43' 



NATURE 



[December 17, 1914 



suitable formulas to be freely available to manufac- 

 turers. Another committee has been formed to con- 

 sider the needs of this country as regards laboratory 

 reagents and the standards of purity necessary for 

 such substances. 



Probably the most interesting structural steel work 

 on the new Lotschberg-Simplon Railway is the steel 

 arch bridge over the Bietsch Valle}% of which an illus- 

 trated description appears in the Engineer for Decem- 

 T>er II. This bridge is remarkable for the fact that 

 it is built on a short-radius curve of only 300 metres, 

 ■and also on a gradient of 222 per 1000. The situation 

 is over a craggy ravine, between two tunnels piercing 

 the spur on either bank. The arch has a span of 

 95 metres between the centres of the hinges and a rise 

 from this chord of 23-79 nietres. Supported partly 

 upon this arch and partly by the masonry approach 

 arches are two trussed girder spans. These girder 

 ■spans are attached to the back of the central arch by 

 means of pivoted expansion brackets, and this part of 

 the design is of peculiar interest in view of the com- 

 plexity of the movements arising from change of 

 temperature and vertical and lateral loading. The 

 •three structural elements in the bridge are all recti- 

 linear, while the bridge floor and its bracing alone 

 are curved and continuous between the pier abutments. 



The thirtj'-first annual issue of the "Year-Book of 

 the Scientific and Learned Societies of Great Britain 

 -and Ireland " has now been published by Messrs. 

 Charles Griffin and Co., Ltd. This useful reference 

 volume is a record of the work done in science, litera- 

 ture, and art during the session 1913-1914 by numerous 

 societies and Government institutions, and has been 

 compiled from official sources. On the whole it pro- 

 vides a comprehensive survey of the activities of asso- 

 ciations with which it is concerned, but we have failed 

 to find any reference to the Wireless Society of Lon- 

 don, the Illuminating Engineering Society, and the 

 Historical Association. It is a pity, too, that in a 

 volume published at the end of 1914 the extended 

 reference to the British Association should deal almost 

 wholly with the 1913 meeting at Birmingham. The 

 volume, the price of which is 75. 6d. net, deserves 

 a place in every reference library. 



Messrs. J. Wheldon and Co., 38 Great Queen 

 Street, W.C., have just issued a classified list of 

 books and other works on mineralogy, metallurgy and 

 mining, geology and palaeontology, and related sub- 

 jects. The catalogue includes recent purchases and 

 selections from several libraries, and it should be 

 seen by geological bibliophiles and librarians of 

 scientific societies 



Messrs. G. P. Putnams Sons ask us to say that 

 the price of "The Essence of Astronomy," by Mr. 

 E. W. Price, reviewed in Nature of November 12 

 {p. 280), is not los. 6d. net as there stated, but 2^. 6J. net. 



OUR ASTRONOMICAL COLUMN. 

 Comet 1913/ (Delavan). — The following ephemeris 

 is taken from the Ephemeris-Circular of the Astro- 

 nomische Nachrichien (No. 469, 1914), being com- 

 municated by J. Fischer-Petersen and Vinter Hansen 

 of the Copenhagen Observatory : — 



NO. 2355, VOL. 94] 



Two photographs of this comet are reproduced in 

 the current number of the Monthly Notices of the 

 R.A.S. (vol. Ixxv., November, 1914). They were taken 

 on September 20 and 26 with the 35-in. portrait lens 

 and 30-in. reflector of the Royal Observatory, Green- 

 wich. 



The Spanish Solar Eclipse Expedition. — The 

 Madrid Observatory dispatched an expedition to 

 Theodosia, in the Crimea, to observe the total eclipse 

 of the sun on August 21. The party included MM. 

 Ascarza, Carrasco, and Tinoco, with one or two 

 voluntary helpers. The weather seems to have been 

 favourable at their station, and the results obtained 

 were satisfactory, and are briefly described in the 

 Compies rendus for November 30 (vol. clix.. No. 22, 

 p. 738). The corona is described as of a form 

 analogous to that of minimum sunspots with polar 

 ra3S a little more pronounced. Photographs of J:he 

 spectra of the corona and chromosphere were success- 

 fully secured, and, in M. Carrasco's case, with special 

 attention to the red, yellow, and green regions. 

 While details regarding the wave-lengths will be pub- 

 lished later, M. Carrasco directs attention to a red 

 coronal radiation, the wave-length of which he gives 

 as A 6373-87 A U. He describes the green coronal 

 radiation as being very feeble or absent. 



The Recent Transit of Mercury. — Accounts of the 

 observations of the transit of Mercury in November 

 last are published by numerous observers in several 

 journals. In the Monthly Notices of the Royal Astro- 

 nomical Society (vol. Ixxv., No. i, November) papers 

 are communicated by the Royal Astronomers of 

 Greenwich and Edinburgh, Mr. R. Jonckheere, Prof. 

 Fowler, and Dr. J. L. E. Dreyer. The different 

 phases seemed to have been well observed at Green- 

 wich, and the Astronomer Royal states that " none 

 of the observers saw the ' black drop,' a halo round 

 Mercury or a bright spot on the planet. The pheno- 

 menon appeared just as might have been expected 

 from geometrical considerations." This communica- 

 tion is accompanied by a plate illustrating seven posi- 

 tions of the planet, taken with the photoheliograph 

 just about the times near the beginning of the 

 transit. M. Jonckheere discusses the 368 measures 

 of the diameter of the planet as made at the Royal 

 Observatory, Greenwich, by several observers during 

 the transit. At the Royal Observatory, Edinburgh, 

 no distinctive marking on the planet's disc could be 

 detected nor any halo, and the second internal con- 

 tact was noted as " quite clean," no ligament of any 

 kind being visible. 



Prof. Fowler's observations corroborate the above. 

 An additional observation by him to determine by 

 spectroscopic means whether there was any 

 strengthening of the telluric lines near the limb of 

 the planet led him to conclude that no efi^ect of the 

 kind was seen. Dr. Dreyer's observations at the 

 Armagh Observatory show that while he observed no 

 halo round the planet, he noted the black drop at 

 egress and a bright point or dot on Mercury's disc. 

 In the Compies rendus for November 2;^ (vol. clix.. 

 No. 21) MM. Gonnessiat and Chretien present two 

 notes on the transit. 



