BRITISH CHEMICAL ABSTRACTS
A . - P U R E CHEM ISTRY
MARCH, 1931.
G en era l, P h y s ic a l, an d I n o r g a n ic C h em istry .
H y p e r f in e s t r u c t u r e fo rm u la e f o r o n e - e le c tro n s p e c t r a . G. B r u i t (Physical R ev ., 1931, [ii], 37, 51— 5 2 ; cf. H argreaves, A ., 1930, 832; F erm i, ibid., 393).— M athem atical. T h e energy level sep aratio n s cau sed b y a n u clear m agnetic m o m en t in a one- electron sp ectru m are derived b y a sh o rt a n d rigorous
m eth o d . N . M. B l ig h .
V a r ia tio n of s p a r k p o t e n t i a l w i t h t e m p e r a t u r e i n g a s e s . H . G. B o w k e r (Proc. P h y sical Soc., 1931, 4 3 , 96— 112).—T h e effect of tem p e ra tu re on th e sp ark p o te n tia l in hyd ro g en a n d n itro g en a t o rd in a ry p re s
sures h a s been in v estig a ted u p to 860°. T he sp a rk p o te n tia l depends on th e d e n sity of th e gas, b u t is in d e p en d en t of te m p e ra tu re a n d pressure for a given
d ensity. A. J . M e e .
C o n tin u o u s s p e c t r a of a t o m i c a n d m o l e c u l a r h y d r o g e n . D . C h a l o n g e a n d N . T. Z e (J. P hys.
R ad iu m , 1930, jyii], 1, 416— 425).— W hen a n u n co n densed discharge is passed th ro u g h hy d ro g en a t a p ressure of a few m m . th e seco n d ary sp ectru m a n d a continuous sp ectru m of m olecular origin are em itted . T he energy cu rv e of th e la tte r has a m axim um a t 2350
A.
W ith sufficiently condensed discharges th e secondary sp e ctru m disappears, th e B alm cr lines becom e m ore intense, a n d th e continuous sp ectru m becom es p u rely atom ic, consisting of tw o sp ectra connected w ith th e B alm er a n d P asch en series. T he form er is m ore intense th a n th e la tte r, th e energy in each case being evenlv d istrib u te d th ro u g h th e spec
tru m . C. W . G ib b y.
I n t e n s i t i e s o f B a l m e r lin e s . I I . L. S. O rn - STEijf a n d H . L ix d e m a n (Z. P h y sik , 1931, 6 7 , 1—6).
—A rep ly to th e criticism s raised b y K o p ferm an n and L ad en b u rg (cf. A., 1930, 1487) on th e a u th o rs ’ earlier w ork (ibid., 1073). R . W . L e n t .
In flu e n c e of t r a c e s of h y d r o g e n o n th e s p a r k i n g p o te n tia l of h e liu m . A. G u n t h e r - S c h u l t z e an d P. K e l l e r (Z. P h y sik , .1930, 66, 219— 223).— E x p e ri
m ents w ith com m ercial ty p e s of low -voltage rectifiers consisting of iro n electrodes in a helium atm osphere a t 20 mm. are described. Spectroscopic ex am in atio n of th e arc u n d e r n o rm a l a n d overload conditions has shown t h a t th e fo rm e r is associated w ith th e d is
appearance of tra c e s of hydrogen w hich are evolved rap id ly u n d e r overload conditions. R . W . Lu n t.
F in e s t r u c t u r e of h y d r o g e n - lik e a t o m s i n a n in h o m o g e n e o u s e le c tr ic fie ld . S. G u p ta (Z.
P h y sik ; 1930, 6 6 , 246—256).—T heoretical. T he D a r
w in m odification of D ira c ’s e q u atio n is U sed to cal-
tr 2"
c u late th e S ta rk effect in a n inhom ogeneous electric field; th e field gives rise to a q u a d ra tic as w ell as a lin ear te rm in th e p o te n tia l energy, a n d th e effect of th e q u a d ra tic te rm is calculated.
A. B. D . C a s s ie . E x te n s io n of s im p le s p e c t r a . F . P a s c h e x (Sitszungsber. P reuss. A kad. W iss. B erlin, 1930, 32.
7 p p .).— T he sim ple sp ectra due to th e e x c itatio n of a single-valency electron are ex ten d ed if m ore th a n one valen cy electron is p rese n t, a n d th e se are sim ul
ta n eo u sly excited. T he tw o-electron sp e c tra of helium , beryllium , m agnesium , a n d A1 n are d is
cussed. A. J . MeE.
H y p e r f m e s t r u c t u r e of S a n d P t e r m s of tw o - e le c tr o n a t o m s , w i t h s p e c ia l r e f e r e n c e t o Li+. G.
B r e i t a n d F . W . D o e r m a x x (P hysical R ev ., 1930, [ii], 3 6 , 1732— 1751; cf. G oudsm it a n d B acher, A., 1930, 265).— M ainly m a th e m a tic a l. A n expression is deduced for th e in te ra c tio n energy betw een th e nuclear m agnetic m o m en t a n d th e electronic system of a m an y -electro n ato m . R e su lts are ap p lied to th e L i+ 5485
A.
line a n d to th e calcu latio n of th e m agneticm o m e n t of Li. N . M. B l ig h .
L a r g e d i s p la c e m e n ts i n th e s p e c t r a of io n is e d n it r o g e n . K . A s a g o e (Sci. R ep . T okyo B unrika D aig ak u , 1930, 1, 47— 62).— T he sp e c tra of N n an d N i n w ere stu d ie d b y a m e th o d sim ilar to t h a t e m ployed in th e s tu d y of th e b roadening a n d displace
m e n t of th e halogen sp e ctra (A., 1927, 2, 602).
A.
J . M ee.E x c ita tio n of t h e n e g a tiv e n i t r o g e n b a n d b y e le c tr o n c o llis io n s . A. E . L i x d h (Z. Physik, 1931, 67, 67— 74)1— T he in ten sities of th e lines of th e R bran ch of th e n eg ativ e nitro g en b a n d hav e been m easured for exciting electrons of 150 a n d 175 volts energy a n d a t tw o different c u rre n t densities.
M easurem ents hav e also been m adę of th e effective ta r g e t a re a of th e n itro g en m olecule for th e ex citatio n of th e above b a n d in th e ra n g e ,50— 350 volts. T he values o b tain ed arc m uch lov er t h a n th o se of R am - sau er a n d B rode. R . W . Lu>tt .
E m i s s i o n h a n d s of s u l p h u r . R. K . A s u n d i (N atu re, 1931, 127, 93— 94).— S pectrogram s of th e b an d s of su lp h u r e m itte d in a discharge tu b e co n ta in in g su lp h u r v a p o u r a n d argon u n d er pressure in d icate t h a t argon ten d s to a rre st th e : predissociation of th e su lp h u r m olecule. N ew bands degraded to w ard s th e sh o rte r .w ave-lengths have been p h o to graphed in th e Tegion 2100
A.
L. S. T h e o b a ld ./ D
Spectrum of singly-ionised chlorine (Cl il). K.
M u r a k a w a (Sci. P ap ers In st. P h y s. Chem. R es.
T okyo, 1930,
15,
41— 67).— T he first sp a rk sp ectru m of chlorine w as o b tain ed b y a condensed discharge th ro u g h a narrow Geissler tu b e w ith tu n g ste n electrodes, one co ntaining a sm all q u a n tity of sodium chloride. T he ground te rm is given as 3p3P 2, an d th e ionisation p o te n tia l as 23-115 volts.
A. B . D. C a ssie .
Spectra of doubly-ionised argon, krypton, and xenon.
S. C. D e b a n d A. K. P u t t (Z. P hysik, 1931, 67, 13S— 146).—T h e sp e c tra of A ++, K r ++, an d X e ++ hav e been classified, a n d tab les of th e m u ltip lets of these sp ectra are given. T he values of th e ionisa tio n p o ten tials are 36-75, 31-23, a n d 2S-51 volts, resp ectiv ely (cf. D éjardin, A., 1924, ii, 284, 709).
W . R , A n g u s.
Zeeman effect for quadrupole lines.
