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Mechanical lantern slide illustrative of the phenomenon of a total solar eclipse: Mr. W. Shackleton. A white disc representing the sun is projected on a screen; by moving an opaque disc representing the moon, this is gradually obscured, and the preliminary partial phases of a total solar eclipse are shown. A moment before complete obscuration a twin shutter is opened, which allows the corona and chromosphere to be projected, thus reproducing totality, which may last as long as desired.Stereoscopic views of the sun and stars of estimated parallax: Mr. T. E. Heath. The perspective drawings were made from a plan and elevations in which the scale of stellar distances was ten light-years to 1 inch, and of stellar discs such that the sun (or a star which gives equal light) was 150th of an inch in diameter. The magnitudes were made to vary with the varying distance of the spectator. (1) Microscope and goniometer stage for examining the optical qualities of minute grains of sand; (2) set of petrological quartz wedges; (3) photomicrographic camera, designed by Mr. J. W. Gordon for taking small direct photomicrographs while the instrument is in use after observation without attention to the adjustments : Messrs. R. and J. Beck, Ltd.

(1) Photomicrographs of section of gun tube showing change in structure of steel after 2000 rounds; (2) photomicrographs of alloys of aluminium with nickel; (3) photomicrographs of alloy of copper with cobalt and nickel : Dr. Hodgkinson, Captain Playfair, R.A., and Mr. Coote. -(1) Apparatus for polishing and preparing metals for microscopic examination; (2) specimens of steels in the cast and forged condition containing phosphorus: Mr. J. E. Stead, F.R.S.-Transverse sections of slip-bands and other microscopic features of metallic surfaces: Mr. W. Rosenhain.-A series of alloys of iron and steel tested at liquid air temperature: Mr. R. A. Hadfield. The specimens showed the effect of liquid air (temperature -182 C.) upon almost pure iron (Swedish charcoal iron "S.C.I.," 0-04 carbon, 99.82 iron) and a large number of alloys of iron with other elements. The well known ductility of iron disappears, while its tenacity is more than doubled. Similar effects occur with nearly all the alloys of iron with carbon and other elements, except those containing nickel, which metal appears to modify considerably the embrittling effect of low temperatures upon iron.

Clock and chronometer by Thomas Mudge: Mr. A. Mallock, F.R.S. The clock was made about 1776, and contains Mudge's moon motion. Mudge's object in making this motion was to show that any desired velocity ratio nould be approximated to very closely with comparatively few wheels. The train of wheel-work he employed makes the mean lunation 0-03 second less than the actual mean lunation, that is, the error is less than 1 in 2 millions. There are other remarkable features in this clock connected with the balance wheel, escapement, and temperature correction.-(1) Tangent-micrometer for theodolites, &c.; (2) endless-tangent screw for sextants: Mr. E. A. Reeves. By the addition of a micrometer drum," and a simple arrangement for clamping the outer rim or dial carrying the numbers, combined with a special indicator, a carefully constructed tangent-screw serves also as a micrometer, and renders it possible to read the arc with the same accuracy as with the usual form of micrometer, while the instrument need not be larger than the ordinary vernier theodolite. The sextant device consists of a tangent-screw constructed with an endless thread, by means

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which the vernier arm can be made to pass from any une part of the arc to another. For making rough confats the tangent-screw is raised from the arc by means " lever pressed by the finger. When the pressure on the lever is released the tangent-screw, actuated by a ong, again comes in contact with the arc, and serves clamp.

1 direct reading cymometer for measuring the lth of the waves used in wireless telegraphy: Prof. J. A. Fleming, F.R.S. The instrument consists of a *d ng tubular condenser and an inductance coil, the Capacity and inductance being varied together in the same proportion by one movement of a handle. The circuit is red by a copper bar, which is placed alongside the rial wire indicating the electric waves. The handle of

