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NATURE 



[January 29, 1920 



building, having 757 vessels under construction, with 

 an aggregate gross tonnage of 2,994,249. This ligure 

 is 27,734 to"s in excess of the tonnage now in hand 

 in the United States. In all other countries of the 

 world, including the United States and the British 

 Dominions, but excluding Germany (for which country 

 the figures are not yet available), there are 1381 vessels, 

 makirlg 4,867,114 tons in all; so that British tonnage 

 building now amounts to more than 38 per cent, of 

 the world's total. Our shipbuilding industry is thus 

 in a highly satisfactory condition. More than one- 

 third of the total British tonnage now under con- 

 struction is building in Clyde shipyards. 



An interesting paper on radio direction and position 

 finding was read by Capt. H. J. Round to the Institu- 

 tion of Electrical Engineers on January 14. Capt. 

 Round gave a history of the development of the radio 

 goniometer for war purposes which took place im- 

 mediately war broke out. ITie record of the 

 difficulties that were overcome is instructive. It was 

 soon found out that the German Navy directed its 

 Zeppelin fleets by direction-finding from land stations. 

 On several occasions, however, when there were nine 

 or ten Zeppelins in a raid all doing their utmost to 

 communicate with their base stations for bearings the 

 German messages got into a hopeless tangle. Our 

 Naval Intelligence operators believed that one special 

 German operator was so skilful that whenever he 

 took control everything proceeded smoothly. The 

 Germans had two radio phare stations which enabled 

 their Fleet and submarines to determine their posi- 

 tions in the North Sea without the necessity of trans- 

 mitting signals. In each station there was a rotating 

 frame continually sending messages and giving a 

 special zero signal once every revolution. Any opera- 

 tor noting the time-interval between the zero signal 

 and the instant at which the received signal was a 

 minimum could tell at once the angular position of 

 the ship with respect to the station. Doing this for 

 both stations, the position of the ship was deter- 

 mined. During nig"ht-time many anomalous results 

 were obtained when direction-finding, the reasons for 

 which have not yet been satisfactorily explained. 



Messrs. A. and C. Black, Ltd.. announce "Insect 

 Life," by C. .\. Ealand, illustrated, and a new edition 

 of "Studies in Fossil Botany," by Dr. D. H. Scott, 

 part i., Pteridophyta, illustrated. Messrs. Crosby 

 Lockwood and Son promise " Oils, Fats, and Waxes : 

 Their Manufacture, Refining, and Analysis, including 

 the Manufacture of Candles, Margarine, and Butter," 

 by Dr. G. Martin; "Applied Chemistrv for Technical 

 Students," by Dr. C. K. Tinkler and H. Masters; 

 and "The Principles of .^ir Navigation," by J. E. 

 Dumbleton. The S.P.C.K. is bringing out an edition 

 of Clerk Maxwell's "Matter and Motion," revised and 

 brought up to date by Sir Joseph Larmor; also the 

 following new books : " Archimedes," by SirThomas L. 

 Heath (in the Pioneers of Progress : Men of Science 

 Series); "The Nature-Study of Plants in Theory and 

 Practice for the Hobby-Botanist," by T. A. Dymes; 

 and "The Book of the Sea-shore," by W. P. Pvcraft 

 (the first of a new series entitled The Nature Lovers' 

 I,ibrary). 



NO. 2622, VOL. 104] 



I 



; O.LR .ASTRONOMICiL COLUMN. 



New Comet 1920a. — A comet of the loth magnitude 

 has been discovered by Sejior Comas Sola at Barce- 

 lona. It was photographed by Mr. Wilson at Carleton 

 College Observatory, Northfield, Minnesota, U.S.A., on 

 January 2od. i5h. 5i-8m. G.M.T. R..A. 7h. s7m. 4o-5s., 

 N. decl. 21° 40' 54", referred to the equinox of 19200. 

 No information is to hand about its motion. The 

 comet's appearance is almost stellar. 



Spectrum of Comet Brorsen-Metcalf. — Pubs. .-Xstr. 

 Soc. Pac. for December contains an account by Prof. 

 Slipher of the spectrum of this comet photographed at 

 Flagstaff on October 17. It resembles that of comet 

 h 1914 (Zlatinsky) fairly closely. The third and fourth 



! carbon bands and the first, second, and third cyanogen 

 bands are shown, also six unidentified lines between 

 4016 and 4074. There is also a faint continuous 



j spectrum. 



The Fireball of January 16.— .\ few additional 

 observations of this brilliant object have come to 

 hand, and they prove it to have been of a very excep- 

 tional character, .'^t Diss, in Norfolk, the streak it 

 left remained visible for fifteen minutes. 



The height of the meteor was from about 52 to /.4 

 miles, and its velocity 15 miles per second. Its course 

 at first lay above Saffron Walden, w-hence it travelled 

 to above Watford, and then disappeared. Its radiant 

 point appears to have been in the northern region of 

 Cancer, which was not far above the north-east 

 horizon at the time of the meteor's apparition. 



This particular part of the sky seems to be the focus 

 of emanation of many fine meteors in January, but 

 they do not appear to favour any particular date. 

 Thus on January i, 1913, January 21, 1898, and 

 Januarv 29, 1905, bright meteors were traced to the 

 same point, and it has also been conspicuously active 

 in the months of November and March. 



Open Stellar Clusters. — Dr. Harlow Shapley hto 

 extended his studies of the globular clusters to in- 

 clude the more widely extended clusters chiefly found 

 in the Galaxy (Proc. Nat. .\cad. Sci., Washington, 

 August, 1919). He determines the distances of thest: 

 objects by methods similar to those employed for the 

 globular ones ; the distances range from 60 parsecs for 

 the Pleiades to 16,000 parsecs for one cluster and 

 14,000 parsecs for four others (i parsec = 3i light- 

 vears). The average of the seventy clusters discussed 

 is 6000 parsecs. Their centroid is distant some 3000 

 parsecs from the sun towards galactic longitude 270°. 

 Since these clusters would .seem to be embedded in the 

 galactic star-clouds, these results would indicate a 

 greater distance for the latter than that which was 

 uritil lately thought probable. 



Dr. Shaplev is inclined to abandon his earlier view 

 that the globular clusters cannot exist in the galactic 

 plane, and break up as soon as they enter it. He 

 realises the cogencv of the evidence that there is much 

 absorbing matter in this plane, which conceals objects 

 lying beyond it. He still thinks that the open clusters 

 are the remnants of former globular ones, but does not 

 postulate such a sudden transformation from one type 

 to the other as he did at first. 



The .A^stronomer Roval and Mr. Melotte give some 

 details about one of these veiled regions, which 

 lies in the constellation Taurus (Monthly Notices 

 R..\.S., November. 1919). -Since the paucity of stars 

 in the region is the same for all magnitudes, it is 

 concluded that the obscuring cloud is comparatively 

 near us. This diminishes the difficulty of the great 

 1 mass that would be required if the cloud were more 

 remote. 