E . S e g r é (Z. P h ysik, 1930, 66, 827— 829).— The p o ta ssium lines 2S m —2Î ) 5/a a n d 2S m —2D 3/2, a t 4642-17 an d 4641-58 A., respectively, m a y be q u adrupole tr a n s i
tions, or m a y be due to th e influence of a n inhom o- geneous electric field. P h o to g ra p h s of th e inverse Zeem an c an d ~ com ponents of these lines, duo to a field of 12,700 gauss, show th a t th e tra n sitio n s agree w ith th e assu m p tio n of a quad ru p o le electric m om ent.
A. B . D. C a ssie .
Interferom etric m easurem ents in the arc spectrum of iron.
C. V . J a c k s o n (Proc. R oy. Soc., 1931,A, 130,
395—
410).—
T en lines in th e sp ectru m of th e iro n arcin
a ir in th e region 4000—4400 Â.hav e been m easured b y m eans of th e u su al in terfero m etric m eth o d a n d found to be in alm o st perfect agreem ent w ith th e values a d o p ted b y th e I. .U . in 1928, th e m ean sy stem atic difference being only -f-0-0003 A. a n d th e m ean accid en tal difference
¿ 0 -0 0 0 6 A. S ixty-eight lines in th e region 2300—
3100 A. have also been m easured interferom etrically.
L. L . B ir c u m sh a w .
Spectrum of doubly-ionised arsenic. K. R. R
ao (Proc. P hysical Soc., 1931, 43, OS— '71).— T he do u b let system of doubly-ionised arsenic (As h i) is considered in d etail, a n d th e w ork of L ang (A., 1929, 112) is am ended. I t is now possible to ev a lu a te a t r u s t w o rth y schem e of term s of As h i b y assum ing a probable value for th e 5g2G term . T he value used is 39,500 c m r 1 A te rm tab le is given. A. J . M e e .Spectrum of singly-ionised ziconrium .
C. C.K ie s s a n d H . K . K ie s s (B ur. S ta n d . J . R es., 1930,
5,
1205— 1241).— M ost of th e lines observed in th e sp a rk sp ectru m of zirconium hav e been classified as com binations betw een term s of th e q u a d ru p le t an d d o u b le t sy stem of Zr n . T h e te rm s w hich hav e been found a re in all cases those req u ired th e o retically for a n a to m w ith th ree o u ter electrons.W . E . D o w n e y .
Intensity anom alies in the m ultiplets of silver and gold.
S. S a m b u r s k y (Proc. K . A kad. W etensch.A m sterd am , 1930,
33,
1025— 1027 ; cf. A., 1930, 831).— T he ra tio 2 : 1 has been o b ta in e d for th e relativ e in ten sities of th e silver lines a t 3382-8 an d 3280-6 A.
a n d 2-4 :1 fo r those of th e second d o u b let of th e p rin cip al series (X=2069-S a n d 2061-2 A.). W h en F e rm i’s th e o ry (A., 1930, 388) is a p p lied to these
re su lts th e ra tio of th e tr a n s itio n p ro b ab ilities of th e 2P a n d 3 P levels to th e g ro u n d s ta te ( / 2/ / 3) is found to be 20, w hereas th e e q u iv a le n t ra tio s for th e alkali m etals lie betw een 100 a n d 200. T he intensity, ra tio of th e gold lines 32£ —22P 3 2 a n d & S - 2P m (x=4241-8 a n d 3650-7 A.) is also th e n o rm al value of 2 : 1. T he diffuse series 22P —32D in b o th silver a n d gold a n d th e 2 - P —4-D series in silver show m a rk e d d e p artu res from th e th eoretical ra tio . T h is is ex p lain ed b y assum ing th e existence of a low 2D te rm . J . W . S m ith .
Spectrum of doubly-ionised iodine.
J . B.S e t h (N ature, 1931, 127, 165).— M any of th e stro n g lines in th e visible a n d id tra -v io le t regions originate in term s of 20 2P V 20 2P 2, a n d 20 2P 3 electronic con
figurations ; all th e q u a d ru p le t term s for these hav e been recognised. The 2 0 2 ( P - ^ ---- P 2) a n d 20., (P.,4---- P 3) lines are grouped a b o u t 3900 A. a n d 3100 A.,
respectively. L. S. T h e o b a ld .
Spectrum of trebly-ionised cerium (Ce iv).
J . S. B ad am i (Proc. P h y sical Soc., 1 9 3 1 ,4 3 ,5 3 — 58).—
T he spectrum of th e condensed sp a rk of cerium has been stu d ied in th e ultra-v io let. T h e sp ectru m is simple, being sim ilar in electronic stru c tu re to th e spectra of Ca I, B a n , a n d L a h i. A ta b le of term values an d ionisation p o te n tia ls of L a i n a n d Ce iv is
given. A. J . M e e .
Influence of pressure and tem perature on the absorption of excited m ercury atom s in a neon atmosphere.
0 . M a s a k i (Z. P h y sik , 1930, 66, 229— 240).— T he ab so rp tio n of lig h t corresponding w ith th e tra n sitio n s 23P 0i1>2—23£ 1 of ex cited m ercury v ap o u r in th e presence of a n excess of neon has been exam ined b y m eans of a K ö n ig -M arten s sp e c tro photom eter. T he m echanism s suggested in ex p la n atio n of th e p h enom ena observed are discussed a tlength. R . W . L u n t .
Optical m easurem ents on the m ercury atom.
M. SciiErN (H elv. phvs. A cta, 1930,2, Supp. 1 ,3 — 1 1 1 ; Chem. Z entr., 1930,\ 3009).— As a sensitive m ethod for m easuring sm all spectroscopic w ave-length differ
ences th e a b so rp tio n of a m onochrom atic ra y is em ployed in a m onochrom atic absorbing m edium w ith th e light a n d ab so rp tio n frequencies co n tin u ally o u t of phase. T he m eth o d succeeds w ith m ercu ry reson
ance fluorescence absorbed in m ercu ry v ap o u r, and has been applied to d eterm ine th e S ta rk a n d D oppler
effects. L. S. T h e o b a ld .
Mercury band system in the neighbourhood of the resonance line.
(L o r d ) R a y l e i g h (N ature, 1931, 1 2 7 , 125).— A dditional b an d s betw een t h a t a t 2540 A. a n d th e resonance line 2536-52 hav e been m easu red ; th e b an d s are sh ad ed from th e re d an d th e w ave-lengths are 2540-37, 2538-44, a n d 2537-32 A.Two bands shaded from th e re d hav e also been m easured a t 2535-82 a n d 2535-35 A.
L . S. T h e o b a ld .
High-frequency discharges in m ercury, helium , and neon.
C. J . B r a s e f i e l d (Physical R ev ., 1931, [ii], 3 7 , 82— 8 6 ; cf. A., 1930, 837).—M easurem ents of th e p o te n tia l d ro p a t th e electrodes a n d th e electric force in th e positive colum n of high- freq u en cy discharges in m ercury, helium , a n d neon for a range of gas pressures a n d oscillation frequencies
G E N E R A L , p h y s i c a l, a n d i n o r g a n i c c h e m i s t r y.
of 1-25— 22-5 m egacycles show ed th a t, in general, th e m ag n itu d e of th e electric force w as insufficient to produce electrons of velocity necessary to ionise or
excite th e gas. N . M. B l i g h .
Intensity determ inations w ith the m ultiplets of m ercury and neon by excitation of the lines by electron collision.
W . E n d e (Z. P hysik, 1931, 67, 292— 293; cf. A., 1929,1119).—-The in te n sity re la tio n ships given in th e form er p a p e r are corrected.A. J . Me e.
Intensity distribution in the m ercury triplet 2S’31—
23P
0j1j2and the m ean glow period of the triplet com ponents.
R . F r i s c h a n d P . P r in g s - heem (Z. Physik, 1931,67,
169— 178).— B y irra d iatio n of th e lines 5461 a n d 4047
A.
th e fluorescence em ission of th e visible m ercu ry tr ip le t 23<SX—23P 0iJi2 was obtained. The relativ e in te n sity of th e th re e lines is in d ep en d en t of w h eth er th e green or th e violet com ponent is used for th e excitation. I t is concluded t h a t th e in e q u a lity observed b y R an d all (A., 1930, 970) in th e life period of th e th re e lines c a n n o t be cleared u p b y consideration of hyperfine stru c tu re (cf. R ich ter, th is vol., 8). A. J . M e e.Polarisation of the continuous X-rays from single electron im pacts.
