matter relating to the economic aid given by the institution to planting in Ceylon and elsewhere. Referring to the gradual decline in the cultivation of coffee, Dr. Trimen mentions, as one of the causes, that it has suffered severely during the last few years from the attacks of a scale-insect or "bug" which has in some places actually killed out the bushes. Practical planters think the insect different from either of the "bugs" familiar hitherto as foes to coffee-Lecanium coffeæ and L. nigrum, the brown coffee and black bugs. The distinctions between the three have been pointed out by Mr. E. Green in a paper with illustrations printed by the Government of Ceylon. He names the new pest L. viride, it being generally known as the green bug. Dr. Trimen mentions that his principal employment during the past year has been the compilation, with the aid of the library and herbarium, of a catalogue of the contents of the gardens, for use by the staff, the public, and correspondents in other countries. The list as now completed is brought down to the end of 1886, and contains about 3000 species, mostly trees and shrubs. He also reports the commencement of the long projected museum of economic botany.

A VOLUME on the life and works of Lavoisier, by Prof. E. Grimaux, of the Polytechnic School of Paris, has just been published. It is illustrated by many interesting engravings, two of which represent Lavoisier in his laboratory. A number of hitherto unknown documents relating to Lavoisier have been discovered by Prof. Grimaux.

MESSRS. MACMILLAN AND BOWES, Cambridge, will have ready in a week a “Bibliography of the Works of Sir Isaac Newton, together with a List of Books illustrating his Life and Works," by G. J. Gray.

MESSRS. MACMILLAN AND Co. will shortly publish a work on "The Theory and Practice of Absolute Measurements in Electricity and Magnetism," by A. Gray, M.A., Professor of Physics in the University College of North Wales. Though nominally a second edition of the small book by the same author published in 1884, it has been entirely re-written and extended in plan, so as to form a fairly complete treatise on the absolute measurement of electric and magnetic quantities. This has necessitated the division of the work into two volumes, of which the first, extending to over 450 pages, is about to be issued. The following is a synopsis of the contents :-Vol. I. contains a sketch of the theory of electro-statics and flow of electricity, chapters on units, general physical measurements, electrometers, comparison of resistances, comparison of capacities, and measurement of specific inductive capacities, and concludes with an appendix of tables of units, resistances, and useful constants. The chapter on the comparison of resistances contains full details of the various methods of comparing high and low resistances, calibration of wires, &c.; the chapter on capacities discusses methods generally, and contains an account, as full as possible, of the principal determinations of specific inductive capacity made up to the present time. Vol. II. will contain an account of magnetic theory, units and measurements; electro-magnetic theory and absolute measurement of currents, potentials and electric energy; the definitions and realization of the ohm and other practical units; the relations of electro-magnetic and electrostatic units and the determination of v; practical applications of electricity, and especially related points of theory and measurements. (This volume is in hand, and will be issued as soon as possible after Vol. I.) An attempt has been made to arrange the work so as to avoid any too sharp distinction between what is theoretical and what is practical, and at the same time preserve a logical order in the former and prevent the constant introduction of digressions on theory into accounts of instruments and processes of manipulation.

"Excursions

A WORK of some interest and importance, zoologiques dans les Iles de Fayal et de San Miguel (Açores),” has just been produced by M. Jules de Guerne, at the expense of Prince Albert de Monaco. Of the new species mentioned, some, perhaps all, have been elsewhere recorded in contemporary periodicals. M. de Guerne concludes from his researches that the land fauna of the Azores has a definitely European character; that the fresh-water fauna has the same character, many of the species composing it being probably cosmopolitan, most of them provided with powerful means of dissemination, which have enabled them to reach the Azores ; that most of the species have been brought by the wind and by birds, the wind playing only a secondary part; that the lakes in the craters are of modern origin, due to the accumulation of rain-water, and have not taken long to people; that the character of the aquatic types and the absence of any great struggle for existence suffice to explain this rapid peopling of the waters; that the land species, like those of the water, have been fortuitously introduced from the nearest islands and continents,, though at a remoter epoch and more distant intervals, this greater antiquity accounting for the greater differentiation of the land fauna, and in especial of the Mollusca; that the alpine character of the land fauna has not been demonstrated, and that, on the theory of the gradual submergence of the islands, the animals of the littoral region in retiring to the higher grounds would have there produced a varied and numerous assemblage of species, which, as a fact, is not found. Incidentally, M. de Guerne points out a mistake which has crept into works of importance-a sudden depth of 58 fathoms at a single spot being attributed to the little Lagoa Grande in the Island of San Miguel, instead of the true depth, which is about 17 fathoms.

