at Newcastle-on-Tyne: Sir Charles Eliot. This paper was an attempt to settle the synonymy of various Nudibranchiata of the Indo-Pacific with the help of Kelaart's drawings and the collections made by him and Walter Elliot, and now preserved at Newcastle. It also contained some new information as to the anatomy of several species (particularly Platydoris formosa, P. papillata, Doriopsilla miniata, Kalinga ornata, and several Pleurophyllidiida). -An account of the Entomostraca taken during a bathymetrical survey of the New Zealand lakes, and a comparison of this fauna with that of the English lakes: Dr. G. S. Brady. A paper dealing with the higher Crustacea obtained during the above-mentioned survey: Prof. C. Chilton. A classification of the Selachian fishes C. T. Regan. The author stated that the Selachii were regarded as entitled to rank, at least, as a well-marked subclass, and he divided them into two principal groups, viz. Trematopnea and Chasmatopnea, the latter including the single order Holocephali.-An account of the polyclad Turbellaria from the Cape Verde Islands collected by Mr. C. Crossland: F. F. Laidlaw. The collection shows that, on the whole, the fauna of this region of the Atlantic agrees closely with that of the Mediterranean so far as the polyclads are concerned. The most interesting of the sixteen or seventeen species represented in the collection are, perhaps, a species of Anonymus (of which several specimens were taken) and Traunfelsia elongata, gen. et sp. nov. The latter is an elongated form remarkable for the possession of marginal tentacles, which are not usually associated with a long, narrow body in this class. A unique feature in this genus is the presence of a pair of alveolar glands, each with a long duct opening on either side of antrum masculinum. The genus is referred to the Diposthiida of Woodworth.-A large unknown marine animal observed off the coast of Brazil during a cruise in the Earl of Crawford's yacht the Valhalla : E. G. B. Meade-Waldo and M. J. Nicoll (see p. 202).

Royal Microscopical Society, June 20.-Dr. Dukinfield H. Scott, F.R.S., president, in the chair.-The structure of some Carboniferous ferns: Dr. D. H. Scott. The author pointed out the change which had taken place during the last three years in our conception of the Carboniferous ferns. So many examples of fern-like plants were now known to have borne seeds, or were suspected of having been seed bearers, that comparatively few undoubted ferns were left, and it was questioned whether, at least in the Lower Carboniferous, true ferns existed. One family, the Botryopterideæ, was admitted to be well represented in Lower as well as Upper Carboniferous times, and Mr. Newell Arbor had proposed to establish a group of Primofilices to include this and other primitive ferns of the Palæozoic age. The object of the communication was to give a few illustrations of this ancient race of ferns. The Botryopterideæ were first described, beginning with the type-genus Botryopteris. The genus Zygopteris was next considered. A new genus from the Lower Coal-measures of Lancashire, for which the name of Botrychioxylon was proposed, was then described. Two or three other examples of the family having been noticed, Dr. Scott described certain annulate fern sporangia. The germination of spores within a sporangium was demonstrated, and this sporangium had quite recently been identified as belonging to Stauropteris Oldhamia.