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NA TURE 



[November 25, 1922 



Action of Cutting Tools. 



In the interesting letter which appeared in Nature 

 of August 26, p. 277, Mr. Mallock objects to the use 

 of the word cutting as incorrect when applied to 

 tools used for metal work, and it is surprising, there- 

 fore, to find that his own paper to which he refers 

 in support of his contention is entitled " The Action 

 of Cutting Tools," although it is almost entirely 

 <1 voted to showing that the action of such tools is 

 that of shearing. 



In a further letter in Nature, p. 603, of November 

 4, Mr. Mallock dismisses my paper as having no 

 reference whatever to the action of cutting tools, 

 apparently on the ground that it is entirely devoted 

 to a consideration of elastic strains. So far as the 

 tool itself is concerned, it is only useful so long as it 

 does not become permanently deformed, and to the 

 maker of tool steel, the stresses and strains produced 

 within the elastic range are therefore matters of 

 interest, so that an attempt was made in this paper 

 to show the distribution of stress in the tool itself 

 under these conditions. 



In another section an account is given of the stress 

 effects in the work when the tool is removing material 

 therefrom, which are quantitative within the range 

 for which the laws of photo-elasticity are known, 

 and qualitative in the plastic region, as present 

 knowledge is not sufficient to interpret fully the 

 interference effects observed. Mr. Mallock ignores 

 these latter effects, although they are undoubtedly 

 of importance. They show, for example, that the 

 action is sometimes discontinuous, and under other 

 conditions is not so, although Mr. Mallock states 

 quite definitely that it is always discontinuous and 

 quasi-periodic. Mr. Mallock's letter also lays stress 

 on the curling up of the shaving, but this does not 

 always happen, as the discussion on my paper 

 brought out the interesting fact that, as the speed 

 increases, the curls of steel shavings increase in 

 radius until at speeds of about two feet per second 

 the shavings become practically straight and are 

 often a danger to workmen. This effect has also 

 been produced in nitro-cellulose at low speeds with 

 a suitable tool, and it is then found that these straight 

 shavings show permanent stress effects similar to 

 those produced when a thin curved beam is flattened 

 out. E. G. Coker. 



Engineering Laboratory, University College, 

 London, W.C.i. 



A New Worship? 



" Therefore no man that uttereth unrighteous things 



shall be unseen ; 

 Neither shall Justice, when it convicteth, pass him by. 

 For in the midst of his counsels the ungodly shall be 



searched out ; 

 And the sound of his words shall come unto the Lord 

 To bring to conviction his lawless deeds : 

 Because there is an ear of jealousy that listeneth to all 



things. 

 And the noise of murmurings is not hid. 

 Beware then of unprofitable murmuring." 



After a period of ennobling worship in that 

 greatest of our English Cathedrals, the Scafell massif, 

 on my return to town I chanced to enter that strange 

 building, Burlington House, wherein be installed 

 many altars to the great god, Science. Visiting 

 that which ranketh first, I found an impassive 

 figure, seated in a chair, at the High Altar, with a 

 brass bauble before him : he needed but the peculiar 

 head-dress to be an Egyptian Priest-King. More- 

 over, the service was apparently Graeco-Egyptian, 

 if not Babylonian. The officiating young priest used 

 many beautiful words clearly of Grecian origin, 



NO. 2769, VOL. I IO] 



though at times an American phrase was noticeable, 

 as when he spoke of Arrhenius doing chores, as I 

 understood, for the god Isos. Most remarkable, 

 however, was the way in which, at intervals, turning 

 towards the altar, he solemnly gave utterance to 

 the incantation — " See, Oh, Too ! " My impression 

 was that Too was the great king in the chair. The 

 priest apparently was in fear of impending disaster, 

 for at the close of his address he spoke much of 

 concentration of the Hydrogen Ikons and their 

 attack and repulse, often repeating the phrase " See, 

 Oh. Too " — but Too seemed not to notice. 



Two young acolytes then cast pictures of writing 

 upon the wall as difficult to interpret as was that 

 message expounded by Daniel in days long ago. 



Most marvellous was the closing sermon, in which 

 an account was given of the confusion wrought 

 among a strange people, called " Lysodeiktics," by 

 adding tears, nasal secretion, animal stews, turnip 

 juice — seemingly muck of any kind — to their food : 

 and how some of them were not killed. To one of 

 an old faith, it seemed a strangely degenerate worship ; 

 indeed, that such service could be held worthy of 

 attention amazed me. 



In the evening, it chanced that I was led to peruse 

 an article, in The Times Literary Supplement, on 

 " Tradition and the French Academy," wherein is 

 given Matthew Arnold's quotation, in his well-known 

 essay, from the Academy's statutes : — 



" The Academy's principal function shall be to 

 work with all the care and all the diligence possible 

 at giving sure rules to our language and rendering 

 it pure, eloquent and capable of treating the arts and 

 sciences." 



The whole article is worth reading ; at the end 

 is a quotation from a work by the late Pierre Duhem, 

 the closing words being — 



" le respect de la tradition est une condition essentielle 

 da progris scientifique." 



It is scarcely necessary to point out the application 

 of these quotations ; yet shall I ever pray : See to it, 

 Oh, see to it, great Oh, Too ! 



Henry E. Armstrong. 



The Spectrum of Neutral Helium. 



A most significant feature of the success of the 

 quantum theory in explaining the sequence of 

 radiation-frequencies forming the Balmer type of 

 series in the spectra of hydrogen and ionised helium 

 is that it also offers an intelligible explanation of the 

 differences in the intensities of the successive lines in 

 the sequence, and that its postulates are not incon- 

 sistent with the known facts regarding the sizes of 

 the atoms in their normal states. The fundamental 

 assumption in the theory is that the states of the 

 atom represented by increasing quantum numbers 

 depart more and more from the normal state, and the 

 greater intensities of the earlier lines in a sequence are 

 readily understood as due to the greater probability 

 of transitions actually occurring between states re- 

 presented by smaller quantum numbers. 



Any attempt to build up a theory of spectra which 

 ignores these fundamental considerations must be 

 received with caution. The remark just made 

 appears to be particularly applicable to Dr. Silber- 

 stein's attempt (Nature, August 19) to explain the 

 spectrum of neutral helium on the assumption of the 

 independence of the electrons. Looking over the list 

 of frequencies given in his letter, and comparing them 

 with the maps and tables of the helium spectrum 

 contained in Prof. Fowler's report, it is noticed at 



1h.1t the well-known intense yellow line of 



helium at X5876, which is the first member of the 

 diffuse series of doublets, is given by Dr. Silberstein the 