THE Bancroft Company, San Francisco, announces that there will shortly be added to the series of guide-books to the Pacific Coast a hand-book of the Lick Observatory, which has been prepared by Prof. Edward S. Holden, Director of the Observatory. This book is intended to give all the information which will be of value to each one of the many visitors to the Lick Observatory, which possesses the largest and most powerful telescope in the world, and is situated in one of the wildest and most romantic portions of California. Besides the useful and necessary information of a mere guide-book, the work is to contain interesting and popular accounts of the various astronomical instruments, and of the way in which they are made and used. It will be illustrated by twenty or more woodcuts from photographs and drawings.

MR. HENRY BEDFORD, of All Hallows College, Dublin, writes to us :-" I see among the notes in your last number (p. 87) that Herr Sander, in his paper on some recently deciphered runic inscriptions in Sweden, says that in four of them appeared the word Pim or Piment (i.e. a strong drink composed of wine, honey, and spice), which, as well as Klaret, was mentioned in the Saga of Rollo the Ganger and the Normans,' and that 'all these inscriptions were referred to the close of the pagan age.' Now if the word Klaret refers like Piment to some kind of

drink, does not this point to the direction in which we are to look for some more satisfactory explanation of our modern word Claret than that which our dictionaries give-as a derivation from the French clairet-although the word is not used in that language to describe the French wine to which we apply it. Perhaps you or some of your readers will throw some light upon the origin of this obscure word."

THE 800th anniversary of the University of Bologna will be celebrated on June 12 next. An oration will be delivered by the poet Giosué Carducci. There will also be a musical performance, an ode having been written for the occasion by Panzacchi, and set to music by Baron Franchetti.

The re

LAST week we printed a letter from M. Julius, of Delft, Holland, asking a question with regard to tables of reciprocals. Mr. T. S. Barrett and Mr. A. Freeman write to us recommending Barlow's tables of squares, cubes, square roots, cube roots, and reciprocals of all integers up to 10,000. ciprocals are given to seven places of significant figures, besides the leading zeros. The work was edited by the late A. De Morgan, and published for the Useful Knowledge Society by Taylor and Walton, London, 1840.

PROF. BALL, General Director of the Science and Art Museum, Dublin, mentions in his report for 1887, that early in the year he brought before the Council of the Royal Irish Academy the desirability of its handing over to the Museum an old collection of moulds of Irish crosses and miscellaneous sculptures, together with casts, most of which had been prepared for the Exhibition of 1853. To this proposition the Academy cordially assented, and, after much piecing together of broken fragments, it was found that the material provided a very valuable and representative set of casts. It is proposed that casts of many objects of ancient Irish art not included in this collection shall also be obtained. The collection, when completed and properly arranged in the new Museum, ought to be of great service not only to archaeologists but to workmen, who would be well rewarded for a careful and elaborate study of the ideas of the medieval craftsmen of Ireland.

HERR H. FORSELL has been chosen President of the Swedish Royal Academy of Science for the ensuing year, in place of Herr C. G. Malmström.

THE Biological Society of University College will hold its annual soirée at the College on Thursday, June 7, beginning at 8 p.m. Prof. W. H. Flower, F. R. S., will deliver a lecture at 9 p.m. on “The Pygmy Races of Men." Tickets may be had

on application to the secretaries of the Society.

WE have received the Annuaire for the year 1888 of the Paris Society for the Encouragement of National Industry. Among the contents are a list of the members, and an extract from the ¡ programme relating to the prizes to be given by the Society from 1888 to 1893.

THE Danish Government has granted a sum of £500 for the purpose of having the oyster-banks in Denmark examined by an expert. His object will be to ascertain the results of their continued preservation, with a view to the resumption of fishing.

