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and are free to follow the bent of this or that special study. In the long run, their united work is immensely profitable. Here is commercial rivalry, and more; here S a better understanding of the right conditions of applied science."

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Lord Cromer, president of the society, took as a signal instance of the necessity for experiments on animals the recent discovery of a serum treatment in cases of epidemic cerebro-spinal meningitis, that ghastly disease which goes by the foolish name of " spotted fever." It is an acute septic inflammation of the membranes of the brain and the spinal cord. By experiments on animals it was proved to be due to special germs of the order of diplococci. Flexner and Jobling, working at the Rockefeller Institute, discovered a way of preparing, from immunised horses, a serum containing a direct antidote, and this serum first used in the spring of 1907. Before that time there was no special treatment of the disease, and the mortality ranged from 68.4 per cent. to 80.5 per cent. The children it was mostly children-suffered terribly, and died in a few days; and of those who survived many were left, from the intensity of the inflammation, imbecile, paralysed, or blind. By the use of the serum the mortality has been reduced to 36.7 per cent. In Belfast, of 275 cases treated before the use of the serum, 72.3 per cent. died, and of ninety-eight cases treated with the serum 29.6 per cent. died.

The Research Defence Society exists to keep the public informed of such facts as these, and we hope that it will have a long record of such victories over disease.

IS THE ASSOCIATION OF ANTS WITH TREES A TRUE SYMBIOSIS?

THE fact has long been known that some species of

ants occur in constant association with certain kinds of trees. Thus members of the dolichoderid genus Azteca are often found inhabiting the interior of the stems of Cecropia peltata, and among the Pseudomyrmini P. bicolor forms its nests within the spines of the bull's-horn acacia. The view has been held by many naturalists, amongst others by Fritz Müller and Bates, that in these cases the benefit is mutual, the tree affording both shelter and sustenance to its occupants, and receiving in return. protection from the attacks of the formidable leaf-cutting ants of the genus Atta and of other enemies. Doubts on this point have been expressed by several authorities, among them by Dr. David Sharp, in whose opinion “ there is reason to suppose that a critical view of the subject will not support the idea of the association being of supreme importance to the trees."

A careful investigation of the relations subsisting between the arboreal species of Azteca and Pseudomyrma and the trees which they inhabit has lately been conducted in Paraguay by Karl Fiebrig, who has published his results, illustrated by numerous photographic reproductions, in the current volume of the Biologisches Centralblatt. His conclusions may be summarised as follows:

Azteca not only makes use of internodal cavities already existing in the stem of Cecropia peltata, but excavates fresh spaces or enlarges existing ones at the expense of living tissues of the tree. Fritz Müller described certain pits in the stem of Cecropia where the wall is much thinner. These spots, he says, are selected by the female ant for the purpose of gaining access to the interior of the stem. But, according to Fiebrig, the ants effect their entrance into new internodal spaces by perforating the partitions in the stem before they have gnawed through the thin bottoms of the pits; moreover, openings to the exterior are often made irrespective of the situation of the pits, and when the latter are perforated the boring is, in certain cases, effected from within, and not from without. Neither the internodal spaces nor the pits can therefore reasonably be considered as myrmecophilous adaptations. Again, the alleged protection against leaf-cutting ants must often be superfluous, since the Cecropia, with its

1 "Cecropia peltata und ihr Verhältnis zu Azteca Alfari, zu Atta sexdens und anderen Insekten. Ein kritischer Beitrag zur Ameisenpflanzen-Hypothese." By Karl Fiebrig (San Bernardino, Paraguay).

inmates, is apt to be found in marshy situations where these enemies cannot reach it. Most of the trees in Paraguay are subject to the attacks of the leaf-cutting Atta, but, nevertheless, though unprotected by the presence of Azteca, they continue to maintain their existence, even if belonging to introduced, and not native, species. Cecropia itself is not tenanted by ants until it is some years old. The presence of colonies of Azteca does not prevent Cecropia from receiving much damage from the attacks of other insect enemies, and Fiebrig is of opinion that the constant loss suffered by the tree from the depredations of Azteca itself involves a more serious drain upon its vitality than the occasional raids of the leafcutters. Finally, the occupation of Cecropia by these ants not only fails to afford protection against enemies other than the leaf-cutters, but even encourages the assaults of such formidable foes as woodpeckers and internally feeding lepidopterous larvæ.