the cymometer is then moved until a neon vacuum tube used as an indicator shines most brightly, and thus determines when the cymometer circuit is tuned to the frequency of the aërial. A pointer moving over a scale then indicates the wave-length of the radiated wave in feet or metres.-An oscillation valve for rectifying electrical oscillations and rendering them measurable on an ordinary galvanometer: Prof. J. A. Fleming, F.R.S. The valve consists of a bulb enclosing a carbon filament made like an incandescence lamp. The filament is surrounded by a metal cylinder. The bulb is highly exhausted. When the filament is incandescent, negative electricity can move through the vacuum from the hot filament to the cylinder, but not in the reverse direction. Hence the arrangement can separate out the two opposite currents in an electric oscillation. It can be used in combination with a dead beat galvanometer as a receiver in wireless telegraphy. The valve replaces the coherer and other appliances, and the signals are given by long and short deflections of the galvanometer. (1) Resonance induction coil and high potential apparatus; (2) resonance electromagnet: Messrs. Isenthal and Co. Electrolytic condensers of very large capacity are charged from the mains through the primary of a suitably wound induction coil, and the circuit broken and reversed at zero potential by means of a motor-driven commutator of special construction. The advantages are no motor transformer is required in primary circuit, no rectifying device in secondary circuit, and there are no interruptors to be cleaned. The apparatus enables a current to be converted sparklessly into pure sine current suitable for space telegraphy. An electromagnet excited from a source of this kind exhibits peculiar physical and physiological phenomena.—(1) High-tension resonance transformer; (2) X-ray stereoscope: Mr. Russell Wright. The special form of step-up " transformer exhibited works direct from the alternating current mains, and produces an alternating discharge of sufficient tension for X-ray work or high-frequency effluve. By means of a small revolving shutter, driven by a synchronous motor, between the observer's eye and two X-ray tubes, stereoscopic images could be clearly seen on an X-ray screen.

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High temperature electric furnaces: Director of the National Physical Laboratory. These furnaces are structed of rare earths such as are used in Nernst lamps. They are available for temperatures between 800° C. and 2000° C. The apparatus used in a recent determination of the melting point of platinum was shown at work, in addition to that for other experiments of a similar character. New models of laboratory electric furnaces: Mr. R. S. Hutton. The furnaces consist of a carbon tube, rod, or plate heated by an electric current. In the tube furnaces the carbon is surrounded by some material of low thermal conductivity, which also serves to protect the hot tube from oxidation. The substance to be heated is placed in a carbon boat or crucible inside the tube, and can thus be brought to a very high temperature. The method employed for conveying the current to the carbon by soldering water-jacketed sleeves to the electro-coppered ends of the carbon forms a novel feature of the construction.

Photographs taken in China by the Carnegie expedition under Mr. Baily Willis in 1904, illustrating a presumably Glacial deposit underlying the base of the Cambrian rocks of the region: Sir Archibald Geikie, Sec.R.S.-Photographs, cast, and model of skull of Diplodocus, a Jurassic dinosaur from Wyoming, and other fossils from the middle west of North America: Dr. W. J. Holland.-Remains of fossil mammals from Crete: Miss D. M. A. Bate. Numerous mammalian remains were found in 1904 in the Pleistocene cave and fresh-water deposits of Crete. These include remains of the following animals :-antelope, deer, elephant, pigmy hippopotamus, shrew, and two species of rodents. The great Indian earthquake, April 4: Prof. J. Milne, F.R.S. Five seismograms of this disturbance were shown from Shide, Isle of Wight. (1-2) Open diagrams on smoked paper showing north-south and east-west motion. (3) Open diagrams of east-west motion on photographic paper. The instrument was a Milne horizontal pendulum. (4-5) Photographic records from a pair of Milne horizontal pendulums vibrated north-south and eastwest. The exhibit also included seismograms of east-west

motion from Edinburgh, Paisley, Beirut, and Toronto.Charts of the Gulf of St. Lawrence, showing the co-tidal lines at mean time of Quebec: Captain Tizard, C.B., F.R.S.-Photographs of the Cullinan " diamond: Sir William Crookes, F.R.S.

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Microscopic preparations illustrating the development of calcareous spicules in various invertebrate animals: Prof. E. A. Minchin and Mr. W. Woodland. Calcareous spicules are small skeletal elements to be found in most of the lower animals. These spicules assume varied and often beautiful forms, those of sponges and sea cucumbers" (Cucumariidæ and Synaptidæ) being especially striking in this latter respect, and are built up in all instances by the agency of scleroblasts-small nucleated protoplasmic masses which deposit the lime. The causes underlying the production of the curious forms which these spicules assume (triradiates, perforated plates, wheels and anchors, &c.) are not by any means yet understood, but are probably several in number, some being purely mechanical in nature, others, perhaps, being those which give rise to crystals.-Cellular constituents peculiar to cancerous and reproductive tissues: Prof. J. B. Farmer, F.R.S., Mr. J. E. S. Moore, and Mr. C. E. Walker. In the cells of malignant tumours, structures known "Plimmer's bodies" are present in most cases. These structures have been regarded as parasitic organisms or as specific cellular peculiarities confined to such malignant tissues. They have recently been identified as also being present in normal reproductive tissues. They form definite organ of the cell during its conversion to a spermatozoon, and they also can be identified in the two preceding divisions. They are absent from other cells of the body. The simplest kind of protoplasm: Dr. Charlton Bastian, F.R.S. One drop of a fluid swarming with common bacteria had been introduced into one ounce of distilled water containing ten grains of neutral ammonic tartrate in solution. The bacteria grow freely in this fluid, and as the constitution of the ammonia salt is 2NHO, CHO1+2HO, they must fashion their protoplasm in some way from C, H, O, and N only, though sulphur and phosphorus, one or both, are commonly regarded as necessary constituents of living matter.

