March 30, 19 16" 



NATURE 



109 



of the town, has for a long time past produced very 

 marked erosion of the right, or concave, bank, with 

 corresponding accretion on the other. It was realised 

 that unless this action could be checked the channel 

 would ultimately be deflected away from the town 

 and the existence of the port jeopardised. The reme- 

 dial work consisted of a training wall, 13,000 ft. long, 

 constructed of stone rubble laid on a brushwood 

 mattress foundation, with a reinforced concrete super- 

 structure finishing at high-water level of neap tides. 

 The work was begun in 19 10 and completed in the 

 spring of 19 14, at a total cost of 921,783/. The stone 

 — a porphyritic diorite — was mainly obtained from 

 quarries specially opened out on an uninhabited island, 

 some 135 miles distant from Rangoon, situated in the 

 open sea off the Tenasserim coast. The total quantity 

 of stone used amounted to nearly 28 million cubic 

 feet. The mattresses for the foundation absorbed 52 

 million bundles of brushwood from local jungles. 



The Institution of Electrical Engineers has issued 

 a new edition of its rules tor the electric wiring of 

 buildings. They differ chiefly in points of detail from 

 the code issued in 191 1. One of the modifications 

 relates to the arrangement of switches and fuses on 

 installations connected to three-wire networks with 

 earthed neutrals, to ensure that the connection to the 

 neutral main shall not be interrupted before those to 

 the outer conductors. Another calls for double-pole 

 switches on all electric heaters rated above i kw. 

 The rules are now adopted by fifty insurance com- 

 panies. 



Messrs. W. Heffer and Sons, Ltd., Cambridge, 

 announce for earlv publication "Methods in Practical 

 Petrology," by H. B. Milner and G. M. Part. The 

 work is intended for petrological students and others 

 who wish to make their own rock slices', and will 

 contain chapters on the preparation of rock slices, 

 examination of rock slices, microchemical methods 

 (staining), and mounting of sands and crushed rock 

 material, with an appendix on the preparation of 

 stains. 



.\ new monthly periodical entitled Physiological 

 Abstracts is about to be issued bv Messrs. H. K. Lewis 

 and Co., Ltd., under the editorship of Prof. W. D. 

 Halliburton. We understand that the term "physio- 

 logical " is used in a wide sense, and that the journal 

 will contain important papers in allied sciences which 

 have physiological bearings ; thus, abstracts will be 

 given of papers in comparative physiology and bio- 

 chemistry, as well as in physiology proper. It is not 

 proposed to print original communications unless there 

 be special reasons for so doing. 



OUR ASTRONOMICAL COLUMN. 



The Pl.anet Venus. — The nearest approach to the 

 Pleiades will occur about 6 p.m. on Tuesday, April 4. 

 Venus will then appear approximatelv 2\9 distant 

 from Alcyone, the brightest star of the cluster. 



New Lines in the Spectrum of Silicon. — Prof. A. 

 Fowler, in a paper communicated to the Roval Astro- 

 nomical Society (Monthly Notices, Ixxvi., pp. 196-7), 

 gives the following lines in the spark spectrum of 

 silicon, most of them observed and identified for the 

 first time. AX 57402 (int. = 10), 4829-4 (4), 4820-1 (3). 

 4813-7 (2), 350O-5, and 3487-1. All have been found 

 to show the laboratory behaviour characteristic of 

 Lockyer's Group IV. lines (i.e. brought out bv the 

 stron-'.'st condensed discharges), and the four less re- 

 frangible also appear in the" Harvard reduction of the 

 spectrum of /? Crucis (Bi. Cru.), which also shows the 

 NO. 2422, VOL. 97] 



I previously known lines of Group IV., AA 4089 and 

 ; 4"6-5. 



< Definitive Orbit of Co.met 1802. — First observed 

 ' by Pons on August 26, 1802, this comet was observed 

 I 140 times during a period of forty-one days, describ- 

 ! ing heliocentrically an arc of 46°. On the basis of the 

 ! orbit calculated by Olbers from his own observations 

 I K. Lundmark has derived the following elements by 

 I the method of Schonfeld : — T = 1802-69; epoch, 1900; 

 I a> = 2i° 51-7' ; (3 =310° 54-6' ; 1 = 56° 59-9' ; log q, 0-0391. 

 I Perturbations have not been calculated, as the comet 

 ! was observed for so short a period, and, moreover, 

 I a graphical examination showed that the comet in its 

 ! path through the solar system had nowhere 

 ; approached the major planets. Identity with comet 

 I 1909 I. would give a period of 106-734 years, and the 

 next earlier apparition would be 1695, ^^^ ^^e orbit 

 of the comet of that year is not known with the 

 requisite accuracy to establish identity. 



A New Method for the Determination of Lati- 

 j TUDE. — ^The solution of the outstanding problems con- 

 I nected with the variation of latitude is now being 

 j sought in variety of methods as contrasted with the 

 i uniformity of the international latitude service. In 

 I this connection attention is merited by a method pro- 

 i posed and successfully employed by Dr. G. Zappa 

 (Atti R. Accademia dei Lincei, vol. iii., p. 69, 1916). 

 The new method is a modification of Struve's, in 

 which high altitude stars are observed in the prime 

 vertical, and the essential improvement consists in 

 the employment of pairs of stars, one E. the other W., 

 chosen so that the observation of both can be made 

 in a short interval of time. It is claimed to afford 

 results comparable with those given by the Horrebow- 

 Taloott method, and may thus possibly serve to clear 

 up the mystery of th^ Kimura term. The mean error 

 of a latitude deduced from nine pairs of stars (Boss, 

 P.G.C.) is ±0-10", whilst the latitude of the Observa- 

 tory of Capodimonte has been determined with a mean 

 error of ±0-35", but the relevant number of observa- 

 tions is not stated. The " Carpe " premium has been 

 awarded to Dr. Zappa for his memoir. 



The Plane of the Solar Motion. — ^.\ further paper 

 by Prof, von S. Oppenheim on the subject of stellar 

 inotions appears in Astronomische Nachrichten. 

 No. 4830, and nominally concerns the plane of the 

 solar motion. Shortly after Kobold's well-known 

 memoir on this subject was published, Harzer showed 

 that the method reduced to the solution of a cubic 

 equation giving the axes of what Prof. Oppenheim 

 now terms the " momenten-ellipsoid." -Although the 

 Bessel-Kobold method gave a good value for the right 

 ascension it failed to determine the declination of the 

 apex, and no further attention appears to have been 

 given to the Harzer ellipsoid. Prof. Oppenheim has 

 now found the possible significance of the remaining 

 axes by an application to the case of the geocentric 

 motions of the minor planets. In a recent paper (see 

 Nature, October 21, p. 209) he employed the Bessel- 

 Kobold method to investigate the plane of the solar 

 motion, and incidentally found that the Charlier sec- 

 tors were divided into two groups, about half giving 

 the normal value for the ^, whilst for the others the 

 value was found to be 360°- $7. as though direct and 

 retrograde stellar motions had been discriminated. 

 The two groups have now been treated separately, 

 and it is stated that the momenten-ellipsoids are 

 enantiomorphous. One axis of each is, of course, 

 directed towards the solar apex ; by analogy with the 

 minor planets it appears that the second axis points 

 to the pole of the plane of the solar motion, whilst 

 the third is directed to the ideal centre of the stellar 

 orbital movements. 



