BRITISH CHEMICAL ABSTRACTS
A . - P U R E CHEMISTRY
J U L Y , 1931.
G en era l, P h y s ic a l, an d In o r g a n ic C h em istry .
C o n tin u o u s s p e c tr u m of h y d ro g e n . I n t e r p r e t a tio n of e x c ita tio n p o te n tia l c u rv e . W . Fi n k e l n-
b u r g a n d W . We i z e l (Z. Physik, 1 9 3 1 , 6 8 , 5 5 7 — 584).
D is tr ib u tio n of in te n s ity a m o n g th e fin e - s tr u c - tu r e c o m p o n e n ts of th e s e r ie s lin e s of h y d ro g e n a n d io n is e d h e liu m a c c o rd in g to th e e le c tro n th e o ry of D ira c . M. Sa h a and A. C. Ba n e r j i (Z.
Physik, 1931, 68, 704—720).
S p e c tr a of h y d ro g e n a n d h e liu m p ro d u c e d b y co n d e n se d d is c h a r g e . H . Na g a o k a and T. Fu t a-
gami (Proc. Im p. Acad. Tokyo, 1931, 7, 54—55);—
Using a disruptive discharge in H 2 th e Balm er lines become diffuse, an d sharp lines of th e secondary spectrum can be observed among them . W ith He the lines become slightly diffuse, b u t the broadening is very small com pared w ith th a t in th e Balm er lines.
W ith 0 2 th e lines are as sharp as w ith an ordinary
discharge. E . S . He d g e s.
B o ltz m a n n d i s tr i b u ti o n in th e h y d ro g e n a rc . L. S. Or n s t e i n, J . G. Ev m e r s, and J . Wo u d a (Proc.
K. Akad. W etensch. A m sterdam , 1931, 34, 505—
507).—The B oltzm ann distribution holds for the H2 arc spectrum . T he tem p, determ ined for three arcs are 4900, 5300, and 6300° Abs.
E. S. He d g e s. S p e c tr u m of b e r y lliu m . F. P aso h e n an d P . G.
Kr u g e r (Ann. Physik, 1931, [v], 8, 1005— 1016).—
The spectra Be I and Be n , especially two series of singlets therein, have been experim entally investigated.
‘ W . Go o d. S in g le ts of th e tw o -e le c tro n s p e c tr a B xi, C III, N rv , a n d O v . B. Ed l ê n (N ature, 1931, 127, 744).—D ata for certain com binations and transitions are recorded. L. S. Th e o b a l d.
D is p la c e m e n t of c e r ta in lin e s in th e s p e c tr a of io n ise d o x y g e n (O II, O i l l) , n e o n (Ne il) , a n d a rg o n (A i l ) . W. E. Pr e t t y (Proc. Physical Soc., 1931, 43, 279—304; cf. A., 1929, 1205).—M any lines are displaced tow ards t h e red. C. W. Gi b b y.
S tr u c t u r e a n d Z e e m a n effec t of th e n e o n s p a r k s p e c tr u m , N e n . T. L. d e Br u i n and C. J . Ba r k e r (Z. Physik, 1931, 69, 19—35).—280 Ne i i
lines are tab u la te d ; the Zeem an effect in 40 of th e lines is also given. A. B. D. Ca s s i e.
C o llisio n s of th e s e c o n d k in d a n d t h e i r effect on th e fie ld in th e p o s itiv e c o lu m n of a g lo w d is c h a rg e in m i x tu r e s of th e r a r e g a s e s . L. B.
He a d r ic k and 0 . S. Du f f e n d a c ic (Physical Rev.,
3 F 7 7 9
1931, [ii], 37, 736—755).—M easurements of th e electric held and spectroscopic observations were m ade over a range of currents an d pressures for m ixtures of two of the gases H e, Ne, an d A, an d a m ixture of each w ith H g vapour. T he electrical and spectral characteristics of the uniform positive column can be explained principally in term s of collisions of th e second kind betw een ions or m etastable atom s of one gas and n eu tral atom s of th e other.
