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This would indicate that from August to Thomson, and which I have previously menNovember, 1884, the pole of the earth had tioned. None of these investigations have approached Berlin more closely by 20 to 30 given a satisfactory formula for the predicfeet than in the time from March to May. tion of the latitude of any place.

This conclusion was fortified by the ex- In 1891 Dr. S. C. Chandler, of Cambridge, amination of other data, obtained from the Mass., began his investigation of the probobservations made at Pulkova by Nyrén. lem. He remarks :

Here, then, was evidence of a compara- “I deliberately put aside all teaching of tively rapid change in latitude. New ob- theory, because it seemed to me high time servations were undertaken at Berlin, Pots- that the facts should be examined by a dam, Prague, and Bethlehem, Penn. (all by purely inductive process; that the nugatory Talcott's method), and all agreed in show- results of all attempts to detect the exising plus and minus changes in latitude for tence of the Eulerian period (of 305 days) the years 1888–90.

probably arose from a defect of the theory There were still some doubters. More- itself, and that the entangled condition over it was decided to critically test the of the whole subject required that it matter by sending an expedition to the should be examined afresh by processes Sandwich Islands, which is 180 degrees unfettered by any preconceived notions (nearly) in longitude from Berlin. If it whatever. The problem which I therefore was known the latitude of Berlin increased, proposed to myself was to see whether it then a point in the northern hemisphere 180 would not be possible to lay the numerous degrees away from Berlin should simul- ghosts in the shape of various discordant, taneously show a decrease in latitude, for if residual phenomena pertaining to determithe pole moves toward Berlin it must move nations of aberration, parallaxes, latitudes from the point on the other side of the earth. and the like, which have heretofore flitted

Our own Government joined in the effort. elusively about the astronomy of precision Marcuse of Berlin and Preston of Wash- during the century, or to reduce them to ington spent more than a year on the Sand- some tangible form by some simple consiswich Islands observing for latitude, while tent hypothesis. It was thought that if at the same time observations were con- this could be done a study of the nature of tinued at Berlin, Prague and Strassburg in the forces as thus indicated, by which the Europe, and at Rockville, Bethlehem and earth's rotation is influenced, might tend to San Francisco in the United States. The a physical explanation of them." results of all these observations have been Dr. Chandler proceeded to examine his published, and show, without a chance of own work with the Almucantar at Camerror, that the earth's axis is moving, that bridge, the observations of Küstner, Gyldén, , the latitudes at the Sandwhich Islands in- Nyrén, the Washington observations and creased when the latitudes in Germany di- others. He found that they all seemed to inminished and vice versa.

dicate that the pole of the rotation axis was The law of the change was eagerly and moving from west to east about the axis of industriously sought for by some of the figure of the earth in a period of 427 days. ablest mathematical astronomers of the Other observations did not seem to confirm world. They first worked on the idea that this period. Finally he made an elaborate the changes must conform to the 305-day analysis of 33,000 observations between 1837 period of Euler, combined with an annual and 1891, and the result was an empirical change due to causes set forth by Sir W. law which can be announced as follows:

The pole of the rotation axis of the earth which Dr. Chandler has lately published is moved with its greatest velocity about the that the fluctuation with a period of 427pole of the axis of figure about the year 428 days is a circular one, as theory seems 1774; the period then was 348 days. The to demand, while the annual fluctuations velocity has diminished with an accelerated

appear elliptical in character. rate since then. In 1890 the period was An exceedingly interesting and important 443 days. The distance of one pole from confirmation of the Chandlerian period of the other was about 22 feet = 0.22''.

427 days, or about 14 months, was lately Further elaborate examination of this announced by M. Tisserand. Examination material developed the exceedingly impor- has been made of the tide records of the tant and interesting result that the changes Helder in Holland. These are kept with in latitude were the sum of two periodic fluc- great accuracy. It has been found that betuations superposed on each other. One had tween 1851 and 1893 these tide records a period of about 427 days and an ampli- show a variation in the average sea level tude of 0.12" The second had a period of indicating a 14-month period. The greatest a year with an amplitude that was variable divergencies are very small, only 14 mm.= between .04" and .20"

4 inch about, but they appear unmistakably Sometimes these two fluctuations worked and are what theory would demand. together, giving a total range of .33", and In a letter recently received from Dr. at times they conspired against each other, Chandler he states that he finds that the reducing the range to a minimum of a few annual part of the polar motion is an ellipse hundredths of a second. He compared his three or four times as long as broad, and theory with the observations, and the result he expresses the law of the motion of the was in the main exceedingly satisfactory. pole in this ellipse as that the areas de

His conclusions were attacked as to the scribed from the centre are proportional to 427-day term. The annual term could be the times. explained as due to meteorologic causes. We can conclude safely, therefore, that

Professor Newcomb, however, in March, no large changes of latitude have taken 1892, explained in a paper communicated place for many thousands of years ; in to the Monthly Notices of the Royal Astro- fact, in geologic times, that there is no nomical Society that in deducing the Eu- adequate proof of progressive changes in the lerian period of 305 days the earth, as we latitude of any place; but finally that very have remarked, was considered absolutely small periodic changes have occurred, and rigid ; that when the effect of the mobility they are such as can be and are observed. of the oceans and of the lack of perfect rig- The feeling is growing in the minds of idity of the earth were taken into account, those who have given the subject close atthe mathematics required a time of rotation tention that we shall find that many and of the true pole about the axis of figure various causes enter into the problem of longer than the previously accepted 305 determining the law of changes. It will, no days. Making certain assumptions New- doubt, take many years of careful observacomb obtained a period of 443 days.* tion to obtain the data necessary to fully An additional interesting conclusion test Dr. Chandler's or any other hypothesis.

