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NATURE 



[February 5, 1920 



Entente Scientific Literature in Central Europe during 

 the War. 



The chief object of my letter, " A Tribute from 

 Prague," published in Nature of December ii, 1919, 

 was to congratulate the Editor upon the jubilee 

 number and to express my delight at again being able 

 to obtain this invaluable journal after an interval of 

 more than five years. I thought it worth while 

 to state very briefly that this break was caused by 

 political reasons. 



The letter by Mr. Lawson published in Nature of 

 January 1 induces me, unwillingly, to enter a little 

 into non-scientific details. 



There is a decided difl^erence between the point of 

 view during the war of an interned distinguished 

 foreigner enjoying the well-known hospitality of the 

 inhabitants of the capital of the late Austro-Hungarian 

 Empire and that of us Bohemians or Czechs whose 

 country was, by the Government of the same Vienna, 

 nearly converted into a desert, whose best men (even 

 poets) were imprisoned and condemned to death for 

 their regard for the Entente, and who, had the war 

 lasted only half a year longer, would have experi- 

 enced the same fate as 1,500,000 Slavonic, chiefly 

 Serbian, children in Bosnia and Herzegovina, con- 

 demned to starvation. Their parents, in so far as 

 they were not shot down, escaped from death only 

 by eating grass and other herbs ! 



No Englishman can wonder that we (Austrian) 

 Slavs fully sympathised with the contents of the fol- 

 lowing two remarkable articles, which I select from a 

 great number : 



(i) The leader, "The War and After," published in 

 Nature of September 10, 1914 (p. 29). Never 

 previously had such a fine political article been pub- 

 lished in your columns, and 1 would beg readers to 

 convince themselves that its greftt truth, and even 

 prophecy, were fulfilled to the last point. 



(2) An article published by Sir Oliver Lodge 

 during the early part of the war in the Psycho- 

 logical Review. Sir Oliver says that there exists a 

 Great Justice watching over the destinies of mankind 

 who will never allow a crime to become a law. The 

 editor of our leading daily paper introduced this view 

 as " strange ideas of a spiritualist," and only by this 

 trick did it escape the watchful eye of the censor. I 

 thank Sir Oliver for this article, which kept many 

 of my countrymen and me firm in the davs of our 

 greatest distress. 



All this was known to the Austrian Government, 

 and it is well understood whv it withheld during the 

 whole war the _ circulation of periodicals which con- 

 tained such articles as those referred to above. 



Towards the end of the war, when everyone saw 

 that the old Monarchy was going to pieces, the .Austro- 

 Hungarian Foreign Office -and I assure Mr. Lawson 

 that I am by no means "unaware of the fact "—asked 

 the Senate and professors of our Universitv to fill a cir- 

 cular with the names of the Entente scientific journals 

 which they would like to obtain. I denoted several 

 Journals — in the first place. Nature. 1 know that 

 those belonging to the "privileged nations" obtained 

 the journals they wished, but no notice at all was 

 taken of my desire or that of any other Bohemian 

 scientific institution up to the Very end of the 

 Monarchy. Bohuslav Brauner. 



Chemical Laboratory, Bohemian LIniversitv, 

 Prague, January 20. 



Percussion Figures in Isotropic Solids. 



Ajx anthropologists will be glad to see the subject 

 of percussion figures receiving attention in the pages 

 of Nature (October 9 and November 20, 1919), as the 

 NO. 2623, VOL. 104! 



figures form the basis of flint-fracture— the important 

 factor in determining the age and origin of man. 

 Unfortunately, the fracture cone is by no means so 

 simple and constant in outline as one might be led to 

 expect from what has already been advanced, and a 

 number of factors enter into the question, such as the 

 shape and elasticity of the percusser, the velocity of 

 the blow, the striking angle, the perfection of 

 surface of the percussed, its elasticity, and, above all, 

 its varying refrangibility. 



In Nature and practice we generally find that after 

 the cone has maintained itself for a distance, the sur- 

 face resolves into a cylinder in the striking plane, 

 which is maintained for a certain varying distance ; 

 then it resolves outwards in a more conical direction, 

 which may extend until rupture takes place ; or it 

 may even resolve again and again as before, giving 

 rise to step-cones. Specimens before me show seven 

 such steps. Further, from causes into which we can- 

 not now enter, the well-known conchoidal ripplings 

 may be set up. These may be very simple and con- 

 centric or the very reverse, and may be either apical 

 or marginal ; they pass into step-cones. Frequently 

 the surface turns inwards, producing cylindrical frac- 

 ture more or less normal to the striking plane. 



Generally, with glass and flint there is another set 

 of features in the form of stellate lines, which ma\ 

 be very few or numbered by hundreds. An examina- 

 tion of these shows the cone to be a surface of revolu- 

 tion, and the direction of the gyrations is shown by 

 the steps made by every radial (some dozen of these arc 

 faintly shown in Prof. Raman's illustration in Nature 

 of October 9). These mav increase in size until we 

 get step-fracture, where the steps may be, say, 3 mm. 

 or 4 mm. high. It may be noted in passing that those 

 are the lines along which fracture in plate-glass takes 

 place. 



Perhaps the most remarkable thing about these 

 steps is that they indicate right and left revolutions in 

 relation to the cone. Sometimes the two hemironep 

 coincide, and we get a perfect cone. At other times 

 the fracture-waves overlap for a distance, giving rise 

 to the mysterious iraillure ; they mav also meet in a 

 re-entrant angle, which mav become verv acute, sav 

 down to 30°. This is only the beginning of the com- 

 plications. Cones may be quite asymmetrical ; one 

 hemicone may be reduced to a plane. There are also 

 faceted cones, shell-cones (cones in cones), and cones 

 in cups. Then there are the phenomena of cone- 

 capture, and still greater complications of positive and 

 negative hemicones, and multiple hemicones which 

 by mutual capture produce large flat surfaces, and 

 many others. 



T suggest that the study involves something more 

 than isotropics, seeing that in glass, silica, and manv 

 other substances new atomic or molecular re-arrange- 

 ments set in which soon render them anisotropic or 

 anisoclastic, and in one direction end in spontaneous 

 disruption into forms which call for mathematical 

 explanation quite as much as, and indeed more than, 

 .simple percussion figures in ideal isotropes ; and, on 

 the other hand, colloids pass into crystals where both 

 optical and dynamical properties varv according to 

 the lines along which the alterations take place. 



W. J. Lewis Abbott. 



St. I.eonards-on-Sea. 



Change of Colour in Plumage of Captive " Sun-birds " 

 or " Honey-suckers." 



We have had considerable success at the Zoological 

 Gardens here in keeping in health nine varieties of 

 "sun-birds" or, as locallv known, " honev-suckers," 



