in refusing the demands made upon the national purse. To a certain extent, what happened in the case of the Eclipse Expedition of 1870 has been now repeated. Our readers will recollect that on that occasion the mere personal application of the Astronomer Royal was at once very properly refused, while a proper representation by the leading Societies was at once as promptly acceded to.

We beg to draw our readers' attention to a new medical journal which commenced its career yesterday, the Medical Record, and which, judging from the prospectus and the contents of the first number, is likely to be of the very highest service to the important department with which it is connected, and to the sciences on which that department depends. The Medical Record is a weekly review of the progress of medicine, surgery, obstetrics, and the allied sciences, but does not seek to trench on the ground already occupied by other medical journals. The object of this weekly periodical will be to supply medical readers with a condensed, readable, and reliable analysis of the immense mass of information relating to the medical sciences now scattered over the surface of British and Foreign periodical medical literature. The number, the bulk, the cost, and the diffusion of the transactions and periodicals at home and abroad, in which this information is contained, are now so great as to place it beyond the reach of the most industrious. The annual transactions of the great societies of Europe and America alone occupy some scores of volumes, therefore the idea is a happy one of gathering the cream of these transactions and presenting it in an accessible and manageable form, before the transactions are out of date, to those who otherwise might never get a glimpse of them. Moreover, as the prospectus says with truth, the age of year-books has passed away, and to make the labours of scientific inquirers in the medical as well as in other departments intelligible and of practical use, they must be studied and appropriated when first announced. To enable this to be done for medicine is the object of the Medical Record, and we have every reason to believe it will be eminently successful in attaining its end. The new journal will be edited by Mr. Ernest Hart. The abstracts will be signed in all cases. The staff includes upwards of forty of the best known scientific members of the profession, most of them hospital teachers in London, Edinburgh, and Dublin.

SIR WILLIAM JENNER has been elected President of the Pathological Society, London.

THE Lectureship on Botany of the St. Thomas's Hospital Medical School is vacant through the resignation of the Rev. J. W. Hicks. Applications should be sent to the Medical Secretary on or before January 10.

A NEW Society has been organised in Sacramento, California, under the name of "The Agassiz Institute." It has been formed on the model of the Essex Institute, Salem, Massachusetts, and owes its birth in great part to the recent visit of Prof. Agassiz in California.

A NEW work on the Cetaceans and other Marine Animals of California, is announced by Captain Scammon. It will be published by subscription through the Naturalist's Agency, Salem, Massachusetts, U.S.A.

THE planet (128) which we noted last week as having been discovered by M. A. Barrelly on the night of December 4-5, is the same as that discovered by Prof. Watson, Ann Arbor Observatory, on the night of Nov. 25, noted in NATURE of December 19 last.

THE association proposed for the promotion of explorations in Africa by the Berlin Geographical Society has constituted itself under the title of the African Society, its principal members being Drs. Schweinfurth, Rohlfs, Bastian, Peschel, Bruhns, and Petermann.

THE Challenger left Lisbon yesterday.

THE United States Coast Survey party, in charge of W. H. Dall, arrived in San Francisco on the 20th of September, on the Humboldt, after an absence of thirteen months. This time had been chiefly spent in the region between Kadiah and Oonalaska, among the Aleutian Islands. Among the more important results of the work are the determination of ten islands and rocks, fourteen harbours and anchorages (and many minor details) not on any chart; the determination of a great oceanic current, a reflected branch of the great North Pacific easterly stream, which sweeps to the south and west, south of the peninsula of Alaska and the islands, having a breadth of about 350 miles; and the discovery of new fishing tanks off the southern end of Kadiah. Geological and zoological researches were carried on by the members of the party during that portion of their time when hydrographic work was impracticable; and though these investigations were entirely subsidiary to the regular work, they were crowned with unexpected success, especially in the departments of botany and geology, and the various groups of marine vertebrates. These collections, although still but superficially examined, indicate a curious resemblance in some particulars between the fauna of the region visited and that of the Straits of Magellan, a number of forms found being common to both, and not yet discovered in the intervening regions.

