May 29, 1879] 



NATURE 



97 



over-manned, as it consists but of sixteen persons, in- 

 cluding officers, savants, two engineers, and three stokers. 

 It is possible that by this time Nordenskjold may have 

 broken out of the ice and be on his way home by the 

 Suez Canal. The letters received from him, referred to 

 last week, are, Mr. Oscar Dickson informs us, dated 

 February 8. 



Letters from Prejevalsky, dated from Zaisan, March 

 20, inform us that the deep snows which cover the steppes 

 had detained him there much longer than he had calcu- 

 lated. He was, however, to leave on March 21, and 

 expected to reach Khami at the end of May, by way of 

 the River Urunga and the southern spurs of the Altai ; 

 unless prevented by excessive heat and want of water, he 

 y.'as to pursue his journey to the town of Shachjeou. 

 Then he would attempt to ascend the two plateaux of 

 Tibet ; after ascending the second plateau he would have 

 1,000 versts of desert to make before reaching Lassa, 

 from which he hopes to visit South-east Tibet. 



A COMPLETE history of all North Polar Expeditions 

 from the remotest ages down to the present day is about 

 to be published by Cotta of Stuttgart. The title will be 

 " Im ewigen Eis," the author is the popular writer, Herr 

 Friedrich von Hellwald. Numerous illustrations, maps, 

 and plans will enhance the value of the work, which will 

 appear in thirty parts. The well-known explorer, Julius 

 Payer, one of the commanders of the Austrian Polar 

 Expedition in 1874, has accepted the dedication of the 

 work. 



From the Colonies and India we learn that a private 

 telegram from Aden conveys intelligence of the arrival 

 there on the 15th inst. of the British India Steam Navi- 

 gation Companj's steamer Chinsura, from Bombay, en 

 route for Zanzibar, having on board four Indian elephants, 

 the property of the King of the Belgians. These elephants 

 will be employed for the purpose of ascertaining whether 

 such animals can be made a means of transport in Africa. 



The Inter-Oceanic Canal Congress has been diligently 

 carrying on its work in Paris for the last fortnight. It 

 was divided into several sections, each to consider a 

 special department of the subject. On Monday the 

 Technical Section of the Congress met to hear reports 

 from its two sub-committees, the second of which ad- 

 mitted the possibility of constructing a canal with locks 

 by way of Nicaragua, while for a level canal it considered 

 the course proposed by Lieutenants Wyse and Reclus to 

 be the best, subject, however, to certain modifications. 

 The first sub-committee presented estimates of the 

 probable cost of the various routes. 



OUR ASTRONOMICAL COLUMN 

 The Total Solar Eclipse of May 22, 1724. — In 

 \h^ Illustrated London News of Saturday last are some 

 quaint extracts from the newspapers of the time, relating 

 to this eclipse, the last that was total in England. It 

 may not be without interest to examine the general cir- 

 cumstances of this phenomenon, which we arc now 

 enabled to do with much precision, by taking advantage 

 of the data furnished in Prof. Newcomb's recently'pub- 

 lished " Researches on the Motion of the Moon." The 

 elements are as follow : — 



G.M.T. of Conjunction in R.A., 1724, May 22, at sb. 26m. 33s. 



Right Ascension 



Moon's hourly motion in R. A 



Sua's „ „ 



Moon's declination 



Sun's ,, 



Moon's hourly motion in declination ... 

 Sun's „ „ „ 



Moon's horizontal parallax 



Sun's „ „ 



Moon s true semi -diameter 



Sun's „ „ 



59 32 12-8 

 38 2ri 

 2 30-4 

 21 5 7-4 N. 

 20 31 28 '9 N. 

 10 53'3 N. 

 o 29 'o N. 

 60 44-5 

 8-7 

 16 33-1 

 >S 47'4 



The sidereal time at Greenwich mean noon on May 22 

 was 4h. im. 3 ■6s., and the equation of time at conjunction 

 in R.A. was 3m. 49'is. additive to mean time. 



