February 27, 1913] 



NATURE 



699 



or absolute things. All things, i.e. all processes 

 and states, are conditioned by other processes 

 or states. (2) There is no process or state which 

 is dependent on a single factor. All processes or 

 states are conditioned by numerous factors. 

 (3) Every process or state is inevitably deter- 

 mined by the sum of its conditions. Only under 

 similar conditions do similar processes or states 

 occur, and, conversely, different processes and 

 states presuppose different conditions. (4) Every 

 process or state is identical with the sum of its 

 conditions. The totality of the conditions is the 

 process or state. (5) All the conditions of a 

 process or state are of equal value for its occur- 

 rence in so far as they are necessary. But it 

 does not seem difficult to accept all these pro- 

 positions and yet remain a good vitalist. 



Dizionario di Merceologia e di Chiniica Applicata. 



By Prof. V. Villavecchia. Terza editione. 



\'ol. ii. Lettere N-Z e Indice. Pp. 1360. 



(Milan : Ulrico Hoepli, 1913.) Price 15 lire. 

 The scope of this work and its especial features 

 were explained when the first volume was re- 

 viewed. The second volume embraces articles 

 from N to Z, and occupies 11 70 half pages. All 

 the articles are written very concisely ; in fact, so 

 concisely that, e.g., the author has not yielded to 

 the temptation to do more than mention the Italian 

 occurrences of petroleum in the article " Petrolio 

 greggio." 



The remainder of the work, covering 200 pages, 

 forms a very complete index. It is carried through 

 in four languages, and includes also botanical 

 and zoological names. Thus this index very 

 greatly assists the reader who is not sufficiently 

 conversant with the Italian language to depend on 

 the alphabetical arrangement of the subject-matter 

 in the body of the two volumes. 



The Vertebrate Skeleton. By Prof. Sidney H. 



Reynolds. Pp. xvi -1-535. Second edition. 



(Cambridge: University Press, 1913.) Price 



15s. net. 

 This work, belonging to the Cambridge Zoologi- 

 cal series, was reviewed at length in the issue of 

 Nature for July 15, 1897 (vol. Ivi., p. 245), at the 

 time of its original publication. The present 

 edition has been revised and brought up to date. 

 Prof. S. W. Williston has assisted Prof. Rey- 

 nolds in this work, having rewritten the chapter 

 on the Sauropsida and that on the general account 

 of the skeleton in reptiles, as well as contributing 

 some notes on birds and on the Stegocephalia. 



Heaton's Annual: the Commercial Handbook of 

 Canada and Boards of Trade Register, 1913. 

 Edited by E. Heaton and J. B. Robinson. Pp. 

 401. (Toronto: Heaton's Agency; London: 

 Simpkin, Marshall, Hamilton, Kent and Co., 

 Ltd.) Price 55. 

 The ninth issue of this yearly handbook dealing 

 with the resources of Canada is full of interest. It 

 will prove directly useful to teachers of commercial 

 geography, and much of the general information 

 it provides will appeal to scientific readers. 

 NO. 2261, VOL. go] 



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.] 



On the Appearance of Helium and Neon in Vacuum 

 Tubes. 



Since reading before the Chemical Society (see 

 Nature, February 13, p. 653) the paper on the pre- 

 sence of helium and neon in vacuum tubes (contain- 

 ing hydrogen) after the gas had been sparked, we 

 have carefully compared the spectrum lines that are 

 supposed to be characteristic of these gases. The 

 result has been interesting. In the case of neon and 

 hydrogen there appears to be a large number of lines 

 in the secondar}- spectrum of hydrogen that are ven' 

 close to the important lines of neon. If only those 

 lines are taken that differ by less than a quarter of 

 an Angstrom unit (using the measurements of Wat- 

 son), there are fifty-seven instances. It is not neces- 

 sary to give all of them, but if the neon lines of 

 intensitv 4 and greater be taken it is found that there 

 are twenty instances : — 



Intensity Neon 



9 650669 



10 6402-43 

 9 6383-14 



5 6175-09 

 7 t)i43-3i 



6 6096-36 

 6 6074-51 

 5 6030-20 

 5 597576 

 5 588206 



Hydroiren Intensity 



6506-82 

 6402-51 

 6383-20 

 6x75-14 

 6143-30 

 6096-21 

 6074-66 

 6030-30 



5975-68 

 5882-17 



5872-27 

 5852-62 

 5760-74 

 5343-4° 

 5122-40 

 5080-52 



4537-93 

 3682-37 

 3520-61 

 347268 



Hvrtrogi 

 5872-1 

 5852-; 

 5760-; 



5343--- 

 5122-t 

 5080-; 



4537-^ 



3682 



3520 



3472' 



60 



IVIoreover, according to Watson there are only two 

 neon lines of intensity 10, and only four of intensity q; 

 Of these six principal neon lines, five are paralleled 

 in the secondary hydrogen spectrum, and the sixth 

 line of neon (of intensity 9), 633465, is near to a 

 hydrogen one, 6335-53. 



There are also fifty-three neon lines that differ from 

 those of the secondary hydrogen spectrum by less 

 than one Angstrom unit and by more than a quarter. 

 This makes no lines that are paralleled in the two 

 spectra. 



In the case of neon and helium there are also a 

 series of lines that run parallel. Three of these lines 

 were pointed out by Watson (Proc. Roy. See, 

 vol. Ixxxi., p. 185). He says: "The lines at 667S 

 and 3447, however, were very bright on the same 

 plate, and it must be concluded that there are two 

 neon lines almost coincident with the helium lines." 

 "There appears to be a similar pair at 4713, though 

 I was unable to obtain a plate on which the neon 

 line alone was present. The wave-lengths of the lines 

 concerned are : — 



He 6678-37 

 Ne 6678-50 



4713-25 

 4713-51 



3447-73 

 344783 



And no reason can be at present assigned to their 

 close proximity." 



In the case of neon and oxygen, one of the two 

 bright neon lines of inter^sity 8 and wave-length 

 5330-90 is ver\' near to a bright oxygen line wave- 

 length 5330-84. J. Norman Collie. 



Hubert S. Patterson. 



February 22. 