With regard to the association between Acacia cavena and Pseudomyrma fiebrigi, the author points out that this tree, in common with other species of Acacia, is protected against the ground-haunting Atta by the fact that it grows only in situations which are constantly liable to inundation. The thorns in which the ants take up their abode have frequently been already hollowed out and furnished with apertures of access by lepidopterous larvæ; moreover, the spaces tenanted by the ants are not confined to the thorns, but extend also to the stem. In neither situation do they occur naturally, but in both they are excavated, as in Cecropia, whether by ants or caterpillars, at the expense of the living tissues of the tree.

On these grounds Fiebrig concludes that, at any rate so far as the species observed by him are concerned, the benefits of the association between trees and ants are not mutual, but are enjoyed by the ants alone. There is no doubt that the reasons for his view adduced by Fiebrig are of great weight. At the same time, it cannot be said that these observations are sufficient of themselves to disprove altogether the existence of ant-plant symbiosis. F. A. D.

UNIVERSITY AND EDUCATIONAL
INTELLIGENCE.

OXFORD.-The following is the text of the speech delivered by Prof. Love in presenting Dr. G. E. Hale for the degree of D.Sc., honoris causa, at the Encænia on June 24

Inter Astronomos qui ea quæ in æthere solem circumfuso geruntur investigant nemini cedit Georgius Ellery Hale. Qui vir duodeviginti abhinc annos primus omnium fabricatus est instrumentum illud, ad lucis e solis puncto quovis emissæ naturam cognoscendam aptissimum, quo hodie utuntur omnes fere solis observatores. Hoc subsidio fretus potuit flammas illas excurrentes, quæ solis defectu plerumque cernuntur, sole pleno quasi in pictura exprimere: mox plagas lucidissimo candore fulgentes, quas faculas vocant, eodem modo repræsentare. Idem nuper docuit æthera procellis hune vexantibus tenuissimas materiæ particulas quasi turbine quodam agitatas vim magneticam miro modo gignere: quæ omnia nemo demonstrare potuit nisi excogitandi peritissimus, in observando patientissimus, in causis cognoscendis sagacissimus. Neque ei satis erat Naturæ arcana reserare, sed Observatoria duo in orbe terræ maxima fere et instructissima condidit atque ornavit: idem Ephemeridem, in qua recentissima de siderum natura ubique reperta pervulgantur, conscribendam curavit. Sodalicium denique maximum instituit quo omnes omnibus ex terris huius militiæ cælestis contubernales congregarentur.

ST. ANDREWS.-Dr. William Nicoll, who has for some years carried out important researches on the parasites of birds, fishes, and other forms at the Gatty Marine Laboratory, has just been elected to the Ernest Hart memorial scholarship.

Dr. J. C. Irvine, lecturer on organic chemistry in the University, has been appointed by the University court to the chair of chemistry in St. Andrews, vacant by the resignation of Prof. Purdie.

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A DISTINGUISHED American physicist, Prof. E. Nichols, of Columbia University, has been elected president of Dartmouth College, a leading New England institution with more than 1200 students. Dr. Nichols is a graduate of Cornell, and held chairs at Colgate and Dartmouth before being appointed to his present post at Columbia.

THE issue of The Record, the magazine of the SouthWestern Polytechnic Institute, Chelsea, London, for May, contains an account of this year's prize distribution, when Dr. H. A. Miers, F.R.S., the principal of the University of London, delivered an address. The report of the principal of the institute, an abstract of which is printed in the magazine, shows that there were 2573 students under his supervision during 1907-8.

THE King has consented to lay the foundation-stone of the new buildings of the Imperial College of Science and Technology, South Kensington, on July 8. The building is to accommodate the departments of mining and metallurgy of the Royal School of Mines, geology of the Royal College of Science, and the extension of the engineering department (City and Guilds College), and will be situated on the land in Prince Consort Road lying to the east of the Royal College of Music, and extending so far as Exhibition Road.

