September 27, 1900] 



NATURE 



535 



OUR ASTRONOMICAL COLUMN 

 Astronomical Occurrences in October. 

 Oct. 6. I3h. 35m. to I4h. 29m. Moon occults k Piscium 

 (mag. 5). 

 9, lOh. 42m. Minimum of Algol (3 Persei). 

 II. 6h. Sim. Transit (egress) of Jupiter's Sat. III. 



11. 8h. 47m. to 9h. 25m. Moon occults ta^ Tauri 



(mag. 4-6). 



12. 7h. 30m. Minimum of Algol (3 Persei). 



12. i8h. 36m. to I9h. 23m. Moon occults f Tauri 



(mag. 3). 



13. I5h. to i5h. 43m. Moon occults v Geminorum 



(mag. 4). 

 15. Venus. Illuminated portion of disc = 0*637. 



15. Mars. ,, ,, ,, = 0*902. 



16. I7h. 26m. to i8h. 30m. Moon occults k Cancri 



(mag. 5). 



17. Saturn. Outer minor axis of outer ring = 16" '68. 

 19. loh. Conjunction of Jupiter and Uranus. Jupiter, 



o' 25' N. 

 19-21. Epoch of Orionid meteoric shower. (Radiant 



91'+ IS'.) 

 26. I2h. Conjunction of Jupiter and moon. Jupiter, 



o" 27' S. 

 28. 6h. 2im. Jupiter's Sat. IV. in conjunction S. of 



planet. 



28. Probable date of perihelion of Barnard's comet 



(1884 II.). 



29. 8h. 27m. to 8h. 46m. Moon occults d Sagittarii 



(mag. 4-9). 

 29. i6h. Mercury at greatest elongation (23° 46' E.). 

 The Fireball of Sunday, September 2, 6h. 54m.— 

 A very large number of observations of this brilliant object were 

 made, but they were not very exact, as the meteor appeared in 

 daylight. The radiant point was probably in Cepheus at about 

 334° + S?"'. The object, during its visible flight, appears to have 

 descended from a height of eighty-five miles over Richmond, 

 Vorks., to twenty miles over Fleetwood, Lanes., and to have 

 traversed a path of eighty-fi:)ur miles. Another fine meteor was 

 observed on Sunday evening, September 16, at 8h. 44m., and 

 descriptions have come from London, Birmingham, Oxford and 

 Llanelly. The radiant was in the southern sky between 

 Capricornus and Piscis Australis at 324° - 25°. The meteor fell 

 from about fifty miles over Bewdley to thirty-two miles over 

 Wigan, and had a visible course of eighty-six miles. The 

 velocity is somewhat doubtful. 



Ephemeris for Observations of Eros : — 



Sept. 



Oct. 



The co-operative observations for determinations of parallax 

 will commence about the beginning of October. The planet is 

 at present in the constellation Perseus, and passes the meridian 

 of London about 2-40 a.m. 



Ephemeris of Comet Borreli.y-Brooks {\()oob). — This 

 comet is now rapidly becoming fainter, and the following 

 abridgment from a complete Ephemeris furnished by Herr A . 

 Scheller {Astronoinische Nuchrichten, Bd. 153, Nos. 3660, 3663) 

 will doubtless suffice for observers possessed of the necessary 

 optical power : — 



Ephemeris for 1 2/i. Berlin Mean Time, 



R.A. 



Br. 



NO. 1613, VOL. 62] 



Automatic Photography of the Corona.— Mention 

 has often been previously made of Prof. C. Burckhalter's in- 

 genious apparatus for obtaining photographs of the solar corona 

 during an eclipse, and it now appears that he was extremely suc- 

 cessful at the eclipse in May last. Popular Astronomy, vol. viii., 

 contains reproductions from two negatives of the corona secured 

 by him, one uncontrolled as has hitherto been usual, the other 

 the result of intercepting part of the coronal light for varying 

 periods of time during the total exposure. The total exposure 

 in each case was 8*0 seconds, but by means of a system of re- 

 volving diaphragms arranged in one of the cameras, the image 

 was shielded in various regions for different times, thus permitting 

 the details of the inner corona to be photographed on the 

 same plate as the outermost faint streamers. The following are 

 the calculated effective exposures at the several stated distances 

 from the moon's centre (moon's semi-diameter = 15' 58"). 