B. D a s a n n a c h a r y a (Physical R ev ., 1930, [ii],36,
1675— 1679).— P o la risa tio n increased exp o n en tially w ith decreasing th ic k ness of alum inium ta rg e ts, in dicating n e a rly com plete polarisation a t 6 x 10‘8 cm . thickness, a n d dim inished w ith increasing v elocity of th e exciting electrons.
R esults are in agreem ent w ith S u g iu ra’s th e o ry of th e p o larisatio n of continuous X -ra y s (cf. A., 1930, 4).
N . M. B l ig h .
Scattering of short X-rays by m olecular hydrogen.
H . S. W . M a s s e y (Proc. Camb. Phil.Soc., 1931, 27, 77— 8 5 ; cf. D ebye, A., 1930, 843).—
M athem atical. F ro m th e fo rm u la deduced b y W aller (cf. A., 1929, 746) th e in ten sities of sh o rt X -ray s sc attered from m olecular hydrogen are calculated.
N . M. B l i g h .
Spectrum of the radiation from a high potential X-ray tube.
C. C. L a u r i t s e n (Physical Rev., 1930, [ii], 3 6 , 1680— 1684; cf. ibid., 988).—Using a Seem an ty p e spectrograph, a spectrogram w ith th e tu b e a t 600 kilovolts shows a continuous spectrum w ith a m ax im u m in te n sity a t a b o u t 200 kilovolts, a n d a sh o rt w ave-length lim it a t a b o u t 600 kilovolts, th e range covered being 100
—
20A.
N . M. B l ig h .
Origin of L-absorption edges of heavier elements.
A. S a n d s t r o m (Z. P h y sik , 1930, 66, 784— 789).— T he know n A -absorption a n d em ission spectra for th e elem ents tu n g ste n to u ra n iu m in d icate th a t A edges a re d ue to a tra n sitio n from th e A level to th e first incom plete group or sub-group of ex tra- nuclear electrons. A. B. D. C a ssie .Accuracy of interference determ inations w ith m olecules w ith
X -and cathode rays.
L. Bewi- l o g d a (Physikal. Z., 1931, 3 2 ,1 1 4 — 117).— T he a c cu ra c y a tta in a b le b y th e use of X -ray s , a n d of cath o d e ra y s in d eterm in atio n s based on interference is d is
cussed. X -R a y s provide a m ore a cc u ra te re s u lt th a n
ca th o d e ray s, alth o u g h th e la tte r possess th e a d v a n tag e of req u irin g sh o rter exposure tim e.
A. J . M e e.
Discontinuous absorption of X-radiation.
B. B. R a y (Z. P h y sik , 1930, 66, 261— 268).— X -R ad i- a tio n sc a tte re d in a direction inclined to a p rim ary beam suffers a change in w ave-length depending on th e v ecto r change in m om entum , i.e., th e change in w ave-length is due to th e C om pton effect, a n d broadens th e sp e ctral line in th e direction of longer w av e
lengths. A ny R a m a n line is therefore obscured.
R ad iatio n sc a tte re d in th e direction of th e p rim ary beam shows no C om pton m odification in w ave-length, b u t m ig h t show a n an ti-S to k es R a m a n line du e to atom s excited b y C om pton collisions. CuKa, NiA’x, N iX p, WAx, a n d FcA'p ra d ia tio n s sc a tte re d b y carbon, nitrogen, a n d oxygen were exam ined, an d an ti-S to k es lines corresponding w ith CKa, N X a , an d O X a were
found. A. B. D. C a ssie .
Angular intensity distribution of the con
tinuous X-ray spectrum .
Y. S u g iu r a (Sci. P apers In s t. P h y s. Cheip. Res. T o k ju , 1930, 15, 37— 39).—M athem atical. A. B. D. C a ssie .
Change of wave-length of A'-rays on traversing an absorbing m edium .
J . M. C o r k (Compt.ren d ., 1931,
192,
153— 155).— T h e new lines sta te d b y R a y (cf. A ., 1930, 972) to be produced on passing copper K a ra d ia tio n th ro u g h carb o n etc. were n o t o b ta in e d w hen his ex p erim en t w as rep ea ted , nor could a n y such effect be o b tain ed w ith boron.C. A. S i l b e r r a d .
Vacuum spectrograph for precise m easure
m ents of X-rays of long wave-length.
C. E . H o w e (R ev. Sci. In s tr., 1930, [ii], 1 , 749—757).—A plane g ratin g sp ectro g rap h a n d special featu res of design fo r securing high precision are described.N . M. B l ig h .
M ultiple scattering in the Compton effect.
J . W . M. D u m on d (Physical R ev., 1930, [ii],
36,
1685— 1701).— T heoretical. Possible errors due to th e neglect of m ultiple sc a tte rin g in a s tu d y of th e sp ectral d istrib u tio n of X -ra d ia tio n sc a tte re d b y lig h t elem entsare review ed. N . M. B l ig h .
Double-crystal spectrom eter.
J . W . M.D u m on d a n d A. H o y t (P hysical R ev ., 1930, [ii],
36,
1702— 1720).— T he uses, th e o ry , design, a n d technique of op eratio n of th e doub le-cry stal sp ectro m eter aredescribed. N . M. B l i g h .
Infra-red absorption bands in the spectra of the greater planets.
R . W i l d t (N aturw is3., 1931,19,
109— 110).— T he sp ectra of N ep tu n e a n d J u p ite r were p h o to g rap h ed u p to 8600A.
an d com pared w ith th e sp e c tra of th e su n a n d Capella o b ta in ed in th esam e w ay. W . R . A n g u s.
Photo-electric and therm ionic properties of
rhodium.
E . H . D i x o n (Physical R ev ., 1931, [ii],37,
60— 69).— A th in rib b o n of p u re rh o d iu m was s u b m itte d to rigorous h e a t tre a tm e n t in a p y rex tu b e a t 950— 1450° fo r 1050 hrs. in a vacuum . D uring h eatin g , th e long-w ave lim it sh ifted from 2530 to 3150 a n d back to 2509 A . ; th e photo-electric cu rre n t, m easured b y a C om pton electrom eter, increased a b o u t 130% for th e tem p e ra tu re ran g e 25— 950°, w ith asu d d en increase a t 240°. T he therm ionic c u rre n t curve show ed a n irre g u la rity a t 1100°.
N . M. B l ig h . P h o to - e le c tr ic ity . J . W e r n e r (Z. Pliysik, 1931,
67,
207— 226).— M etals a n d sa lts show, in a high vacuum , a n increase in th e photo-electric em ission w ith tim e, w hich is in d ep en d en t of th e rad iatio n . T he cause of th is increased sen sitiv ity , show n only by th e u n s a tu ra te d em ission, is th e rem oval or d im in u tio n of th e layer of gas adsorbed on th e m e ta l or salt.A. J . Mb s. C o n n e x io n b e tw e e n t h e e f f e c t of n i t r o g e n - o x y g e n c o m p o u n d s a n d t h a t of t h e i r c o m p o n e n ts o n t h e p h o to - e le c tr ic s e n s itiv ity of p o t a s s i u m . R . F l e i s c h e r a n d H . T e ic h m a n n (Z. P h y sik , 1931,
67,
184— 191; cf. A ., 1930, 391).—A n ex am in atio n of th e effect of nitro g en dioxide, n itric oxide, nitrogen, a n d oxygen on th e se n sitiv ity of th e potassium cell shows t h a t th e change in p o sition of th e selective m axim um from 334 to 365 m u is due to th e fo rm atio nof n itro g en dioxide. A. J . M e e.
T e m p e r a t u r e r e l a t i o n s h i p of t h e u n i d i r e c t i o n a l l a y e r p h o to -e ffe c t. H . T e ic h m a n n (Z. P hysik, 1931, 67, 192— 193; cf. th is vol., 9).— I n th e te m p e ra tu re range dow n to — 1S0°, em ission of th e c o p p e r- copper oxide cell reaches a m axim um betw een —80°
a n d - 1 1 0 ° . A. J . M e e.