N. M. Bl i g h. I n te n s ity of f o r b id d e n t r a n s i t i o n s in th e a lk a lis . N. Wh i t e l a v and A. F. St e v e n s o n (N ature, 1931, 127,817).—The values of ( 1 S - W ) / ( 1 S - 2 P ) calc, for th e alkali m etals (A., 1930, 1075) are supported by Prokofiev’s experim ental values (A., 1929, 1205).
L. S. Th e o b a l d. W a v e -le n g th s t a n d a r d s in th e e x tr e m e u l t r a v io le t a lu m in iu m s p e c tr u m . J . So d e r q v is t and B. E d l e n (Z. Physik, 1931, 69, 350—365).—W ave
length stan dard s betw een 312 an d 68
A.
were obtained in th e spectrum of ionised A1 w ith an accuracy of 0-003—0-01A.
A. B. D. C a s s i e .T e m p e r a t u r e d e te r m in a tio n f r o m b a n d s p e c tr a . II. R o ta tio n a l e n e rg y d is tr ib u tio n in th e c y a n o g e n a n d A lO b a n d s , a n d t e m p e r a t u r e d i s t r i b u ti o n in th e a rc . L. S. Or n s t e i n
and H . Br in k m a n (Proc. K. Akad. W etensch.
A m sterdam , 1931, 34, 498—504).—The tem p, of th e gas in th e violet kernel of th e C arc has been determ ined as 6500±300° abs. T he value is independent of the length of th e arc (3— 18 m m .) an d of th e cu rren t (1—
12 am p.). E . S. He d g e s.
P e r t u r b a ti o n s a n d p r e d is s o c ia tio n in th e S„
b a n d s p e c tr u m . A. Ch r i s t y and S. M. Na u d e
(Physical R ev., 1931, [ii], 37, 903—919).—The S2 bands were photographed in absorption an d emission between ?. 3500 an d X 2400. W ave-lengths and quantum analysis are tab u lated , and an equation for th e unp erturbed heads is found. P erturbations found are discussed. Predissociation is discussed in term s of the Franck-C ondon principle of tran sition probabilities. The dissociation energies of the lower and upper states are 4-45 and 2-07 volts.
N. M. Bl i g h. S tr u c t u r e of th e s p e c tr a of s u l p h u r : r e la tio n s b etw een, s p e c tr a of th e s a m e m u ltip lic itie s . M. G i l l e s (Ann. Physique, 1931, [x], 15, 267— 410).—
The spectra of S n , S in , an d S rv for th e range 7634—
640
A.,
excited in S vapour in a pyrex Geissler tube, were p h o t o g r a p h e d a n ( j tab ulated. Using an im-7 8 0 BR ITISH CHEMICAL ABSTRACTS.— A .
proved form of tube, w ith a field of 31,700 gauss, th e Zeeman effect for 55 lines of S ii and 51 lines of S i n was investigated. The m ultiplet system s are in terp reted in d etail; th e triplets, quintuplets, and a singlet of S n r, and the quadruplets of S II are re cognised and tab u lated w ith th eir term values.
C ertain doublets of S n reported by Ingram (cf. A., 1929, 965) are verified. N. M. Bl i g h.
H y p e rfin e s tr u c tu r e in th e s p e c tr a of C a II, B a n , a n d T l i . S. Fr i s c h (Z. Physik, 1931, 68, 758—-763).—A dispersion of 0-7
A.
per mm. failed to reveal hyperfine structure in lines due to Ca n and B a ir and the nuclear angular m om entum of these elements is probably zero. A. B. D. Ca s s i e.B a n d s p e c tr a of c a lc iu m h y d rid e . I. B.
