when the train was close to the seismograph, and continued visible until the train had passed off the bridge at the other end. DOES PRECIPITATION INFLUENCE THE MOVEMENT OF CYCLONES? IN Prof. Elias Loomis's first "Contribution to Meteorology," in the American Journal of Arts and Science, he examined the distribution of rain around 152 storms (cyclones) in the United States, in order to determine whether there exists any relation between the velocity of a storm's progress and the extent of the accompanying rain area. He found that "the average extent of the rain area on the east side of the storm's centre is 500 miles; and when the rain area extends more than 500 miles, the storm advances with a velocity greater than the mean; but when the extent of the rain area is less than 500 miles, the storm advances with a velocity less than the mean." In his twelfth "Contribution" he examined 39 storms which moved with exceptional velocity (1000 miles or more per day) and found that "the rain area generally extended a great distance in advance of the storm centre, the average distance being 667 miles." Finally, Loomis examined 29 cases of those abnormal cyclones in the United States which moved toward the west. He says: -“In nearly every case we find a fall of rain or snow in the region toward which the low centre advanced, and in most of the cases the rainfall was unusually great. It may be inferred from these comparisons that the fall of rain or snow is one of the most important causes which determine the abnormal movements of areas of low pressure" (ninth memoir, p. 44). Ley and Abercromby state that in Great Britain the relation of the weather to the cyclone centre is the same whatever the path of the cyclone; thus when storms advance toward the west the greatest cloud development and rainfall is to the west of the cyclone centre. In the Proceedings of the Royal Meteorological Society, vol. xliii., Abercromby gives a table showing the relation between the intensity of trough phenomena" and the velocity of cyclones. This table indicates very clearly that the greater the velocity of the cyclone the more marked the "trough phenomena." Hence, according to Abercromby's definition of "trough phenomena" the heaviest rain and cloud areas are massed toward the front of rapidly advancing cyclones, while immediately after the passage of the line of minimum pressure the sky begins to show signs of clearing. This is especially well marked in cyclones passing off the northeast coast of the United States. When the cyclones are moving with unusual rapidity, not only all the rain, but almost all of the cloud area is confined to the front half of the cyclone. Loomis suggested that the excess of rain in front of rapidly advancing cyclones was one of the causes of the rapid advance; but when investigating heavy rainfalls in the United States he concludes that "the forces which impart that movement to the air which is requisite to an abundant precipitation of vapour, instead of deriving increased strength from the great volume of rain, rapidly expend themselves and become exhausted;" and after examining certain cyclones which were accompanied by no rain he adds: So that it seems safe to conclude that rainfall is not essential to the formation of areas of low barometer, and is not the principal cause of their formation or of their progressive movement." Hann arrives at similar conclusions from investigations in Europe. After investigating an especially heavy rainfall which occurred in Austria and vicinity in August 1880, he concludes thus: The appearance of a barometric minimum in Hungary occasioned abnormal and extended precipitation on the west and north-west side of this barometric depression. The reaction of this precipitation on the position of the centre of the depression is scarcely perceptible. . . . We find, therefore, through the investigation of the relative lowest barometer reading in its behaviour to rainfall, that our former conclusions are confirmed" (lxxxii. Bunde d. Wiss. ii. Ab., November 1880). This investigation does not necessarily prove that precipitation does not appreciably influence the movements of cyclones in general, but at least suggests that in the first cases mentioned above the unequal distribution of rain around rapidly moving cyclones was not the cause, but the result of the cyclone's advance. In cyclones which move very slowly, as do tropical cyclones, the air ascends almost uniformly around the centre; but when cyclones have a more rapid progressive motion, the air in the rear, which has not only to enter, but to follow the cyclone, is more retarded by friction than