Uecembek 24, lyoJ 



NA TURE 



Zeeman Effect in Weak Magnetic Fields. 



According to V'oigt, the displacement of the outer com- 

 ponents of the Zeeman triplet plotted against the strength 

 of the magnetic field is represented by a hyperbola, when 

 the light is observed at right angles to the field. The hyper- 

 bola approaches asymptotically to a straight line in strong 

 fields, where most of the observations have hitherto been 

 made by different e.\perimenters. Moreover, tlie intensity 

 of the component towards the red is greater than that 

 towards the violet in weak fields, and gradually tends to 

 equality as the field is increased. Gehrcke and von Baeyer 

 examined the separation of the satellites of the mercury 

 line 546-1 /tyn in a field of 535 Gauss, but did not notice 

 the asymmetry as indicated by theory. 



On account of the double difficulty of obtaining fine 

 spectrum lines and of using instruments having strong 

 resolving power, the theory of asymmetry in weak fields 

 has not yet been placed under thorough experimental test. 

 When it is impossible to measure the effect on distinctly 

 separated lines, we can infer the nature of the change by 

 measuring the broadening of the lines, provided they are 

 sharply defined. For this purpose, the gold lines 

 K = b2-j-i> tifi and A = 583-5 /i/i are characterised by having 

 sharp edges in the spark spectrum, when the self-induct- 

 ance and capacity of the circuit are properly adjusted. By 

 using an echelon spectroscope made by Hilger, of resolving 

 power A./5a. = 430,000 for A. = 500 p-ji., I made numerous 

 observations with Mr. Amano, and found that the effect 

 for a triplet of the red gold line is measurable in a field of 

 240 Gauss, and on following the curve to strong fields it 

 is approximately represented by a branch of hyperbola 

 with very short axis, showing a slight bend in H = 300o, 

 which is probably caused by the asymmetry in the intensity 

 of the component lines. .A similar result was obtained with 

 the copper line A = 5 10-5 y-fi, which is divided into a triplet. 

 The utmost care was necessary to have the electromagnet 

 producing the field well demagnetised before each experi- 

 ment, by a special device of alternately passing gradually 

 diminishing current in rapid succession. 



With the quartet of the yellow gold line, the nature of 

 the change of the inner components is somewhat similar 

 to the triplet before mentioned, but the curvature is more 

 pronounced. The displacement of the outer components 

 is more complex in weak fields, but from H = sooo up- 

 wards it keeps approximately linear relation with the 

 field. Similar observation was also made with the 

 magnesium line b.. 



The principal source of error in the present experiment 

 is the uncertainty as to the difference in the intensity of 

 the component lines ; this will no doubt affect the breadth 

 of the superposed lines. When the lines are separated by 

 applying sufficient magnetic force, the difference in the 

 breadth and intensity of the components is not to be dis- 

 tinguished by mere eye observation. 



H. Nag.aoka. 



Physical Institute of the University of Tokyo, 

 November 25. 



Women and the Chemical Society. 



The council of the Chemical Society, at a recent meet- 

 ing when it was determined to exclude women from the 

 fellowship, but to admit them to the society as " sub- 

 scribers," decided, " after mature deliberation " — the 

 phrase is the senior secretary's — that the appellation 

 " subscriber " should be printed with a big S ! 

 Daughters of Eve ! So zealous to pursue 

 The work in Life by which you seek to live ! 

 When F.C.S.^ you claim, as is your rightful due — 

 The S alone is what they, grudging, give ! 



Be patient ! Time is on your side. 

 Reason and justice will your cause defend. 

 Ignoble spite and arrogance of pride 

 Shall meet their retribution in the end ! 



Autumn, and After. 



_ The following table may be of interest at the present 

 time. It indicates the years in which (as in this) all three 

 months of autumn have been dry at Greenwich (1841- 

 NO. 2043, VOL. 79] 



1907), and the character, as regards temperature, of each 



of the three months of winter following (-(- meaning 

 warm and — cold). 



December January February 



(1) 1847 ... + ... - ... 4- 



(2) 1850 ... 4- ... 4- ... 4- 



(3) 1851 -•• + ... 4- ... 4- 



(4) lSS4 --- + 



(5) 1S5S ■■■ + --- + -.. + 



(6) IS6S ... + ... + ... -H 



(7) iSSi ... + ... + ... 4- 

 (S) 1SS4 ... + ... - ... + 

 (9) 1890 



(10) 1900 ... + ... + 



(11) 1901 --■ + --- + 



(12) 1902 ... -I- ... 4- ... 4. 



(13) 1904 ... -t ... - ... + 



Warm 

 Cold 



9 = 29 

 4=10 



Three things may here be noted : — 



(i) December has nearly always been warm (twelve cases 

 out of thirteen). 



(2) In the total of the winter groups, warm months have 

 been about three times as numerous as cold (twenty-nine 

 to ten). 



(3) Excepting 1S54-5 ^"<1 1890-1, each winter has had 

 two or three months warm. 



The present December promises (December 15) to be 

 warm. What the season as a whole will bring forth 

 remains to be seen. Alux. B. MacDowall. 



THE DARWIN COMMEMORATION AT CAM- 



BRIDGE {JUNE 22-24, 1909). 

 T^HE Darwin Celebration Committee appointed by 

 -*■ the Council of the Senate to make the necessary 

 arrangements has issued invitations to a large number 

 of British and foreign universities, colleges, academies,, 

 and learned societies. The committee has already 

 received the names of nearly 200 delegates who pro- 

 pose_ to attend the celebration in June. Among those 

 nominated by universities and societies in the United 

 States are the following : — Prof. Baldwin (Johns 

 Hopkins University), Prof. Loeb (University of Cali- 

 fornia), Prof. Farlow (.'American Academy of Arts and 

 Sciences), Prof. Minot (Boston Society of Natural 

 History), Prof. Coulter (Chicago University), Dr. 

 Davenport (Cold Spring Harbour Experimental 

 Station), the president of Cornell University, Prof. 

 Chittenden (Yale University), Prof. Peck (the Con- 

 necticut Academy), the president of the Academy of 

 Arts and Sciences (New York), Prof. E. B. Wilson 

 (Columbia University), Dr. Biggs (New York Uni- 

 versity), Dr. Harrison (University of Pennsylvania), 

 Dr. A. E. Brown (Philadelphia .\cadeniv). Dr. Osborn 

 (.'\merican Philosophical Society), the p'resident of the 

 Carnegie Institute (Pittsburg)', the secretary of the 

 Smithsonian Institute, the president of the Carnegie 

 Institute (Washington), Dr. Howard (Academy of 

 Sciences, W'ashington). 



The University of Chile, Santiago, is to be repre- 

 sented by the Envoy Extraordinary of Chile. From 

 -Austria-Hungary the following are expected : — Prof. 

 Ludwig von Graf! (Gratz), Prof, .\pathv (Kolozsva), 

 Prof. Vejdovsky (Prague), Dr. Steindachner and 

 Prof. Wettstein (Vienna). The Belgian delegates 

 include M. Laneere (pro-rector of the University of 

 Brussels), Prof, van Beneden and Prof. Dupont 

 (Brussels), Prof. Dorlodot (Louvain). Prof. Hoffding 

 and Prof. Jungersen are coming from Copenhagen. 

 .Among French delegates are Prof. Malaguin (Lille), 

 Prof. Cu(5not (Nancv). Prof. Dantec (Universitv of 

 Paris), Prof, van Tie.ghem, M. Perricr, Prince Roland 

 Bonaparte (Institute of France), Prof. Papillaut, Prof. 

 Metchnikoff, Dr. Manouvrier (Paris). 