Distance from 

 moon's centre 16' ... 20' ... 32' ... 50' .^ no 



Exposure ... 004s. ... 0-235. ... 176s. ... 3-203. ... 800s. 



The photograph shows the inner coronal detail close to the 

 limb of the moon, the outer streamers extending for more than a 

 lunar diameter. Several of the inner coronal tufts appear to 

 be projected on the long broader streamers as background. 



THE IRON AND STEEL INSTITUTE. 



■yHE Iron and Steel Institute held its autumn meeting in 

 -*■ Paris on September 18 and 19, under the presidency of Sir 

 William Roberts- Austen, K.C.B., F.R.S. Besides a long pro- 

 gramme of ten papers, visits to the Exhibition, to the works at 

 St. Chamond, at Hayange in Lorraine, and at St. Denis near 

 Paris, were arranged by an influential reception committee, of 

 which Mr. Robert de Wendel was president and Mr. Henri 

 Vastin honorary secretary. The attendance was unusually 

 large, and the meeting was in every respect a successful one. 

 The proceedings began on September 18 at the house of the 

 Societ6 d'Encouragement, with an address of welcome by Mr. 

 Robert de Wendel, president of the French Association of Iron- 

 masters. Sir William Roberts-Austen, having acknowledged 

 the welcome, delivered a presidential address dealing in fault- 

 less literary style with the history of metallurgy in France, 



The first paper read by the secretary, Mr. Bennett Brough, 

 was by Mr. II. Pinget, secretary of the Comite des Forges, and 

 dealt with the development of the iron industry in France since 

 the Institute's last visit to Paris in 1889. The increase in out- 

 put of iron and steel has been much greater than it was in the 

 interval between the two previous exhibitions in Paris. No 

 striking technical invention has been made, but great progress 

 has been effected in increasing the power of the appliances used 

 and in improving the quality of the products. There is a marked 

 tendency to replace cast iron by cast steel, and success has 

 attended endeavours to cast complicated forms in metal which is 

 both tough and of high tensile strength. Moreover, special 

 steels are now available for the requirements of particular appli- 

 cations, such as the growing exigencies of armour plate. The 

 discussion on this paper was confined to complimentary remarks 

 from Sir Lowthian Bell, F.R.S., Mr. Greiner and others. 



The second paper, the most important submitted to the 

 meeting, was that by Mr. J. E. Stead on iron and phosphorus. 

 It is typical of modern metallurgical research, and contains a 

 mass of original observations showing how phosphorus occurs in 

 iron and steel. The subject is dealt with in four sections: (l) 

 the constitution, properties and microstructure of iron contain- 

 ing form traces to 24 per cent, of phosphorus ; (2) the effect of 

 carbon when introduced by the fusion or cementation process 

 into iron containing phosphorus; (3) the microstructure of pig 

 iron containing phosphorus ; and (4) the diffusion of solid 

 phosphide of iron into iron. There are appended to the paper 

 useful notes on eutectics, on solid solutions, on the method of 

 determining free phosphide of iron in iron and steel, and on 

 heat-tinting metal sections for microscopic examination. The 

 observations recorded show that iron will retain as much as 

 I 75 per cent, of phosphorus as phosphide in solid solution, and 

 that when more than that is present, the excess separates and 

 is found as free phosphide of iron mixed up with the mass of 

 iron. It is also shown that carbon added to solid solutions of 

 phosphorus in iron throws out of solution the dissolved phos- 

 phide, which appears in a separate state. The most remarkable 