THE American papers talk with just pride of the great engineering feat which is now nearly completed at the expense of the Massachusetts Treasury, and which will shorten the railway distance between Boston and Troy; and Albany, by 40 miles. A tunnel 4.66 miles through the Hoosac mountains has been in progress since 1855, but was not seriously entered on till 1863. The cutting was made from both ends, and so nice were the calculations of the engineers, that when on December 12th last, the two boring parties met, the two cuttings were found to vary not more than a foot either in grade or in line.

SIR BARTLE FRERE and his suite left Aden on board the Enchantress for Zanzibar last Saturday.

IN reference to the Cambridge Natural Science Tripos a correspondent informs us that the new scheme of examination has been carried out for the first time in this Tripos. It is as follows:-The examination occupies eight days, six in one week and two in the next, the first three of which are devoted to six papers, intended to test a general elementary know. ledge of all the subjects. Two days are then occupied by practical examinations in chemistry, anatomy, and physiology; and in the last three, six papers are set, each containing several questions relating to the higher branches of each subject; and a candidate may not be placed in the first class unless he show a competent knowledge of botany, chemistry, geology, mineralogy, or physics, or of any two of the following,-Anatomy, Physiology, or Zoology; the intention being that a student should confine his high reading to one, or at most two subjects.

THE third series of meetings of the Cambridge Natural Science Club, established in March 1872, by some of the junior members of the University, was held during the last October Term; a paper was read at each meeting by the member in whose rooms the Club met, and the attendance of members and of visitors was usually good, though as the examination for the Natural Sciences Tripos approached, it fell off slightly. The following is a list of the papers, which were illustrated as far as possible with drawings, specimens, or experiments :-The Theory of Pangenesis, by Mr. F. M. Balfour (Trinity); Geological Faults, by Mr. R. D. Roberts, B.Sc. (Clare); Some Bone-caves in Herefordshire, by Mr. J. J. H. Teall (St. John's); The Rock-fragment of the Cambridge Upper Greensand, by Mr. A. J. Jukes-Browne (St. John's); The recent Deep-sea Dredging Expeditions, by Mr. P. H. Carpenter (Trinity); The derived Fossils of the

Cambridge Upper Greensand, by Mr. A. F. Buxton (Trinity); The Mechanism of Consciousness and Volition, by Mr. H. N. Martin, D.Sc. (Christ's).

MR. G. F. RODWELL lectures at the London Institution on Wednesday, 15th inst., on "Ancient Science."

THE Sunday Lecture Society has issued a very satisfactory programme for the next three months. On Jan. 26, Mr. A. H. Green gives a lecture "On the Glacial Period; a Chapter of English Geology." On Feb. 23, Mr. A. Balmanno Squire lectures on "The Skin; its Structure and Uses." Last Sunday Mr. W. J. Lewis lectured on "The Next Transit of Venus, and the Measurement of the Distances of the Planets from the Sun."

THE Mercers' Company have given notice that during the ensuing Hilary Term the lectures founded by Sir Thomas Gresham will be read to the public gratuitously in the theatre of Gresham College, Basinghall Street. Among them are lectures on Astronomy by the Rev. Joseph Pullen, on the 11th, 13th, and 14th inst.; Physic, by Dr. Symes Thompson, on the 17th and 18th; Geometry, by the Dean of Manchester, on the 25th and 27th.

A FUND is being raised for founding, at University College London, an Exhibition in commemoration of the services of the late W. A. Case, M. A. The Exhibition is to be held by students on leaving the college school, with which Mr. Case was connected for twenty years. The amount already promised is upwards of 300%.

THE Professor of Mineralogy (Mr. Miller) at Cambridge, will lecture on Mineralogy on Mondays, Tuesdays, Wednesdays Fridays, and Saturdays, from 1 to 2, in the lecture-room at the north end of the west wing of the new museum, commencing January 31.

Two very interesting birds have just been received by the London Zoological Society, an American Stilt or Stilt-plover (Himantopus nigricollis), and a Darter (Plotus anhinga), both of them remarkable in form and appearance, and new to the Society's collection. They are to be seen in the Fish-house.

THE first number of the new monthly journal of popular antiquities, Long Ago, is a capital one, the contents being very varied and of wide range. If it keeps up as it has begun, it will be of real and lasting value.

A NEW series of the Mechanics' Magazine is to be commenced this month, under the new and admirably brief title of Iron.