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be cut into four pieces that may be re-assembled to form a square, with some examples of a general method for transforming all rectilinear triangles into squares by dissection.

Oil painting, a Friday evening lecture at the Royal Institution: Mr. H. J. Brooks.

ATMOSPHERIC ELECTRICITY OBSERVED
FROM BALLOONS.

IT is now some years since attempts were first made to
investigate the electrical conditions of the upper atmo-
sphere by aid of manned balloons; but it is only within the
last three years that the difficulties of the observations and
the proper methods to be used have been anything like
understood.

Measurements of the normal potential gradient were first attempted. The early observers worked very much in the dark, Linke being the first, in 1901, to investigate the errors due to the mere presence of the balloon itself. He found that for the influence of an uncharged balloon to be small enough to be neglected, the upper of the two collectors used must be at least 10 metres below the basket. Linke also investigated the efficiency of different forms of collectors. The original form of collector used in balloon work was a modification of Kelvin's drop collector. A wire was lowered from an insulated vessel out of which water flowed and ran down the wire; the drops forming on the end of the wire and then falling off brought the whole wire to the potential of the air at its end. There are many objections to this form of collector; it is very slow in action, uses a large quantity of water, and will not work when the temperature falls below freezing. Flame collectors are obviously out of the question for balloon work on account of their danger, and, much to the regret of the experimenters, radium did not come up to expectation. The difficulty with radium collectors is that the radium ionises a large volume of air, which, on account of the absence of relative motion between the balloon and the surrounding air, travels along with the balloon and completely alters the electrical conditions of the atmosphere in its neighbourhood. By a simple device Linke has finally overcome all difficulties connected with the collectors. an A vessel containing spirits is insulated on a shelf fastened to the outside of the basket. From this vessel hangs a long thin lead or other flexible pipe. At the lower end of the pipe is a nozzle which forms the collector proper. As stated above, the collector must be

The parasite of kala azar": Brevet Lieut.-Colonel W. B. Leishman. This protozoal organism is found in the spleen and other organs in cases of "kala azar, extremely fatal disease occurring in epidemic form in Assam, and also, in endemic form, in other parts of India and the tropics. Nothing is yet known as to the mode of infection or as to the life of the parasite outside its human host. In artificial cultures it develops into a flagellated organism closely resembling a trypanosome. Specimens and sketches were shown of the parasites as they occur in the tissues, and of the flagellated forms into which they develop in artificial cultures.-The isolation of B. typhosus from water by means of alum precipitation: Mr. H. S. Willson. Alum is added to the infected water in the proportion of 0.5 gram to the litre. When the precipitate of aluminium hydrate has fully formed, the water is centrifugalised and the sediment containing most of the bacteria present in the water is spread on plates of suitable media, and incubated at 42° C. The precipitate, which is known to be destructive to many water and sewage organisms, has no germicidal action on B. typhosus.

(1) Stone adze heads in various stages of manufacture, and chips from the neighbourhood of Suloga, Woodlark Island, British New Guinea; (2) photographs of straight-haired individuals from Nara district central division, British New Guinea; (3) wood carvings and drawings, principally from Massim district, British New Guinea: Mr. C. G. Seligmann. Specimens of cross-bred maize illustrating inheritance in accordance with Mendel's law: Mr. R. H. Lock.-Living representatives of the Plymouth marine fauna: Marine Biological Association. Material obtained with the dredge from certain typical grounds in the neighbourhood of Plymouth was shown, together with representatives of the animals living on each ground.-Photographs illustrating young cuckoo in the act of ejecting egg and young bird from nest of foster-parent: Mr. W. Percival Westell.