the air in front, and hence does not enter the cyclone so freely, so that the formation of cloud and rain in the rear is retarded; while, on the other hand, a larger volume of new air enters the progressing cyclone in front, and increases the amount of precipitation. Thus, between February 12 and 14, a cyclone passed across the American continent with the exceptionally high velocity of 58 miles per hour. During its passage the highest wind velocity reported on any of the United States Signal Service morning weather maps was 40 miles per hour, occurring immediately in the rear of the cyclone at Father Point, Can., on the morning of the 14th. At none of the other 130 stations did the maps show a wind velocity exceeding 30 miles per hour during the passage of the cyclone. This is an example of many similar cases which show that in rapidly moving cyclones the air in the rear near the earth's surface does not move as rapidly as the cyclone itself. Hence, it seems evident that the air near the surface immediately in the rear of these cyclones is not air which has followed the cyclone near the surface, but air which has descended from above. Espy showed many years ago that, on account of mechanical heating by compression, no descending air can be accompanied by precipitation; and an explanation is thus afforded why there is none, or but little cloud and precipitation in the rear of rapidly moving cyclones. On the other hand, in order that a cyclone may advance rapidly, there must be a rapid decrease in pressure, and consequently a rapid removal of the air, in front of the advancing depression. Since, according to the normal circulation of a cyclone, there is an inward movement near the earth's surface and an upward and outward movement near the top, this upward and outward movement is necessarily increased in unusually rapid-moving cyclones, and hence also the cloudiness and precipitation are increased. Hourly observations of cloud movements made during the day hours for nearly two years at Blue Hill Observatory indicate that the velocity of storm movement, and especially the variability of the weather, are intimately connected with the velocity of movement of the general atmosphere. The writer is hence led to believe that the main cause of rapid cyclone progression is an unusually rapid drifting of the atmosphere over large regions; and the unequal distribution of rain around the cyclone is due to the rapid progress of the cyclone. H. HELM CLAYTON. Blue Hill Observatory, Boston, June 18. NOTES. MR. JOHN WHITEHEAD returned to Labuan in safety from his second expedition to Kina Balu, and is daily expected in England. He ascended the mountain to its summit, and attained to an altitude of 13,500 feet. His collection will contain many novelties, the small portion sent by him in advance to Mr. Bowdler Sharpe exhibiting many curious features. The new species will be described by Mr. Sharpe in the forthcoming number of the Ibis, and four genera and twelve species appear to be quite new to science. Mr. Whitehead spent altogether eight months on the mountain of Kina Balu, and is at present known to have discovered thirty-one new species of birds. On his last expedition he met with fifteen different kinds of rodents, and his collections of reptiles and insects are also very large. MR. ALFRED EVERETT, the well-known explorer of Borneo and the Philippine Islands, has had to return to England to recruit his health, sorely shattered by his nineteen years' residence in the tropics. He has brought with him a collection of birds and animals, amongst which are apparently many interesting species. He also discovered in the Brunei district the nest of Machærhamphus alcinus, the curious crepuscular Honey-Kite of the East, but unfortunately the tree in which it was placed proved to be inaccessible. This remarkable genus of Hawks occurs in the Malayan peninsula, Borneo, and again in New Guinea. It has an Ethiopian representative, M. anderssoni, which inhabits Damara Land and Madagascar. THE summer meeting of the Institution of Mechanical Engineers will be held in Dublin on Tuesday, 31st inst., and the two following days, under the presidency of Mr. Edward H. Carbutt. An influential Committee has been formed for the reception of the Institution, under the chairmanship of Lord Rosse, F.R.S. On Friday, August 3, a visit will be paid to Belfast, on the invitation of a local Committee presided over by the Mayor, Sir James H. Haslett. THE half-yearly general meeting of the Scottish Meteorological Society was held in the hall of the Royal Scottish Society of Arts, Edinburgh, on Monday, July 23, at two p.m. The