WE would draw the attention of our readers to a series of letters on the marriage of the Emperor of China which have been appearing in the Daily News, especially to the one in Tuesday's issue describing the structure of "the Temple of Heaven" and other tem les, in which certain astronomical notions seem to be involved, suggesting comparison with certain theories about the pyramids of Egypt.

WE are glad to see, from some scraps sent us from the New York papers, under the title of "News Splinters," that Prof. Tyndall is making excellent use of Mr. W. Spottiswoode's polariscope apparatus. So impressive and popular apparently are his lectures on polarisation, that one of the "splinters" remarks that “if anybody don't go who can get a ticket to go to hear this very remarkable course of lectures, he or she deserves rectilinear propagation into outer darkness." We believe that Prof. Tyndall is expected back on the 25th or 26th inst.

WE are glad to see, in the Mercantile Marine Magazine, an article on "Meteorology: Past, Present, and Future, General and Particular." It would, however, have been better had the writer had the courtesy to acknowledge that his article was

suggested by, and is largely based upon, an article in NATURE for December 12 last, on the "Meteorology of the Future."

WE learn from the British Medical Journal, that there is some prospect that a long-talked of scheme-the removal of the Medical School of St. Andrew's University to Dundee—may be carried out. A large field for medical instruction is to be ob tained in connection with the Dundee Royal Infirmary; and a similar step, that of the University of Durham, which established a Medical School in Newcastle, has not been without success.

THE following is from the Medical Record :-" The recent meeting at Bordeaux of the French Association for the Promo. tion of Science, in its first annual session, appears to have sown seed which is likely to ripen in good fruit in that city. At a preliminary meeting held on Dec. 20, a committee was named, consisting of well-known physiologists, chemists, and men of science and others, to carry out a proposed scheme of general regulations for a laboratory of physiological and chemical research. Important sums were offered for the purpose, and the muncipality of Bordeaux, appreciating the importance of encouraging scientific labours, will, it is stated, contribute handsomely to the installation and maintenance of the proposed laboratory."

THE feuilleton of the Gazette Medicale for January 4 contains a number of details concerning English medical education, medical fees and etiquette.

THE number of L'Institut for January next commences a new series. This Journal has been in existence for forty years. STANLEY'S "How I found Livingstone," is being translated in Le Tour du Monde.

THERE is a very good article in the Field for January 4, exposing some popular delusions with regard to the dangers incurred by living in or travelling through countries where snakes are abundant. The writer thinks it would be difficult to produce a well-authenticated instance of a European having been killed by a snake in any tropical country. Many of these delusions the writer ascribes to the sensation stories found in some popular novels, e.g. "Tom Cringle's Log," and some of Marryatt's works, as also in the narratives of credulous travellers, and even in the works of such an eminent ornithologist as Audubon. "The actual risk incurred," the writer says, "by those who visit and explore the haunts of snakes is practically so inconsiderable as very soon to become habitually as much disregarded as is the existence of the common adder in this country." He also animadverts with justice on the extreme vagueness of the multitude of popular names applied to snakes, and speaks of the necessity of always recognising the established system of technical nomenclature, without which all is vague and delusory.

WE have received a lecture delivered before the Torquay Natural History Society by its Vice-president, the Rev. T. R. R. Stebbing, M.A., on "Museums and Our Museum," in which he gives some very excellent hints as to what a model museum, both general and local, ought to be. This society has been in existence for twenty-eight years, and during that time has done much useful scientific work, and accumulated a valuable collection of specimens illustrating the natural history of the country, which already exceeds the accommodation at the society's disposal. Its reference library is also rapidly increasing in bulk, and the society has therefore appealed to the Torquay public to assist in raising such a building as will satisfy the requirements of the lectures, library, and museum. Not only for the sake of the society, but for the sake of their own highest good, we hope the public of Torquay will respond liberally to the society's appeal.

reading. It should, however, be used in conjunction with the Miller-Casella thermometer, so as to ascertain how far the two instruments are comparable; and this point having been settled, Mr. Siemens's instrument should be used in all serial soundings; and frequent readings should be taken with it, both in descending and ascending.

A question raised by the observations of the U.S. Coast Surveyors in the Florida Channel, and by those of our own surveyors in the China Sea, is the extent to which the colder and therefore heavier water may run up hill on the sides of declivities. The position of the Azores will probably be found very suitable for observations of this kind. Temperature-soundings should be taken at various depths, especially on their north and south slopes, and in the channels between the Islands; and the temperatures at various depths should be compared with those of corresponding depths in the open ocean.