THE fourth annual issue of the "Girls' School Year Book (Public Schools)" has now appeared. The book becomes year by year more complete, and certainly provides a useful directory for those interested in the education of girls. It is, however, still difficult to understand the editors' method of selection of schools for detailed treatment. Among new features this year are articles on domestic science, teachers' registration, the teaching of music in public secondary schools, and a list of lecturers suitable for schools. The volume is published by the Year Book Press, c/o Messrs. Swan Sonnenschein and Co., Ltd., and its price is 2s. 6d. net.

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A FULLY illustrated description of the college of engineering of the University of Illinois is contained in the issue of the University of Illinois Bulletin for March Descriptions are provided of the work and equipment of the eight departments of the college, as well as those of the engineering experiment station and the school of railway engineering and administration. The college has been organised to give such training to young men will enable them to do efficient work in the branch of engineering or architecture they may select, to meet the demand for highly specialised instruction and research, and to conduct investigations of value to the industrial enterprises of Illinois and distribute the knowledge gained.

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IN the course of his recent presidential address to the Society of Chemical Industry, of which a short abstract appeared in NATURE of June 3, Prof. Meldola made the following appreciative remarks on the modern methods of laboratory instruction in chemistry : It is unnecessary here to dwell at too great a length upon the general practical training, although I should like to add that if the level has been raised, and if our teaching has become more philosophical, we are mainly indebted to a former occupant of this chair, Prof. Emerson Reynolds, who is unquestionably the pioneer reformer in the laboratory teaching of chemistry. I am glad of this opportunity of acknowledging the indebtedness of teachers to Prof. Reynolds, because, amidst the later clamour, his share in the development of chemical teaching has been overlooked." address is published in full in the current number of the journal of the society.

This

EVIDENCE of the rapid development of the Chinese Empire will be found in an article in Engineering for June 18 dealing with the engineering and mining college at Tang Shan, North China. This college was founded in 1906 for the education of Chinese students, and is in connection with the Imperial Railways of North China, both being under imperial administration. The staff

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consists of a president (Mr. S. S. Young), four English professors in mechanical engineering, civil engineering. mining, and physical faculties respectively, two Chines literati, and a clerical staff. A four years' course prescribed, and there are now more than 200 students ir regular attendance from various parts of the country. Residential accommodation is provided for 160 students, i together with houses for the staff, dining hall, and thre educational buildings. All technical lectures are delivere in English. While the equipment is as yet far from being complete, it is indisputable that the existence e such an institution is a factor which cannot be disregarded i when considering the future position of the Empire.

MR. DAVID BOYLE, the curator of the Provincial Museur of Toronto, had the degree of LL.D. of the University & Toronto conferred on him on June 12, for his eminent services in the cause of archæology and ethnology. Dr. Boyle has been incapacitated for some time, and as h was too ill to attend the regular Convocation, the authorties paid him the unique compliment of holding a speci Convocation at his residence, and of conferring the degree while he was lying in bed. Dr. Boyle was presented by Prof. Galbraith, and in the absence of the president, who I had sailed for England, the degree was conferred by the vice-president, Prof. Ramsay Wright. Dr. Boyle went to Canada in 1856, and in the face of great difficulties has built up the fine archæological and ethnological collections in the Provincial Museum of Toronto. He is best know to students as the editor of, and chief contributor to, the annual archæological reports of the museum. They were begun in 1898, and form a valuable record of Canadiar archæology and ethnology. The later reports have beer duly noticed in NATURE. We congratulate Dr. Boyle o this academic honour, which crowns a life of sacrificing and poorly remunerated toil for the subjects he has so much at heart.

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THE proceedings at the inauguration of Mr. R. C. Maclaurin as president of the Massachusetts Institute of Technology have been reported at considerable length in the American Press. One of the chief speakers was Mr. Bryce, who greeted the new president as a fellow-Briton, a fellow-Scotsman, and a fellow-member of Lincoln's Inn. Mr. Bryce said that Englishmen and Scotsmen would naturally be sorry that Mr. Maclaurin was not serving their country "in one of the new institutions which we have lately founded to try to make up for lost time in the promotion of scientific instruction." Still, a scientific inquirer and teacher helps the whole world by the work which he does anywhere in it." In his own inaugural address, President Maclaurin emphasised the following articles in his creed as an educator :-(1) that the end of education is to fit men to deal with the affairs of life honestly, intelligently, and efficiently; (2) that in the higher education of a large and increasing section of the community science should play a very prominent. if not a leading, part; (3) that science and culture must go hand in hand, science being studied and taught in such a way as to make for that broad and liberal outlook on the world that is the mark of the really cultured man; and (4) that "above all we must preserve in our students the freshness and vigour of youth, and see to it with all care that their natural powers of initiative are improved and not checked by our training."