A v o id a n c e of a n in f in ite s i n g u l a r i t y a t th e e le c tr o n . W . A n d e r s o n (Z. P h ysik, 1930, 66, 712—720).—A m b arzu m ian a n d Iv an en k o concluded (cf. A ., 1930, 1335) th a t electrons in cry stal fo rm atio n could n o t ap p ro ach closer th a n 6-34e2/»i()c2, a n d th is is precisely th e m inim um d ia m eter possible fo r elec
tro n s w hen considered as gas of com pressible electric p articles (cf. A ., 1929, 1137). N o ex p lan atio n of th is coincidence could be found. A. B. D. C a s s i e .
N e w m e t h o d f o r r e c o r d i n g e le c tr o n s . P . H . C a r r (Rev. Sci. Iristr., 1930. [ii], 1, 711—743).—The use of photographic p lates fo r recording electrons is reviewed. U sing a slightly m odified a p p a ra tu s, th e experim ents of Cole (cf. A., 1926,1189) were repeated, an d it was found th a t photographic p lates are rendered m ore sensitive to electrons by th e application of sm all am o u n ts of c e rtain oils, pro v id ed th e electrons strike th e plate a t speeds n o t less th a n 25 e q u iv a le n t volts.
The. sen sitiv ity is m ainly due to cathodo-lum inescence of th e oil, a n d th e failure a t low speeds is due to th e high electrical resistance of th e photographic em ulsion.
T he regions of m etal surfaces bom barded b y electrons re a c t differently from th e u n b o m b a rd ed regions to w ard s c e rtain vapours, th e effect being observed for electron speeds dow n to 12 equ iv alen t volts. E x p erim ental d etails ai'e given for gold and silver, for w luch m ercu ry an d iodine vapours, respectively, were found th e m ost satisfacto ry developers. T he effect w as also in v estig ated for o th er m etals, an d possible explanations are discussed. T he ad v an tag es an d scope of th e tw o m ethods are com pared.
N .M . B l ig h . L o n g itu d in a l d i s t r i b u t i o n of p h o to - e le c tr o n s . L. Sim on s (N ature, 1931,
127,
91— 92).— A ssum ing th e w ave-m echanical principle of interference P(0) cc sin2!) a n d th a t in d ep en d en t groups of p h o to electrons originate from a sm all, plane circular area ofrad iu s b norm al to th e ray , a n d a sm all spherical volum e, rad iu s a, th e p ro b a b ility P(0)d0 cc (Abro2-)- B 1- ^ cos O) sin3 OdO, w here A 1 a n d B 1 are in d ep en d en t of 0, is obtained. This expression m u st be regarded as u n ilateral and integrable only betw een th e lim its 0 to -12. E x p erim en t has confirm ed th e existence of longitudinal sym m etry. L. S. T h e o b a ld .
E le c tr o n d if f r a c tio n a t o x y g e n a d s o r b e d o n tu n g s te n . W . Boas an d E . R u r r (Ann. P h ysik, 1930, [v], 1, 983— 1000).—A n a p p a ra tu s for stu d y in g th e diffraction of electrons of 100—2000 volts energy a t surfaces th e tem p e ra tu re of w hich could be raised to 3000°, is described, an d th e possible errors are discussed. R esu lts are given for p m e tu n g ste n a n d for tu n g ste n "with a n adsorbed lay er of oxygen.
A. B. D. C a ssie . C a p tu r e of e le c tr o n s b y p r o to n s . K . W o l f (Ann. P hysik, 1930, [v],
7,
937— 946).— A n a p p a ra tu s which brings p ro to n s an d electrons of variable relativ e velocity in to th e sam e stream is described. T h e stream is subseq u en tly analysed in to electrons, protons, a n d hydrogen atom s. According to D avis a n d B arn es’ results, for a-particles (A., 1929, 971), n e u tra l hydrogen ato m s should ap p ear a t definite relativ e velocities. N o such phenom enon w as o b served. A. B . D. C a ssie .
A n g u la r s c a t t e r i n g of e le c tr o n s i n g a s e s . F . L . A r n o t (Proc. Camb. Phil. Soc., 1931,
27,
73—7 6 ; cf.A., 1930, 1493).—T he erro r in tro d u ced in to experi
m ents on th e a n g u lar scatte rin g of electrons in gases b y th e p o te n tia l g rad ien t betw een th e electron beam an d a p o in t outside i t resulting from th e slig h t difference in co n cen tratio n betw een th e positive ions an d electrons due to th e g re a te r m obility of th e form er
is discussed. N . M. B l i g h .
D i a m a g n e t i s m of th e f r e e e le c tr o n . C. G.
D a r w in (Proc. Cam b. Phil. Soc., 1931,
27,
86— 90).—M athem atical. L an d au , in his calculation of th e diam agnetic effect d ue to th e m otion of electrons in a m agnetic field (cf. A., 1930, 1355), m ade a n allow ance for bou n d ary considerations. A special case is con
sidered, ad m ittin g of ex act solution, in w hich th e bou n d ary is replaced b y a w eak field of force. T h e resu lt reduces to L a n d a u ’s form ula, an d shows B o h r’s arg u m en t of th e creeping of th e electron ro u n d th e
b oundary wall. N . M. B l ig h .
D if f r a c tio n of a n e le c tr o n w a v e a t a s in g le la y e r of a to m s . M. v o n L a u e (Physical R ev ., 1931, [ii],
37,
53— 59).—A m ath em atical exam ination of th e tre a tm e n t b y Morse of th e incidence an d reflexion of electrons a t th e surface of a space la ttic e (cf. A., 1930, 976), N i M. B l i g h .E ffe c t of r e s o lv in g p o w e r o n m e a s u r e m e n t s of t h e a b s o r p t i o n c o e ffic ie n t of e le c tr o n s i n g a s e s . R . R . P a lm e r (Physical R ev., 1931, [ii],
3 7 ,
70— 81).—Using a M ayer ty p e a p p a ra tu s w ith a n opening of variab le a p e rtu re a t th e end of th e scatterin g cham ber, th e ab so rp tio n coefficient of electrons in helium an d m ercu ry v ap o u r for th e ran g e 20— 135 v o lt electrons w as stu d ied as a fun ctio n of th e aper- a tu re for 2— 11°. N . M . B l ig h .
P h o t o g r a p h i c d e te c tio n of a s y m m e t r i c a l a n g u l a r d i s t r i b u t i o n of d o u b ly - r e f le c te d e le c -
G E N E R A L , P H Y S IC A L , A N D IN O R G A N IC C H E M IS T R Y . 279
trons. E. R
upp(N aturw iss., 1931,1 9 ,
109).—U sing an o n -ro tatin g analyser a n asy m m etry has been observed in th e a n g u lar d istrib u tio n of doubly-reflected electrons.
A pencil of electrons w as reflected b y gold foil of a fibrous s tru c tu re inclined a t 45° to th e in cid en t pencil.
U sing 220-kilovolt electrons diffraction p a tte rn s h av e been o b tain ed showing definite asym m etrical in te n sity d istrib u tio n of th e doubly-reflected electrons, th e in te n sity being g re a te st in th e plane of th e incident a n d reflected pencils a n d tow ards th e side of th e electron source. T he intensities a t rig h t angles to th is plane were equal. T his asy m m e try was n o t due to th e fibrous stru c tu re of th e foil, since th e sam e effect w as observed w ith th e foil tu rn e d th ro u g h 90°. T he effect is n o t observable w hen alum inium foil is s u b stitu te d for gold. J . W . S m ith .
Discrete range groups of JT-particles expelled from alum inium . II. Dependence of sharing and energy of //-particles on the angle between the prim ary and secondary rays.
H . P o s e (Z.P h y sik , 1931, 6 7 , 194— 206 ; cf. A ., 1930, 1086, 1232).
— I t is shown th a t th e b ackw ard sharing is a b o u t 30% sm aller th a n t h a t in th e forw ard direction.
T he velocities of th e //-p a rtic le s calculated from th e ranges decrease as th e angle betw een th e p rim a ry a n d secondary ra y increases. A . J . M e e.
Recoil atom s
i ngases.