A new problem on superposition: Mr. H. E. Dudeney. This was a demonstration that an equilateral triangle can

10 metres below the balloon; thus there is at least a 10-metre head of liquid acting at the nozzle. The pressure due to this causes a very fine jet to escape from a pinhole in the nozzle. As the jet breaks up into exceedingly fine drops, a very rapid collector action takes place. Collectors of this form have acted splendidly, and their use makes it possible to measure the potential gradient with accuracy and ease.

The rate of dissipation of electricity from a charged body, and the degree of ionisation of the air, have also been made subjects for investigation in the upper atmosphere. Ebert and Linke have devoted several ascents to measurements of the dissipation, and Ebert designed the first instrument to measure the natural ionisation of the air; but the ionisation has been most carefully investigated by Gerdien, who improved Ebert's instrument so that it measures not only the ionisation, but the conductivity of the air also.

It was when making these latter investigations that a number of difficulties connected with the casting of ballast were first observed. Ebert found that the pouring of sand from the ballast bags so highly charged the balloon with friction electricity that electrical observations became impossible. Gerdien found that after sand had been cast the balloon remained for some minutes in an atmosphere filled with fine sand dust, which greatly affected the measurements of the ionisation. Linke also found that on account of the sudden upward acceleration given to the balloon after sand had been cast the position of the electroscope leaves changed without any change of voltage. Gerdien was the first to overcome these difficulties. Besides sand, he took two large watertight sacks filled

with water. By having pipes and taps fitted to the sacks water could be discharged as desired. Sand still remained the ordinary ballast; but when electrical measurements were being made water only was used. In order to prevent the water freezing in the cold upper atmosphere, Gerdien filled the sacks with boiling water, which, experience proved, kept sufficiently warm to prevent freezing before it was all used. This method was found to be entirely satisfactory, for it not only got over all difficulties connected with the sand, but by regulating the flow of the water much greater control could be exercised over the balloon than had before been possible with sand.

These and other difficulties have been so recently recognised and overcome that trustworthy results have as yet hardly been obtained, but the observations appear to justify the following conclusions:

The normal potential gradient remains positive to the highest point yet investigated (5900 metres by Gerdien), but decreases in magnitude as the height increases. This points to the lower regions of the atmosphere containing a positive charge equal to the negative charge on the earth's surface, so that the globe as a whole is not charged. The number of ions in a cubic metre of air is the same at all heights.

Electricity is dissipated more rapidly from a charged body the higher it is in the atmosphere, this being, no doubt, due to the greater ease with which ions move in rarified air.

These results require further verification before they can be accepted as final, and it is to be hoped that facilities will be forthcoming for the investigations to be followed up in this country. It is a strange fact that no Englishman has yet devoted himself to a study which combines science and sport in such an attractive manner.

GEORGE C. SIMPSON.

UNIVERSITY AND EDUCATIONAL
INTELLIGENCE.

CAMBRIDGE.-The syndicate the proposals of which with regard to the previous examinations were thrown out by the Senate last term, was elected to consider the studies and examinations of the University, and, although it has so far considered but one examination, a determined attempt is being made to bring its deliberations to a close. The period for which the syndicate was appointed lapses at the end of this term, and the grace which authorises its re-appointment will to-day be non-placetted" in the Senate. A short time ago four members were added to the syndicate. Their nomination was not objected to, though the action of the council in appointing them was termed inexpedient. It seems a strange piece of courtesy acquiesce in the appointment of men like the master of Gonville and Caius, Mr. S. H. Butcher, late professor of Greek in Edinburgh, Dr. Adam, and Mr. Hardy to a syndicate which the opponents of change intended, so far as Jay within their power, to render moribund.

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The natural sciences tripos continues to increase. There are 140 candidates entered for part i. and 30 candidates for part ii., both of which began this week. In the first part of the mathematical tripos there are 57, and in the first part of the classical tripos there are 102 candidates, in the second part 12. The entrances for the mechanical sciences tripos, part i., are 45.

The Board of Agricultural Studies reports a continuous increase both in the number of students attending the agricultural courses and in the number presenting themselves for the examinations. The number of students is now close upon fifty, and shows an increase of seven within the last twelvemonth.

The honorary degree of M.A. will to-day be conferred on Mr. Robert Stephenson, late chairman of the Cambridgeshire County Council, in recognition of his services to education, and especially to the promotion of agricultural education in the university.

The Rede lecture will be delivered on Saturday, June 10, at 11.30 a.m., by Sir Francis Younghusband, K.C.I.E. His subject is "Our True Relationship with India."