SOME months ago a large consignment of salmon ova was despatched from Denmark to Buenos Ayres, vid Hamburg, for the stocking of certain lakes and rivers in the Argentine Republic. The experiment has proved very successful, the ova ariving in excellent condition, and further consignments are to be made.

THE following incident in the trial of the great patent case, Edison and Swan Electric Light Company v. Holland and others, now proceeding in the Chancery Division of the High · Court of Justice, before Mr. Justice Kay, is taken from the shorthand report in the Electrician of May 18. On May 16, *Prof. James Dewar, F.R.S., Professor of Chemistry in the University of Cambridge was under examination. A small crucible was produced and handed to the witness, who said: In that crucible I have, with Mr. Gimingham, carbonized filaments in the precincts of the court, using no packing and no luting of any description. The filament was a thread so far as he could remember.

Sir Horace Davey urged that this did not arise out of the cross-examination.

Mr. Justice Kay said it should have been produced in the › examination-in-chief. If it were pursued, Sir Horace Davey would be entitled to ask any questions upon it.

Sir Horace Davey, cross-examining:-About what heat was

this produced at ?—It was a mere experiment. It was a spiritlamp that was used.

Do you suggest that this coil, or whatever you like to call it, has been heated to a sufficient heat for use as a conductor in an incandescent lamp? -Not at the present time.

Then it is not completely carbonized ?—It is carbonized; but it does not conduct well enough. It wants to be heated for a longer time at a higher temperature.

Has it been heated to a degree at which the oxygen would combine with or attack the carbon ?-That I cannot say. I think it is probably at a low red heat.

Mr. Justice Kay: I am very much disgusted. I am here trying all I can to understand the case, and this is clearly an attempt to mislead. I am greatly disgusted.

Prof. Dewar: I have no desire to mislead your lordship. I have stated that this was a mere experiment. I did not produce it. It was put to me.

Mr. Justice Kay: You may stand down.

THE additions to the Zoological Society's Gardens during the past week include a Rhesus Monkey (Macacus rhesus ) from India, presented by Mr. George Somerford; a Barbary Ape (Macacus inuus ) from North Africa, presented by Miss Waterman; a Brazilian Tree Porcupine (Sphingurus prehensilis) from Pernambuco, presented by Mr. Clement J. Bateman; a Barbary Wild Sheep (Ovis tragalaphus), from North Africa, presented by Mr. E. H. Forwood; a Greater Black-backed Gull (Larus marinus), British, presented by Prof. E. Ray Lankester, F.R.S., F.Z.S.; a Herring Gull (Larus argentatus), British, presented by Mr. E. Wright: a Cape Dove (Ena capensis), a Tambourine Pigeon (Tympanistria bicolor) from South Africa, presented by Mr. R. H. Milford; a White-handed Gibbon (Hylobates lar) from the Malay peninsula, a Chimpanzee (Anthropopithecus troglodytes Q), a Marabou Stork (Leptoptilus crumeniferus) from West Africa, two Caracals (Felis caracal juv) from Africa, three Red-crowned Pigeons (Erythrænas pulcherrimus), a Praslin Parrot (Coracopsis barklyi), two Kestrels (Tinnunculus gracilis) from the Seychelles, a Laughing Kingfisher (Dacelo gigantea), a Black-backed Piping Crow (Gymnorhina tibicen), a Greater Sulphur-crested Cockatoo (Cacatua galerita) from Australia, two Glass Snakes (Pseudopus pallasi) from Dalmatia, deposited; six Common Pintails (Dafila acuta), eight Common Teal (Querquedula crecca), eight Garganey Teal (Querquedula circia), ten Wigeon (Mareca penelope), a Shoveller (Spatula clypeata), British, purchased; a Red Kangaroo (Macropus rufus), born in the Gardens.

OUR ASTRONOMICAL COLUMN. COMET 1888 a (SAWERTHAL).-At the beginning of last week, apparently on May 20 or 21, the comet suddenly became very much brighter, gaining fully three magnitudes. It has since faded again. Only a few observations have as yet come to hand, but it is to be hoped that everyone who has observed it during the last fortnight, and made any estimate of its brightness, will publish his observations without delay.

