November 12, 19 14] 



NATURE 



291 



biochemistry of respiration. Dr. H. M. Vernon shows 

 i\v recent research points in the main to its being 

 .1 pendent on intracellular enzjmes — in seme cases 

 purely hydrolytic, in others partly hydrolytic, partly 

 oxidative. Dr. R. \\". Hegner deals with the germ- 

 cell cycle in animals, Mr. A. G. Thacker has a paper 



n extinct apes, whilst Mr. W. L. Balls considers 



ic question of the aid to be t;i\ en bv science in the 

 Uiture to the growing and utilisation of cotton. The 

 theories of dyeing are discussed by Mr. E. A. Fisher, 

 the problem of smoke abatement by Mr. J. B. C. Ker- 

 shaw, whilst Mr. James Huneker has a short illus- 

 ited article on tornadoes and tall buildings. 

 The geared turbine Atlantic liner Transylvania ran 

 her trial trips a fortnight ago, and the observations 

 of a representative of the Engineer who was present 

 are of interest. There is some vibration in certain 

 parts of the ship, but nothing to be compared with 

 that which would be experienced with reciprocating 

 t ngines. It was local, and of a very innocent descrip- 



ion; it fact, it might be described as merely an 

 >sence of stillness. Owing to the high revolution 



ijeed of the turbines — 1500 r.p.m. — the vibration speed 

 i> high. The noise in the engine-room is at present 

 quite considerable, and is the typical roar of high- 

 speed gearing. It is not easy to see how the noise 

 may be eliminated entirely, in spite of the beautiful 

 machines invented for cutting the gears. On the 

 third-class passenger deck, gear noise disappeared 

 totally at a distance of about 150 ft. from the engine- 

 room entrance. On the deck above this, the noise 

 disappeared at about 90 ft. from the companion-way. 

 In fact, in the space used for passengers, the noise 

 is just noticeable while listening carefully for it, and 

 hence cannot be considered objectionable from the 

 passengers' point of view, especially as the sound is 

 not high-pitched. 



The Carnegie Institution of Washington has issued 

 the first part— A to H— of the " Index to United States 

 Documents relating to Foreign Affairs, 1828-61," 

 w hich is to be completed in three parts. The index is 

 the work of Miss Adelaide R. Hasse, the head of the 

 department of documents in the New York Public 

 Library, and an idea of the magnitude of her task can 

 formed from the fact that the present instalment 

 the index runs to 793 large pages. In addition to 

 the reports of Congress, the following series of docu- 

 ments have been indexed : the Senate Executive 

 journal, for diplomatic and consular appointments and 

 iieaty ratifications; the Opinions of the Attorneys- 

 neral, for decisions on questions of international con- 



:i>versy; the Statutes-at-Large, for acts and resolu- 

 tions relating to international affairs; and the Con- 



ressional Globe and its predecessors for speeches and 

 rrespondence. 



OUR ASTRONOMICAL COLUMN. 



Colours of St^rs in the Cluster M13 (Hercules). 

 \\ hen stars are too faint to be spectroscopicallv 

 amined, some idea of the type of spectrum involved 

 n be gathered from their visually observed colour, 

 may happen that the stars are even so faint when 

 t ;n jn a powerful telescope that thev exhibit no 

 !our at all; it is then that the photographic plate 

 NO. 2350, VOL. 94] 



is called in, the sensitive film being a great differentiator 

 of colour. In the case of star clusters the opportunity 

 is afforded of comparing a great number of stars, and 

 it is of extreme value to know whether the stars 

 involved are all of one physical condition or same 

 spectral type, or whether they show representatives of 

 all types. Especiallj' is this the case when it is re- 

 1 membered that star clusters are most remote and 

 1 must therefore be of immense magnitude. The photo- 

 j graphic determination of the colours of some of the 

 stars in the cluster M13 in Hercules is therefore of 

 great value in this connection, and the research which 

 we owe to Prof. Barnard {Astro pliysical Journal, 

 vol. xl., No. 2, September) is one that will be read 

 with interest. In this paper the stars are practically 

 divided into two colour classes, namely, blue stars and 

 yellow stars, and this has been done by comparing 

 two photographs of the same cluster taken under 

 two conditions. One photograph was secured with 

 the 13-in. astrographic refractor of the Potsdam Ob- 

 servatory, and the other with the 40-in. refractor of 

 the Yerkes Observatory. The optical conditions on 

 the Potsdam photograph were such that the blue stars 

 were relatively brighter than the yellow- stars, while 

 on the Yerkes plate the reverse was the case. A 

 comparison of the plates thus afforded a means of 

 separating these coloured stars, but care had to be 

 taken to eliminate all comparisons of star images 

 where variability might be involved. Prof. Barnard 

 concludes that in this cluster there exist stars of 

 extremely different types, and hence, by inference, that 

 there are stars of all the different spectral types. The 

 paper is accompanied by reproductions of the Yerkes 

 and Potsdam plates and an index chart. 



The Electric Arc .and Spectral Line Displace- 

 ments. — Numerous references have been given in 

 this column to investigations on the causes in terres- 

 trial spectra of displacements of lines from their 

 normal positions. In fact, the inquiry which was 

 started some years ago to select and adopt certain 

 standards of wave-length of iron, etc., show that little 

 was known about the behaviour of lines under 

 different conditions of electric current, arc length, 

 etc. All attempts therefore to arrive at a final selec- 

 tion of lines suitable as standards are of fundamental 

 importance to spectroscopists and astro-physicists, 

 and in this report the communication by Mr. T. Royds 

 (Kodaikanal Observatory, Bulletin xl.) on an in- 

 vestigation of the displacement of unsymmetrical lines 

 under different conditions of the electric arc will be 

 welcomed. To find a light source giving normal 

 wave-lengths for all classes of lines is therefore an 

 inquiry of the first order, and the present paper is 

 an advance in that direction. The results of the 

 present work are summed up in a series of brief 

 paragraphs at the end of the paper, and while only 

 a few of these can be referred to here, the reader 

 should consult the original bulletin. When the 

 spectrum of the region of the arc near the negative 

 pole is compared with that of the centre, the un- 

 symmetrical lines are displaced in the direction of 

 their greater widening; symmetrical lines have ver}- 

 small or no displacements. The displacement near 

 the positive pole is about half that at the negative. 

 A displacement of the same sense as that at the poles 

 is produced at the centre of the arc by increasing the 

 current or shortening the arc. The displacement at 

 the negative pole is reduced if only the positive pole 

 is supplied with the material producing the spectrum. 

 Displacements occur in the arc in vacuo, but to a 

 much smaller extent than in air, and he suggests that 

 the arc in vacuo is a better source for the determina- 

 tions of standards of wave-length and for comparisons 

 i with the sun's spectrum. 