The scientific men abroad are discussing * Professor R. S. Woodward has lately obtained by

the advisability of establishing several oba new discussion of the theoretical problem a formula that seems to indicate the correctness of Chandler's

servatories at various places on the earth's empirical formula.

surface, for the purpose of collecting the data.

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any time.

Ultimately Dr. Chandler's formula, or a land area of the globe would be 55,814,000 slight modification of it, may be proved square miles. Wagner finds confirmation correct, and with it we may be able to state of his figures in the results independently what the latitude of any place will be at obtained by K. Karstens, who has recently

made a new reckoning of the area and mean

depth of the oceans. The lecture was followed by some illustrations showing that revolving bodies pre

THE "FLY-BELT! IN AFRICA. ferred to revolve about their shortest axis

The remarkable control over the occupaor around the axis about which the moment

tion of Africa, exercised by the little tse-tse of inertia was a maximum.

fly, whose bite is fatal to horses and cattle, Charts and diagrams were exhibited show

leads to the introduction of cheaply coning the results of observations made at

structed narrow-gauge railways across the Pulkova, Prague, Berlin, Strassburg, Bethle

belt of country dominated by this pest. The hem and the Sandwich Islands, etc.

Portuguese district, next south of the ZamThese results were compared with the

besi river on the east coast, with its capital deductions from Chandler's formula and

at the little settlement of Beira, attains some shown to agree therewith to a remarkable

commercial importance from its relation to extent.

Mashonaland and the gold district of the inThe preliminary results of the observa

terior; but in order to connect the two, a tions made at Columbia College from May, railway a hundred and twenty miles long '93, to July, '94, were exhibited.

has been made to bridge the fly-belt.' The lecturer threw on the screen illus

The coast exhibits a combination of equatrations of several forms of Zenith Tele

torial and tropical rainfall, having high scopes and described the new form made

temperature and heavy rain from October by Wanschaff, of Berlin.

to April, but from June to September the

J. K. REES.
COLUMBIA COLLEGE.

weather is almost pleasant. At Beira the
scarcity of water in the dry season threatened

a few years ago to be a serious question, as CURRENT NOTES ON PHYSIOGRAPHY (VII.).

a supply had to be brought from the upper AREA OF LAND AND WATER.

course of the rivers at a considerable cost; PROFESSOR H. WAGNER, of Göttingen, con- but “in 1893 a Scotch plumber was imtributes to the April number of the Scottish ported, and all anxiety on this score came Geographical Magazine an abstract of his to an end," as he made galvanized iron recent studies on the land and water areas tanks in which rain water could be gathered of the globe for successive latitude belts. and stored from the roofs (Scot. Geogr. He contends that Murray's figures, pub- Mag., April, '95). lished in the same magazine for 1886 and 1888 and based on Bartholemew's maps,

COLD AND SNOWFALL IN ARABIA. are inaccurate to a significant extent. THE ordinary association of heat with Wagner's measures of the better known the dryness of deserts tends to give the imlands between 80° north and 60° south pression that Arabia has no cold weather. latitude is 51,147,100, against Murray's 51, Nolde's account of his expedition into the 298,400 square miles. Taking 250,000 for Nefud desert of the Arabian interior, latilands yet undiscovered in the Arctic regions, tude 28 north, altitude 3,000 feet, tells of and 3,500,000 for Antarctic lands, the total the severe cold that he experienced there in

February, 1893. The days were warm and hemisphere. It may be remarked that the pleasant; but the nights cooled to -5° or association of these winds with the counter -10° C; the changes of temperature being current that runs eastward in the Pacific extremely sudden. For example, on Feb- a little north of the equator confirms the ruary 1, at noon, the thermometer read suggestion that the equatorial counter +50.5, with a cool wind; at 2 o'clock, +6°, currents in general are caused by the extenat 4, 7.5°; then came a rapid rise to 25.5°, sion of the trade winds of one hemisphere for which no special explanation is given. across the equator into the other hemiJust after sunset there was a sudden fall of sphere. They are thus deflected from a thirty-three degrees, to -8°; and the mini- westward to an eastward course, and hence mum of the night was -11°. The cold and locally produce eastward currents. blustering wind caused much discomfort in

THE METEOROLOGISCHE ZEITSCHRIFT. traveling. The greatest surprise that Nolde met was on February 2, when a storm The thoroughness so characteristic of clothed the Nefud far and wide with a German scientific work appears in this exsheet of snow several inches deep, making cellent journal, the leader of its class, with it resemble a Russian steppe rather than its able original articles, its rich variety of an Arabian desert. The Bedouins, how- notes and its exhaustive bibliographic reever, said that snowfall there was very un- views. Originally established thirty years usual. (Globus, 1895, No. 11.)

ago by the Austrian Meteorological Society,

and edited successively by Jelinek and CENTRAL AMERICAN RAINFALL.