Gr u n d s t r o m (Z. Physik, 1931, 69, 235—24S).—The recorded system s of bands in CaH2 (A., 1927, 185) have been more closely analysed, and new bands near 7500
A.
were obtained w ith 3— 4 atm . H ,. The p ro nounced pressure effect in th e C-system is explained as predissociation. A. B. D. Ca s s i e.P r o p e r tie s of s o m e zin c, c a d m iu m , a n d m e r c u r y b a n d s . J . G. Wi n a n s (Physical R ev., 1931, [ii], 37, 902; cf. A., 1929, 481).—Zn bands a t w ave
lengths 2139, 2064, and 2002
A.
resemble the corresponding bands of Cd and H g in emission and in
absorption. N. M. Bl ig h.
Z e e m a n effect a n d k r y p to n s p a r k s p e c tr u m ( K r n ) . C. J . Ba r k e r and T. L. d e Br u i n (Z- Physik, 1931, 69, 36—51).—The Zeeman effect in 90 K r n lines an d some new term s in this spectrum are described. A. B. D. Ca s s i e.
A rc s p e c tr u m of z irc o n iu m . C. C. Ki e s s and H . K . Ki e s s (Bur. S tand. J . Res., 1931, 6, 621—672).
—N early 1600 lines have been m easured between 20S5 anil 9300
A.
About 80% have been classified as com binations between term s of the singlet, trip let, and quintuplet system s. The term s, w itho ut exception, arc those required by H u n d ’s theory, and m any have been confirmed by Zeeman effect. The ionisation potential of the n eutral Zr atom is 6-92 volts.C. W . Gi b b y. T e m p e r a tu r e c la s s ific a tio n of th e s p e c tr a of e u ro p iu m , g a d o lin iu m , te r b iu m , d y s p ro s iu m , a n d h o lm iu m , 3850—4700 A. A. S. Ki n g (Astro
physics J ., 1930, 72, 221—255).— Electric furnace, arc, and spark spectra of these rare earths have been obtained, and examined w ith regard to th e segregation of neutral and enhanced lines, tem p, classification, and hyperfine structure. Hyperfine stru ctu re occurs regularly in the spectra of rare earths of odd at. no., an d is absent in those of even no. L. S. Th e o b a l d.
A fte rg lo w p e r io d of c a d m iu m v a p o u r f lu o re s cence. W. Ka p u ś c i ń s k i (Naturwiss., 1931, 19, 400—401).—A phosphoroseopic m ethod was used.
The m ax. in ten sity of th e visible band fluorescence does no t coincide w ith th e m oment of excitation, b u t occurs 2-5 x lO -5 sec. later. The fluorescence diminishes a t a ra te ra th e r greater th a n exponential.
A. J . Me e. R a d ia tio n p r o p e r tie s of o x id is e d p a lla d iu m . W. Zo b e l (Ann. P hysik, 1931, [v], 9, 519—536).—Pd, when oxidised by heating in air, shows a max. of tem p.
radiation when heated a t 300—600° in vac. This radiation m ax. is due to a change in th e capacity of the elem ent for absorption in consequence of th e decomp, of th e oxide layer and recrystallisation of th e reduced Pd. A t th e same tim e there is a m in. of reflected
radiation. A. J . Me e.
E n e r g y of d is s o c ia tio n of m e r c u r y m o le c u le s . J . G. Wi n a n s (Physical Rev., 1931, [ii], 37, S97— 901).
—The absorption spectrum of H g vapour in the Schum ann region showed th ree continuous bands with m ax. a t 1808, 1849, and 1692
A .