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In recent years there has grown up in connection with local education authorities in all parts of the country systems of scholarships providing for the education of boys and girls of varying ages and attending schools of different grades, and also for young men and women anxious to continue their education after school days are The report of the higher education subcommittee on the scholarship scheme of the London County Council, recently adopted by the Council, provides an exhaustive account of the educational facilities offered in London to the sons and daughters of parents of limited incomes who have sufficient ability, as tested by examinations, to profit by continued attendance at school and college. The report indicates that in London, as elsewhere, there has been a disposition to multiply unduly the number of scholarships offered for competition, with the result that in certain districts there has had to be a marked lowering of standard

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of efficiency so that the scholarships might be filled up. This danger, with others, has been under the consideration of the committee, and steps have been taken in the case of certain classes of scholarship to reduce the number available, so that an efficient standard may be maintained. In framing the regulations which will govern the award of scholarships and exhibitions during the next academic year, the committee has endeavoured to arrange that, so far as possible, "no child or young person shall be debarred by poverty from obtaining the kind of education which will prepare him for the career for which his talents and character best fit him, and that the pecuniary emoluments attaching to the scholarships shall be sufficient to enable students to obtain the kind of education, whether industrial, scientific, or literary, which is best suited to their needs and capacities, but not sufficient to induce them to undertake a particular course of study with the object of securing the pecuniary advantages attaching to the scholarship.'

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As indicating the wide scope of the London County Council scholarship scheme, which has recently been amended, it may be said that in 1905 the Council awarded (a) 2600 junior county scholarships to children between the ages of eleven and twelve, and that the annual cost of awarding one of these scholarships annually was 851. ; (b) 390 probationer scholarships, each costing 561., to children of thirteen to fourteen years of age; (c) 100 intermediate county scholarships, each costing 1297., to boys and girls of from fifteen to seventeen years of age; (d) fifty senior county scholarships, each costing some 200l., to students more than eighteen years of age; and (e) various scholarships in science, art, and technology, at an expenditure of more than 18,000l. To state the scholarships which are to be offered for competition this year will indicate some of the changes which have been made. as the result of four years' experience. There are to be (a) 1800 junior county scholarships, costing each the same as in 1905, and 300 supplementary junior scholarships of lower value; (b) 300 intermediate county scholarships, but the value of each, for sufficient reasons, has been reduced to 72.; and (c) 150 senior county scholarships, each as in 1905, costing 200l. But, whereas the total expenditure in 1905 was 283.940l., the amount in 1909 has, notwithstanding the greater wisdom of the conditions of award in the scheme, been reduced to 263,080l. The report of the Education Committee gives very satisfactory evidence to show that the object the education authorities in London have in view is to secure a high quality in the results they obtain, rather than to spread an incomplete and rudimentary education far and wide.

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A NUMBER of people interested in the teaching of housecraft and domestic science visited Battersea Polytechnic on June 29 to see the domestic economy training department. Since the department was opened in 1894 more than 400 students have obtained diplomas, and are occupying responsible positions in leading institutions and schools; the present number of students above eighteen years of age in the department is 130. Students of the department attend, in their first year, a course in "science as applied to household work,' which includes physics, chemistry, physiology, and hygiene. This course is taken in addition to the purely practical work of the domestic arts. During the second session the scientific basis of knowledge thus obtained is applied in the practice kitchens, laundries, and housewifery rooms and hygiene laboratories. In the third year's course the same subjects are treated in greater detail, special attention being directed to bacteriology and the examination of food-stuffs. The main objects of the science work are:-(a) to explain, so far as possible, the chemical composition and properties of the materials dealt with in household work; (b) to explain the principal chemical and physical changes taking place in the common household operations involved in cookery, laundrywork, &c.; (c) to give a training in the principles of scientific method. Special stress is laid on the fact that household work generally is really an application of a number of facts and principles in chemistry, physics, hygiene, bacteriology, &c., and that, in order to understand the rationale of the ordinary household processes, a knowledge of the general principles of the branches of knowledge just mentioned is

necessary.