Hann, of Vienna, it was enlarged eleven PROF. M. W. HARRINGTON shows in an years ago by further assistance from the article under the above title (Bull. Phil. Soc. German Meteorological Society, when KöpWashington, xiii., 1895, 1-30) that the pen, of the naval observatory at Hamburg, northeast slope of Guatemala and Hon- became associate editor ; his place being duras has rainfall maxima in June and Oc- lately taken by Hellman of the Prussian Metober, following the zenithal passages of the teorological Institute at Berlin.

Berlin. Dr. Hann, sun and a moderate winter maximum in however, still retains his position as leading January, ascribed to the encroachment even editor and is a frequent contributor to the in these low latitudes of cyclonic areas from pages of the journal. One of his latest esthe westerly winds of the temperate zone. says (January, 1895) is on the rainfall of This gives an interesting repetition of the the Hawaiian Islands, in which he brings case of northern India, as described by together all available material, and disBlanford. The rainfall on the southwest cusses it more completely than has hitherslope of Central America has maxima in to been done. Dutton's explanation of the June and September-October, corresponding considerable rainfall on the southwest slope to the two zenithal passages of the sun. The of Hawaii is quoted with acceptance. A July-August minimum is faintly marked, meteorological peculiarity of these islands while that of January and February is very seems to be that their richer windward low and for a time almost rainless. It is sides, sloping to the northeast with a plennoteworthy that the zenithal rains here tiful rainfall, are on a large part of the coast are often accompanied by strong squally with difficulty approached from the sea on winds from the southwest, suspected of account of the cliffs that have been cut being occasional extensions of the southeast along the shore by the strong surf from trade wind across the equator into our waves driven by the trade winds.

FOEHN-LIKE EAST WINDS IN AFRICA. must prove useful to the teacher, for in
DANCKELMAN, who for some years has

spite of a recent assertion to the effect that made a special study of African meteor- the meteorological aspects of geography are ology, contributes a note on the foehn-like well taught in our schools, there is room east winds felt on the southwest coast of for much improvement in this direction. Africa, about the southern tropic (Met.

The April number contains notes on signs Zeitschr., January, 1895). In the interior, of a recent change of popular opinion con- . temperatures above 27°C are unknown in cerning the effect of cultivation on rainfall the winter (April to October); but on the in Iowa, the proceedings of the last meeting coast in this season, maxima over 30°, and of the New England Meteorological Soeven as high as 39°, are reported, east ciety—the only society of the kind, we bewinds and low humidity occurring at the lieve, in this country—and diagrams of a same time. As so high a temperature can

curiously curved storm track from the Pilot not be ascribed to heat from the interior, chart of the Hydrographic office; reviews Danckelman explains it as the result of the of the Blue Hill (Mass.) observations for dynamic warming of the wind during its 1893, of Ley's new work on clouds, and of a descent from the interior highlands. This

new Danish series of monthly pressure is only one more illustration of the impor

charts for the North Atlantic. The editor tance of adiabatic changes of temperature in contributes an account of Swiss studies of meteorological phenomena ; the Swiss foehn thunderstorms, and a description of meteor. and our western chinook, the extraordinaryological work in India and Australia. The foehn-like winds of west Greenland, the wind known as the 'southerly burster,' hot winds of India and of Kansas, as as felt at Sydney, has recently been studied well as the ordinary warm or hot southerly in a prize essay; it recalls in many particucyclonic winds, or 'siroccos, allowing a

lars the northers' of our Texan coast. greater or less share of their high temperatures to the heat developed by compression

NOTE ON CROLL'S GLACIAL THEORY. during the descent of air from higher to

A BRIEF article by the undersigned (relower levels.

printed in Amer. Met. Journal for April

from the Trans. Edinb. Geol. Soc., vii., THE AMERICAN METEOROLOGICAL JOURNAL.

1894, 77–80) suggests a common explanaThe American Meteorological Journal, tion for three forms of geologically recent conducted for a number of years by Profes- climatic change, namely, the glaciation of sor Harrington at Ann Arbor, and since many northern lands, the expansion of 1892 edited by R. DeС. Ward and published many interior lakes, and the production of by Ginn & Co., Boston, is an able exponent wadies by water action in the now dry of the science of the atmosphere for this Sahara. Accepting Croll's theory of the country. The closing number (April, 1895) coincidence of glacial conditions with long of the eleventh volume opens with a note aphelion winters during periods of great by the editor, reviewing the recent work of orbital eccentricity, it is argued that the the journal, and making an excellent show- chief cause of snowy precipitation at such ing for its continuation. Its original arti- times must be the greater activity of cyclonic cles make it of value to the investigator; processes, then intensified by the stronger its notes and reviews place much important general circumpolar circulation, in turn acmaterial before the general student; and celerated by the increased winter contrast its more elementary or educational articles of polar and equatorial temperatures ;

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