June 5, 1913] 



NATURE 



347 



LETTERS TO THE EDITOR. 

 [The Editor does not hold himself responsible for 

 opinions expressed by his correspondents. Neither 

 can he undertake to return, or to correspond with 

 the writers of, rejected manuscripts intended for 

 this or any other part of Nature. No notice is 

 taken of anonymous communications.] 



A Plea for Uniformity in Radio-active Nomenclature. 



In a letter to Nature (vol. lxxvi., p. 661, 1907) Prof. 

 Rutherford advised against an immediate adoption of 

 a permanent system of nomenclature for the radio- 

 elements since the discovery of a new element in the 

 midst of a series would entail the alteration of the 

 names of a possible half-dozen others which follow it. 

 It was considered, however, that the number of pro- 

 ducts still to be discovered was nearly exhausted, and 

 that when there was a general consensus of opinion 

 that such was the case, chemists and physicists should 

 meet together in order to revise the whole system of 

 nomenclature. 



An opposite view was taken by Mr. Norman R. 

 Campbell (Nature, vol. lxxxiv., p. 203, 1910), who 

 urged the adoption without further delay of a system 

 of nomenclature for the radio-elements which would 

 admit of interpolation, and would explain rela- 

 tionships between objects named. Since this would 

 constitute a permanent system of naming, those names 

 which are acknowledged as temporary might be at once 

 dispensed with without having to wait for an in- 

 definite time in the future when all the elements in a 

 series are assumed to have been discovered. 



Little attention, however, seems to have been given 

 to this suggestion. New elements have been dis- 

 covered since then, and the names assigned to some 

 of them are even more unsystematic than the names 

 previously given to other elements of the same series. 

 As examples of this diversity of naming may be 

 mentioned mesothorium 1, radium C 1 , and radium C,. 



It might be urged in defence of the names now 

 in use that no satisfactory system has yet been de- 

 vised which would provide for the naming of elements 

 yet to be discovered, and would show relation- 

 ships between elements either in a straight or 

 branched series. The most favoured system of naming 

 the radio-elements seems to be that by which an 

 element is designated by a letter or number following 

 the name of the first of a group of elements. Such 

 a system, however, does not admit of interpolation, 

 and there may thus be good grounds for the delay 

 in adopting a permanent system of nomenclature. 



The object of the present note is to direct attention 

 particularly to the diversity and careless use of symbols 

 selected to represent the names of the radio-elements 

 now in use. The lack of uniformity in the use of 

 symbols is illustrated by the following examples, most 

 of which were taken from recent numbers of the 

 Philosophical Magazine and the Physikalische Zeit- 

 schrift :— 



Uranium. — U and Ur. 



Actinium. — Ac, Act, and Akt. 



Radium A. — Ra A, RaA, and Ra-A. The symbols 

 of all other elements designated by a letter are like- 

 wise written in one or other of the three ways repre- 

 sented. 



Uranium 2. — U 2 (or Ur 2), U : , U-2, U-two, and 

 U n . A similar diversity is observed in the svmbols 

 of all elements which are designated bv a number. 



Radio-thorium.— Radio-Th, Radioth, Ra Th, Radth, 

 Rad Th, Rad-Th, and Rt. 



Mesothorium. — Meso-Th, Mesoth, Mesth, Mes-Th, 

 and Ms. 



Radium A, Radium B, and Radium C when con- 

 siderpd collectively. — Ra A, Ra B, and Ra C; Ra A, 



NO. 2275, VOL. gi] 



B, and C; RaA+B + C; Ra(A + B + C); A, B and C; 



A+B + C. The active deposit of other series is like- 

 wise referred to in a corresponding variety of ways. 



Such a diversity of symbols must be very confus- 

 ing to the student in radio-activity, and particularly to 

 the future student when referring back to the work 

 of the present day. 



No less confusing is the use of duplicate names in 

 the case of several of the elements. Thus the product 

 following radium is sometimes called radium emana- 

 tion (Ra Em), and sometimes nitron (Nt); that fol- 

 lowing radium C is called radium D, and also radio- 

 lead ; and that following radium E has the duplicate 

 names radium F (Ra F) and polonium (Po). These 

 different names for the same element are often to 

 be found in the same article. In the same way the 

 terms X-ray and Rontgen ray are still used for the 

 same radiation. 



In an abstract journal like Chemical Abstracts, 

 where only the symbols of the elements are used, it 

 is particularly desirable that each element should be 

 always represented by the same symbol. In the case 

 of some of the radio-elements this is not possible since 

 no standard symbols have yet been decided on. It 

 would thus seem worth while to adopt by general 

 agreement uniform symbols for the radio-elements, 

 even although the names of some of the elements 

 may be considered as only temporary. 



William H. Ross. 



H. Jermain Creightox. 



Su.irthmore College, U.S.A., May 14. 



Pianoforte Touch. 



I have been very much interested in Prof. Bryan's 

 article on pianoforte touch in Nature of May 8. 

 There is, of course, no question with anyone who 

 is a pianist that dynamic differences of touch produce 

 enormous differences of quality in the tones of a 

 well-made pianoforte. My own observations in the 

 matter do not go very far, but, amongst other things, 

 it has seemed to me that two things are important : 

 (1) the harmonics of a note have always seemed to 

 me to be most prominent when the note has been 

 produced by the least possible "hit" by the fingers, 

 in fact, when the note is practically produced by 

 pressure alone. Pressure alone is, of course, unable 

 to produce a note, and a certain fractional hit is 

 always necessary to give the hammer the necessary 

 momentum. 



(2) As a result of (1), it seems worthy of note that 

 variations in quality must be produced by differences 

 in the time the hammer is in contact with the string. 

 Since the sensitive fingers of a trained pianist will 

 be able to produce an infinite variety of pressure and 

 hit from the heaviest arm staccato to the merest 

 "caress" of a key, it is possible to produce very large 

 differences of quality as well as large differences in 

 intensity. 



My own experiences with a player-piano have made 

 me well-nigh despair of its capabilities in its present 

 form. In spite of the instinctive control it is certainlv 

 possible to obtain with it, its mechanical details seem 

 to me to fall far short of the ideal that a musician 

 can demand. It is, of course, practically impossible 

 to produce a differentiation of intensity between notes 

 of the same chord, and to a musical ear it is this 

 difference of intensity which enables differences in 

 quality to be detected and appreciated. Prof. Bryan 

 seems to have been able to control this differentiation 

 in quality in a solo passage, and if he can produce 

 a mechanical arrangement which can even approxi- 

 mate to the sensitiveness of a pianist's fingers, he 

 will certainly go far to make the piano-player more 

 acceptable to musicians. 