It is in the southern oceans that the study of ocean-temperatures at different depths is expected to afford the most important results; and it should there be systematically prosecuted. The great ice-barrier should be approached as nearly as may be deemed suitable, in a meridian nearly corresponding to the centre of one of the three great southern oceans ;-say to the south of Kerguelen's Land; and a line of soundings should be carried north and south as nearly as may be.

In connection with the limitation of the area and depth of the reef-building corals, it will be very important to ascertain the rate of reduction of temperature from the surface downwards in the region of their greatest activity; as it has been suggested that the limitation of living reef-builders to 20 fathoms may be a thermal one.

Wherever any anomaly of temperature presents itself, the condition of such anomaly should, if possible, be ascertained. Thus there is reason to believe that the cause of the temperature of the surface-water being below that of the sub-surface stratum, in the neighbourhood of melting ice, is that the water cooled by the ice, by admixture with the water derived from its liquefaction, is also rendered less salt, and therefore floats upon the warmer and salter water beneath. Here the determination of Specific Gravities will afford the clue. In other instances a warm current may be found beneath a colder stratum; and the use of the "current-drag" might show its direction and rate. In other cases, again, it may happen that a warm submarine spring is discharging itself,- -as is known to occur near the island of Ascension. In such a case, it would be desirable to trace it as nearly as may be to its source, and to ascertain its composition.

Movements of the Ocean.-The determination of SurfaceCurrents will, of course, be a part of the regular routine, but it is particularly desi able that accurate observations should be made along the line of sounding in the Southern Ocean, as to the existence of what has been described as a general "Southerly set" of Oceanic water, the rate of which is probably very slow. It is also very important that endeavours should be made to test by the "current-drag," whether any underflow can be shown to exist from either Polar basin towards the Equatorial region. A suitable locality for such experiments in the North Atlantic would probably be the neighbourhood of the Azores, which are in the line of the glacial flow from the North Polar Channel. The guide to the depth at which the current-drag should be suspended, will be furnished by the thermometer, especially where there is any abrupt transition between one stratum and another. It would be desirable that not only the rate and direction of surface-drift, but those of the subsurface-stratum at (say) 200 fathoms' depth, should be determined at the same time with those of the deep stratum.

Tidal Observations.-No opportunity of making tidal observations should be lost. Careful observations made by aid of a properly placed tide-pole in any part of the world will be valuable. Accurate measurements of the sea-level once every hour (best every lunar hour, i.e. at intervals of 1h 2m of solar time) for a lunar fortnight (the time of course being kept) would be very valuable information.

Bench-marks. In reference to the interesting question of the elevation or subsidence of land, it will be very desirable, when sufficient tidal observations can be obtained to settle the mean level of the sea, that permanent bench-marks should be established, recording the date and height above such mean level. Even recording the height to which the tide rose on a certain day and time, would render a comparison possible in future years.

A good determination of the mean sea-level by the simple

operation of taking means may be made, in less than two days, with even a moderate number of observations properly distributed so as to subdivide both solar and lunar days into not less than three equal parts. Suppose, for example, we choose 8-hour intervals, both solar and lunar. Take a lunar day at 24h 48 solar time, which is near enough, and is convenient for division; and choos. ing any convenient hour for commencement, let the height of the water be observed at the following times, reckoned from the com

The observations may be regarded as forming three groups of three each, the members of each group being separated by 8 hours solar or lunar, while one group is separated from the next by 8 hours lunar or solar. In the mean of the nine results the lunar and solar semi-diurnal and diurnal inequalities are all four eliminated.

Nine is the smallest number of observations which can form a complete series. If the solar day be divided into m and the lunar into n equal parts, where m and n must both be greater than 2, there will be mn observations in the series; and if either mor n be a multiple of 3, or of a larger number, the whole series may be divided into two or more series having no observation in common, and each complete in itself. The accuracy of the method can thus be tested, by comparing the means obtained from the separate sub-series of which the whole is made up.

Should the ship's stay not permit of the employment of the above method, a very fair determination may be made in less than a day, by taking the mean of n observations taken at intervals of the nth part of a lunar day, " being greater than 2. Thus if n=3, these observations require a total interval of time amounting to only 16h 32m. The theoretical error of this method is very small, and the result thus obtained is decidedly to be preferred to the mere mean of the heights at high and low water.

