July 6, 191 1] 



NATURE 



The Radial Velocities of Nebulae. — Prof. Campbell, 

 writing to the Astronomische Nachrichten (No. 450S), 

 - that as many radial velocities of nebulas should be 

 nined as is possible. 



Keeler's observations of the radial velocities of twelve 

 planetary nebulae show that these objects probably have 

 very high actual velocities, something of the order of 

 25 km. per second. On the other hand, observations of 

 the Orion nebula, and others, indicate that these extended 

 nebulae have very low radial velocities, or are at rest 

 relatively to the stars of our system. If these facts can 

 be accepted as a generalisation, many problems connected 

 with stellar evolution are opened up. For example, it is 

 suggested that the extended, amorphous nebulae are masses 

 of primordial substance antecedent to the stellar state, 

 whereas the quickly moving planetary, or condensed, 

 nebulas are the results of collisions, or near approaches, 

 &c, of rapidly moving aged stars. Some support is given 

 to this suggestion by the observation that helium (early) 

 stars show but small radial velocities (6 km.), whereas the 

 older, reddish stars give much higher (16 or 17 km.) 

 velocities. 



The Interferometer in the Study of Nebuue. — In the 

 June number of The Astrophysical Journal (vol. xxxiii., 

 No. 5, p. 400) MM. Fabry and Buisson describe an 

 apparatus they have employed in the spectroscopic study of 

 nebula;. This apparatus is compact and light, and can 

 readilj be attached to any telescope of sufficient aperture 

 for the work. They have used it with the Marseilles 

 refractor of 10 inches (26 cm.) aperture and 10 feet 

 (3-1 metres) focal length, and have secured useful observa- 

 tions of the Orion nebula ; but a reflector of large relative 

 aperture would be much better for the work, because of 

 it- achromatism. 



The method is capable of giving very accurate measures 

 for the wave-lengths of the different nebula lines, and, 

 therefore, using the hydrogen lines should give the radial 

 velocity with great precision. By finding the variations of 

 wave-length from one part of the nebula to another, the 

 circulatory movements of the gas might be determined. 



The Rotation of Stars about their Axes. — In a note 

 published in No. 7, vol. lxxi., of the Monthly Notices 

 P' S7^)i Prof. George Forbes makes an interesting sugges- 

 tion on the possibility of determining the rotation of stars 

 about their axes and the direction of the axes. In the 

 case of the sun this rotation causes a displacement of the 

 lines in the limb spectra, which in the case of the 

 integrated light of the stars would become a broadening 

 of the lines. But if the star is an Algol variable the light 

 from each limb is periodically arrested by the eclipsing 

 satellite, and the spectral lines should then show broaden- 

 ing on one side only. When the other end of the bright 

 star's equator is eclipsed, broadening on the other side of 

 the line would result. Relatively this would amount to a 

 periodical displacement of the lines about a mean position, 

 such as has been observed in some cases, and a measure 

 of the displacement might provide material from which the 

 iirection of the star's axis and the velocity of equatorial 

 regions of the star could be approximately deduced. 



The Tails of Comet 1910a. — From Prof. K. Pokrowski, 

 of the Dorpat Observatory, we have received an interest- 

 ing monograph dealing exhaustively with the several tails 

 of comet 1910a. From fifty-nine observations made by 

 various observers — many of which were recorded in these 

 columns — Prof. Pokrowski determines the positions of 

 different points in the tails, and then calculates the time 

 at which the matter forming them was ejected and the 

 value of the repulsive force which drove them away from 

 the nucleus. He thus finds that the chief tail conforms 

 to Bredichin's second type, the repulsive action being about 

 equal to the gravitational attraction ; the western branch 

 of the tail was probably ejected, under rather greater re- 

 pulsive force, from the nucleus about January 18. 



The second, smaller tail, belongs to the third type, being 

 formed under a repulsive force considerably less than the 

 gravitational repulsion by particles which left the nucleus 

 about January 16. The anomalous tail, directed towards 

 the sun, is likened to those of comets 1844 III., 1862 III., 

 and 1S82 II.. where the particles left the nucleus with a 

 verv small velocity, in this case about 0-5 km. per second. 