The council of the Senate has promulgated a grace proposing that a syndicate be appointed to consider the de

sirability of establishing in the university a diploma in forestry, and to draw up, if it thinks fit, a scheme of instruction and examination in forestry; that it be empowered to consult with any persons or bodies; and that it report to the Senate before the end of the Lent term, 1906. The next combined examination for sixty-two entrance scholarships and various exhibitions at Pembroke, Gonville and Caius, King's, Jesus, Christ's, St. John's and Emmanuel Colleges will be held on Tuesday, December 5, 1905, and following days, commencing at 9 a.m. on Tuesday, December 5. Mathematics, classics, and natural sciences will be the subjects of examination at all the above-mentioned colleges, and certain colleges examine in history, modern languages, and Hebrew.

OXFORD. Dr. Henry Wilde, F.R.S., has presented 100l. to the Hope Department of Zoology for the purchase and preparation of specimens illustrating mimicry and protective resemblance.

The Romanes lecture for 1905 will be delivered by Prof. Ray Lankester, F.R.S., in the Sheldonian Theatre on Wednesday, June 14, at 2.30. The subject of the lecture will be Man and Nature.

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Mr. R. de J. Fleming Struthers has been elected to a senior scholarship in chemistry at Exeter College.

The Junior Scientific Club will hold a conversazione at the Museum on Tuesday, May 30.

MR. E. P. CULVERWELL has been elected to the professorship of education founded by the Board of Trinity College, Dublin, for a period of five years.

A REUTER telegram from Toronto reports that the Ontario Government has announced a provisional grant of 100,000l. to the University of Toronto toward the proposed new buildings which, it is estimated, will cost 320,000l.

IT has been announced, Science states, that the trustees of Columbia University have received 100,000l. from an anonymous donor for the construction of a new college hall; and that the Legislature of Minnesota has made direct appropriations for the University of Minnesota for the next two years amounting to 142,000l., besides 12,000l. derived from the insurance on the old main building, destroyed by fire last September.

AN International Exhibition of Pedagogy, under the patronage of H.M. the King of Spain and of H.M. Queen Maria Christina, will be held in Barcelona from May to October. Particulars as to the scope of the exhibition and the conditions attaching to exhibits are given in the official programme, a limited number of copies of which can be obtained on application to the Director of Special Inquiries and Reports, Board of Education Library, St. Stephen's House, Cannon Row, Whitehall, London, S.W.

PRESIDING at the annual meeting of the British and Foreign School Society, Mr. A. H. D. Acland moved the adoption of the report on the year's work of the association. During the course of his speech, he remarked that in many schools too much is done for the brain and too little for the body. If hygiene, instead of being merely a special subject, were made part of the teacher's general outfit, much would be done for the health of the nation. Mr. Acland said he hopes also that by degrees the pest of examinations will be modified and got rid of a matter in which the old universities are among the greatest sinners. Whoever could wipe out two-thirds of the examinations would be one of the greatest benefactors of the human species.

The

THE question of the concentration of the teaching of the preliminary and intermediate subjects of the medical curriculum in London at a few centres has long occupied the attention of those interested in medical education, as it has been felt that this step must result in greater efficiency in teaching, as well as economy in expenditure. Westminster Hospital Medical School has been the first to take definite action in the matter, and has just completed negotiations with King's College by which arrangements have been made for the teaching of physics, chemistry, biology, anatomy, physiology, and materia medica (that is to say, the subjects of the preliminary and intermediate examinations) to Westminster students

of King's College. Students will enter Westminster Hospital Medical School as in the past, and will remain Westminster men; they will not become matriculated students of King's College, but they will be taught the earlier subjects of study at that institution. The scheme will come into effect at the commencement of next winter session in October. At the same time, the teaching of the subjects of the final examination is being completely re-organised. It is believed that this commencement of a probably more general concentration of the teaching of the preliminary and intermediate subjects of the curriculum cannot but promote the best interests of medical education in London.

SOCIETIES AND ACADEMIES.
LONDON.

Royal Society, March 9.-"On some Continuous Observ. ations of the Rate of Dissipation of Electric Charges in Communithe Open Air." By Dr. C. Coleridge Farr. cated by Dr. C. Chree, F.R.S.

During part of 1902 and 1903 the author resolved to take as many observations of the rates of dissipation of electric charges as possible, and to continue them over the whole day, and, when opportunity offered, over longer periods.