L . G o l d s t e i n (Compt.rend., 1930,
191,
1450— 1452 ; cf. A ., 1929, 1358).—T he curve show ing th e relatio n of yield of a c tiv a tio n to pressure shows a ra p id rise to a m axim um of 50%
for a pressure of a b o u t 2 cm . m ercury, followed b y an asy m p to tic decline to a b o u t 26% fo r pressures in excess of 45 cm. I t is suggested th a t th e m axim um occurs w hen th e field is ju s t stro n g enough to bring all recoil atom s on to th e electrode, th e subsequent decline being caused b y increased ionic d en sity d ue to increased pressure resulting in m ore com plete u tilis
atio n (in ionisation) of th e a-particles.
C. A. SlLBERRAD.
Method of ion counting in the free atmosphere.
Y. I t i w a r a (Physikal. Z., 1931, 3 2 , 97— 106).—The use of th e ion counting tu b e for determ ining th e num ber of ions in th e free atm osphere is discussed.
I t is show n t h a t if i t is used b y th e charge m ethod, i.e., the o uter electrode of th e cylindrical condenser is raised to
a
co n sta n t po ten tial, th e n th e charge on th e inner electrode w hich w as originally e a rth ed m easures only a fractio n of th e to ta l nu m b er of ions. The counting tu b e of Gocltel, as used b y H ess, co u n ts only the large ions, an d if a suitable correction is applied to his figures, th e y agree m ore closely w ith those ofother observers. A . J . M ëe.
[Method of ion counting in the atm o
sphere. ] Y.
P . H e s s (P hysikal. Z.,1931, 32,106).— .
D oubt is c a st on th e q u a n tita tiv e v alue of th e w ork of Itiw ara (cf. preceding ab stra c t). T he experim ents of Itiw a ra in no w ay to u ch th e w ork of H ess on th e ionisation balance of air over la n d an d open sea.
À. J . M e e .
Form ation of negative ions in gases.
W. H e y an d A. L e ip u n sk y (Z. P hysik, 1930, 66, 669—685).— E xperim ents to determ ine th e p ro b ab ility of th e form ation of n egative ions in argon, m ercury, an d iodine vapours asa
function of th e electron velocity aredescribed in w hich care has been ta k e n to elim inate th e sources of error to w hich are a ttrib u te d th e discrepancies in th e d a ta of o th er w orkers. T he p ro b ab ility in all cases is of th e order of lCk5 in th e range 0—20 electron volts. Iodine v a p o u r ex h ib its a well- defined m axim um in th e neighbourhood of 2-5 volts a n d th e re a fter th e p ro b ab ility a tta in s a n ap p ro x im ately c o n sta n t value. Below 10 volts th e p ro b a b ility in argon a n d m ercu ry v a p o u r is very sm all an d rises ra p id ly in th e range of 10— 20 volts. R . W . L u n t .
Production of high-speed canal rays without the use of high voltages.
E . O. L a w r e n c e an d D. H , S l o a n (Proc. N a t. Acad. Sci., 19 3 1 ,1 7 , 64— 70).Value of
M [ tn . W . N . B o n d (N atu re, 1931, 1 2 7 , 164).—Evidence, a g ain st E d d in g to n ’s suggested value of 1849-6 for MJm is quoted. L . S. T h e o b a ld .M asses of the electron, the proton, and the universe.
(S ir ) A. S. E d d i n g t o n (Proc. C am b.P hil. Soe., 1931, 2 7 , 15— 19; cf. A., 1930, 518).— A n extension of th e th e o ry of th e value 137 fo r th e con
s ta n t he 12ne2 is o utlined ; i t gives satisfacto ry values fo r th e m asses of th e electron, p ro to n , a n d universe.
N. M. Bligh.
Eleventh report of the German com m ission on atom ic w eights.
M. B o d e n s t e i n ,O.
H a h n , 0 . H o n ig sc h m id , a n d R . J . M e y e r (Ber., 1931, 6 4 . [B], 1— 21).— T he re p o rt follows th e general lines of its predecessors. T h e following changes are a d o p ted : As ==74-93 in stead of 74-96; T a = 1 8 1 -3 6 in stead of 1S1-5; R e= 1 8 6 -3 1 in stead of 18S-7. H . W r e n .Fundam ental at. w ts. IX. At. wt. of sulphur.
Synthesis of silver sulphide. O.
H o n ig s c h m id an d R . S a c h t l e b e n (Z. anorg. Chem., 1931, 1 9 5 , 207— 227; cf. A ., 1929, 370).—B y d irect com bination of silver a n d su lp h u r v a p o u r a t 250° th e value of 1-148621 h as been o b tain ed for th e ra tio Ag2S :2A g, w hich gives 32-0664 fo r th e a t. w t. of sulphur.” Silver sulphide does n o t dissociate a t 150— 300°.R . C g t h i l l .
Revision of at. wt. of calcium . At. wt. of calcium from sylvine.
0 . H o n ig s c h m id a n d K . K e m p te r (Z. anorg. Chem., 1931, 1 9 5 , 1— 14).—D eterm in atio n of th e ratio s CaCI2: 2 Ag an d CaCl2:2AgCl h as given th e value 40-085+0-00060 fo r th e a t. w t. of calcium . T he a t. w t. of calcium o b tain ed from sylvine is norm al, in d icatin g th e absence of a n y appreciable a m o u n t of th e calcium isotope Ca41.
R . C ut h l l l .
At. wt. of uraninite lead from Wilberforce, Ontario, Canada.
G. P . B a x t e r a n d A. D . B l i s s (J. Am er. Chem. Soc., 1930, 5 2 , 4 8 5 1 -4 8 5 3 ).—T he a t. w t. of lead e x tra c te d from u ra n in ite is fo u n d to b e 206-195 a n d on c e rta in assum ptions th e th o riu m / u ran iu m co n sta n t is com puted to be 0-27.J . G. A. G r i f f i t h s .
At. w t. of uranium lead from Sw edish kolm .
G. P . B a x t e r an d A. D. B l i s s (J. A m er. Chem. Soc., 1930, 5 2 , 4848— 4851).—T he a t. w t. of u ra n iu m lead e x tra c te d from Swedish kolm , in w hich th o riu m could n o t be detected,is
206-01. J . G. A. G r i f f i t h s .Determ ination of the isotope ratio from
intensity m easurem ents of the boron m onoxide
spectrum .
A. E l l i o t t (Z. P hysik, 1931, 6 7 , 75—88).—T he in te n sity of a spectral line depends on th e n u m b er of m olecules in th e original sta te , a n d on th e tra n sitio n probabilities. If th e curve showing th e n u m b er of m olecules w ith a given energy is selective to a ran g e of energies, as is th e case w ith boron m o n oxide in a n active nitrogen discharge tu b e, th e n because of th e difference betw een th e energies of v ib ratio n of tw o isotopic molecules, th e isotope ratio m a y n o t be proportional to th e relative in ten sities of th e corresponding lines. T he erro r in assum ing th is pro p o rtio n ality for boron m onoxide isotopes is 4— 7% . T he corrected isotope ra tio is 3-63;LO-02, an d th e corresponding a t. w t. is lO - lO t^ 0-001. T he effective tem p eratu re of active nitrogen in such a discharge
tu b e is 470°. A. B. D. C a ssie .
I s o to p ic c o n s titu tio n a n d a t. w ts . of z in c , t in , c h r o m iu m , a n d m o ly b d e n u m . F . W . A s t o n (Proc, R o y . Soc., 1931, A , 130, 302— 310).—W ith th e o b ject of d eterm in in g th e re la tiv e ab u n d an ce of isotopes in a n u m b er of elem ents, a tte m p ts h av e been m ade to m easure th e p hotom etric in te n sity of m ass sp ectra lines. T h e use of cadm ium m eth y l a n d germ anium e th y l led to u n sa tisfa c to ry re su lts for these m etals. I n th e experim ents on zinc, zinc m eth y l w as used. T he p acking fractio n of Znfi4 w as fo u n d to be —9-9, th e percentage of th is isotope being 4S-0. T he a t. w t. of th e m e tal w as calcu lated to be 65-380J r 0-02, in e x a c t agreem ent w ith th e b est chem ical d e term in atio n s. T he m e th y l com pound w as also used for tin , w hich gave a packing fractio n of
—7-3 for Sn120 a n d a t. w t. 118-72±0-03. Chrom ium hexacarbonyl w as used for chrom ium , a n d fo u r iso
topes, 50, 52, 53, a n d 54, were discovered, 52 being m uch th e stro n g est. A provisional value for th e packing fractio n of Cr52 is —10, giving a t. w t. 52-011 ± 0 - 0 0 6 .~ T he h exacarbonyl w as also used for m o ly b denum a n d seven isotopes, 92, 94, 95, 96, 97, 98, a n d 100, were observed. T his group shows a sim ilarity of abun d an ce m ore strik in g th a n t h a t of a n y o th er elem ent of such com plexity. T he p acking fractions of Mo98 a n d Mo100 were fo u n d to be th e sam e, —5-5 (approx.), giving a t. w t. 95-97±0-06.