THE SHORT PERIOD COMETS AND ASTEROIDS.-Prof. Kirkwood, who has already given reasons for thinking that two short period comets originally belonged to the group of asteroids, has extended his argument in the Sidereal Messenger for May to include the class of short period comets as a whole. He points out that, of the twenty comets concerned, seven have disappeared, either by dissolution into fragments, like Biela's comet, or by the transformation of the orbit by the influence of Jupiter, as in the case of Lexell's comet. The instances of the comets of Lexell and Wolf (1884) are representative, Prof. Kirkwood considers, of the mode in which asteroidal may have been changed into cometary orbits. Had the latter, indeed, been discovered before its perturbation, it would probably have been considered simply an asteroid of unusually long period, for its eccentricity and inclination were

well within asteroidal limits. Of the twenty comets, not only have seven disappeared, but five, or, including Encke's and Biela's, seven, have periods commensurable with that of Jupiter; all the twenty have direct motion; all but one have smaller inclination than Pallas; and, as with the asteroids, there is a tendency of the perihelia to concentrate in the 180° from 290° to 110°.

NEW MINOR PLANET.-A new minor planet was discovered by M. Borrelly on May 12 at Marseilles. This may possibly, but not very probably, prove to be Xanthippe, No. 156. Should it be really a fresh discovery, it will rank as No. 278, whilst the one discovered by Herr Palisa on May 16 (see NATURE, vol. xxxviii. p. 89) will be numbered 279.

IN the Report of the Survey of India for 1886-87, Colonel Strahan gives an account of the survey and exploration of the Nicobar Islands by himself and party. A very careful survey of the whole group was made, and the coast-lines at last accurately laid down. Owing to the dense vegetation, the party were unable to penetrate any distance into the interior, and only a few heights could be measured. The culminating point of the whole group, 2105 feet above sea-level, stands near the south-east corner of

Great Nicobar, the area of which is 375 square miles, the total area of the group being 678 square miles. The scenery, especially of Great and Little Nicobar, is of indescribable beauty. There are several rivers in the former island which are navigable by boats for some miles, especially the Galatea, on the south coast. Its course is very tortuous, the banks are fringed with tree-ferns, canes, bamboos, and tropical vegetation of infinite variety, through which occasional glimpses are obtained of high mountains in the interior covered with dense forests to their very summits, and generally cloud-capped. The country through which the stream runs is almost uninhabited; a few huts appear here and there tenanted by an inland tribe of savages called "Shom Pen," of whom very little is known, except that they are in such an utter state of barbarism as to be held in contempt even by the Nicobarese inhabiting the coasts. On most of the islands the forest grows luxuriantly down to the beach. Mangroves, except in the island of Kamorta, are not very plentiful, and in this respect these islands differ widely from the neighbouring Andaman group, where the creeks are fringed with mangroves mile after mile. The sea-beach consists largely of coral. The climate is very equable day and night all the year through, and most pleasant to one's feelings, but unfortunately its character for unhealthiness is only two well established. The rainfall, which averages about 100 inches, is pretty evenly distributed throughout the year. The thermometer stands very steadily between 80° and 85° in the shade, and hardly varies day or night. The inhabitants of these islands, Colonel Strahan states, are allied to the Malays, and are a complete contrast to their tiny, intensely black, woolly-haired neighbours, the Andamanese. The Nicobarese are very strong, thicklybuilt men, not much if at all inferior to Europeans in physique, of a reddish-brown colour. They are unconquerably lazy, having no inducement whatever to exertion. They have a wonderful talent for learning languages. Fortunately, Mr. Man, the Settlement Officer at Kamorta, who has done so much for Andaman anthropology, has been carefully studying the Nicobarese, their habits and language, and is now engaged on a book on the subject, which will shortly be published.

MR. C. M. WOODFORD, the successful naturalist explorer of the Solomon Islands, is about to leave England on a third visit to the group. After spending some time in various parts of the islands not previously visited, he will investigate Santa Cruz, Woodlark Island, and other islands lying to the south-east of New Guinea.

