568 



NA TURE 



[April 14, 1898 



Copper river, and other water routes of the Territory, the United 

 States Congress having granted 100,000 dollars for the purpose. 



Scientific facts are presented to the public freely and 

 attractively in three lectures which have been arranged at the 

 Whitechapel Free Public Library and Museum. On Tuesday 

 Prof. Hobday lectured on "The Horse and Dog and their 

 relations and friends." On Tuesday, May 10, Prof. W. F, R. 

 Weldon, F.R.S., will discourse upon "Butterflies"; and on 

 June 7, Prof. Marshall Ward, F.R.S,, will give an address upon 

 "A Piece of Wood." Admission to the lectures is free by ticket, 

 which can be obtained in the Museum and Library. 



Appendix IL for 1898 of the Kew Btdletin is entirely occu- 

 pied with a list of New Garden Plants of the year 1897, includ- 

 ing also the most noteworthy of those which have been re -intro- 

 duced after having been lost from cultivation. In addition to 

 species and botanical varieties, all hybrids, whether introduced 

 or of garden origin, with botanical names, and described for the 

 first time in 1897, are included. 



Messrs. J. and A. Churchill announce that they will 

 publish in a few days a new work -on "The Blood: how to 

 examine and diagnose its diseases," by Dr. Alfred C. Coles, 

 illustrated with six coloured plates. They will also issue a fifth 

 edition of " A Manual of Dental Anatomy, Human and Com- 

 parative," by Mr. Charles S. Tomes, F.R.S., with many new 

 illustrations. The part dealing with comparative odontology 

 has been expanded to meet the requirements of students of 

 biology. 



The additions to the Zoological Society's Gardens during the 

 past week include a Macaque Monkey (Macacus cynomolgus) 

 from India, presented by Mrs. Grace Currie ; a White-tailed 

 Sea Eagle {Haliatus albicilla) from the Liautung Peninsula. 

 China, presented by Mr. J. W. Carrell ; ten Californian Quails 

 {Callipepla californica) from California, presented by Captain 

 Thos. Yardley Powles ; a Common Viper ( Vipera berus). 

 British, presented by Mr. R. Tucker ; an Egyptian Jerboa 

 {Dipus cEgyptius), four Egyptian Ichneumons (Herpesles ichneu- 

 mon), six Gulls {Larus, sp. inc.), a Common Kestrel {Tinnun. 

 culm alaudarius) from Egypt, a Leopard {Felis pardus) from 

 West Africa, a Reticulated Python {Python reticuiatus) from 

 Malacca, deposited ; a Chimpanzee {Anthropopithecus troglo- 

 dytes, (J ) from West Africa, a Rosy-billed Duck (Metopiana 

 teposaca, ? ) from South America, purchased. 



OUR ASTRONOMICAL COLUMN. 



The Doubling of the Canals on Mars. — The origin 

 of the doubling of the canals visible on the surface of the 

 planet Mars has again come to the front, and this time M. 

 Antoniadi has put forward an explanation. His suggestion is 

 that the doubling is only a phenomenon caused probably by 

 the eye of the observer ; in fact, it is the result of slight focus- 

 sing errors when observing these markings. A full account of 

 this curious cause of error is contributed to Cosmos (No. 687) by 

 M. Th. Moreux, and M. Antoniadi himself gives a complete 

 summary of his suggestion in the Bulletin de la Soci^te Astro- 

 nomique de France for April. According to the latter, a thin Hne, 

 when gradually put slightly out of focus, becomes slowly double, 

 the inner parts of which are blurred ; in fact, a regular germina- 

 tion is observed. In addition tothis,he finds that if several lines be 

 made to cross at a point, all of these do not become double, but 

 only certain of them. Not only do straight markings, but round 

 and elongated spots become alike doubled.. At the end of his 

 paper, after remarking on the curious phenomenon of canals, as 

 actually observed, becoming double in the course of a few hours, 

 he says : — 



" Ainsi, si Mars est couvert de ' canaux,' la vision impar- 

 faite devra dedoubler ces lignes. Pareille vision indistincte 

 peut provenir, ainsi que nous venons de le voir : 1° d'une minime 

 erreur de mise au point ; 2° d'oscillations diplopiques (fatigue) 



NO. 1485, VOL. 57] 



de I'oeil. Voila ce qui doit fatalement arriver, el ce qui arrive 

 en realite." 