following was the "business" :-(1) Report from the Council of the Society; (2) the temperature of the air and surface-water of the North Atlantic, by H. N. Dickson; (3) the climate of the Isle of Man, by A. W. Moore; (4) note on earth currents on Ben Nevis, in connection with anticyclones, by R. T. Omond; (5) St. Elmo's fire observed at the Ben Nevis Observatory, by A. Rankin. Photographs of clouds, &c., from Ben Nevis were exhibited. saying what the number and what the value of such distinctions would have been. The honorary degree was given “agli scienziati saliti in altissima fama,” and this would hardly apply to all the chosen or self-constituted representatives of the world's Universities. We quote the folowing words from the article in the Revue Internationale for July :-"Il a paru dans le Times quelques correspondances très acerbes, sans grande portée cependant, étant donné le caractère du journal. En lisant le Times, la pensée du lecteur se reporte souvent instinctivement à ce Sir John Davenne, qui, au dire de Ruffini, était un parfait galant homme, un vrai gentilhomme, mais auquel il pouvait arriverun peu par l'effet de son caractère individuel, un peu par l'effet du caractère national-de ne pas se montrer trop impartial, trop juste, ni trop tempéré dans ses jugements." DESPATCHES have been received from Dr. Nansen announcing the safe departure of his expedition for Greenland from the Isa Fjord, in Iceland, on board the steam whaler Jason. AN astronomical observatory is about to be erected within the walls of the Foreign College at Pekin. A CORRESPONDENT of an English newspaper published in China furnishes the following account of the new foreign College being erected at Tientsin by the Viceroy Li Hung Chang :—“ In coming up the Peiho to Tientsin, the first object of importance that will now strike the eye of a stranger is the new College building which is being erected just outside the mud rampart by the Viceroy, for the instruction of Chinese youth in the mysteries of the English language and of foreign science. This is a massive edifice, two stories high, built around the four sides of a square which forms a large interior court not less than one hundred feet on either side, around which, on the inner sides of the buildings, are spacious verandas. The construction of the building, under the careful supervision of a capable foreign engineer, is all that could be desired. If the educational results are equal to what has been accomplished by brick and mortar, the Viceroy will have great occasion to be proud that he has been privileged to start such an institution. It was hoped that the College would be ready for opening this autumn, but there seems little prospect that it can be opened before next spring." It is reported from China that Dr. Dudgeon, of Pekin, has published in Chinese a work on anatomy which he has had in preparation for some years; that a companion work on materia medica is in the press, with treatises on physiology and photography, in the latter of which the dry process is explained. Dr. Dudgeon is also preparing bi-lingual vocabularies of medical and anatomical terms. WE are glad to learn that the Mikado of Japan has been pleased to bestow the Order of the Rising Sun on Prof. John Milne, of the Imperial University of Tokio, the well-known investigator of seismic phenomena. VOL. II. Part I of the Journal of the College of Science of the THE death is announced of Dr. Ludwig Julius Budge, the Japanese Imperial University, contains an important summary eminent physiologist and anatomist. He was born at Wetzlar, September 6, 1811, and died at Greifswald on July 14. THE Geologists' Association have issued the programme of a long excursion to the Forest of Dean, Wye Valley, and South Wales, from August 6 to 11. THE Revue Internationale, published at Rome, contains a description of the eighth centenary of the University of Bologna, and a dignified reply to the criticisms of the correspondent of the Times. The correspondent maintained that all delegates of foreign Universities, including American Colleges, ought to have received honorary degrees, without by Prof. Sekiya of the results of seismometric observations in Tokio during two years, from September 1885 to September 1887, with special reference to the measurements of vertical motion. The observations recorded by Prof. Sekiya were for the most part made with Prof. Ewing's seismographs, some on the soft marshy ground of the lower part of the city, and some on the stiff soil of the upper parts. Particulars are recorded very fully for 119 earthquakes in a table setting forth the greatest horizontal and