L. L. B ir c u m sh a w . C o n s titu tio n of o s m i u m a n d r u t h e n i u m . F . W . A s t o n (N ature, 1 9 3 1 ,1 2 7 , 233).— T he m ass sp ectru m of osm ium tetro x id e indicates t h a t th e m e ta l has fo u r stro n g a n d tw o w eak isotopes, one of th e la tte r being isotopic w ith tu n g sten , W 18G. T he m ass n u m bers a n d % relativ e abundances (provisional) a re 186 a n d 1-0, 187 an d 0-6, 18S a n d 13-5, 189 an d 17-3, 190 an d 25-1, a n d 192 a n d 42-6, respectively. T he p a c k ing fra c tio n is —1 -0 ^ 2 -0 a n d th e deduced a t. w t. is 190-31d;0-06, suggesting t h a t th e accepted value of 190-9 is to o high. T he b ehaviour of ru th e n iu m tetro x id e in th e discharge m akes th e following d a ta u n certain , b u t six isotopes, w ith possibly a fa in t sev en th , ap p e a r to be p resen t. T he m ass num bers an d p ercentage ab u n d an ces are 96 an d 5, (98) a n d — , 99 a n d 12, 100 an d 14, 101 an d 22, 102 a n d 30, a n d 104 a n d 17, respectively. A ssum ing a p acking fra c tio n of ap p ro x im ately —6, these give an a t. w t. of 101-1, b u t th e divergence from th e accepted value of 101-7 can be p a rtly explained in th is case.
L. S. Th e o b a l d.
I s o to p e s a n d liv in g o r g a n i s m s . W . V e r n a d s k y (Com pt. ren d ., 1931, 1 9 2 , 131— 133).—To d e te r
m ine w h eth er living organism s hav e th e pow er of sep aratin g isotopes, com pounds of potassium , iron, m agnesium , zinc, calcium , silicon, a n d su lp h u r have been p rep ared from th em an d th e a t. w ts. are to be determ ined (cf. Low ry, th is vol., 141).
C. A. SlLBERRAD.
R e m o v a l of r a d o n f r o m a n e m a n a t i o n c h a m b e r a f t e r u s e . C. L. U t t e r b a c k a n d D . D e v a p u t r a (R ev. Sci. In s tr., 1931, [ii], 2 , 53—54).—A n a p p a ra tu s an d m ethod a re described for th e ra p id rem oval of ra d o n a fte r w ork on solutions co ntaining rad iu m u p to 10~7 g.
p e r litre, b y a lte rn a te ev acu atio n of th e em an atio n cham ber an d sweeping o u t w ith specially d ried air.
N. M. B l ig h . M a g n e tic s p e c t r a of a - r a y s . S. R o s e n b ltjm (J.
P hys. R adium , 1930, [vii], 1, 438—444).—Tw o pieces of a p p a ra tu s are described. I t is show n t h a t all th e a-rays from th o riu m -C do n o t tra v e l w ith identical speeds, b u t in groups. C. W . G ib b y.
A n o m a lo u s s c a t t e r i n g of a-p a r tic le s b y l i g h t n u c le i. E . Gu t ii a n d T. S e x l (Z. Physik, 1930, 66, 577—580).— A m eth o d is in d icated fo r th e e x a c t cal
culation of anom alous scatterin g of a-particles by a G am ow -G urney-C ondon p o te n tia l field, in stead of by th e usual successive ap p ro x im atio n m ethod.
A. B. D. C a ssie . C a p tu r e of e le c tr o n s b y a - p a r tic le s . H . C.
W e b s t e r (Proc. C am b. P h il. Soc., 1931, 2 7 , 116—
130).— T he c a p tu re of one an d tw o electrons b y sw ift a-particles, rep o rte d b y D avis an d B arnes (cf. A., 1929, 971; 1930, 393), w as in v estig ated , using a n electrical co u n ter in stead of a scin tillatio n screen, w ith com pletely n eg ativ e resu lts. D etailed considerations of v ario u s aspects of th e ex p e rim e n ta l conditions an d in te rp re ta tio n of d a ta show no possibility of reco n ciliation w ith th e re p o rte d effect. N . M. B l i g h .
S c a t t e r i n g of s lo w a - p a r tic le s b y h e liu m . P . M. S. B l a c k e t t a n d F . C. C ham pion (Proc. R oy.
Soc., 1931, A , 1 3 0 ,3 8 0—388).—M o tt has show n (A., 1930, 269), from consideration of th e sy m m etry of th e w ave functions, th a t th e sc a tte rin g of p articles b y a n inverse sq u are field is q u ite different from th a t of th e classical th e o ry w hen th e sc a tte rin g a n d s c a t
te re d p articles are identical. B y using a n a u to m atic W ilson cham b er containing a m ix tu re of helium an d oxygen, th e sc atterin g of a-particles b y helium has been followed dow n to a velocity of 108 cm. p e r sec., corresponding w ith a range of 0-5 m m . in air a t
N .T .P . L. L. B ir c u m sh a w .
A t t e m p t t o d e m o n s t r a t e t h e e x is te n c e of s h o r t - r a n g e a - p a r tic le s f r o m r a d iu m - C . G. H . H e n d e r s o n a n d J . L. N ic k e r s o n (Proc. N o v a Scotia I n s t. Sci., 1 9 3 0 ,1 7 , 256— 258).— A n a tte m p t to d e tect sh o rt-ran g e p articles from ra d iu m -C b y th e W ilson ch am b er m eth o d show ed th a t no group of p articles of definite ran g e could be d ete c te d above th e general
background. H . B u r t o n .
A b s o r b a b le r a d i a t i o n a c c o m p a n y in g a - r a y s f r o m p o lo n iu m . (Mme.) I. C u r ie a n d F . J o l i o t (J. P h y s. R ad iu m , 1931, [vii], 2, 20— 28).— A m ore d etailed acco u n t of w ork a lread y n o ted (A., 1930, 130).
G E N E R A L , P H Y S I C A L , A N D IN O R G A N IC C H E M IS T R Y . 2S1
Loss of energy by (3-particles, and its distri
bution between different kinds of collisions.
E . J . W ill ia m s (Proc. R oy. Soc., 1931, A , 130, 328—
316).— T heoretical. T he req u irem en ts of th e classical and q u a n tu m theories are com pared, an d i t is show n th a t th e q u a n tu m th e o ry is in general agreem ent w ith e x p erim en t an d provides an ex p lan atio n of several p re v io u s ^ obscure effects, p a rtic u la rly in con
nexion w ith p rim a ry ionisation.
L. L. B ircu m sh a'w . R a t e of lo s s of e n e r g y b y p - p a r tic le s i n p a s s i n g t h r o u g h m a t t e r . E . J . W illia m s (Proc. R oy.
Soc., 1931, A , 130, 310— 327).—M ost of th e previous ex p erim en tal w ork w hich h a s been carried o u t on P-particles is v itia te d b y th e effects due to sc atterin g a n d straggling. E x p e rim e n ta l values w hich are p ra c tica lly free from these effects are now given for th e ra te of loss of energy b y p-particles w ith velocities ranging from a b o u t 0-1 to 0-97c.