The absorption spectrum in th e region 1900—1804A.
is correlated with a pair of p otential energy curves for H g2, which give th e energy of dissociation of H g2 as 0-15 volt.N. M. Bl ig h. E m is s io n b a n d s in th e m e r c u r y s p e c tr u m u n d e r lo w e x c ita tio n . (Lo r d) Ra y l e ig h (Nature, 1931, 127, 662).—The diffuse absorption bands from 2943 to 2614
A.
are obtained in emission when Hg vapour fluoresces under th e F e a r c ; th e in ten sity is increased when th e vapour is superheated. Superheating also increases th e continuous emission from 2950 to 3600
A .,
b u t extinguishes th e green visual fluorescence. L . S. Th e o b a l d.E x is te n c e of a tw o -v o lt t e r m in th e m e r c u r y a to m . V. Ko n d r a t e e v (Physikal. Z., 1931, 32, 288—2S9).—The existence of a 2-volt term (probably 3F ) in th e H g atom is deduced from considerations of optical an d therm ochem ical d a ta on H g halides and
H gH. W. R . An g u s.
P o te n tia l d r o p a n d io n is a tio n a t m e rc u ry a r c c a th o d e . E . S. La m a r and K . T. Co m pto n
(Physical Rev., 1931, [ii], 37, 1069— 1076).—By means of a m ovable L angm uir collector, th e potential, ion concentration, an d electron tem p, were measured a t various distances from a statio n ary H g cathode spot a t various arc currents. N. M. Bl i g h.
T h e o r y of th e m e r c u r y a rc . K . T. Co m p t o n
(Physical R ev., 1931, [ii], 37, 1077— 1090).—The theory of heat balance a t th e cathode is extended.
Expressions are obtained giving th e tem p, of the cathode spot and th e v. p. outside it. The thickness of the cathode fall space is less th a n th e electron mean
free p ath . N. M. Bl ig h.
V e rific a tio n of h y p e r fin e s t r u c t u r e th e o ry . J. Wu l f f (Z. Physik, 1931, 69, 70—77).— Observed hyperfine stru ctu re of th e doublet ground levels of T1 is consistent w ith theory. A. B. D. Ca s s i e.
H y p e rfin e s t r u c t u r e in io n is e d b is m u th . R. A.
Fi s h e r an d S. Go u d s m it (Physical R ev., 1931, [ii], 37, 1057— 1068).—Measurements of th e hyperfine stru ctu re of lines in the spectra of Bi i i an d Bi h i are tab u lated w ith intensities an d classifications. Level separations obtained from th e analysis are compared w ith theoretical formulae (cf. th is vol., 6641.
N, M. Bl i g h. I n te n s ity r e la tio n s in t r a n s i t i o n s d u e to in n e r e le c tric fie ld s. S . Samiiu r s k y (Z. Physik, 1931, 68, 774—7S1).—The intensities of transitions for
bidden by ordinary selection rules were calc, by means of the K ram ers-H eisenburg dispersion formula, assuming a disturbing electric field a t th e atom .
A. B. D. Ca s s i e.
G EN E R A L , PH Y SIC A L , A N D IN OR G A N IC CHEM ISTRY. 7 8 1
M u ltip le t in te n s ity a n d a r c te m p e r a tu r e . L. S. Or n s t e i n and S. Sa m b u r s k y (Proc. K . Akad.
Wetensch. A m sterdam , 1931, 34, 339—340).—The sum rule for th e relative intensities of th e m u ltiplet components in a t. spectra depends on th e term s of the initial state, differing by j , being alm ost th e same in each case. W hen these differ considerably, deviations from th e rule occur. This has been confirmed by measurem ents w ith th e Au arc. J . W. Sm it h.
D u ra tio n of m e ta s ta b le s ta te s . J . M. An d e r s o n
(Canad. J . Res., 1931, 4, 312—321).—Decay curves of the absorption of th e line 7635 A. in A have been obtained a t room tem p, an d a t —180°. T he half life of the 3P 0 sta te is approx. 2 x l 0 -4 sec. and is short compared w ith th a t of th e SP 2 state.
C. W . Gi b b y. Q u a d r a tic S t a r k effec t le v e ls. K . P . He r z f e l d
(Z. Physik, 1931, 69, 249—252).—Theoretical.