vertical motion, the period of the motion, the maximum velocity and rate of acceleration, the duration of the disturbance, and the approximate locality of the origin. At the end of the paper the results are collated, and averages are deduced, from which it appears that the greatest horizontal motion is about six times the greatest vertical motion in those earthquakes in which vertical motion was sensible. These, however, formed only 28 per cent. of the whole number recorded. The period of the vertical motion was little more than half that of the horizontal. In only 18 per cent. of the recorded shocks was the extent of motion greater than one millimetre. The paper forms the most extensive collection of data in absolute seismometry that has yet been published, and is a very valuable contribution to seismology. ACCORDING to a telegram sent through Reuter's agency from Yokohama on July 18, a volcanic eruption had occurred at Makamats (? Takamatsu). Four hundred persons are reported to have been killed and 1000 injured. of the climate; in the winter season the mean only amounts to about three-tenths in each month. A NEW base has been discovered in tea by Dr. Kossel, of Berlin. It appears to be an isomer of theobromine, the wellknown base present in cocoa-beans, possessing the same empirical formula, C,H,N4O2, but differing very materially in physical and certain chemical properties. The new base, to which has been assigned the name theophylline, was discovered during the investigation of large quantities of tea extract, which, after treatment with sulphuric acid to remove foreign matters, was saturated with ammonia-gas and precipitated with ammoniacal silver solution. The silver precipitate was then digested with warm nitric acid, and, on cooling, the silver salt which separated out was filtered off and the filtrate rendered slightly alkaline with ammonia. On allowing this alkaline iiquid to stand until the next day, a brownish deposit was noticed, which, on examination, proved to be the silver compound of a new base. The solution was therefore further concentrated, and a second and much larger yield of the silver salt obtained. This was next decomposed by sulphuretted hydrogen, the free base being thus obtained in solution. The liquid, after removal of the silver sulphide by filtration, deposited on standing a small quantity of xanthine, C,HNO, a derivative of uric acid, whose presence in tea has previously been shown. The mother-liquors were afterwards IN our issue of the 6th October last (vol. xxxvi. p. 546) we drew attention to the useful work of Mr. Wragge, the Govern ment meteorologist of Queensland, in issuing daily weather charts for Australasia. The entire meteorological observingsystem of that colony is in course of reconstruction, upon the lines adopted by the Meteorological Office in London and other similar institutions abroad, and Mr. Wragge invites attention to the new series of weather charts now prepared at 9h. a.m. daily (except Sundays and holidays), files of which are kept at the Meteorological Office and at the office of the agent for Queensland, both in Victoria Street. The charts, which are on a large scale, contain observations received by wire from seventy-treated with mercuric nitrate solution, which precipitated the two selected observatories distributed over the Australian continent, Tasmania, and New Zealand, show very clearly the general atmospherical conditions, and contain besides collated | information from about 300 smaller stations. A prominent feature in the new meteorological service is the preparation of a complete digest of the meteorological conditions of each colony, together with forecasts, which are issued about 5h. p.m. to the press. These publications have, of course, a special value to men of science generally, while to those interested in agricultural and shipping pursuits they have a practical bearing hitherto unequalled in Australia. theophylline in the form of a mercury compound, fro n which the base itself could readily be obtained by treatment with sulphuretted hydrogen as before. Analyses of the theophylline obtained after purification indicate the formula C-H ̧NO2, which is that of theobro nine. But the two substances are certainly not identical: their crystals are quite distinct, those of theophylline containing one molecule of crystal water which is expelled at 110°, while theobro nine crystallizes anhydrous. The crystals also are totally unlike those of the other known isomer of theobromine, paraxanthine, from which theophylline differs most materially in its behaviour with soda. Again, the meltingpoints of the three isomers