L. L. B ir o u m sh a w . P h o t o g r a p h i c e ffe c ts of y - r a y s . J . S. R o g e r s (Proc. P h y s. Soc., 1931, 4 3 , 59— 67).— A lthough slow, a p h o to g rap h ic m eth o d can be used for m easuring intensities of y -ray s, ev en w hen v e ry sm all. T he p hotographic action of y -ray s from rad iu m an d ra d o n in equilibrium w ith th e ir short-lived p ro d u cts has been in v estig ated . T he v ariatio n of photographic d en sity w ith tim e of exposure (using co n sta n t in te n s
ity) a n d th e v a ria tio n of d en sity w ith in te n sity (con
s ta n t tim e) w ere exam ined for. y-ray s filtered th ro u g h lead screens of different thicknesses. T he index in th e Schw arzschild re la tio n is u n ity fo r all lead filters.
A p h otographic m eth o d has been developed for th e determ in atio n of ab so rp tio n coefficients. T he ab so rp tion coefficient of lead for y -ray s is 0-533 cm .-1- for thicknesses of lead from 1 to 7 cm. T his is th e sam e value as w as fo u n d b y Ivohlrausch for th e h a rd e r ray s from radium -C , b u t is som ew hat less th a n th a t obtained b y A hm ad w ith a filter of lead 1 cm . th ick .
A. J . M ee.
A b s o r p tio n c o e f fic ie n ts of y - r a d i a t i o n f r o m r a d i u m - / ) a n d -E , a n d th e n u m b e r of e m i t t e d q u a n ta . (M iss) S. B r a m s o n (Z. P hysik, 1930, 66, 721— 740).— A bsolute m easurem ents h av e been made of ionisation c u rre n ts d ue to y -ra d ia tio n from radium -D a n d -E, a fte r passage th ro u g h alum inium and copper. R a d iu m -/) show ed ab so rp tio n coeffi
cients corresponding w ith th e w ave-length 2-G
x
10~°cm., an d ra d iu m -// th e w ave-lengths 1-55 a n d 0-5
x
10-9 cm. T h e longer rad iu m -/? w ave-length is a Ka.
radiation from polonium , b u t th e sh o rte r p ro b a b ly arises in th e rad iu m -D nucleus. T he m ag n itu d e of ionisation c u rre n ts show ed th a t ev ery 100 d is
integrating rad iu m -D ato m s e m itte d 3-1 ± 1 -2 , a n d every 100 d isin teg ratin g radium -D ato m s e m itte d O-SiO-25 y-qU antum . T he in te rn a l ab so rp tio n coeffi
cient is know n for radium -D , a n d in d icates th a t ev ery d isintegrating rad iu m -D nucleus em its one y -q n an tu m .
A . B . D . C a ssie . N u m b e r of y - q u a n ta e m i t t e d f r o m r a d iu m - D . E. S t a h e l a n d G. J . S izoo (Z. P h ysik, 1930, 66, 741— 747).— T he n u m b er of y -q u a n ta e m itte d from radium -D due to d isin teg ratio n w as d eterm in ed b y m eans of a n ionisation cham ber containing m e th y l iodide. D -R adiation from excited ato m s was a b
sorbed b y 1 m m . of alum inium a n d (3-radiation w as deflected b y a m agnetic field. E n erg y absorbed by th e m e th y l iodide t h a t does n o t co n trib u te to ionis
a tio n w as allow ed for. E v e ry 100 d isin teg ratin g rad iu m -D ato m s e m it 2-4fl; 0-7 y -q u a n ta .
A. B. D. C a ssie . M e th o d s of in v e s t i g a t i n g t b e in t e n s i t i e s of y - r a y s . C. D. E l l i s a n d D. S k o b e l t z y n (N ature, 1931, 127, 125).—T he m ethods of Skobelzyn (A., 1930, 8) a n d of E llis a n d A ston {ibid., 1339) for m easurem ents of th e in ten sities of th e y-ray s of radium -D a n d - 0 are discussed in re la tio n to each o th e r a n d are show n to be com plem entary. Con
fidence in th e values of th e ind iv id u al in ten sities of th e y-ray s m easured b y th e photo-electric m eth o d is also given b y th is agreem ent. L. S. T h e o b a ld .
P h o to - e le c tr ic a b s o r p t i o n of y - r a y s . L. H . G r a y (Proc. C am b. P h il. Soc., 1931, 27, 103— 112).—
A vailable d a ta for th e d e riv atio n of a fo rm u la for th e photo-electric ab so rp tio n coefficient of X -ra y s a n d y-rays are review ed. N. M. B l ig h .
A b s o r p tio n la w f o r s h o r t w a v e - le n g th y - r a y s . L. M e i t n e r an d H . H . H u p f e l d (Z. P h y sik , 1931, 67, 147— 168).— T he abso lu te sc a tte rin g coefficient of y-rays of w ave-length 4-7 X from th o riu m -6 '", filtered th ro u g h 4 cm . of lead, w as d eterm in ed fo r different sub stan ces a n d w as found to correspond w ith th a t calcu lated from th e form ula of K lein an d N ish in a (A., 1929, 373) for carb o n o n ly ; in general, ae in creases w ith increasing nuclear charge. F o r y-rays fo r radium -C th e scatterin g coefficients for alum inium an d carb o n are id en tical an d accord w ith th e theory.
A. J . M e e . T h e o r y of a to m ic d is in t e g r a t i o n . I I . G. B e c k (Z. P h y sik , 1931, 67, 227— 239; cf. A ., 1930, 1233;
th is vol., 16).— The case of a h e a v y nucleus is co n sidered w here th e in cid en t a-rays c a n n o t p e n e tra te far, an d th e ex citatio n of a nucleus b y d irect collision w ith a-rays is discussed. A. J . M e e .
P r e s e n t s t a t u s of t h e o r y a n d e x p e r i m e n t a s to a to m ic d i s i n t e g r a t i o n a n d a to m ic s y n th e s is . R . A. M i l l i k a n (Science, 1931, 73, 1— 5).— An
address. L. S. T h e o b a ld .
M i c r o c a l o r i m e t r i c m e a s u r e m e n t s of a t h e r m i c e ffe c t v a r y i n g w i t h tim e . A. D o r a b i a l s k a (Rocz.
Chem., 1931, 1 1 , 35— 39).— T he increase in h e a t p ro d u ctio n of 2-2 m g. of ra d iu m sep a ra te d from e m an atio n a n d from slowly d isin te g ratin g p ro d u c ts can be m easured b y m eans of a n ad ia b a tic m icrocalorim eter., a n d is a m easure of th e accu m u latio n of em an atio n .
R . Tr u sz k o w sk i. R a d i a t i o n a n d m o l e c u l a r p r o p e r t i e s . R . D . K le e m a n (Z. anorg. Chem ., 1931, 1 9 5 , 164—172).— T heoretical. I t is show n t h a t th e a u th o r ’s th e o ry of a sta tic ato m is capable of affording a com prehensive e x p la n a tio n of th e p h enom ena of p h o to ch e m istry (cf.
A., 1930, 1340). I t also yields a satisfa c to ry physical in te rp re ta tio n of ra d ia tio n a n d ionisation p o ten tials.
R . C u t h i l l . Q u a n tu m - m e c h a n ic a l m o tio n of f r e e e le c tr o n s i n e l e c tr o m a g n e tic fie ld s . E . H . K e n n a r d (Proc.
N a t. A cad. Sci., 1931, 17, 58— 63).
T r a n s f e r of e n e r g y b e tw e e n a t o m s o n c o llis io n . 0 . N . R ic e (Proc. N a t. A cad. Sci., 1931.1 7 , 34— 39).—
M athem atical. A n outline is given of a m odification of B o rn ’s tr e a tm e n t of th e q uestion of energy exchange b etw een a to m s or molecules w hich ta k e s in to acco u n t th e re la tiv e tra n sla tio n a l energy a n d also m eets th e objections raised by K allm an n a n d L ondon (A., 1930, 395) to F re n k e l’s view t h a t B o rn ’s m e th o d m a y be ap p lied d ire ctly (ibid., 132). T he m eth o d yields in a n y given case a n u p p e r lim it for th e ra d iu s of ac tio n w hich is considerably sm aller th a n t h a t fo u n d b y K allm an n a n d L ondon (A., 1929, 487).