A. B. D. Ca s s i e. T h e o r y of c o m p le x s p e c tr a . II . E .U . Co n d o n
and G. H . Sh o r t l e y (Physical R ev., 1931, [ii], 37, 1025— 1043; cf. this vol., 2).—Formulae for th e relations betw een th e energies of m ultiplets arising from th e same electron configuration for a num ber of two- and three-electron configurations are deduced by.
Slater’s m ethod (cf. A., 1930, 126); applications to available d a ta are discussed. N. M. Bl ig h.
T o ta l in te n s itie s of F r a u n h o f e r lin e s . M.
Min n a e r t and 0. Sl o b (Proc. K . A kad. W etensch.
Amsterdam, 1931, 34, 542—549).—The m ethod of calculation is described and results are given.
E. S. He d g e s. S ta tis tic a l a n a ly s is of th e s p e c tr u m of a n ionised a to m . E . Se g r e (N u o v o Cim., 1930, 7, 326—329; Chem. Zentr., 1931, i, 1239).—An ex
tension of F erm i’s m ethod. A. A. El d r i d g e. F o r m of th e p o s itiv e c o lu m n b y s h o r t p e r io d ic ex c itatio n . O. Ba r t e l t (Ann. Physik, 1931, [v], 9, 679—703).—Two forms of th e positive colum n are found in cylindrical rare-gas discharge tubes, (1) luminous cylinder w ith central dark space, (2) whole cylinder lum inous. Only th e first form is found w ith other gases. J . Fa r q u h a r s o n.
In flu e n ce of s l i t w id th o n th e in te n s ity of s p e c tra l lin e s . I I . P . H . v a n Cit t e r t (Z. Physik, 1931, 69, 298—308; cf. ibid., 1930, 65, 547).—The work is extended to include absorption and dispersion of the apparatus, and lines obtained w ith an absorbing prism are shown to bo considerably bro ad en ed ; a 15°
prism can advantageously replace the 60° prism of a quartz spectrom eter in the extrem e ultra-violet.
A. B. D. Ca s s i e. M odes of s p e c tr o g r a p h s l i t ir r a d ia tio n . D . C.
St o c k b a r g e r and L. Bu r n s (Physical R ev., 1931, [«],_ 37, 920—922).—Photographs of the H g lines i3650—63 showed a m ax. sharpness an d resolution for a crit, slit w id th ; m ultiples of this w idth produced multiple lines, and narrow er w idths caused diffraction patterns to appear between th e lines.
N. M. Bl ig h. S p e c tro g r a p h p l a t e s h ie ld . J . T. La y and I. C.
C o rn oc (Rev. Sci. In str., 1931, [ii], 2, 293—296).
M o re in te n s e X -r a y s p e c tr a o b ta in e d w ith c o n c a v e c r y s ta ls . H . H . Jo h a n n (Z. Physik, 1931, 69, 185—206).—The possibilities of X -ray reflexion spectra from concave crystals is discussed theoretically an d experim entally. A. B. D. Ca s s i e.
T h e o r y of C o m p to n effect. S. Ki k u c h i (Z.
Physik, 1931, 68,80 3—812).—Theoretical. Q uantum electrodynam ics verifies Com pton’s classical calcul
ation of th e scattering of X -rays. A. B. D. Ca s s i e. S t r u c t u r e of X - r a y a b s o r p tio n e d g e s of th e li g h te r e le m e n ts m e a s u r e d b y a n e le c tro n - c o u n tin g tu b e . H . Ne u f e l d t (Z. P hysik, 1931, 68, 659— 674).—The m easurem ent, b y means of an electron-counting tu be, of absorption edges in the long w ave-length region of X -rays from 15 to approx.
50 A. is discussed. D etails of th e ap paratus and technique are given. T hin sheets of celluloid, Cr, and Be were m easured. Fine stru ctu re edges due to O, X, an d C were detected in th e results obtained from celluloid. Be sheets could not be prepared free of oxide an d th e absorption edges of O appear in th e absorption curve. A ta b le showing th e dependence of th e mass absoiption coeff. on th e w ave-length is given for each of th e substances investigated.