are considerably removed from each other, and their different solubilities in water are conclusive THE Pilot Chart of the North Atlantic Ocean for July shows that no severe cyclonic storms entirely crossed that ocean in June, but two or three depressions were formed in the mid-proofs of their different internal structures. Theophylline forms Atlantic, and caused gales off the Irish coast from the 8th to the 12th inclusive. Much fog was experienced off the American coast, north of Hatteras, and in the English Channel, and in the early part of the month fog-banks were frequently met with east of the 40th meridian. Icebergs and field ice have been encountered, principally off the eastern and southern coasts of Newfoundland. A few bergs, however, have been seen as far south as the 43rd parallel, in longitude 43° west. The chart also contains valuable information with reference to the West India hurricanes which are now likely to be encountered. IN the Berlin Meteorologische Zeitschrift for June, Dr. Hann gives an interesting account of the winter temperature of Werchojansk (Siberia), deduced from several years' observations. The town, which lies in the valley of the Jana, about 9 feet above the level of the river, in latitude 67° 34′ N., longitude 133° 51' E., and at a height of about 350 feet above the sea, has the greatest winter cold that is known to exist upon the globe. Monthly means of 58° F. occur even in December, a mean temperature which has been observed nowhere else in the Polar regions; and minima of - 76° are usual for the three winter months (December-February). In the year 1886 March also had a minimum – 77°, and during that year December and January never had a minimum above - 76°, while in January, 1885, the temperature of - 89° was recorded. These extreme readings are hardly credible, yet the thermometers have been verified at the St. Petersburg Observatory. To add to the misery of the inhabitants, at some seasons the houses are inundated by the overflow of the river. The yearly range of cloud is characteristic a well-crystallized series of salts with the mineral acids, and with platinum, gold, and mercury chlorides; and, like theobromine, yields with silver nitrate a silver substitution-compound, C,H,AgN4O2, which, as may be concluded from the above method of isolation, is readily soluble in nitric acid. Finally, to complete the proof of its isomerism with theobromine, which is the dimethyl derivative of xanthine, the silver compound was found to react with methyl iodide to form tri-methyl xanthine, better known as caffeine or theine, the remarkable base of the coffee and tea plants. 66 The IN a letter lately submitted to the Elliott Society, and printed in its Proceedings, Mr. G. W. Alexander, of Charleston, S.C., tells a strange tale of a humming-bird. Mr. Alexander heard in his garden what he knew must be a cry of pain; and going to a vine, from which the cry seemed to proceed, he found a hummingbird "struggling violently, but unable to extricate itself." He took it in his hands, and, to his astonishment, saw that it was in the clutches of an insect, which he identified as a mantis, popularly known in those parts as "Johnny-cock-horse." bird," says Mr. Alexander, "was wounded under the wing, upon one side of the breast, which had evidently been lacerated with the powerful mandibles of its captor. The wound looked ugly enough to lead me to fear that it would prove fatal; nevertheless my children and I cared for it as tenderly as we knew how, but we found it difficult to administer nourishment to a humming-bird. So at night I placed it among the leaves of the vine-for it was a warm night-and in the morning the little sufferer lay dead on the ground beneath." A SERIES of volumes to be entitled the "Fauna of British India," containing descriptions of the animals found in British India and its dependencies, including Ceylon and Burma, is about to be issued, under authority from the Government. For the present the work will be restricted to vertebrate animals. The editorship has been intrusted by the Secretary of State for India in Council to Mr. W. T. Blanford, formerly of the Geological Survey of India, and the printing and publication to Messrs. Taylor and Francis. The descriptions of vertebrates will occupy seven volumes, of which one will be devoted to mammals, three to birds, one to reptiles and Batrachians, and two to fishes. The mammals will be described by Mr. Blanford, the reptiles and Batrachians by Mr. G. A. Boulenger, of the British Museum, and the fishes by Mr. F. Day, Deputy Surgeon-General. The arrangements for the volumes on birds are nearly