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A report of the travels of Dr. Fritz Jaeger in German East Africa has been issued, and is interesting, as it gives a concise account of the Great Rift Valley of East Africa in which is included Lakes Magadi, Manyara, and Balangda.

The French travellers M. Rohan Chabot and Captain Grimaud have returned after exploring the region of Mossamedes and examining the cataracts of Middle Kunene, the journey being continued to the western basin of the Upper Zambesi. Commander Tilho has explored the region around Lake Tchad, and Dr. Abdul Ghani, a member of a Turkish mission, has given an account of the Jarabub oasis in Northern Africa which he had visited.

Miss Lowthian Bell has accomplished an enterprising journey to the south and south-east of Damascus, finally reaching Shammar, and has obtained interesting archæological results; and Captain Shakespear, British Resident at Koweit, has travelled the country from the Persian Gulf to Suez, along a route seldom trodden by Europeans.

METEOROLOGY.

J. R. A.

Some changes have been introduced in the arrangements and work of the Meteorological Office in consequence of an increased grant received from the Treasury. In the reports the Scottish National data are now to be included, so that one publication will contain the whole data of the British Isles; additional instrumental equipment is to be provided at Kew; a weather station is to be established at Falmouth; and several junior professional assistants are to be added to the staff.

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Recently published accounts of balloon ascents show that the mean height of the stratosphere is 10 kilometres, the temperature being 54°.5 C., the temperature at the maximum height of 14.7 kilometres being 52° C. The average temperature of the air column between 1 and 9 kilometres is - 21° C.

Dr. Walker, in the memoirs of the Indian Meteorological Department, emphasises the necessity for the correlation between two quantities to be a high one if it is to express the probability of a physical relation; chance may give a correlation factor which when carefully interpreted has no physical meaning.

In Terrestrial Magnetism reports appear of the work done by the Carnegie in her second cruise round the world. It is stated that along the Gulf Stream to Hammerfest the deviation of the compass west of true north is greater in general, by as much as 1° to 2°, than that given by British and American charts. The potential gradient is much the same over the sea as over the land, but the radio-activity is smaller, and the specific conductivity greater, on water than on land.

At Eskdalemuir Observatory electrical observations of the atmosphere have not been taken over any long period, but what have been recorded differ considerably from the results at Kew. In the north the conditions are much more disturbed than in the south, especially in the summer, the mean potential gradient being higher at Kew than at Eskdalemuir. At the latter station the number of ions between summer and winter is small and uncertain.

Messrs. Stewart and Jörgensen have made observations of the potential gradient of the atmosphere in the industrial district around Leeds, and they find it is exceptionally large, a result attributable to the gases poured into the air from the numerous furnaces in the vicinity.

The relation of annual drainage yield to rainfall has been discussed by D. Halton Thomson, who shows that a rainfall, over say twenty years, of a given frequency produces a yield of the same frequency, and that a simple formula can be obtained connecting these quantities. Thus at Sheffield the yield is equal to the rainfall minus fourteen inches, the evaporation of fourteen inches being quite constant whatever the rainfall. This constancy of evaporation does not hold at all places, for at Torquay the evaporation varies to a small degree with the amount of the rainfall.

An unexpected and curious see-saw between the rainfall of Havana and of the South-West of England and South Wales has been discovered by Mr. A. H. Brown in the course of a study of Cuban rainfall. In Havana during May to October there is a wet season, and an excess of rainfall in this season is very generally associated with a deficient rainfall at the beginning of the next year in the parts of England mentioned; on the other hand a deficiency at Havana is the precursor of excess in the southwesterly parts of England and Wales.

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A paper on I Canadian Weather Forecasting," by Mr. B. C. Webber, has been issued by the Meteorological Office of Canada. It covers the period 1874-1904 and supplies a quantity of statistical information on percentages of low pressure areas causing storms, the directions in which depressions move, etc. On the Great Lakes November is the stormiest month, but on the Gulf of St. Lawrence storms are most frequent in January and February. Since January, 1912, the Canadian Meteorological Office has issued a daily meteorological chart of the northern hemisphere, but the advance of forecasting has not been very rapid and further progress will probably not be made until more detailed information of the upper air, especially of the stratosphere, is obtainable, as it is now recognised that the character of the ground weather is much influenced by the condition of this layer of air.