NO. 2 175, VOL. 87] 



CO.\FEKE.\CE ON EDUCATION AND 

 TRAINING OF ENGINEERS. 

 '"THIS conference, organised by the Institution of Civil 

 Engineers, held its meetings at the rooms of the 

 institution on June 2S and 29, under the presidency of Mr. 

 Alexander Siemens. The subjects were discussed under 

 three sections, general education, scientific training, and 

 practical training, the chairmen ut these being respectively 

 Mr. Anthony G. Lyster, Dr. YY. C. Unwin, and Mr. R.'. 

 Elliott-Cooper. There were very large attendances at all 

 of the meetings. 



In opening the conference, the president stated that the 

 council of the institution had endeavoured to define the 

 scope of discussion by declaring that its object was to 

 consider the methods of preparation to be adopted by those 

 who contemplate entering the engineering profession in 

 compliance with conditions laid down by the by-laws for 

 election into the institution. In addition to a sound 

 general education, to a competent know-ledge of science 

 and to practical training, there is the necessity common 

 'to all professions, which Prof. Max Muller defines thus : — 

 " . . . No science and no art have long prospered and 

 flourished among us, unless they were in some way sub- 

 servient to the practical interests of society . . . that 

 interest depends on the practical advantages which society 

 at large derives from these scientific studies." This prin- 

 ciple may be expressed by saying that a young engineer 

 should be educated so as to become a dividend-earner for 

 his employer, for this is the most trustworthy indication of 

 his merit. He should possess some knowledge of business 

 methods and of law, and he will find one or more modern 

 languages very useful in obtaining remunerative employ- 

 ment. No definite resolutions would be taken on the sub- 

 jects under discussion, as the object of the conference is 

 rather to form opinion than to arrive at and to record, 

 definite conclusions. 



Sir Wm. White directed attention to the danger of too 

 much devotion to the theoretical side. At one time train- 

 ing in engineering science could scarcely be obtained, but 

 there was a modern tendency to go too far in the other 

 direction at the expense of the practical side of the 

 engineer's training. The evils of coaching for examina- 

 tion purposes were also pointed out by the same speaker. 

 Sir J. Wolfe Barry justified the introduction of admission 

 to the institution by examination, and considered that in 

 the engineer's course of training the general education of 

 an accomplished gentleman should not be lost sight of. 



Mr. Anthony G. Lyster considered that education, to be 

 of real value, should not only furnish information and 

 knowledge, but should also train and expand the intelli- 

 gence and develop that type of character which fits a man 

 to lead the best and most useful life. The demand for 

 special training for the engineer becomes increasingly 

 urgent, and unless he is to be debarred from our universi- 

 ties or public schools, it behoves the authorities to bring 

 their educational standards into line with modern require- 

 ments. There is no desire that members of the engineer- 

 ing profession should be engineers and nothing else ; on the 

 contrary, every opportunity should be given to the best 

 type of man that the university and public school can 

 produce to start with the best intellectual equipment as an 

 engineer. 



In the general education section, Dr. James Gow, head- 

 master of Westminster School, opened the discussion on 

 literary education and engineering by stating that his 

 experience as examiner in Latin for the institution showed 

 that Latin is seldom included in the preliminary education 

 of an engineer, or that boys who intend to be engineers 

 pay little attention to this subject. It is probable that, 

 where Latin is neglected, no very close study is given to 

 any other language. He did not contend that literary 

 studies are of any direct or immediate use to the engineer ; 

 his work must be largely deductive and mathematical, on 

 which a literary education has no bearing. But pre- 

 sumably there are occasions when he is called upon to 

 make use of chemistry or geology, or some other deductive 

 science, and he is not properly equipped unless he has a 

 fair knowledge of these sciences. Now it is notorious, at 

 least to schoolmasters, that a bov who passes from the 

 classical side to the modern side of a school has an 

 immense advantage in inductive science owfr those who 