Hence it appears that the central eclipse began at 

 3h. 4r6m. in long. 151° 39' W., lat. 13° SS' N. ; it occurred 

 with the sun on the meridian in long. 82° 36' W., lat. 

 54° 30' N., and ended in long. 11° 57' E., lat. 45° 28' N., 

 or the sun set centrally eclipsed near Padua. 



It was therefore late in the afternoon with the stm at 

 small altitude that the eclipse was witnessed in these 

 islands, and the following figures must very nearly define 

 the course actually pursued by the moon's shadow : — 



Longitude. 

 4°W. 



2''W. 

 0° 



2°E. 



N. Limit. 

 5°2 37 



51 57 



51 15 



so 32 



Latitude. 

 Central Line. 



5°! 29-9 

 so 49'S 

 5° 7 '6 



49 24-4 



i 



S. Limit. 



o ' i 



50 24 



49 43 

 49 I 

 48 18 



The popular interest excited in this eclipse we may 

 infer was mainly due ^to the publication of a chart of 

 its track by Halley, then Astronomer-Royal. A copy 

 of this chart is preserved at the apartments of the Royal 

 Astronomical Society; it is entitled "A Description of 

 the Passage of the Shadow of the Moon over Europe, as 

 it maybe expected May 11, 1724, in the Evening, by 

 Edm. Halley, Ast. Reg." It was "Engraved and Sold 

 by John Senex at the Globe against St. Dunstan's Church 

 in Fleetstreet, Price u." Halley concludes some foot- 

 notes as follows : — " At London we compute y' Beginning 

 at 5h. 40m. P.M., y"= Middle, when it will be nearly Total 

 at 6.37, and y'' End 7.29. We wish our Astronomical 

 Friends a clear Sky." ' 



It will be borne in mind that the old style was still in 

 use in this country in 1724, and the eclipse was thus dated 

 May II. Halley's predicted track is in very close 

 accordance with that we have obtained above. His chart 

 shows the central eclipse passing just south of Wexford, 

 north of Bridgwater, over the Isle of Wight and south of 

 Dieppe to near Venice ; his northern limit of total phase 

 passes just south of Dublin, over Leominster and Oxford, 

 and Brentford near London, by Cambray and just north 

 of Strasburg ; the southern limit passes a little south of 

 Kinsale, Padstow, Chartres, &c. 



Dr. Stukeley observed the eclipse from Haradon Hill, 

 near Amesbury, Wilts, and the account of it which he 

 published in his Itinerariutn Curiosum has been frequently 

 transferred to our popular works. Assuming his position 

 to have been in about 1° 47' west of Greenwich, with a 

 latitude of 51° 11', we find by the above elements that 

 totality would commence at 6h. 26m. os. local mean time, 

 and continue 2m. 34s., the sun being at an altitude of 12°. 

 The eclipse was central at or close to Ventnor, and was 

 total there for 2m. 47s. ; the newspaper of the time says, 

 more than ij minute. Observations were made by 

 Delisle and others at the Observatory of Paris, and by 

 Maraldi and Cassini, at the Trianon, Versailles, "eii 

 presence du Roy." The calculated duration of totality at 

 Paris is 2m. 23s., the middle at 6h. 49m. 41s. apparent 

 time ; Gaudin observed the duration 2m. 22s., and the 

 middle at 6h. 50m. 2s. ; other observers made the duration 

 twenty seconds longer, which is certainly an error ; at the 

 Trianon it was observed to be 2m. i6s., a little less than 

 the calculation makes it. The original observations of 

 the French astronomers are given at p. 129 of Prof. 

 Newcomb's work. 



The next total eclipse of the sun visible in England will 

 take place early on the morning of June 29, i927> but 

 totality will only continue some ten seconds. 



THE MIGRATION OF BIRDS 



IN a reply of Dr. Weismann's to some remarks by 

 Prof. A. Newton in his paper on the migration of 

 birds (Nature, vol. xix. p. 579), a statement of mine is 