The mean level thus determined is subject to meteorological influences, and it would be desirable, should there be an oppor tunity, to redetermine it at the same place at a different time of year. Should a regular series of observations for a fortnight be instituted, it would be superfluous to make an independent determination of the mean sea-level by either of the above methods at the same time.

Besides taking observations on the ordinary waves of the sea when at all remarkable, the scientific staff should carefully note circumstances of any waves attributable to earthquakes.

Specific Gravity.-The Specific Gravity of the surface and bottom-water should be carefully compared, whenever soundings are taken; and whenever Serial Soundings are taken, the Specific Gravity at intermediate depths should be ascertained. Every determination of specific gravity should be made with careful attention to temperature; and the requisite correction should be applied from the best Table for its reduction to the uniform standard of 60°. It would be well to check the most important results by the balance; samples being preserved for examination in harbour. Wherever the temperature of the surface is highespecially, of course, in the intertropical region- samples should be collected at every 10 fathoms for the purpose of ascertaining whether any effect is produced upon the specific gravity of the upper stratum by evaporation, and how far down this effect

extends.

Transparency of the Water.-Observations for transparency should be taken at various depths and under different conditions by means of Mr. Siemens's photographic apparatus. As, however, the action of this depends upon the more refrangible rays, and the absorption of these and of the more luminous rays might be different, and that in a manner varying with circumstances, such as the presence or absence of suspended matter, &c., the transparency of the sea should also be tested by lowering a white plate or large white tile to various measured depths, and noting the change of in'ensity and colour as it descends, and the depth at which it ceases to be visible. The state of the sky at the time should be mentioned, and the altitude of the sun, if shining, roughly measured, or if not shining, deduced from the time of day.

Relation of Barometric Pressure to Latitude-In Poggendorf's Annalen," vol. xxvi. 1832, p. 395, is a remarkable paper by Prof. G. F. Schouw on the relation between the height of the barometer at the level of sea, and the latitude of the place of

The expedition might contribute to the examination of this law, not only by giving special attention to the barometer observations at about the critical latitudes o°, 30°, 65°, 70°, but also by comparing any barometers with which long series of observations have been made at any port they may touch at, with the ship's standard barometer.

It appears probable from Schouw's paper, that certain meridians are meridians of high pressure and others of low pressure. For comparison of barometer and measures of heights, it appears that the aneroid barometer constructed by Goldschmid of Zurich, would be very useful.

It is very desirable that the state of the barometer and thermometer should be read at least every two hours.

(To be continued.)

TERRESTRIAL MAGNETISM*

II:

THE problem was attacked later on by General Sabine in a much more definite manner, and with much greater chance of success. The earth, as we are all well aware, moves round the sun in an elliptic orbit, the nearest approach of the two bodies occurring at about the time of the winter solstice; if, therefore, there be an annual inequality, it will probably attain its maximum when the earth is in perihelion, and its minimum at aphelion, since the magnetic force is known to vary inversely as the square of the distance. The year was, therefore, divided by Sabine into two equal parts, and the mean of all the observations taken during the six winter months compared with the mean for the six summer months. The records of the three British observatories of Hobarton, Toronto, and Kew all agree in showing that the magnetic intensity of the earth is greater in winter than in summer. This was very satisfactory; but the same calculations have since been made for other magnetic stations, where monthly determinations of the three elements are carried on without interruption, and some of the results are far from confirming the above conclusion; for we find that observatories as near as Kew and Greenwich are in direct opposition on this point. A more extensive series of comparisons will finally show how far this disagreement depends on the accidental nature of the observing stations; but at present the preponderance of the evidence is decidedly in favour of a semi-annual inequality.

A similar investigation of the effect of the moon's action on terrestrial magnetism requires a series of observations made at much less distant intervals than the monthly ones, which suffice for the study of the annual variation. This new question preThe effect of the sents itself to our view under a twofold aspect. moon may be studied either in its independent action, or as it acts conjointly with the sun; in the former case we must group the observations with respect merely to the position of the moon in its orbit, and, as this is an ellipse with the earth in the focus, the force, varying inversely as the square of the distance, will have its maximum disturbing influence at perigee and its minimum at apogee. The range also of the inequality will depend

on the eccentricity of the orbit, and the period of variation will coincide with the siderial, or more strictly the anomalistic, month of a little over twenty-seven days.