H . F . Gil i/b e. A b s o r p tio n c o e ffic ie n t of e a r t h r a d i a t i o n i n a ir . G. A. Su ck sto rff (N aturw iss., 1931, 1 9 , 87— 88).—
T he ab so rp tio n coefficient of e a r th ra d ia tio n fo r free a ir (10 m etres above gro u n d level) w as found to be 3-4 x lO -5 cm .-1 ; for a ir in a n iron tow er 10 m e tres high tho v alu e w as 4-5 X lO -5 cm .-1 Tlio a b so rp tio n curve in free air can be rep resen ted b y th e a d d itio n of th re e ab so rp tio n curves w ith coefficients, 4'6, 3-2, a n d 2-6 X lO -5 cm .-1, w hich correspond w ith th e io n is
ing influences of rad iu m , th o riu m -C ", a n d potassium ,
respectively. W . R . A r g o s .
T r a n s f o r m a t i o n of l i g h t in to h e a t i n s o lid s . I.
J . F r e n k e l (P hysical R ev., 1931, [ii], 3 7 , 17—4 4 ; of. A., 1930,126, 132).— M ainly m ath em a tic al. F ro m th e analogy betw een a c ry sta l a n d a m olecule th e electronic e x c ita tio n form ing th o first stop in th e process of lig h t ab so rp tio n is d istrib u te d am ong th e a to m s in th e form of “ e x c itatio n w aves,” sim ilar to sound w aves, w hich are used to describe th e h e a t m otion in th e sam e cry stal. N . M. B l i g h .
B u ild in g u p of e le m e n ts i n s t a r s . W . A n d e r s o n (Z. Pliysik, 1931, 67, 294— 295).— T he s ta te m e n t of A tk in so n a n d H o u te rm a n s (A., 1929, 738) t h a t th e te m p e ra tu re of sta rs is of th e o rd er of 4 x 107°
an d t h a t th o d e n sity is a b o u t 10 g. p e r c.c. does n o t agree w ith M ilne’s v alue of 10u °. A. J . M e e .
V a n d e r W a a ls f o r c e s f o r h y d r o g e n a n d h e l i u m a t l a r g e i n t e r - a t o m i c d is ta n c e s . H . R . H a s s e (Proc. C am b. P h il. Soc., 1931, 27, 60—7 2 ; cf. E isen- schitz, A ., 1930, 525; L en n ard -Jo n e s, th is vol., 17).—
M athem atical. T he inte rato m ic force a t large d is
tan ces is calculated from th e principle of m inim um energy b y a m e th o d based on t h a t used fo r th e p o larisab ilitv of helium (cf. th is vol., 14).
N . M. B l i g h . S e p a r a t i o n of th e tw o t y p e s of io d in e m o le c u le a n d t h e p h o to c h e m ic a l r e a c t i o n of g a s e o u s io d in e w i t h h e x e n e . R . M. B a d g e r an d J . W . U r m s t o n (Proc. N a t. A cad. Sci., 1 9 3 0 ,1 6 , SOS—811).
— W ood a n d Loom is (J. F ra n k lin In s t., 1928, 2 0 5 , 481) fo u n d t h a t th e fluorescence sp ectru m of iodine ex cited b y th e green m erc u ry line (5461
A.)
contained only h alf th e n u m b e r of lines of th e fluorescence sp ectru m excited b y w hite lig h t. T h e lines ap p earin g u n d e r e x c ita tio n b y 5461A.
are ascribed to a n“ o rth o ” ty p e of iodine m olecule. T herefore b y irra d ia tin g iodino w ith 5461
A.
i t is possible to a c tiv a te selectively ‘ ‘ o r th o 5 ’ molecules. E x p erim en ts w ere perform ed in w hich th e a c tiv a te d “ o rth o ” m olecules re a c te d w ith hexene are discussed. I t is claim ed t h a t a fte r irra d ia tin g a m ix tu re of iodinean d hexene w ith 5461
A.
for 24 h rs., th e residual iodine consists largely of m olecules w hich can n o t absorb th e m ercu ry green line. W . R . A n g u s.P h o t o m e t r i c p r o p e r t i e s of g r o u n d a n d f r o s t e d g la s s . J . D o u r g n o n a n d P . W a g u e t (Com pt. rend., 1931, 192, 155— 156). C. A. S i l b e r r a d .
H i g h ly - a tte n u a te d f la m e s of a l k a l i m e t a l v a p o u r s w i t h h a lo g e n h y d r id e s . G. S c h a y (Z.
physikal. Chem., 1930, B , 1 1 , 291— 315; cf. A., 1930, 832).— R eactions betw een opposing stream s of halogen hydrides a n d vapours of sodium or p o tassiu m hav e been stu d ied b y th e m eth o d s described in earlier p apers. T he p rim a ry re a c tio n is M + H X = M X -f -H , a n d th o lum inescence observed is due to su b seq u en t rea ctio n of th e h ydrogen atom s. A p a r t of tho e m itte d lig h t is d ue to a rea ctio n H + H X = H 2-}-X a n d th e rem ain d er p ro b a b ly to com bination of h ydrogen ato m s w ith sodium adsorbed on th o walls of th e tu b e, a n d su b seq u en t reactio n of tho h y d rid e w ith atom ic hydrogen. T he lig h t e m itte d b y th e sodium flam es is t h a t of th e sodium D line, w hereas tho potassium flames give a continuous spectrum .
F . L . Us h e r. A m m o n ia d i s c h a r g e tu b e . G. I . L a v in an d J . R . B a t e s (Proc. N a t. A cad. Sci., 1930, 1 6 , 804—
808).— T he activ e p ro d u cts in th e e x it tu b e of a n am m onia discharge tu b e h av e been exam ined an d seem to consist of atom ic hydrogen a n d N H or N IL - T he c a taly tic effects of c e rtain sub stan ces a n d th e c h aracteristic lum inescences a t various surfaces hav e been ex am in ed (A., 1930, 659) a n d are discussed.
W . R . A n g u s . B a n d s p e c t r u m i n t e n s i t i e s f o r s y m m e t r i c a l d ia t o m i c m o le c u le s . I I . E . H u t c h i s s o n (P h y sicalR ev ., 1931, [ii], 3 7 ,4 5 — 50).— M athem atical.
T he ap p ro x im ate expression previously deduced (cf.
A., 1930, 1331) is ex tended, using th e S chrödinger p e rtu rb a tio n th e o ry a n d rem oving th e re stric tio n of linear oscillations. N . M. B l i g h .
T h e o r e tic a l v a lu e s of t h e q u a n t u m of e n e r g y of v i b r a t i o n of u n e x c ite d g a s e o u s a lk a li io d id e s . H . J . v a n L e e u w e n (Z. P h ysik, 1930, 66, 241— 245).
— T heoretical. B riick ’s m e th o d (A., 1929, 381) is used to calculate th e energy of in te ra c tio n of a com p a ra tiv e ly sm all positive io n a n d th e électrons of a com pleted O shell, w here th e 0 shell m oves in a field of force due to a nucleus of effective charge Z.
E xam ples discussed are lith iu m , sodium , a n d ru b id iu m
iodide. A. B . D. C a ssie .
A n a ly s is a n d i n t e r p r e t a t i o n of h y d r o g e n c h lo r id e h a n d s i n t h e u ltr a - v io le t. M. K u l p (Z.
P h ysik, 1931, 6 7 , 7— 23).— T he b a n d sp ectru m o b ta in e d b y a Geissler discharge in stream in g gaseous hydrogen chloride w as m easured (cf. A ., 1930, 1089 ;
th is vol., 19). W . R . A n g u s;
In flu e n c e of t h e c r y s t a l l a t t i c e o n t h e a b s o r p t i o n s p e c t r u m of a c o m p o u n d . H . F e s e f e l d t (Z. P h y sik , 1931, 67, 37— 41).—A b so rp tio n spectra betw een 180 a n d 600 m g a re given fo r silver an d th a lliu m iodides a t o ne. te m p e ra tu re below th e inversion p o in t, a n d a t a n o th e r above th e inversion p o in t. V ariatio n of th e a b so rp tio n c o n s ta n t w ith te m p e ra tu re of silver iodide a t 480 m g is also given,