complete, and there is every probability of their being undertaken by a competent Indian ornithologist very soon. A half-volume of mammals will be issued immediately. expected that one or two volumes will be published each year. The work will be illustrated by cuts. It is MESSRS. SAMPSON Low will publish shortly the "Life and Correspondence of Abraham Sharp," the Yorkshire mathematician and astronomer, with memorials of his family, by William Cudworth. The work will be illustrated with numerous drawings specially prepared for it. Abraham Sharp, a member of an ancient family at Horton, near Bradford, was assistant in 1689 to Flamsteed, the first Astronomer-Royal, and designed and fixed the mural arc and other astronomical instruments with which the Astronomer-Royal made his observations at Greenwich Observatory. He also computed the places of many of the fixed stars in Flamsteed's famous "Catalogue," and was the principal means of completing and publishing the second and third volumes of the "Historia Celestis," published after Flamsteed's death. For many years after Abraham Sharp left the Observatory, a correspondence was kept up between him and Flamsteed, which gives much insight into many of the scientific events of the period, and especially refers to the difficulties experienced by Flamsteed in the publication of his great work, and to the doings of his contemporaries, Sir Isaac Newton, Dr. Halley, Sir Christopher Wren, and others. This correspondence will form the basis of Mr. Cudworth's work. THE third number of vol. vi. of the Proceedings of the Bath Natural History and Antiquarian Field Club has been issued. Among the contents are the following papers: on some Ostracoda from the fullers' earth Oolite and Bradford clay, by Prof. T. Rupert Jones, F.R. S., and C. Davies Sherborn; landslips and subsidences, by W. Pumphery; remarks on some HemipteraHeteroptera taken in the neighbourhood of Bath, by Lieut.Colonel Blathwayt; recent "finds" in the Victoria gravel pit, by the Rev. H. H. Winwood; note on Webbina irregularis (d'Orb.) from the Oxford clay at Weymouth, by C. Davies Sherborn. MESSRS. WILLIAM WESLEY AND SON have issued No. 90 of their "Natural History and Scientific Book Circular." It contains lists of works relating to astronomy and mathematics. THE heat in Norway this summer is most intense, the temperature exceeding any registered this century. At Christiania the thermometer has several times registered 30° to 32° C. in the shade, and at Nyborg, in the Varanger Fjord, near the White Sea, it was 35° C. at the end of June. A CURIOUS ornithological phenomenon is witnessed at Oddernæs, in the south of Norway, this season, the ring throstle (Turdus torquatus) nesting there. Generally, the bird only breeds in the extreme north. Prof. Esmark is of opinion that the present unusual occurrence is due to the severity of the spring. DURING the spring of the present year some 200 eider-fowl were caught in fishermen's nets on the south coast of Sweden. THE remains of several prehistoric canoes have been found at the bottom of some lakes drained off in uplands in Central Sweden. They were made by the hollowing out of trunks of trees by fire. One had evidently been sunk on purpose, being full of large stones. AN unusually large skull of the Rhinoceros tichorrhinus was lately discovered in a well-preserved condition at Rixdorf, near Berlin. It has been sent to the Natural History Museum of Berlin. THE additions to the Zoological Society's Gardens during the past week include a Green Monkey (Cercopithecus callitrichus ? ) from West Africa, presented by Mrs. Holden; a Rhesus Monkey (Macacus rhesus 8) from India, presented by Mr. Herbert C. Oates; two Californian Quails (Callipepla californica 88) from California, presented by Mrs. Fanny Lloyd; a Lesser Kestrel (Tinnunculus cenchris) European, presented by Mr. Harold Hanauer, F.Z.S.; two Esculapian Snakes (Coluber @sculapii) from Germany, presented by Mr. P. L. Sclater, F.R.S.; seven Slender-fingered Frogs (Leptodactylus pentodactylus) from Dominica, W.I., presented by Dr. H. A. A. Nicholls; two American Black Bears (Ursus americanus 8 Q) from North America, a Grey Parrot (Psittacus erithacus, white var.) from West Africa, an Esculapian Snake (Coluber asculapii) from Germany, a Tabuan Parrakeet (Pyrrhulopsis tabuensis) from the Fiji Islands, deposited. Comet Sawerthal. Right Ascension. h. m. I 6'4 Declination. 53 4 N. I 4.6 53 37 Mercury at greatest elongation from the Sun 19° west. Saturn in conjunction with the Sun. 22 250... 57 51 N. July 30, 2 M signifies maximum; m minimum. Meteor Showers. R.A. Decl. 7 ... 