But if we consider the moon as acted upon by the sun, receiving its magnetic power, as it does its light and heat, from the central body of our system, or merely having its own inherent magnetism modified by solar action, then we must choose as our

* Continued from p. 173.

unit the lunation, or synodic month of 29'5 days, observing the changes that take place as the moon approaches to or recedes from the sun. A careful sifting of the Greenwich observations led Mr. Airy to a belief in the existence of a menstrual inequality of the declination, attaining its maximum on the fifth day of the moon's age, and of a semi-menstrual inequality of the horizontal force whose maximum occurs on the second day. The solar effect on the moon's magnetic power would, therefore, appear to be cumulative, and not to be fully developed till several days subsequent to the conjunction of the two bodies.

No examination seems to have been as yet made to test the existence of a monthly variation due to the independent action of the moon, as the sole disturbing force.

The

The sun's rotation on his axis presents another not improbable cause of periodic magnetic disturbance. For if the sun acts as a large magnet directly upon the earth, and the poles of the sun's axis of rotation are not coincident with its magnetic poles, the rotation will present the solar magnetic poles alternately to the earth, and these acting singly, the result must be a synodic inequality, dependent on the period of the sun's rotation. absence of any such irregularity is adduced, by a recent author on terrestrial magnetism, as a proof that the variations of the earth's magnetic force are due solely to the indirect action of the sun; but Prof. Hornstein has just succeeded in detecting in the magnetic records of Prague and Vienna an inequality in very close accord with the synodic period of the rotation of the solar spots. The magnetic period of 26 days 8 hours would give, as the true time of the sun's rotation, 24d. 13h. 12m., whereas Spörer, from the most accurate observations of spots near the sun's equator, found the time to be 24d. 12h. 59m. It becomes, therefore, probable that the sun has a direct magnetic action upon the earth, but this need not in the least interfere with the probability of its simultaneous indirect action by means of its thermal energy.

Having been able to detect, in the manner just described, the inequalities arising from the orbital motions of the earth and moon, we are immediately tempted to suppose that the diurnal rotation of the earth must also exert a not inconsiderable effect on the magnetism of any particular station on the earth's surface, and possibly even affect terrestrial magnetism as a whole. It is well known that change of temperature has a very powerful influence on magnetism, and therefore we should be astonished to ing range in the earth's magnetic elements. The freely-suspended find that the daily range of temperature induced no correspondmagnet is the most delicate of thermometers, and consequently, unless we wish the diurnal variation of the earth's magnetism to be completely veiled by the more extensive changes due to the varying heat of the magnet itself, we must take the greatest care to keep the suspended needle in a locality not directly affected by the daily alternations of temperature. Attending to this precaution, by building our magnetic chamber at a considerable depth below the surface of the ground, we still find that there exists a most decided daily range in the motion of the magnet, to which the most delicate thermometer is wholly insensible. This daily range was detected by Graham as early as 1724, and a momentary inspection of nearly any two days' march of the suspended needle will suffice to make this point evident. The maximum west declination, about 2 P.M., is constant throughout the year, whilst the principal minimum varies with the seasons, as do also the secondary maximum and minimum. Canton has accounted for the leading feature in this diurnal change by the fact that the solar heat lessens the magnetic power of that portion of the earth on which it directly falls, and thereby gives a preponderating influence to the opposite portion, whose strength remains undiminished; the needle, therefore, moves towards the West in the morning, and only returns towards the East as the Western sun restores the balance of attracting forces.

But there are other variations of the daily range besides those just mentioned, for not only do most of the inflections of the diurnal curves alter their time with the progress of the sun in his orbit, but the amplitude of the range passes through a constant order of phases as each year advances. Dr. Lloyd discovered that the maximum range of declination in summer is greater than in winter, and Quetelet not only confirms this, but also finds that the range is greater at the equinoxes than at the solstices. It was whilst engaged upon this investigation that the Director of the Brussels Observatory made the curious discovery, that the magnetic energy varies in the same manner as the vegetable force, both attaining their maximum in April, and diminishing gradually until they reach their minimum of intensity in the