W. R . An g u s. W a v e -le n g th a n d s t r u c t u r e of th e I f a b s o r p tio n e d g e of c o b a lt. M. A. Va l o u c h (Coll. Czech. Chem.
Comm., 1931, 3, 205—215).—The wave-length of the K absorption edge of Co, deposited electrolytically on A1 foil, is 1-6044
A.,
th a t of th e Co ion in alcoholic solution is 1-6026A .,
a n d in aq. solution is 1-6022 A.H. F . Gi l l b e. A n o m a lo u s X - r a y d if f r a c tio n in te n s itie s . W. A.
Wo o d (Nature, 1931, 127, 703).— Cr-plated wires w ith a high lustre show variations in th e relative intensities of th e lines of any X -ray spectrum w ithou t a corresponding change in at. arrangem ent.
L. S. Th e o b a l d. P a r t i a l a b s o r p tio n of X -ra y s . 0 . Be r g and W. Er n s t (Naturwiss., 1931, 19, 401).—The partial absorption lines observed b y R ay (this vol., 277) can be explained as emission lines of certain rare earths.
A. J . Me e. R a d ia tio n f r o m m e ta ls b o m b a r d e d b y lo w - s p e e d e le c tro n s . F. L. Mo h l e r and C. Bo e c k n e r
(Bur. Stand. J . Res., 1931, 6, 673— 681).—A con
tinuous spectrum is em itted by m etal surfaces in dis
charges in Cs and K vapours an d in He. Assuming t h a t these spectra are analogous to X -ray spectra, observed lim its indicate work functions of 1-95 volts for Cu, 2-1 volts for Ag, and 1-45 volts for W, all in
Cs vapour. C. W . Gi b b y.
S c a tte r in g of X -r a y s f r o m g a s e s . E. O.
Wo l l a n (Physical R ev., 1931, [ii], 37, 862—872).—
The in ten sity of scattering of X -rays for scattering angles from 10° to 90° by H 2, He, 0 2, Ne, an d A was m easured. Calc, values of th e stru ctu re factors for Ne and A are com pared w ith those found by wave
m echanics. N . M. Bl ig h.
I n te r a c tio n of X -ra y s w ith b o u n d e le c tro n s . A. J . O ’Le a r y (Physical R ev., 1931, [ii], 37, 873—
883).—Fine stru ctu re previously repo rted for scattered X -rays (cf. A., 1929, 985), an d a change in w ave-length
7 8 2 BR IT ISH CHEMICAL ABSTRACTS.— A .
reported by R ay (cf. A., 1930,1334) and by M ajum dar (of. this vol., 288) are not confirmed.
N. M. Bl i g h. S o ft X -r a y s p e c tr a . V. Do l e j s e k (Compt. rend., 1931, 192, 1088— 1089).—By a modification of Osgood’s m ethod (cf. A., 1927, (302), using Mg for both cathode and anticathode, a series of lines th e m ost intense of which form a doublet a t about 480 Â. and an absorption band a t about 500 Â. were obtained.
C . A. SlL B ER R A D .
F e r m i- D ir a c s ta tis ti c s a p p lie d to th e p r o b le m of sp a c e c h a rg e in th e r m io n ic e m is s io n . R . S.
Ba r t l e t t (Physical Rev., 1931, [ii], 37, 959—909).—
M athem atical. N. M. Bl i g i i. E x p e r im e n ts on e le c tro n e m is s io n b y i n c a n d e s c e n t m e ta l s n e a r t h e i r m e ltin g p o in ts . I. Am e is e r(Z. Physik, 1931, 69, 111—140).—E xp eri
ments on Ag, Au, and Cu indicate th a t electron emission diminishes and surface p otential remains unchanged as the m etal passes to th e liquid phase.
A. B. D . Ca s s i e. O x y g e n film s o n tu n g s te n . I. S tu d y of s ta b ility b y e le c tro n e m is s io n in c æ s iu m v a p o u r.
