72 



NATURE 



[March 28, i< 



sulphide are required per annum. Dr. Naef has found 

 that by treating nitre-cake at 3oo°-35o° C. with super- 

 heated steam 90 per cent, of the free acid is driven 

 off, but the product is too dilute to concentrate. 



Vol. ii.. No. 4, of the Memoirs of the College of 

 Science, Kyoto Imperial University, contains a series 

 of metallographical publications by Prof. Chikashige 

 and his pupils. These deal with the working out of 

 the equilibrium diagrams of the following series of 

 binary alloys : (i) Tellurium and aluminium, and (2) 

 selenium with antimony, cadmium, zinc, and 

 aluminium respectively. The methods adopted are 

 those in general use and do not call for any special 

 mention. The authors content themselves with the 

 determination of the main features of the diagrams, 

 without saying anywhere whether any of the alloys 

 are likely to prove of practical value. 



The reviewer of Dr. Knox's book on "Radiography 

 and Radio-therapeutics," in Nature of March 14, re- 

 marked : "We regret the omission of the. biblio- 

 graphy." The publishers direct our attention to the 

 fact that a selection of the literature of the subject 

 appears on p. iv. at the end of the volume. We are 

 sorry that our reviewer did not notice this bibliography 

 in spite of having looked for it, and that he incorrectly 

 said it had been omitted. 



QJJR ASTRONOMICAL COLUMN. 



Planetary Perturbations and ^Ether-drift. — In a 

 paper entitled "Continued Discussion of the Astro- 

 nomical and Gravitational Bearings of the Electrical 

 Theory of Matter " {Philosophical Magazine, February, 

 1918), Sir Oliver Lodge continues a discussion com- 

 menced by the suggestion that the shift in Mercury's 

 perihelion might be explained by a drift of the solar 

 system through the aether. Prof, Eddington showed 

 that a drift that would account for this would bring 

 inadmissibly large eirors into the other elements of the 

 inner planets. Sir Oliver Lodge admits an error in 

 his former work in the following words : "If the addi- 

 tional inertia due to motion is acted on by gravity the 

 varying factor m will enter twice into the equation of 

 motion and the perturbation will be increased instead 

 of being annihilated." Making this change, he 

 examines once more whether it is possible to find a 

 drift that will satisfy the observed perturbations within 

 their limits of error. After many trials, he concludes 

 that they cannot all be satisfied in this way. He tends 

 to the. conclusion that gravity has joined the conspiracy 

 to defeat our efforts to detect motion through the aether, 

 and that we are led to accept the conclusion that the 

 gravitation-constant itself is a function of the speed of 

 the attracting masses. In support of this he quotes 

 some electrical results which lead him to believe that 

 electrical attraction does actually vary with speed. "If 

 such a fact 'be established [for gravity] it may begin 

 to throw some light on the family relationship of that 

 force." 



Perturbations of Neptune's Satellite.- — In a com- 

 munication to the Observatory, for March, Prof. 

 Armellini states the chief results of an investigation 

 referring to the well-known perturbations of the satel- 

 lite of Neptune. The pole of the satellite's orbit de- 

 scribes a circle about a point in R.A. 288° and declina- 

 tion 40°, and two hypotheses have been suggested to 

 account for this motion. Tisserand attributed it to 

 the attraction of the protuberant matter about the 

 planet's equator, whilst H. Struve suggested that it 

 might be due to some unknown perturbing mass. 

 Prof. Armellini has investigated the latter hypothesis 

 on the supposition that the unknown body is a satel- 



NO. 2526, VOL. lOl] 



lite, which may not have been observed on account 

 of its small mass. He has shown that a satellite 

 having a mass sufficient to explain the observed per- 

 turbations would probably not be much fainter than 

 the 14th magnitude, and would be unlikely to have 

 escaped detection. Struve's hypothesis is accordingly 

 considered much less probable than that of Tisserand. 



Motion of Our Stellar System.— Dr. V. M. Sli- 

 pher, director of the Lowell Observatory, has made a 

 preliminary investigation of the motion of our stellar 

 system, on the supposition that the spiral nebulae are 

 stellar systems, similar to our own, situated at very 

 great distances (Proc. American Philos. Soc., No. 5, 

 1917; quoted in Journ. R.A.S. Canada, vol. xii., p. 72). 

 The radial velocities of twenty-five spiral nebulae have 

 been determined, and the motion of our system with 

 respect to them has ibeen derived in the same way as 

 that of the sun with respect to the staVs of our own 

 system. The somewhat scanty material available in- 

 dicates that we are moving in the direction of 

 R.A. 22 hours, and declination —22°, with a velocity 

 of about 700 km. per second. Dr. Slipher considers 

 that these oibservations strengthen the view that our 

 stellar system and the Milky Way are to be regarded 

 as a great spiral nebula which we see from within, 

 and that if the solar system h.as evolved from a nebula, 

 the nebula was probably not one of the class of spirals 

 dealt with in this invesitigation. 



FOOD RATIONS FOR MANUAL WORKERS 



AND SCIENTIFIC LABORATORIES. 

 T T has been announced in the Press that the Ministry 

 ■*■ of Food intends to grant extra rations to manual 

 workers from some date after April 7. The extra 

 ration will not be ordinary butcher's meat, but bacon ; 

 and the eligibility of applicants will be determined by 

 sub-committees of the local Food Control Committees, 

 to which the Food Ministry will issue a classification 

 of those persons entitled to extra food. The motive 

 of this proposal is evidently sound from the scientific 

 point of view. Considerable difficulties are, however, 

 likely to arise in practice owing to the lack of exact 

 knowledge respecting the energy needs of different 

 kinds of industrial work. Relatively few experiments 

 have been made and published, those of Amar upon 

 metal filers being- the best known. It is to be hoped 

 that the scientific advisers of the Food Ministry will 

 organise physiological investigations to elucidatfe dis- 

 puted points. Complete calorimetric measurements are, 

 of course, impracticable, but sufficiently precise results 

 can be reached through a study of the respiratory 

 metabolism by Zuntz's method, the apparatus needed 

 for which is portable. 



The Medical Research Committee has recently 

 brought to the notice of Lord Rhondda the special 

 difficulties confronting the directors of pathological and 

 other scientific laboratories in the regulations relating 

 to food supply Many instances have been brought to 

 the notice of the committee in which scientific work 

 of the highest national importance has been endangered 

 by difficulties in obtaining under existing conditions 

 necessary foodstuffs in sufficient amount or variety, 

 though the total amount required is quite negligible in 

 relation to the general food supply. The Ministry of 

 Food has now issued the following memorandum for 

 the guidance of Food Control Committees :— 



Supplies of- Foodstuffs to Pathological Labora- 

 tories. 

 (i) Lord Rhondda 's attention has been directed to 

 the difficulties experienced by scientific laboratories in 

 obtaining the small quantities of foodstuffs required 

 I by them for the purposes of their scientific work. 