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The observations were made on the Canterbury Plains of New Zealand, about 20 feet above sea-level, and five miles due west from the sea coast. The apparatus used was Elster and Geitel's Zerstreuungsapparat. Corresponding observations were made of the direction and intensity of the wind (Beaufort), the humidity, and the potential difference between a point about 10 feet above the ground and the earth. This was determined by a Kelvin portable electrometer and a water-dropper.

The dissipation apparatus was read by a telescope, and at night it was illuminated by a bull's-eye lantern, but only during the actual time of reading.

The conductivity of the air is very irregular, but on an average negative electricity is dispersed more rapidly than positive.

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conductivity of air for -ve electricity, Taking conductivity of air for +ve electricity

six ordinary days, embracing several hundreds of observations, gave an average of q=1.16.

Yet on several occasions for some hours together during these six days, positive electricity was dissipated the more rapidly. The examples considered apparently indicate that a low value for q is, as might be expected, accompanied with a reversal of sign of the atmospheric charge. On one occasion, however, the potential became - 185 volts with q about unity.

Again, considering the six days only, as more typical of ordinary conditions than two others to be referred to, there is distinct evidence of a double maximum and minimum

value for the conductivity throughout the day for charges of both signs.

Of two other days, viz. February 1 and 2 and December 15 and 16, the former exhibits no distinct maxima and minima, but a strong south-west gale was blowing; the latter day is incomplete.

Observations on February 1 and 2, and on March 1 and 2, during south-west gales gave a much higher value for the conductivity for both positive and negative charges than usual. Since the wind on these two days was in the same direction, there is only a slight amount of evidence that the excessive conductivity is due to the strength rather than to the direction of the wind.

Two days not yet mentioned, viz. February 18 and March 16, may now be referred to. On the first of these a strong gale from the north-west was blowing when the observations were begun. On the latter, at 6.30 a.m., it was calm; at 8 a.m. there was a light south-west wind, and at 9.30 it was blowing strongly from the northwest with a characteristic falling barometer. These "nor'westers blow over a range of mountains reaching 7000 feet, and deposit their moisture on the western slopes, though the rain often extends to the eastern side. In 1 Elster and Geitel, "Terrestrial Magnetism," vol. iv., p. 213 et seq.

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Christchurch they are invariably dry and hot, being of the nature of Foehn winds, and have a depressing effect upon most people.

Though the above days are the only two of the class upon which, so far, the author has taken dissipation observations, yet potential observations indicate that the winds are negatively charged relatively to the earth, which is contrary to the usual condition. On both days the dissiThe earliest pation curves show marked peculiarities. observation, at 11.15 a.m. on February 18, gave q=0·4, with a negative potential difference between water-dropper and earth of 300 volts at 10.20 a.m., -150 volts at 11.40 a.m., and -50 volts at 12.45 p.m. Corresponding with this rise of potential there is also a marked rise in the value of q.

On March 16 the whole history is apparent. At 7.30 a.m. the wind was light south-west, q=1-3, potential +90 volts. At 9.45 a.m., wind north-west, strong, q=0.7, potential -250 volts. At 10.30 a.m., wind northwest, strong, q=11, potential -100 volts approximately. The north-west wind seemed then to have thoroughly established itself. The values of q became less and less, the curves indicating the conductivity of the air for positive and negative charges diverging rapidly, that for positive reaching a high value, whilst the negative curve reached remarkably low values. Corresponding with the extremely low value for q the potential reached its greatest negative value, 1885 volts. After this q increased and the negative potential decreased, until at 4.30 p.m. q=0-94, potential -30 volts.

March 30.-" On a New Type of Electric Furnace with a Re-determination of the Melting Point of Platinum." By Dr. J. A. Harker. Communicated by Dr. R. T. Glazebrook, F.R.S.

The first part of the paper deals with a description of a new type of electric furnace for the attainment in absence of noxious gases of temperatures between 800° C. and 2200° C. The conductor conveying the electric current is a tube of solid electrolytes similar in composition to the filament of a Nernst lamp. An essential feature is that, for many purposes, the usefulness and life of a furnace constructed in this way may be much increased by adopting a "cascade " system of heating. That is, the energy supplied may be divided, so that only sufficient is put through the tubular conductor itself to raise its temperature, say 1000° C. above its surrounding, the surrounding itself being maintained at 1000° C., thus enabling a temperature of 2000° C. to be attained in the tube without straining it unduly.

The regulation of temperature in small furnaces of this type is so perfectly under control that very well defined melting points may be taken with very small quantities of substance.