I. LANGMUiRand D. S. Vil l a r s (J. Amer. Cliem. Soc., 1931, 53, 486—4 9 7 ; cf. A., 1925, ii, 254).—The electron emission from a W wire coated w ith Cs is about 1021-fold th a t from bare W a t th e sam e tem p.
(e.g., 590° abs.), and increases w ith rise of tem p, to a max. and th en decreases owing to evaporation of Cs.
Admission of Cs to a filament coated w ith 0 , followed by flashing a t 1000— 1800° abs., affords an electron emission, a t S50° abs., 105- to 10°-fold th a t observed wit h Cs alone on th e filament . The 0 retains th e Cs with greater tenacity th a n th e bare W. The ra te of evaporation of 0 from W a t 2070°, 197S0, and 1856°
abs. has been evaluated from th e change produced in th e electron emission of th e surface a t 800— 1100°
abs. in the presence of Cs by each exposure to the evaporation tem p. The results indicate a heat of evaporation of O from th e adsorbed layer of 162 kg.- cal. per g.-atom . J . G. A. Gr i i f i t h s.
K in e tic e n e rg y of p o s itiv e th e r m i o n s of a lu m in iu m p h o s p h a te . E . Ba d a r e u (Bui. Fac. Stiintc C ernanti, 1927, 1, 1— 3; Cliem. Zentr., 1931, i, 1238).
S o u rc e s of p o s itiv e io n s. E . Ba d a r e u (B u i.
Fac. Stiintc Cernauti, 1927, 1, 4— 13; Cliem. Zentr., 1931, i, 1238).
A c tio n of a c r y s ta l a s a tw o -d im e n s io n a l la ttic e in d iffr a c tin g e le c tro n s . W . L. Br a g g and F. Ki r c iix k r (N ature, 1931, 127, 738—739).—R e
lations betw een crystal orientation and electron diffraction are described. L. S. Th e o b a l d.
D y n a m ic a l p r o b le m s of fie ld th e o r y a n d e le c tro n c o n s ta n ts . M . Ma t h i s s o x (Z. Physik, 1931, 69, 3 8 9 -4 0 8 ).—Theoretical.
A. B. D . Ca s s i e. E le c tr o n ic v e lo c itie s in th e p o s itiv e c o lu m n of h ig h -fr e q u e n c y d is c h a r g e s . E. Hi e d e m a x x
(Physical R ev., 1931, [ii], 37, 978—982).—Theoretical.
Small values of the electric force do not prohibit th e production of electrons of sufficient velocity to excite or ionise gas mois. N. M. Bl ig h.
H e r tz th e o r y of t h e m o tio n of s lo w e le c tro n s in g a s e s . V. A. Ba i l e y (Z. Physik, 1931, 68, 834— 842).—H e rtz’s diffusion equation is a special case of th a t given by Maxwell (Phil. T rans., 1S67, 73).
A. B. D. Ca s s i e. E n e r g y lo s s a n d s c a tt e r i n g of e le c tro n s of m e d iu m v e lo c ity o n p a s s a g e t h r o u g h a g a s (N a).
M. Re x x i x g e r (Aim. Physik, 1931, [v], 9, 295—337).
—The energy loss of electrons of velocity 200—2000 volts in N 2 was determ ined. The N 2 was a t low pressure so th a t collisions were single. A. J . Me e.
A n g u la r d i s t r i b u ti o n of e le c tro n s s c a tte r e d by m e r c u r y v a p o u r . J . M. Pe a r s o x a n d W . N. A rx -
q u is t (Physical R ev., 1931, [ii], 37, 970—977).
S p e c ific c h a r g e of th e e le c tro n . F . Ki r c h x e r
(Ann. Physik, 1931, [v], 8, 975—1004).—Direct m easurem ent of th e velocity of cathode rays gives e/»i0= (l-7 5 9 8 ± 0 -0 0 2 5 )x l0 7 electrom agnetic units.