Professor W. R. Blair observes that up to 1 kilometres above the earth's surface the same type of daily variation of weather elements is found as at ground level, but above this height a second maximum appears after midnight, the time of which alters with increasing altitude.

An interesting paper in Himmel und Erde, by Professor G. Hellmann, deals with superstitions relating to weather, and under the head of character and causes of the weather he reminds us of the prevalence of the belief in equinoctial gales, although the evidence of careful observers is not in favour of stormy winds at the equinoxes. Sayings in relation to the colour of the sky in the morning and evening are not without some measure of truth in predicting the weather, but prognostications of the weather from the moon, although persistently found, have very little to support them when tested by reliable observations. Lastly, the making of weather, for example the firing of cannon to produce rain, or the warding off of thunder by the ringing of church bells, still in vogue in parts of Switzerland, is a superstition which dies hard, although completely dis credited by science,

Dr. A. E. Douglass has published an account of his investigations on tree growth in relation to rainfall, and from an examination of the growth of rings in trees, involving 10,000 observations, he concludes that definite rainfall information in the past can be obtained from the mode of growth of trees. The average age of the trees examined was 348 years.

Upper air investigations are likely to suffer from the advent of the war. International days were fixed to the end of the year but not after, and meetings of International Committees will probably be suspended. The Manchester station has been closed since the beginning of the year and the station at Pyrton Hill ceased to be available in the spring, but its work is now being carried on at Benson six miles W.S.W. of Pyrton Hill. In all parts of the British Isles the mean temperature of the year was in excess by as much as 2o in the East and North-East of England and the Midland counties, and by about 1° in other parts of the country. The high temperature of 90° in the shade was touched in the South of England and the lowest temperature of the year, namely 7°, occurred in the East of Scotland. The rainfall was greatest in the North of Scotland, where it reached 49.31 inches, and least in the North-East of England, the fall there being 24-82 inches; in most parts of England and in the south of Ireland the amount was decidedly above the average. Sunshine was normal.

The Terrestrial Magnetic Elements at Greenwich for the year 1913

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The constitution of the atom continues to be a subject of experimental inquiry. According to Sir Ernest Rutherford's views on the scattering of a-rays the atom consists of a central nucleus of positive electricity around which one or more electrons revolve. Mathematicians have objected that such a system is not stable, but N. Bohr has evaded this difficulty by introducing Planck's theory of a quantum of energy, which states that energy is not emitted continuously but in discrete atomic quantities. For the simple atoms of hydrogen and helium Bohr's theory gives some remarkably accurate representations of certain properties of these elements, especially in relation to the spectral lines. Van der Broek contends that the nuclear positive charge is exactly equal to the atomic number, and certain experiments by Moseley on the x-ray spectra of the elements are regarded as confirmatory of this.

The quantum hypothesis of Professor Planck, referred to above, which regards energy as transferable in definite units and not continuously, is being applied to several physical problems with some measure of success. For example, Professor Nernst has recently investigated the specific beats of the solid elements at very low temperatures and by the application of a formula due to Debye, involving the quantum hypothesis, a very good agreement between theory and experiment is obtained. An excellent review of this work and the bearing of the quantum hypothesis on such

different subjects as photo-electricity, the line spectra of the elements, and radiation generally, has been written by Mr. J. H. Jeans and published by the Physical Society of London. Mr. Jeans inclines to the view that the classical Newtonian Mechanics must be revised to meet the conditions which the quantum hypothesis have called forth.

Professor Millikan has attempted direct proof of a cardinal feature of this hypothesis, namely the direct proportionality between the frequency and the energy of radiation, by showing experimentally that the energy of the electrons ejected from metals by the action of light is proportional to the frequency of the light vibrations.

An important discovery has been made by J. Stark that hydrogen in a state of luminescence when subjected to an electric field has its spectral lines resolved into three or more components, an effect analogous to the Zeeman effect in which the spectral lines are resolved into components by the action of a magnetic field. The effect has been observed independently by Lo Surdo whilst working on the positive rays in a vacuum tube. The two outer components of an electrically resolved line are polarised at right angles to the remainder, the separation of the components being proportional to the field intensity and increasing with decreasing wave length. The electric effect is not the same in all its details as the magnetic effect and is not always quite easily interpreted, but the discovery puts a new means in the hands of the physicist for the investigation of the structure of the atom.

