15- 



NATURE 



[August 4, 19 10 



evident that many observations hitherto unexplained will 

 be capable of explanation on lines sugj^ested by these 

 results. 



In a paper entitled " Absorption and Adsorption with 

 Reference to the Radio-active Emanations," published in 

 the Bulletin of the Macdonald Physics Buildings of McGill 

 University, Dr. R. \V. Boyle shows that the radio-active 

 emanations behave as all ordinary gases in obeying the 

 iaws of solution and of gaseous adsorption. In the case 

 of thorium emanation, the experiments described .show that 

 the amount of emanation absorbed by charcoal is propor- 

 tional to the concentration of the emanation in the gas in 

 contact with it. The absorption also depends on the 

 nature of the charcoal and the amount of surface exposed, 

 and, as with ordinary gases, the absorption decreases with 

 increase of temperature. On comparing the results of 

 several experiments, it appears that thorium emanation is 

 four times as soluble in water as radium emanation, but 

 in petroleum the former is only half as soluble as the 

 latter. E.\periments with thorium emanation showed that 

 this gas is less soluble in solutions such as copper sulphate 

 and calcium chloride than in pure water, and the most 

 powerful solvents used were petroleum and alcohol. The 

 order of the solubilities of radium and thorium emanations 

 in ditTerent solvents was found to be the same. The paper 

 concludes with a brief notice of current ideas on adsorp- 

 tion, and there is appended a bibliography on the subjects 

 treated. 



The University of Illinois Bulletin No. 41 contains an 

 account of tests ' made on timber beams by Mr. .'\. N_,,i 

 Talbot. The tests were made with the view of adding 

 data on the properties of timber in the form of stringers, as 

 used in many railroad structures. The timber stringers 

 were 8 inches by 16 inches by 15 feet to 7 inches by 

 12 inches by 14 feet in size. One hundred and twelve 

 samples in all were tested, including long-leaf pine, short- 

 leaf pine, loblolly pine, and Douglas fir. The load was 

 applied equally at one-third points of the span length. The 

 dimensions of the specimens were such as to bring out 

 the strengths of timber in horizontal shear. The influence 

 of knots, seasoning checks, and wind shakes can be traced 

 in the results. Much of the data in existence is based on 

 tests made on small specimens, and a valuable feature of 

 the present series consists of the results of tests on minor 

 specimens cut from the stringers. The flexural and shear- 

 ing strengths of these smaller specimens were determined, 

 and the relation of their properties to those of the full- 

 sized stringers may be studied from the results given. In 

 addition to many tables of results, the bulletin includes 

 photographs showing characteristic fractures under the 

 bending and shearing tests. 



OUR ASTRONOMICAL COLUMN. 

 A Centr.al Bureau for Meteor Observations. — Under 

 the auspices' of the ."Vstronomical Society of Antwerp, a 

 central office has been established for the collection and 

 coordination of observations of meteors. A beginning was 

 made in 1907, and in twenty-two months 5960 observations 

 were recorded by forty observers in thirty-six localities. 

 This essay showed that a much wider organisation was 

 desirable, and the new Bureau Central Meteorique hopes 

 to receive the cooperation of all observers of meteors, 

 amateurs and otherwise, the world over. In the Publi- 

 cation No. I is given a complete set of directions and 

 advice, so that anyone, astronomer or not, who can observe 

 regularly, may at once join in the international cooperative 

 scheme. In a circular which accompanies the publication, 

 M. Birkenstock points out that the expenses of the new 



NO. 2127, VOL. 84] 



organisation will be large, and asks all those interested in 

 meteoric astronomy to assist by making an annual sub- 

 scription of at least 5 francs. 



The Rotation of Sun-spots. — To No. 4429 of the 

 Astrvnomisclie Nachnchlcn Herr P. Kempf contributes 

 some interesting results derived from sun-spot observations 

 made during 1891—3. 