ACCORDING to the new Survey Report, triangulation surveys have already been effected over 15,000 square miles in Upper Burma, and the out-turn of reconnaissance surveys amounts to 11,000 square miles on the scale of 4 miles to an inch, in the following States and districts: Northern Shan States and Ruby Mines district, 3000 square miles; Southern Shan States, 3000 ;Yemethin and Mehtila district, 2000; Yaw country, 1000; Mandalay and Kyaukse districts, 2000.

IN the summary Report of the Geological Survey of Canada for 1887, some of the results are given of the expedition under Dr. G. M. Dawson last summer, of the exploration of British Columbia. Mr. Ogilvie's instrumental survey to the intersection of the Yukon with the 141st meridian will form a sufficiently accurate base-line for future explorations in this region. In addition to this the geographical results include the completion of an instrumental survey of the Sitkine to Telegraph Creek by Mr. McConnell, which is connected with Dease Lake by a carefully placed traverse by Mr. M'Evoy. Thence a detailed running survey was carried by the Dease, Liard, and Pelly Rivers, connecting with Mr. Ogilvie's line at the mouth of the Lewis River, a total distance of 900 miles. Taken in conjunction with Mr. Ogilvie's line, these surveys include an area of over 6000 square miles, the interior of which is still, with the exception of reports received from a few prospectors and from Indians, a terra incognita. The same remark may be applied to the whole surrounding region outside the surveyed circuit, but much general information has been obtained respecting the entire district, which will facilitate further explorations. The whole region is more or less mountainous, though intersected by wide areas of flat or valley country. The country, though generally mountainous in character, includes large tracts of flat and slightly broken land, and, according to Dr. Dawson, may eventually support a population as large as that found in. corresponding latitudes in Europe.

THE anniversary meeting of the Royal Geographical Society was held on Monday in the hall of the University of London, General R. Strachey presiding. The report, which was read by Mr. Clements R. Markham, having been adopted, General Strachey was for the third consecutive year elected President of the Society. The Founder's Medal for the encouragement of geographical science and discovery was presented to Mr. Clements R. Markham, who retires from the honorary secretary. ship after twenty-five years' service, in acknowledgment of the valuable services rendered by him to the Society during that period. Lieut. H. Wissmann was awarded the Patron's Medal in recognition of his great achievements as an explorer in Central Africa; Mr. J. M'Carthy, Superintendent of Surveys in Siam, the Murchison Grant; Major Festing, the Cuthbert Peek Grant, for his services as a cartographer on the Gambia River and the country in the neighbourhood of Sierra Leone. The Gill Memorial for 1888 was secured by Mr. Charles M. Doughty. Various scholarships and prizes to students in training colleges were also distributed. The President then delivered his annual address, passing in review the chief geographical events of the year.

THE LINNEAN SOCIETY.

THE hundredth anniversary meeting of this Society was held on Thursday last, 24th inst., at Burlington House, in the library, the usual meeting-room being inadequate for the reception of the large number of members present on this occasion. The President, Mr. Wm. Carruthers, F. R.S., took the chair at three o'clock, and was supported by the two former Presidents who are happily still with us-Prof. Allman and Sir John Lubbockthe Council of the Society, and many distinguished Fellows, amongst whom we noted Sir Richard Owen, Sir Joseph Hooker, Dr. Günther, Sir Walter Buller, Prof. Duncan, Mr. Romanes, Colon:1 Grant, and amongst the visitors Dr. Henry Woodward, F.R.S., and Mr. Studley Martin, a nephew of the founder.

After preliminary business, H.M. the King of Sweden was elected an honorary member. The Treasurer, Mr. Frank Crisp, laid the last year's accounts before the meeting, and briefly referred to the financial history of the Society during the century now closed. The senior Secretary, Mr. B. Daydon Jackson, presented an account of the Linnean collections from their formation, their purchase by the founder of the Society, and their possession by the Linnean Society. This was succeeded by the President's annual address, which was largely devoted to a review of the Society's past career. He spoke of the original quarto Transactions, then of the octavo Proceedings, finally of the Journal, of which forty-three volumes are extant. During the past year seven parts of the Transactions and twenty of the Journal had been issued, an amount equal to that published during fifteen years in the early part of the century.