The second half of the paper deals with a re-determination of the melting point of platinum by the thermoelectric method in these furnaces, the highest value found being 1713° C., the lowest 1702° C., and the mean result of the experiments 1710° C. 15° C.

May 11." The Effect of Plant Growth and of Manures upon the Soil: the Retention of Bases by the Soil." By A. D. Hall and N. H. J. Miller. Communicated by Prof. H. E. Armstrong, F.R.S.

The investigation deals first with the variations in the amount of calcium carbonate-the only basic substance usually available in soils-in the experimental plots at Rothamsted. In four of the fields which have been unmanured during a long period, the loss of calcium carbonate amounts to about 1000 lb. per acre per annum. This rate of loss is much increased on some of the manured plots; the use of ammonium sulphate and chloride, as sources of nitrogen, causes an increased loss of calcium carbonate which is equivalent to the amount required to neutralise the acid of the salts applied.

When sodium nitrate is used as a manure the rate of removal of calcium carbonate is lower than on the unmanured plots. Farmyard manure has also a similar conserving effect on the calcium carbonate in the soil. Evidence is also brought forward showing that many soils which are initially very poor in calcium carbonate retain their fertility unimpaired for many years, and even show

no decline in the small amount of base they contain, although nitrification is always going on and requires a supply of base from the soil. The authors show, from .speriments with water cultures and from a consideration of the analyses of field crops, that the growing plant withdraws more acid than base from the neutral salts dissolved in the soil water, leaving behind a basic residue in the form of bicarbonate. Calcium oxalate and other organic salts in plant residues are converted by bacterial action in the soil into calcium carbonate. These two agencies restore bases to the soil in quantities approximately equivalent to their removal by nitrification, and so maintain a neutral reaction in the soil.

Zoological Society, May 2.-Dr. W. T. Blanford, F.R.S., vice-president, in the chair.-Specimens of domestic chicks to illustrate peculiarities in the hereditary transmission of white plumage: W. Bateson.-On Leucoselenia contorta (Bowerbank), Ascandra contorta (Haeckel), and Ascetta spinosa (Lendenfeld): Prof. E. A. Minchin. The author pointed out that the nomenclature of the Calcarea Homocoela was in a more tangled state than that of any other group of the animal kingdom, with, perhaps, the exception of the malarial parasites. Dr. Bowerbank, who founded the species, gave a diagnosis that would fit any Ascon, and his type specimens were jumbles of three or four species; consequently Prof. Minchin declared his name to be of no systematic value whatever. To Haeckel's name Ascandra contorta, Prof. Minchin referred a sponge extremely abundant on the Mediterranean coasts of France. Prof. Minchin preferred to name Ascandra contorta, H., as Clathrina contorta. He believed that the Ascetta spinosa was only an age variation of Clathrina contorta, not yet possessing monaxon spicules.-Anatomy of the ferretbadger (Helictis personata), based on a dissection of a specimen that had recently died in the society's gardens: F. E. Beddard. The osteology of the Eurylamidæ, and the question of the systematic position of this group: W. P. Pycraft. While agreeing with the general consensus of opinion as to the primitive character of these birds, the author held that the isolated position which they were supposed to occupy with regard to the remaining Passeres was by no means justified by facts. The pterylography, osteology, and myology of the Eurylamidæ all tended to show that the nearest allies of these birds were the Cotingida. Although undoubtedly primitive, the group, Mr. Pycraft pointed out, presented a number of specialised characters, which were especially marked in the skull and muscles of the wing.

Entomological Society, May 3.-Mr. F. Merrifield, president, in the chair.-A series of Xenarthra cervicornis, Baly, from Ceylon, illustrating the curious structure of the antennæ of the M. Jacoby. Specimens of Tephrossa consonaria, ab. nigra, and melanic examples of Boarmia consortaria, all from a wood in west Kent: G. T. Porritt. These forms were exactly on the same lines as the melanism in west Yorkshire, and it is curious they should occur in such widely separate localities. The two genera, however, are evidently prone to melanism, as Mr. Forritt had now seen black, or almost black, specimens of all the British species except Tephrosia punctulata.H) Two specimens of the very rare Staphylinid, Medon castaneus, Grav., taken in the Oxford district during the last week of April; (2) several examples of both sexes of the giant flea Hystrichopsylla talpae, Curtis, from fieldmouse nests in the same district; (3) the type-specimen of the Bostrichid beetle Dinoderus ocellaris, Steph. (taken by the late Prof. Westwood at "Little Chelsea " previous to 1830), from the Hope collection at Oxford: Commander J J. Walker.-Heliotropism in Pararge and Pyrameis : Dr. G. B. Longstaff. The structure and life-history of Psychoda sexpunctata, Curtis J. A. Dell. The threecolour process as applied to insect photography: Dr. D. H. Hutchinson.