.A number of solar observers have been unable to establish 

 any definite rotation of sun-spots, but here the observer 

 shows from careful observations that in thirteen cases 

 there was a distinct rotatory movement of the spot about 

 its own centre. Seven of these occurred, in the northern, 

 and six in the southern, hemisphere, but there appears to 

 be no relation between the direction of the rotation and 

 the latitude — north or south — of the spot ; only in two 

 cases in each hemisphere was the motion in the negative 

 (i.e. N.W.S.E.) direction. In one case (Greenwich spot- 

 number 2277, -August 5-16, 1891) the spot rotated 139° in 

 eleven days, while the average daily motions ranged between 

 7° and 37° ; for the northern hemisphere the mean was 

 11°, and for the southern 20°. 



Hallev's Comet. — .'\n interesting popular summary of 

 the phenomena presented by Halley's comet during its 

 recent apparition is published in the July number of The 

 World To-day by Prof. Frost. Discussing the " never-to- 

 be-forgotten spectacle " presented by the 100° tail seen 

 about the time of the comet's passage, Prof. Frost affirms 

 that the earth probably passed through a part of the tail 

 on the morning of May 19, and suggests that we were 

 within the forks, or separate streamers, of it for two days 

 following, hence the east and west tails. The strangely 

 iridescent clouds, with a kind of horizontal "rainbow," 

 seen at the horizon, may also have been due, at least in 

 part, to the presence of cometary dust. 



.Some excellent photographs were .secured by Mr. Eller- 

 larj, who led a comet expedition to the Hawaiian Islands. 

 lRGE Meteorites. — A description of the Guffey 

 meteorite, discovered by two cowboys near Guffey, Park 

 County, Colorado, in 1907, is given by Mr. Edmund O. 

 Hovey in a reprint from the American Museum Journal, 

 vol. ix., pp. 237-48. 



This object is a siderite 36-5 inches long, 15 inches 

 maximum height, and 8 inches wide. The mass is roughly 

 pear-shaped, and weighs 682 lb. Two sides show w'ell- 

 developed " thumb marks " or " piezoglyphs," but on 

 another, which is nearly straight, these are not so well 

 developed ; the author suggests that the straight edge and 

 lack of marks indicate that the mass split into two or 

 more parts when near the end of its flight, and that 

 another part may, therefore, yet be found. The mass is 

 very homogeneous, and chemical analysis shows it to con- 

 tain 88-7 per cent. Fe, 10-5 per cent. Ni, 05 per cent. Co, 

 with traces of Cr, C, S, and P ; the specific gravity is 

 7-930. It is supposed that this may be the remains of a 

 vivid meteor which was observed to pass over the Fresh- 

 water River region during the autumn of 1906 ; it now 

 lies in the foyer of the .American Museum. 



Mr. Hovey also describes two other recent additions to 

 the foyer, viz. a slice and cast of the Gibeon meteorite 

 and the largest known portion of the Modoc meteorite. 

 The Gibeon meteorite, weighing 562 lb., was discovered 

 in Great Namaqua Land (lat. 25° 8' S., long. 17° 50' E.), 

 and is in the possession of the Hamburg Natural History 

 Museum. A slice of this and a plaster cast were sent to 

 the American Museum, where it is ingenfcusly mounted 

 with the slice in situ, the two halves of the cast being 

 hinged so as to show the complete form with the polished 

 surface of the slice. 



The " Modoc " is the largest known portion (20 lb. 3 oz.) 

 of a meteorite seen to fall near Modoc, Scott County, 

 Kansas, on September 2, 1905. Twenty-five fragments 

 have been found, and, where pieces have been broken off 

 by the plough, the meteorite is shown to be composed of 

 whitish stony material containing bright specks of iron. 



Photographs of the Guffey and Gibeon meteorites illus- 

 trate tfie paper. 



The United States Naval Observatory. — The report 

 by the superintendent for the year ending June 30, 1909, 

 shows that the .Xstronomical Council, consisting of the 

 various officers and assistants at the U.S. Naval Observa- 