31 N. 55 N. 42 N. ... O m O M 0 m о М Swift; streaks. Swift; streaks. Very swift; streaks. 350 52 N.... Very swift. 33 48 ... GEOGRAPHICAL NOTES. THE Mittheilungen of the Vienna Geographical Society for June has a paper by Dr. Hans Meyer on the German East African possessions which is likely to attract some attention at the present juncture. No attempt is made to give either the area or the population of this ill-defined region, which, however, is stated to comprise the central section of the East African coastlands, terraces, and plateaux for a distance north and south of about 550 geographical miles, and 150 east and west between the Swaheli coast and the water-parting towards the Congo basin. It is conterminous towards the north with the new British East African protectorate, from which it is separated by a conventional line passing from Lake Victoria Nyanza in an oblique direction along the north foot of Mount Kilima- Njaro to the coast at about 5° S. lat. below Mombasa. Southwards the frontier is marked by the Rovuma River, and another conventional line running thence west to Lake Nyassa, while on the east side it is made to reach the Indian Ocean, thus apparently absorbing the ten mile zone of coastlands reserved to the Sultan of Zanzibar by the Anglo-German Convention of October 29, 1886. It is described as orographically and hydrographically the most diversified region in the whole of Africa, including within its limits the highest summit (Kilima-Njaro) as well as the head-waters of streams flowing north to the Nile, west to the Congo, and south to the Zambesi basin. Hence it presents a great variety of climate and vegetation, but nevertheless, except in a few favoured spots, it is not to be compared in productiveness with the rich tropical lands of the Eastern Archipelago. Its prospects as a future field of German colonial enterprise are spoken of in depressing terms. Both servile and free labour in the interior are stated to be alike impracticable, and for the present at least it will be impossible to develop any great commercial activity except on the fertile and more thickly-peopled, but also mostly fever-stricken coastlands. Hence a foundation for the future development of the colony is stated to have been Thus the velocity of light in silver is ten times that in bismuth. How is the velocity of light affected by temperature? and how is it changed by a magnetic field? Kundt proposes to examine these points. PROF. ELIHU THOMSON (U.S.A.) states that he has observed as many as six lightning-flashes very quickly following each other along the same path. He kept his head rapidly wagging during a thunderstorm, and his eyes fixed in one direction. Most people have experienced a peculiar throbbing during a flash of lightning; and a succession of rapid currents, sometimes forming letters, are observed on telegraphs. A lightning discharge may therefore have the same oscillatory character as the discharge of a Leyden jar. But no trace of such an effect is visible in the photographs of lightning-flashes unless it be the mysterious dark flashes that have b.en recorded. CHAPERON AND MERCADIER (Comptes rendus, cvii., June 4, 1888) have shown that the periodic incidence of rays of light upon a cell of silver sulphide, H2SO, and bright silver produces sounds in a telephone by the corresponding variations of E. M. F. They call the effect electro-chemical radiophony. The cell copper-oxide, sodium chloride, copper also forms an electrochemical radiophone. E. G. ACHESON (Electrical World, N.Y., July 7, 1888) has made some very useful measurements on the sparking distance in air of alternate currents used in electric light working. He finds that it varies with the capacity of the circuit and with the cube of the E.M.F. It is expressed by of this ANOTHER of Mr. H. Tomlinson's remarkable papers appears in the Phil. Mag. for July. The chief remarkability of these papers consists in their diffuseness. It is almost impossible to extract the new facts out of them. His terms are peculiar. What is "the specific heat of electricity" which changes sign at varying temperatures? The conclusion long paper appears to be that the temperature at which permanent magnetism begins to suddenly disappear is not the temperature at which permanent torsion begins to suddenly disappear. We find the mechanical qualities, viz. hardness, elasticity, linear expansion, internal friction, tensile strength, molecular structure, torsion, &c., of iron, steel, and nickel inextricably mixed up with magnetic susceptibility and retentiveness, electric resistance and thermo-electric conditions, specific and latent heat, and varying temperatures. |