SOCIETIES AND ACADEMIES.

LONDON.

Royal Society, May 27.-Sir Archibald Geikie, K.C.B., tions president, in the chair.-Notes concerning tidal oscillaupon a rotating globe: Lord Rayleigh.-The absolute value of the mechanical equivalent of heat in terms of the international electrical units: Prof. H. T. Barnes. It is pointed out that the Clark cells used by the author in his determinations of the mechanical equivalent of heat in terms of the electrical units were prepared according to the old specifications. The absolute measurements of the Clark cell now being carried on with such precision in the various standardising laboratorics are expressed in terms of the new form of cell with There is an specially prepared mercurous sulphate. important difference between the cells, which Wolff and Waters have shown amounts to 0.03 millivolts. The author has compared a set of modern cells with cells set up according to the old specifications, and finds the same constant difference. Taking 1-4330 international volts at 15° C. as representing the modern cells, then the cells made by the old specifications must be taken as 1-4333 international volts at 15° C. The author's measurements of the mechanical equivalent at different temperatures were calculated on the basis of a value for the Clark cell equal to 1-4342 international volts at 15° C. Re-calculating on the new basis, the value of the mean calorie is found to be 4-1849 joules. This agrees with Reynolds and mean, which, expressed Moorby's directly determined accurately for an interval of temperature between o° C. and 100° C., comes to 4-1836 joules. Rowland's mean value between 5° C. and 35° C. is 4.185 joules, while the author's value between the same limits of temperature is 4-1826 joules. Thus, assuming the variation of the specific heat of water to be correctly determined, the value of the Clark cell, equal to 1-4330 international volts, brings the electrically determined mechanical equivalent into excellent agreement with the same constant measured by mechanical means. An approximate determination of the boiling Although high points of metals: H. C. Greenwood. temperatures can now be easily attained by means of electric heating, no general investigation of the boiling points of metals has yet been carried out. such values as are available have in most deduced indirectly, and are very discordant. was devised for directly sent investigation apparatus measuring the temperatures of ebullition under atmospheric pressure of a considerable number of metals, allowing of use up to 2700° C. Heating was effected electrically, and the metal, when unaffected by carbon, was contained in on the outside of which a thin-walled graphite crucible the temperature was estimated by means of a Wanner optical pyrometer. The difference in temperature between the internal and external surfaces of the crucible walls was found to be negligible. Accuracy of the temperature measurements was secured by checking the pyrometer "black body melting points of specially The against the 1800° C.; purified strips of platinum, rhodium, and iridium. were found:-aluminium, following values antimony, 1440° C.; bismuth, 1420° C.; chromium, 2200° C.; copper, 2310° C.; iron, 2450° C.; magnesium, 1120° C.; manganese, 1900° C.; silver, 1955° C.; tin, the metals aluminium, In dealing with 2270° C. chromium, iron, and manganese, which readily combine with carbon, considerable difficulty was experienced in avoiding contact with carbon at the high temperatures in This was finally accomplished by the use of question. graphite crucibles brasqued with previously fused magIn the absence of this protective lining the boiling point was very greatly modified by carburisation. The temperatures indicated for aluminium and manganese were far below those hitherto supposed necessary for ebullition. -Some results in the theory of elimination: A. L. Dixon. The eliminant of two quantics (x), 4(x), each of the nth degree, may be expressed as a determinant the elements of which are (a,, r), where (a, r) is [p(a)↓(r) − ¢(r)4(a)}/la − r), and a1, For an 1. .. are two sets of n arbitrary quantities. three quantics p(x, y), u(x, y), x(x, y), each of the form ZAxys (rzn, szm), the eliminant is a determinant the elements of which are F(a, b, at, B) where F(a, b, a, B)=(p(a, b),

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(a, - b.) (a, − br). -The liquidus curves of the ternary system aluminiumcopper-tin J. H. Andrew and C. A. Edwards. The study of the constitution of alloys is of great theoretical interest, and of some practical value; in fact, it may be said that the heat treatment of a given series of alloys cannot be correctly, accomplished without an accurate knowledge of the structural changes which occur with varying temperature and concentration. We are now in possession of accurate data bearing on the constitution of a large number of alloys containing only two elements, but very little work has been published on mixtures of three or more metals. The object of the present research to throw some light on the properties of ternary alloys, and, incidentally, the effect of impurities on binary alloys. The metals from which the alloys were made had the following degree of purity