A novel feature was then introduced, one of those intended to mark the centenary of the Society. Prof. Thöre Fries, the present occupant of Linnæus's Botanical Chair at Upsala, had been invited to pronounce a eulogium on his illustrious predecessor. As he was detained by his professorial duties in his University, his essay was read by the President. In it he spoke of the profound sleep of natural science during the Middle Ages, and the hard struggle which had to be fought before men of science could liberate themselves from a narrow orthodoxy, or the fetters they had themselves forged by attaching infallibility to Aristotle and classic authors. Linnæus bore an honourable part in placing the study of natural science on a logical basis by his clear definitions, and admirable nomenclature, and by the enthusiasm he was able to rouse in his disciples for the same methods. England, unluckily for Sweden, became his heir; many consequently are the ties which unite the memory of Linnæus with this country, the strongest perhaps being the Linnean spirit, the genuine spirit of freshness and enterprise in which scientific research is carried on in England.

Sir Joseph Hooker then pronounced a eulogy on Robert Brown, the greatest botanist of the present century. He specially dwelt on the evidence afforded by the "Prodromus " of his untiring industry, accuracy of observation and exposition, together with sagacity, caution, and soundness of judgment, in which he has not been surpassed. Where others have advanced beyond the goal he reached, it has been by working on the foundations he laid, aided by modern appliances of optics and physics. His memory was wonderful, he seemed never to forget a plant he had examined; and the same with his books

he could turn to descriptions for a statement or a figure without needing a reference. The noble title conferred upon him by Humboldt has been confirmed by acclamation by botanists of every country, "Botanicorum facile princeps."

Prof. Flower, C. B., F.R.S., delivered an address on Charles Darwin, who, he said, had special claims on their consideration, inasmuch as a large and very important portion of his work was communicated to the world by papers read before the Society and published in the Journal. His life was one long battle against our ignorance of the mysteries of living Nature, and he sought to penetrate the shroud which conceals the causes of all the variety and wonders round us. His main victory was the destruction of the conception of species as being fixed and unchangeable beyond certain narrow limits, a view which prevailed universally before his time. That other factors had operated besides natural selection in bringing about the present condition of the organic world was admitted even by Darwin himself. His work, and the discussions which had sprung from it, had marvellously stimulated research, and he had shown by his life and labours the true methods by which alone the secrets of Nature may be won.

Prof. W. T. Thiselton Dyer spoke on George Bentham, who presided over the Society from 1863 to 1874. A nephew of Jeremy Bentham, and trained to some extent under him, he was early imbued with a taste for method and analysis, and through his mother's fondness for plants he was led to study them, with marvellous results. The records of his life-work are

astonishing. Whilst President he delivered a series of masterly addresses, and the latter part of his career witnessed the preparation of the "Flora Australiensis" and a full share of the "Genera Plantarum." He stood in the footsteps of Linnæus, and although the descent was oblique he inherited the mantle of the master whose memory was that day commemorated.

The President stated that the Council had decided to establish a Linnean Gold Medal, to be presented to a botanist and a zoologist in alternate years, but on this occasion it would be awarded in duplicate. The medal bore on the obverse a profile of Linnæus, modelled from the bust in the library; on the reverse, the arms of the Society and the name of the recipient. The President made the first presentation to Sir Richard Owen, recounting the chief services he had rendered to zoology. Sir Richard, with some emotion, expressed his high sense of the honour conferred, and thanked the Fellows for their cordial reception of him. The President then presented a similar medal to Sir Joseph Hooker, with a like recapitulation of the splendid services he had bestowed on botany. Sir Joseph suitably replied, returning his cordial thanks for the distinction.

The remaining formal business included the announcement of the newly-elected Councillors, and the re-election of the officers-Mr. Wm. Carruthers, President; Mr. Frank Crisp, Treasurer; and Messrs. B. Daydon Jackson, and W. Percy Sladen, Secretaries.