Messrs. Kaye and Higgins have continued their researches on the emission of electricity from substances at temperatures of 2000° to 2500° C. from which currents, generally of negative electricity, are obtained of a density as much as 1 to 2 ampères per sq. cm. Boiling brass, however, emits a positive current of 0.5 ampères per sq. cm. The subject is of considerable interest in connection with the problem of the electric and magnetic state of the sun. These experiments, however, are not altogether in agreement with Professor Richardson's view that the emission of thermions from hot bodies is a kind of evaporation of electrons following a law like that of liquid evaporation under rise of temperature.

A most interesting experiment has been carried out by Professor K. Onnes as a branch of his low temperature researches. A coil of lead was constructed and cooled to within a few degrees of absolute zero at which temperature its resistance is 2 × 10-10 of what it is at normal temperature, consequently an induced current when started persists after the inducing electromotive force is withdrawn, as there is no appreciable resistance and therefore no dissipation of energy into heat. In this way it has been possible to realise the conception of electric currents continuously circulating round atoms, which was first introduced by Ampère to account for magnetism.

Professor Jean Perrin in a recent course of lectures has explained his striking and beautiful experiments on the movement of small particles suspended in liquids. When an emulsion of such particles is dilute the laws which are applicable to gases are obeyed, but when the emulsion is concentrated van der Waal's law for dense vapours then holds good, and in this way these important laws of the behaviour of invisible molecules can be ocularly demonstrated.

Hiromu Takagi has examined the change of magnetic properties of magnetite with rise of temperature and is unable to confirm the sudden changes of susceptibility which were said to occur at definite points above the critical temperature. These changes Professor Weiss claimed as one proof of the existence of an elementary indivisible unit of magnetism, which he named the magneton, and the evidence for this unit must therefore rest upon other experiments.

The very large intrinsic field of a magnet required by the kinetic theory of magnetism receives some confirmation by the application of an experiment, by Hurmuzescu, on the electromotive force developed in a cell consisting of two identical pieces of soft iron in dilute acetic acid, one of which is strongly magnetised. Calculation then shows that if the electromotive force arises from an intrinsic field, such a field must have a magnitude of the same order as is required by the theory.

Electrification can be produced by the splashing of water, a subject which has received a good deal of attention as it has a bearing on the origin of atmospheric electricity. Mr. J. J. Nolan has found from his experiments that the charge is of positive sign and inversely proportional to the radius of the drops, and he deduces the result that the charge is proportional to the new surface formed as the water breaks up, and that the magnitude of the charge produced per unit area of water surface is 2.7 × 10 3 electrostatic units.

An interesting example of how pure science is beneficial to industry is afforded by Professor Bone's experiments on surface combustion. It has been a popular lecture experiment for a long time past to exhibit the combination of combustible gases below the flame temperature when they are in contact with solids, and it is in this way possible to keep a solid incandescent by flameless combustion. Applying this result Professor Bone has constructed a boiler in which the water is heated by the metal tubes within it being raised to a high temperature by flameless combustion, and such a boiler has a very high efficiency. A trial on a large scale gave an efficiency of 92.7 per cent.

The work of the National Physical Laboratory has been extended to include a new department for the testing of radium preparations and for certifying the strength of radio-active preparations. This department is under the superintendence of Dr. Kaye.

The death of Professor John Henry Poynting in March last is a loss to English science. His name will always be associated with the theorem on the transference of energy in the electro-magnetic field which he was the first to enunciate.

J. R. A.

CHEMISTRY.

'The constitution of the atom is one of the chief problems in physical chemistry at the present time, and evidence is accumulating that the atomic weight of an element is not, as was once thought, a natural constant, like the ratio of the circumference of a circle to its diameter, but a quantity which can fluctuate within certain limits. Thus, according to Professor Soddy, radium F, on losing an atom of helium, has its atomic weight re

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