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Aluminium Copper Tin Freezing-point determinations.-The freezing points of the alloys were determined directly after mixing by means of a platinum + 10 per cent. iridium thermo-junction. The free ends of the wires were connected by a mirror galvanometer and balancing arrangement similar to that described by Messrs. Carpenter and Keeling in their work on the iron-carbon alloys. In order to locate the position of the isothermal curves, more than 400 alloys and melting-point determinations were made. Conclusions. The character of the liquidus curves indicates that no well-defined ternary compound is deposited from any of the liquid alloys. The affinity of tin for either aluminium or copper is sufficient to overcome the affinity of the last two elements for each other. As a consequence of the above, curves of the melting points of alloys containing a constant percentage of tin bear a striking resemblance to the liquidus curve of the aluminium-copper alloys. Tin is insoluble in by far the greater number of the alloys.-Studies on the structure and affinities of Cretaceous plants: Dr. M. C. Stopes and Dr. K. Fujii. This paper is the first account to be published of the anatomy of Cretaceous plants petrified in calcareous nodules. As an introduction to the flora, eighteen plants are described, all of which are new. The age of these plants is Upper Cretaceous, as is determined from the ammonites which abound in the matrix of the nodules, and the locality of all the specimens described is Hokkaido, northern Japan. The plants include one fungus, three ferns, eight gymnosperms, and six angiosperms. These numbers seem to represent, roughly, the proportions of the flora of the nodules as a whole, of which many more specimens are in the hands of the authors than are described in the present paper. The most interesting of the plants are:-a new type of gymnosperm, Yezonia, of which the vegetative anatomy is different from that of any known genus; a gymnospermic fructification, also new, which there is good reason to believe belonged to Yezonia; an angiosperm which is included in the Sabiacea; an angiosperm of the family Saururacea; and the first petrified flower, Cretovarium, which has three carpels surrounded by the perianth. The names of the described plants are:-Petrosphaeria japonica, Fasciostelopteris Tansleii, Schizaeopteris mesozoica, Niponophyllum cordaitiforme, Yezonia vulgaris, Yezoştrobus Oliverii, Araucarioxylon tankoensis, Cedroxylon Matsumurii, C. Yendoii, Cunninghamiostrobus yubariensis, Cryptomeriopsis antiqua, Saururopsis niponensis,

Jugloxylon Hamaoanum, Populocaulis yezoensis, Fagoxybe hokkaidense, Sabiocaulis Sakurii, Cretovarium japonicum The phylogeny and distribution of these plants is considere. so far as possible.