The annual dinner was held at the Hotel Victoria, Northum. berland Avenue, at seven o'clock. The President took the chair, about sixty of the Fellows being present. In addition to the usual toasts, that of "The Medallists was given, and replied to by Sir Joseph Hooker, who alluded to the fact that he had personally known eight of the Presidents of the Society, and that the founder himself induced his father, Sir William Hooker, to take up the study of botany. As a proof of his close grandfather, father-in-law, and uncle had all been Fellows. connection with the Linnean Society, he added that his father,

The final portion of the centenary celebration took place the following evening, when the President and officers held a reception at Burlington House. A special feature was made of the Linnean manuscripts and memorials, which were displayed in glass cases with descriptions, a catalogue of them being also distributed. Memorials of other distinguished naturalists were also shown, conspicuously those of Robert Brown and George Bentham, lent by Sir Joseph Hooker and M. Alphonse de Candolle, of Geneva, a foreign member of the Society.

UNIVERSITY AND EDUCATIONAL
INTELLIGENCE.

CAMBRIDGE.—The Rede Lecture on June 8, by Sir F. A. Abel, will be upon applications of science to the protection of human life. It will be illustrated by experiments and the exhibition of appliances.

Mr. Percy Groom, B. A., late of Trinity College, has been elected to the Frank Smart Studentship in Botany at Gonville and Caius College.

The fittings of the new Chemical Laboratory are costing £1000 more than was originally estimated (from rough drawings only) by Mr. Lyon, Superintendent of the University workshops. Some of this is due to the fact that the fixing of the tables on a bottom independent of the floors of the rooms, and making the cupboard doors fairly dust-proof, originally recommended, was not adopted till after the tables had been fixed, and much cutting of the floors had to be done. Also much of the iron and steel work was not particularized at first.

The Council are taking steps to carry out the appropriation of the old Chemical Laboratory to the department of pathology. Prof. Darwin will lecture during the long vacation on the theory of the potential, and on attractions, commencing on

Tuesday, July 10. The lectures will treat principally of gravitational problems, including attraction of ellipsoids, Gauss's paper, heat of tin, Jacobi's and Dedekind's ellipsoids, oscillations of a fluid sphere, the foundation of the theory of tides, atmospheres of planets, &c.

SOCIETIES AND ACADEMIES. LONDON.

Royal Society, May 3.—" Effect of Chlorine on the Electromotive Force of a Voltaic Couple.' By Dr. G. Gore, F.R.S. If the electromotive force of a small voltaic couple of unamalgamated magnesium and platinum in distilled water, is balanced through the coil of a moderately sensitive galvanometer of about 100 ohms resistance, by means of that of a small Daniell's cell, plus that of a sufficient number of couples of iron and German silver of a suitable thermo-electric pile (see Proc. Birm. Philos. Soc., vol. iv. p. 130), the degree of potential being noted; and sufficiently minute quantities of very dilute chlorine water are then added in succession to the distilled water, the degree of electromotive force of the couple is not affected until a certain definite proportion of chlorine has been added; the potential then suddenly commences to increase, and continues to do so with each further addition within a certain limit. Instead of making the experiment by adding chlorine water, it may be made by gradually diluting a very weak aqueous solution of chlorine.

The minimum proportion of chlorine necessary to cause this sudden change of electromotive force is extremely small; in my experiments it has been 1 part in 17,000 million parts of water, or less than 1/7000 part of that required to yield a barely perceptible opacity in ten times the bulk of a solution of sal-ammoniac by means of nitrate of silver. The quantity of liquid required for acting upon the couple is small, and it would be easy to detect the effect of the above proportion, or of less than one ten-thousand-millionth part of a grain of chlorine, in one-tenth of a cubic centimetre of distilled water by this process. The same kind of action occurs with other electrolytes, but requires larger proportions of dissolved substance.

As the degree of sensitiveness of the method appears extreme, I add the following remarks. The original solution of washed chlorine in distilled water was prepared in a dark place by the usual method from hydrochloric acid and manganic oxide, and was kept in an opaque well-stoppered bottle in the dark. The strength of this liquid was found by means of volumetric analysis with a standard solution of argentic nitrate in the usual manner, the accuracy of the silver solution being proved by means of a known weight of pure chloride of sodium. The chlorine liquid contained 2-3 milligrammes or o 03565 grain of chlorine per cubic centimetre, and was just about three-fourths saturated.