Mathematical Society, May 11.-Prof. Forsyth, president, in the chair.-The following papers were communicated:-The intersection of two conic sections: J. A. H. Johnston. The object of the paper is to determine the number (0, 2, or 4) of the real intersections of two real monics by means of formule involving the invariants, or other concomitants of the system. The discrimination

depends upon the signs of the coefficients of a certain cubic equation, one root of which can be interpreted, when all the intersections are real, as the area of the quadrilateral formed by them. It is shown that one of the conditions of reality obtained by previous writers admits of very great simplification.-On a system of conics yielding operators which annihilate a cubic, and its bearing on the reduction of the cubic to a sum of four cubes: H. G. Dawson.— Informal communications were made as follows:-High Pellian factorisations: Lieut.-Colonel A. Cunningham. A method was explained for constructing very large factorisable numbers of the form y2+1 (with complete resolution into prime factors) from the Pellian equation y-Dx=-1. Examples were given, among them being a number of 78 digits, viz. (2128 +3.242)+1; this was shown to be expressible as (2+1) (2 + 1), for which the resolution of the factors 2+1 and 256+1 had been obtained by Lucas.-The stability of a loaded column: Prof. A. E. H. Love. When the column can be treated as a thin rod, and the contraction of the longitudinal filaments is taken into account, the critical length is slightly greater than that obtained by the ordinary method, due to Euler, in which this contraction is neglected. The correction of the critical length is found to be rk, where k is the radius of gyration of the cross-section of the column about an axis through its centroid at right angles to the plane of bending.

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Academy of Sciences, May 15.-M. Troost in the chair.--The president announced the death of M. Potier, member of the section of physics.-The permeability of glass vessels M. Berthelot (see p. 88).-The propagation of musical sounds in a tube of 3 metres diameter: J. Violle and Th. Vautier. Notes of low pitch carry much better than those of high pitch, the distance at which the sound ceases to be clearly a musical note being inversely as the square root of the number of vibrations, this result being in accord with the theoretical investigations of Lord Rayleigh. From a large number of observations the conclusion is drawn that the velocity of sounds of different pitch is the same to an accuracy of 1 part in 1000.On the menthones and menthols obtained by the reduction of pulegone by the catalytic action of reduced nickel : A. Haller and C. Martine. Pulegomenthone was obtained when the nickel was maintained at 140° to 160° C.; its physical and chemical properties are given, and there is reason to suppose that the ketone obtained is a mixture of menthones, and further work is being carried out in this direction. By slightly modifying the conditions of the reduction an additional pair of hydrogen atoms is taken up, giving pulegomenthols, two of which, in addition to ordinary menthol, were isolated from the product of the reduction. On the constitution, saccharification, and retrogradation of potato starch: L. Maquenne and Eug. Roux. Natural starch is regarded by the authors as a mixture of two substances, distinguished by the names amylocellulose and amylopectine, possessing different reactions towards iodine and malt extract.-The basic magnesium carbonates from the Santorin eruption of 1866: A. Lacroix. The structure of this mineral, the quantities of which were too small for quantitative analysis, agrees with that of the basic carbonate 4MgCO,.Mg(OH)2.4H2O. As this appears to be a new species, the name of giorgiosite is proposed for it.-On the lifting power of a motor-driven helix: Prince of Monaco.-M. Louis Henry was elected a correspondant for the section of chemistry in the place of Prof. Williamson.-On a photographic meridian telescope for determining right ascension: Jean Mascart and W. Ebert. On the forces giving rise to conical trajecCyparissos Stéphanos. On electrostatic rigidity of gases at high pressures: Ch. Eug. Guye and H. Guye. Measurements were made of the explosive potential in gases at varying pressures. The gases studied were nitrogen, air, oxygen, hydrogen, and carbon dioxide, the pressures varying from 2 to 65 metres of mercury. Up to 10 atmospheres, the explosive potential is a linear function of the pressure, but for higher pressures the ratio of explosive potential to pressure diminishes. The results were unaffected by the presence of a radium salt.-On the effects of Foucault currents and the hysteresis of iron on oscillatory sparks: G. A. Hemsalech. By means of a

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