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June 17-Sir Archibald Geikie, K.C.B., president, it the chair. The nature of the hydrogen flocculi on the Prof. G. E. Hale. Photographs of the Ha h in the spectrum of the solar disc, made on Mount Wilson with high dispersion, were shown on The the screen. line appears as follows:-(1) A broad dark line, differing greatly in intensity and width in different regions of th sun. Except in eruptive or rapidly changing phenomen.. the differences in width are not very marked. (2) With the boundaries of the dark line a narrow single or multipl bright line is photographed in many parts of the sun Sometimes the appearance resembles that of the calcium lines K and K-i.e. the bright line lying on its dark background is divided into two components by a dark line. In other regions the bright line is divided in separation. a larger number of components, varying in width as spectroheliograph plates taken with The images of dark hydrogen flocculi, on camera slit abou equal in width to Ha, appear to be due, in the mair to local increase in the intensity of the dark line. some parts of the sun, particularly those where the line is distorted, variations in the width of the line may also play an important part. The increased intensity of the dark line is probably the result of increased absorption.. Slides were shown to illustrate the fact that prominences at the sun's brink are frequently recorded as dark floccal when photographed in projection against the disc. The possible effects of anomalous dispersion were discussed, and photographs were exhibited of the same region of the sun, taken simultaneously with light from the r and violet edges of Ha. The similarity of these photographs apparently indicates that anomalous dispersion s not the prime factor in producing the hydrogen flocculi. Certain minor differences suggest, however, that it may perhaps play a secondary part in modifying their form.The origin of certain lines in the spectrum of Orionis (Alnitam): Sir Norman Lockyer, K.C.B., F.R.S., F. E. Baxandall, and C. P. Butler. The star € Orionis (Alnitam) is of great importance as offering a possible transition stage between the helium and bright-line stars. and the only outstanding lines of unknown origin were those at 4097, 4379-8, and a conspicuous double at 4647 6 In the case of 4097, the clue to the identification 14650'8 was obtained from a spark spectrum of chromium, showing local intensifications of certain lines at one of the poles. Two of these lines were found to be the previously known silicon (iv) lines, 4089, 4116, probably present as impurities in the fused chromium, while one of the re maining two lines was found to coincide with the Orion's line at 4097. These four lines are shown under various conditions in the plate, indicating the steps taken in tracing their origin to nitrogen. In the spectrum of nitrogen, under the special conditions which gave the above lines at 4097, 4103, another line was found at 4379-8, which was greatly strengthened in comparison with its intensity in the ordinary spark, and this line coincides with the unknown line in Orionis. During the work on the above lines, one of the photographs taken of an alcohol spectrum showed abnormal intensifications either side of the oxygen line 4649-2, suggesting the presence of a new double. The wave-lengths of the components of this double were determined as 4647-6, 4650-8, coinciding with the wave-lengths of the components of the strong double in e Orionis. By a series of comparison photographs of spectra under varied conditions, the origin of the double was traced to carbon, and one of the strips of the plate (carbon spark in hydrogen) shows it quite isolated as it appears in the stellar spectrum. Further evidence of the validity of the identification is afforded by the peculiar nature of the components of the double. -Electric induction through solid insulators: Prof. H. A. Wilson. This paper contains an account of a series of experiments on the variation of the capacity of ebonite and other condensers, with the time of charging and with the potential difference. It is shown that the capacity

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C after a time of charging t is given by the formula C=C(1+Blog (1+pt)), where C, denotes the capacity when to and B and are constants. In the case of ebonite at 30° C. this formula represents the results obtained to within 1 part in 2000. The values of the constants have been found for several substances at different temperatures. The capacity is shown to be independent of the potential difference within the limits of error. It is shown that after the temperature of an ebonite condenser has been changed, then a very slow change in the capacity goes on which continues for more than 100 hours at constant temperature.-The effect of pressure on the band spectra of the fluorides of the metals of the alkaline earths: R. Rossi. It was shown by A. Dufour that the band spectra of the fluorides of the alkaline earths show a marked Zeeman effect, and it was thought interesting to see whether these particular bands would also be displaced by pressure, for it is known that the cyanogen bands, which, like most bands, do not show a Zeeman effect, are not displaced by pressure. The large 21-feet concave grating spectrograph of the physical laboratory of the Manchester University was used, and the bands of the fluorides of calcium, barium, and strontium were found to be shifted by pressure. The order of magnitude of the displacement is about the same as for line spectra.-The components into which the bands are resolved are widened by pressure, and the linear relation between pressure and displacement found by former observers on line spectra seems to hold also for these bands. There does not seem to be any evident relation between the magnitudes of the Zeeman and pressure-shift effect in the case of these bands.-The