One-tenth of a cubic centimetre of this solution (“No. 1 "), or 0.003565 grain of chlorine, was added to 9'9 c.c. of distilled water and mixed. One cubic centimetre of this second liquid ("No. 2"), or 0.0003565 grain of chlorine was added to 99 c.c. of water and mixed; the resulting liquid ("No. 3") contained 0000003565 grain of chlorine per cubic centimetre. To make the solutions ("No. 4") for exciting the voltaic couple, successive portions of or c.c. of ("No. 3") liquid were added to 900 cubic centimetres of distilled water and mixed.

As 1 part of chlorine in 17612 million parts of water had no visible effect, and 1 in 17000 millions had a distinct effect, the influence of the difference, or of 1 part in 500,000 millions, has been detected.

The experiments described in the paper were made with the view of extending to nickel the same lines of inquiry as had been pursued by one of the authors in regard to iron (Phil. Trans., 1885, p. 523). Cyclic processes of magnetization have been studied, in which a magnetizing force of about 100 C.G.S. units was applied, removed, reversed, again removed, and re-applied, for the purpose of determining the form of the magnetization curve, the magnetic susceptibility, the ratio of residual to induced magnetism, and the energy dissipated in consequence of hysteresis in the relation of magnetic induction to magnetizing force. Curves are given, to show the character of such cycles for nickel wire in three conditions: the original hard-drawn state, annealed, and hardened by stretching after being annealed. The effects of stress have also been examined (1) by loading and unloading magnetized nickel wire with weights which produced cyclic variations of longitudinal pull, and (2) by magnetizing while the wire was subjected to a steady pull of greater or less amount. The results confirm and extend Sir William Thomson's observation that longitudinal pull diminishes magnetism in nickel. This diminution is surprisingly great it occurs with respect to the induced magnetism under both large and small magnetic forces, and also with respect to residual magnetism. The effects of stress are much less complex than in iron, and cyclic variations of stress are attended by much less hysteresis. Curves are given to show the induced and residual magnetism produced by various magnetic forces when the metal was maintained in one or other of certain assigned states of stress; also the variations of induced and residual magnetism which were caused by loading and unloading without alteration of the magnetic field. Values of the initial magnetic susceptibility, for very feeble magnetizing forces, are stated, and are compared with the values determined by Lord Rayleigh for iron, and the vestigated. The paper consists mainly of diagrams in which relation of the initial susceptibility to the stress present is inthe results are graphically exhibited by means of curves.

Chemical Society, May 3.-Mr. W. Crookes, F. R. S., in the chair. The following papers were read :-The determination of the molecular weights of the carbo-hydrates, by Mr. H. T. Brown and Dr. G. H. Morris. The law established by Blagden in 1788, that the lowering of the freezing-point of aqueous solutions of inorganic salts is proportional to the weight of substance dissolved in a constant weight of water, was extended by de Coppet in 1871-72, who pointed out that when the lowering of the freezing-point is calculated for a given weight of the substance in 100 grammes of water, the result, which he termed the coefficient of depression, is constant for the same substance, and that the coefficients for different substances bear a simple relation to their molecular weights. Raoult extended the law to organic substances and to other solvents than water, and showed that when certain quantities of the same substance are successively dissolved in a solvent upon which it has no chemical action, there is a progressive lowering of the point of congelation of the solution, and that this lowering is proportional to the weight of the substance dissolved in a constant weight of water. The "coefficient of depression," A-that is, the depression of the point of congelation produced by 1 gramme of the substance in 100 grammes of the solvent-is given by the formula Cxy = A, where C is the observed depression produced by

x x 100

x grammes of the substance dissolved in y grammes of the solvent, and from this value the "molecular depression," T, is calculated by the formula M × A = T, where M is the molecular weight of the substance in question. T is a value varying with the nature of the solvent, but remaining constant with the same solvent for numerous groups of compounds, whence it follows that A and T being known, the molecular weight of the substance in question may be determined from the equation M = T/A. This method of Raoult's, which is of value in cases where a vapour density determination is not possible, has been employed by the authors to determine the molecular weights of the following carbo-hydrates: dextrose, cane-sugar, maltose, milk-sugar, arabinose, and raffinose, and also that of mannitol (the solvent being water), with results which lead to formulæ