January 20, 19 16] 



NATURE 



565 



boys who receive commissions immediately on leaving 

 school are devoting their time to the dead languages, 

 and enter the Army without a scrap of scientific know- 

 ledge. Any headmaster who permits this state of 

 things to continue is an enemy both to the boys and 

 Ills country. 

 1 )ne diflliculty to be encountered is that many 



nee teachers may not be familiar with the matters 

 covered by the syllabus ; but by reference to the pub- 

 lications recommended, supplemented by a further list 

 compiled by Mr. Bryant, they will soon acquire the 

 necessary information. No diffidence need therefore 

 be felt on this score ; and the teacher who adopts the 

 scheme will have the satisfaction of knowing that he 

 is rendering the highest service to his country. 



Work in public schools, however, is only one aspect 

 of the question. There are at present in our armies 

 hundreds of officers who stand in need of instruction, 

 and non-commissioned officers and picked men must 

 also be considered. It is here that our universities, 

 colleges, and technical schools may do invaluable 

 ■work. It is not possible in these cases, owing to 

 considerations of time, to treat the subjects in the 

 ti.ime detail as with boys at school or at Woolwich. 



\\\ my own experience, however, I can confidently 

 .e that twenty hours' tuition, devoted solely to the 

 subjects named, will give any intelligent beginner a 

 grasp of the matters under notice, sufficient to enable 

 him to apply his knowledge to his duties, and so to 

 increase in competence with practical experience. 

 Work of this character has already been conducted 

 with success at the Finsbury Technical College, the 

 Northampton Institute, Clerkenwell, and the Norwich 

 Technical Institute; and if made general throughout 

 the country an incalculable amount of good might be 

 done. At the present juncture, the 

 War Office could not be expected 

 to organise such a scheme, and 

 everything must therefore depend 

 upon the initiative of the indi- 

 vidual teacher. To start a class 

 he should approach the officer 

 commanding troops stationed in 

 his locality with an ofTer to 

 give instructions on fhe lines 

 suggested by the Director of Mili- 

 tary Training. An arrangement 

 may be arrived at for a num- 

 ber of officers, N.C.O.'s, or 

 selected men to attend at speci- 

 fied times ; twenty being the 

 average number who may be 

 dealt with to advantage. The 

 teacher must expect neither finan- 

 cial reward nor official recogni- 

 tion, nor assistance in the matter 

 of equipment. Everything will 

 •depend upon his own voluntary 

 efforts. 



With regard to a syllabus 

 for intensified instruction of this 

 kind, details of apparatus, and 

 sources of special information re- 

 lating to the subjects taught, 

 II should be pleased, subject to 

 the consent of the editor, to 

 supply these through the columns 

 of Nature, provided a demand 

 should exist. I appeal most earnestly to all 

 teachers of physics and chemistry, in the in- 

 terests of the country, to take up this work without 

 delay. One class will suffice to bring home to a 

 teacher the good he can do at the present crisis. 

 With the view of organising future work on the most 



NO. 2412, VOL. 96] 



effective lines I should be glad if all who commence 

 classes would notify me, stating the subjects taught. 



We a^e at present devoting all our attention to the 

 quantity of men in our armies, forgetting that quality 

 is at least equal in importance, and that science alone 

 can prevail against science. Speaking at the recent 

 meeting of Public School Science Masters, an officer 

 returned from France stated that "to his own know- 

 ledge hundreds of lives had been netedlessly lost 

 through the lack of information that should be in the 

 possession of every officer." It lies within the power 

 of the science teachers of England to impart a por- 

 tion, at any rate, of this much-needed knowledge; 

 and it cannot be questioned that a united effort on 

 their part, if promptly made, would be of inestimable 

 service to their countrv. Chas. R. Darling. 



City and Guilds Technical College, 

 Finsbury, E.G. 



A Relation between Atomic Weights and 

 Radio-active Constants. 



Consider the group of chemically identical 

 topic) elements : — 



(iso- 



If logo) be plotted against logo the points will be 

 found to lie along a straight line : — 



TW" 



-P-33 



i?^ 



tM loiw 



m in 



— The radium elements are all marked R. The thorium element' 

 actinium elements are all marked A. 



iJO Atomk Wt/s«r 

 are all marked T. 



238 

 Ihe 



Fig. 

 Dots. 

 Crosses. 

 Dots. 

 Crosses. 

 Dots. 



Crosses. 

 Dots. 



The two circles are the exterpolated points referred to in the text, 

 shows log a. for all the known a-ray elements, as follows : — 



Period VI. 

 Period IV. 

 Period II. 

 Zero Period. 

 P.r.odVlB 



Period Vb 

 Period VI B 



Uranium I (atomic weight 238). Uranium 2 (234). 



Thorium(232). Actinium (230). Radio Thorium (228). Radio .Actinium (2aCX 



Radium (226). Thorium X (224). Actinium X (222). 



Emanations from Kadium (222). Thorium (220). Actinium (218). 



Radium A (218). Thorium A (216;. Actinium A (214). Radium C (214). 



Thorium C (212). [Actinium C' 210 unknown.] 

 Radium C (214). Thorium C (212). Actinium C (210). 

 Polonium=Radium F(2io> [Possible actinium element. ao6.) 



Though some of the lines are somewhat straggling, 

 still each group of isotopes gives a line, and the lines 

 are approximately parallel and equally spaced. The 

 range is thus universally proportional to about the 

 2ist power of w in each case. Moreover, the groups 

 follow one another in a rational order, Period No. 



