October 27, 1923] 



NA TURE 



»i7 



its analysis of the cause of the practical problem and 

 in indicating the direction in which prevention of the 

 disease may be looked for, the authors show clearly 

 how laboratory investigations, at first sight remote 

 from the practical problem, contribute to its solution. 



Laboratory experiments have shown that an exactly 

 similar " brown heart " condition may be produced in 

 home-grown apples, under carefully controlled condi- 

 tions which leave no doubt that the internal decay 

 takes place when the concentration of carbon dioxide 

 in the internal atmosphere, in the air spaces ventilat- 

 ing the tissues of the apples, exceeds a certain toxic 

 limit. The ventilating system and its communication 

 with the external atmosphere, varies with the variety 

 of apple ; naturally, therefore, the toxic limit is 

 reached with different rapidity in different varieties, 

 and thus a reasonable explanation is found of the 

 different varietal susceptibility to " brown heart." 



The authors establish experimentally that within 

 wide limits the oxygen concentration is not responsible 

 for " brown heart," and their examination of the ships' 

 holds where " brown heart " has appeared during the 

 voyage confirms the view that it is to be associated 



with a high percentage of carbon dioxide in the hold 

 where the apples were stored. Thus the importer, 

 the grower, or salesman concerned with the storage 

 of apples and pears has his attention directed to one 

 clearly defined pathological condition to which the 

 fruit is subject, and at the same time a clear suggestion 

 as to the direction in which a remedy may be found. 

 Incidentally the authors think that their work also 

 elucidates an old-standing problem of the grower, 

 whose apples frequently suffer from a functional dis- 

 order known as " bitter-pit." Brown discoloured 

 patches appear just under the skin of the apple and 

 dry up leaving the pits. The original browning and 

 decay seems to be exactly similar to the internal 

 decayed tissue in " brown heart," and is probably 

 traceable to the same cause, a local excess of carbon 

 dioxide in the tissue just below the skin whicli then 

 turns brown. lliis suggestion will greatly interest 

 apple growers. "Bitter pit" much depreciates the 

 value of a good apple, and attention will certainly be 

 turned to the possible causes of such local excessive 

 accumulations of carbon dioxide in the veiuilating 

 system of the apple tissue. 



The New Mechanics.^ 



T T is interesting to speculate on the forecasts which 

 ^ would have been made at the beginning of the 

 century as to the condition of physical theory now. 

 The state of knowledge at that time would have 

 suggested that the atomic theory would proceed to 

 develop along the lines of the older mechanics. One 

 or t\\ o phenomena already known did not seem to fit 

 in very well, but it was not very unreasonable to 

 suppose that the increase of knowledge would remove 

 t]ie>e difficulties. The physicist of that time would 

 ]U)t have conjectured what has actually come to pass. 

 J lu're are at present two great bodies of doctrine, 

 either of which seems to hold over a wide field, but 

 ]!' iiher of which can be at all reconciled with the 

 other. Nature is more like both than like any 

 compromise between them. Of these two doctrines, 

 one is the old-fashioned mechanics, whicli works 

 for many atomic phenomena; the of ik w 



mechanics — is known as the quantum I lie 



underlying true mechanics are really quite uuknoun, 

 but we have a curious set of rules whicli have an 

 extraordinary knack of giving the ' : the 



branch of mathematics with \\\w -. are 



■ I losely connected is, rather mi' xpectccliy (and 



good deal of qualification!, ehinentary arith- 

 metic. It is the purpose of the lecture to illustrate 

 this. 



' ' first illustration is " atomic number." It has 



iiiid possible to number olt aU the elements 



,.,,.,»>,, to chemistr^■, starling from h\(!" ' t, 



helium z. and so on \\y to nraniuni (\z, ; c 



I : iiiii I .1 I ^ h:i \ (• a si m I lie ])h\si( ;:1 mi;i niii" w I i .ic 



: ' ant t hm^ that > 1 loiit the 



Mir :: I ' i!i!ii iiunii ' , 1 J!',- total 



numl i!T ot i re\ ol\ (• n mui 1 i I, 



of 1 he atou 1 U'lieil in a \ ai iri \ 



of whirl: l! iiiiving is the " ia\ I'li'M'' '.;■':. 



ot ( , •! K' ■ 



■■ • • • ■! \^\ Ihe 



Be ii to the 



su i ! i:;i 1 1 1 :' ■ : MUi ( il resonance 



po- .1 n i-l(( t ic .; Ill atom w it h nioie 



i .11 amount oi eiierj- ' ' " i , 



1 the enerf?>' is radial' 



11 n.', . ) _, , 



NO, 25 1 /, VOL. I 12J 



one definite condition to another, and the return 

 causes the emission. A complete theory of the 

 hydrogen spectrum has been founded on this idea, 

 and as a result of this theory the various conditions 

 of the atom can be described by labelling the electron 

 (there is only one in hydrogen) with two numbers — 

 thus 42 or 6,. In the higher elements the same idea 

 works and each electron has certain numbers associ- 

 ated with it ; here, however, the iiuml)er pairs ha\c 

 not quite the precisely defined (h iiainical nieaninns 

 that can be given them in hydro-^en. The s])ectral 

 lines can also be described in terms of numhers. 

 These numbers have not yet been made to vie'.il tlic 

 absolute values of the wave-lengtlis, Imt it is possible 

 by their means to unravel the general cliaracters of 

 what are often highly complicated systems of lines. 

 For a line, two groups of numbers are required, such 

 as 5(3 j), and there are rules as to what pairs 



of nun. i\' go together — for example, the second 



members of the two groups can differ only by i, the 

 third by either i or o, whereas the first may differ 

 by any amount. There is still a great deal of wdrk 

 to be done on the subject, but it seems probable that 

 all spectta will at no very distani date be brought 

 under rules of tiiis kind. 



This is a \ er\ incomplete sketch of the successes 

 of the quantum theory, but that theory is only a 

 partial view of the whol(> of Nature, because it 

 leaves out of account certain indncit \\a\s in which 

 spectral lines exhibit thcniseiv es. Tlu' < liief of these 

 are the orilinary processes of ri/llection ami lefiM' imii 

 of light, which are very well ixplained on the oMer 

 theory. A reconciliation of the iwn \i( w . ^eeius at 

 present (inile impossible, and this i an onU mean that 

 I .some of the fundameutal a>^iiniiv 

 e unconsciousK'. < if these almost 

 ihe (Jills i.iie., thai it Would do au\ eiiod to .d'andou, 

 in the continu'iiis n.ilui. 

 \s h 1 1 h h , 1 \ e 1 1 



,ile the Ik 1 



space, lull 

 Kelatix it\ 



lia\(' ! 

 • itdir 

 I'.instelii 



rather de; 

 1lin1 the 11, 

 u|) t hi 

 even thun.uh 

 before to om 



\\ 



nee again ie\ 

 To an\ oui 



1 line 

 1 In 

 prol 



and 

 the 

 d>lv 



\\ hole 



tiel. 

 it V 



, i-iid 



and niaki 



,11 ..,,,„.,t., 



'hilloiilM'd te 



■ \\ ho tllld> C: 



e\ er\ ( (III 

 it Is I 1 11 1 1 

 1 V . i It ni.i \- 1 II 

 a-iiT to 



u 



I n ! s Is a 

 possible 

 will tidv 

 ■al witli, 

 ess hke th.iii 

 of the world. 