M. Camille Flammarion tells us in the same journal that 

 M. Adolphe de Boe, of Anvers, in the year 1891 suggested, in a 

 letter to him, that this doubling might be the result of secondary 

 images which, under certain conditions, might be formed in the 

 eye. M. Flammarion is, however, no great believer in this 

 idea, as it does not seem to sufficiently explain all the phenomena 

 of doubling, germination, &c., which have been observed on 

 the surface of this interesting planet, although the arguments 

 brought forward reproduce very ingeniously the greater part of 

 the observations. With him we echo the sentiment of wishing 

 to know what M. Schiaparelli has to say on the subject. 



Comet Perrine. — The latest elements and ephemeris of this 

 comet have been calculated by Prof. H. Kreutz, who gives the 

 results in No. 4 Circular recently distributed. 



The elements computed from the observations of March 19, 

 23, 27 and 31, differ slightly from those we ha-ve previously 

 given, being : — 



1 = li 



March 17-37558 Berlin M.T. 



w = 47 34 12*1 



a = 262 33 59-6 [- 1898-0 



i = 72 27 48-I, 

 log q = 0*040842 



The ephemeris for the ensuing week is as follows : — 



1898. R.A. Dec. log r log A Br. 

 h. m. s. 



April 14 23 7 15 -1-40 477 0-0757 0-2233 077 



15 12 13 41 32-9 



16 17 15 42 i6'9 



17 22 20 42 59-7 



18 27 27 43 41-3 0-0851 0-2330 071 



19 32 37 44 21-6 



20 37 49 45 0-6 



21 43 3 45 38-4 



22 23 48 19 -f46 15-0 0-0953 0-2438 0-64 



It will be noticed that the brightness of this comet is gradually 

 decreasing, and by the end of the month it will be about half 

 that at the time of discovery. 



The April Lyrids. — As pointed out in this column on 

 March 31 (p. 519), the April shower of meteors is due on 19-20 

 of this month. The conditions for viewing these bodies if they 

 should be numerous wiH be very favourable, as the moon will 

 be absent. As Mr. Denning tells us, the periodical maxima 

 of this stream of Lyrids has a computed time of revolution of 

 415 years, a brilliant display having occurred on April 20 in the 

 year 1803. The radiant point is 270° -F 32°. 



The Meudon Observatory. — Prof. Janssen is evidently 

 bringing together a very strong force at the Astro- Physical Ob- 

 servatory at Meudon. We hear now that, in addition to the 

 other experienced astronomers who are working there, M. 

 Deslandres has been transferred from Paris, and will in future 

 continue his valuable spectroscopic. researches at Meudon. 



PREHISTORIC RUINS OF HONDURAS AND 

 YUCA TAN. 



TN 1891 the Directors of the Peabody Museum secured from 

 ^ the Government of Honduras (through the liberality of Mr. 

 C. Bowditch, of Boston) the right to explore the ruins of Copan, 

 and to take away half of the objects found in the excavations, 

 during a period of ten years. The preliminary report of the 

 exploration,' now published by the Directors of the Museum, 

 gives the result of the first two years' work, and is accompanied 

 by a plan and many excellent photographic plates. 



All those interested in American archaeology must be for ever 

 grateful to the Committee directing the expedition for one in- 

 struction given to the explorers ; it was to the eff'ect that a wall 

 should be built round the principal group of ruined structures 

 and carved monoliths, so as to save them, if possible, from 

 further destruction. This work has now been most satisfactorily 

 carried out, and the ruins, which were always safe from approach 

 on the river face, are now enclosed on the land side by a sub- 

 stantial stone wall nearly one mile in length. 



^ Memoirs of the Peabody Museum, 6r'c. Vol. i. No. i: "Prehistoric 

 Ruins of Copan, Honduras." "A Preliminary Report of the Explorations 

 by the Museum, 1891-95." 