ionisation produced by an a particle: Dr. H. Geiger. The aim of the experiment was an accurate determination of the number of ions produced by an a particle when completely absorbed in air. The most direct way to find the number of ions would be to measure the whole ionisation produced by the a particles from a known quantity of radium C. Since it is, however, practically impossible to obtain the saturation current due to the a particles at atmospheric pressure, it was necessary to adopt an indirect method. This method was briefly as follows:-The ionisation due to the whole number of a particles expelled from a known quantity of radium C was measured at a low pressure, allowing only a small definite portion of the range of each a particle to be effective. The ratio of the ionisation produced within this small portion of the range to the ionisation produced along the whole path was then found from an accurate determination of the ionisation curve. It was found that the number of ions produced in air by an a particle from radium C along its whole path is 2.37 X 10. Since the a particles from different radio-active products differ only in their initial velocity, it was possible by the aid of the ionisation curve of radium C to calculate the number of ions produced by the other products.-A diffuse reflection of a particles : Dr. H. Geiger and E. Marsden. It was observed that a diffuse reflection takes place when a particles are incident on a plate. The reflected particles were counted by the scintillations produced on a zinc sulphide screen. The effect was found to vary with different metals as reflectors, the amount of reflection being approximately proportional to the atomic weight of the reflecting substance. Using different numbers of thin gold foils as reflectors, it was found that the reflection was a volume effect, and thus similar to the reflection of B particles. Taking a measured quantity of radium C as source, and using a plate of platinum as reflector, it was found that, of the incident a particles, about 1 in 8000 suffers reflection.The decay of surface waves produced by a superposed layer of viscous fluid: W. J. Harrison. An estimate is obtained of the effect of a thin layer of viscous liquid on the decay of waves at the surface of a slightly viscous liquid. The period equation for the motion is of the fourth degree, and has two real and two complex roots in the case of waves of less than a certain length, and four complex roots in the case of waves of greater length. The real roots correspond to dead-bent modes, the complex roots to propagated modes. No general expression of any use can be obtained for the damping, but the equation

In the

can be solved numerically in any particular case. paper the velocity of propagation and the modulus of decay are given for waves of length 2, 5, 10, 20 cm. at the surface of mercury on which is superposed a layer of glycerine 1 mm. in depth. An estimate is also obtained for the damping when the wave-length is small compared with the depth of the layer. Two other problems in the decay of surface waves are discussed. The passage of electricity through gaseous mixtures: E. M. Wellisch. (1) An experimental method (based on Langevin's method) has been devised in order to ascertain whether there are two distinct mobilities for the positive or for the negative ions produced by Röntgen rays in a mixture of two gases, or of a vapour and a gas. (2) No evidence was found of the existence of the two distinct mobilities; accordingly it is necessary to conclude that the motion of the ion through the medium must involve a mechanism of a character such as to produce a statistical average. (3) Experiments were conducted with regard to the effect produced on the ionic mobilities in air by adding small quantities of vapours. The mobilities showed a marked decrease on the addition of alcohol and acetone, but were not sensibly affected by the addition of the heavier vapours of methyl iodide and ethyl bromide. (4) Experiments were performed with regard to the ionic mobilities in mixtures of a gas and a vapour, the ions being formed from the latter constituent only. As a result of the experiments, it was shown that there must be, at all events initially, a transference of the charge (both positive and negative) from the vapour to the gas molecule. (5) Experiments were performed with regard to the stability of the vapour ions in the presence of hydrogen; it was shown that the vapour molecules can accompany the charge to an appreciable extent, even in the presence of a considerable quantity of hydrogen. (6) The mechanism by which the transference of charge from one molecule to another is effected has been discussed; there is reason to believe that the transference takes place by the medium of a detachable unit of positive electricity. (7) From the experimental results a theory of the mechanism underlying the passage of electricity through gases at ordinary temperatures and pressures has been deduced.-A study of the use of photographic plates for the recording of position: Dr. C. E. K. Mees. The coefficients of capacity and the mutual attractions or repulsions of two electrified spherical conductors when close together: Dr. A. Russell. The computation of the electrostatic energy of two spherical conductors when close together is an important problem in spark systems of wireless telegraphy. In this case the formulæ previously given for the capacity coefficients are very laborious to evaluate. By extending a mathematical theorem due to Schlömilch, an approximate formula is obtained for the sum of a certain infinite series. By using this theorem, it is shown that when the spheres are close together the ordinary series formulæ for the capacity coefficients can be written in forms which can be readily computed to any required degree of accuracy. The author has re-computed and extended in this way Kelvin's table for the capacity coefficients of two equal spheres when the least distance between them does not exceed half the radius of either. When the spheres are at microscopic distances apart, the formulæ become very simple. Kelvin's table also for the rates at which the capacity coefficients of two equal spheres alter with the distance between them, when this distance does not exceed half the radius of either, has been re-computed and extended. When the spheres are very close together the laws of attraction and repulsion are simple. Let the radius of each sphere be a, let x denote the least distance between them, and suppose that the ratio V,/V, of the potentials of the two spheres is not nearly equal to unity, and that x/a is very small compared with unity. In this case the mutual force between the spheres is attractive, and is given by

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