W . Go o d. D iffra c tio n of h y d ro g e n a to m s . T. H . Jo h x s o x
(Physical R ev., 1931, [ii], 37, 847— S61; cf. A., 1930, 1232).—Im proved photographs of th e diffraction p attern s produced b y reflexion of a beam of I I atoms from a L iF crystal were o b tained ; th e positions of intensity d istribution m ax. were in good agreement
w ith theory. N. M. Bl ig h.
W a n d e rin g a n d s p a c e c h a r g e of a i r io n s. H.
Gr e ix a c h e r (Physikal. Z., 1931, 32, 406—410).—A simple dem onstration experim ent is described.
A. J . Me e. M e a s u r e m e n ts o n th e d is c h a r g e of h y d ro g e n c a n a l r a y s . J . Ko e x i g s b e r g e r (Z. Physik, 1931, 69, 424—427).—A discussion of possible errors in m ethods described b y B artels (A., 1930, 1493) and
others. ' A. B. D. Ca s s i e.
M e a n fre e p a t h of e le c tro n s . J . S. To w x s e x d
(Ann. Physik, 1931, [v], 8, 805—808).— Controversial.
W. Go o d. M e th o d in th e m e a s u r e m e n t of effectiv e c ro s s - se c tio n s . C. Ra m s a u e r (Ann. Physik, 1931, [v], 8, 809—810).—A reply to Townsend (above).
W. Go o d. E ffectiv e c r o s s - s e c tio n of g a s m o le c u le s t o w a r d s p ro to n s . C. Ra m s a u e r, R . Ko l l a t h, and D. Lil i e x t h a l (Ann. Physik, 1931, [v], 8, 709—736).
—The effective cross-sections of gas mols. towards slowly m oving protons have been determ ined for He, Ne, A, H , and N a t prot on velocities of 30—2500 volts.
The app aratu s is described. E ach curve of effective cross-section against p roton velocity shows, except in th e case of H e, a m in. effective cross-section. F urther experim ents to stu d y th e n atu re of th e action of mols. on m oving protons are described. A com
parison of th e results w ith existing d a ta for electrons leads to th e conclusion th a t th e abs. values of the effective cross-section tow ards protons and electrons are of th e same order of m agnitude. W. Go o d.
P r o d u c tio n of p ro to n s . C. Ra m s a u e r, R . Kol
l a t h, and D. Lil i e x t h a l (Ann. Physik, 1931, [v], 8, 702—708).—An experim ental m ethod of producing
protons is described. W . Go o d.
A n g u la r d i s t r ib u tio n of th e s c a tte r in g of slo w e le c tro n s b y g a s m o le c u le s . C. Ra m s a u e r and
G EN ER A L, PH Y SIC A L , A N D INORGANIC CHEM ISTRY. 7 8 3
R. Ko lla tji (Ann. Physik, 1931, [v], 9, 756—758).—
The scattering of slow electrons by He, A, and H 2 is described. J . Fa r q d h a r s o n.
C o efficien t of r e c o m b in a tio n of g a s e o u s io n s.
0 . Lu h r and N. E. Br a d b u r y (Physical Rev., 1931, [ii], 37, 998— 1000).—Previous values, 12% too high, are corrected ( X108) to : a i r l - 2 3 ± 0 - l ; 0„, l-3 2 ± 0 -l ; N , and A, l-0 6 ± 0 -l ; H 2, 0-28±0-05.
N . M . Bl i g h. P r o to n a n d e le c tro n . H . S. Al l e n (N ature, 1931,127, 662—663).—F iirth ’s relationship (A., 1929, 1123) can be w ritten 2bc/gMn= lG 32, where M n is the mass of the H atom and b= h/2i: ; it also suggests th a t the ratio mass of proton/m ass of electron is 1844-08.
I t is considered th a t contrasted w ith the electron the proton is a space in th e ether w itho ut electric or magnetic m om ent. L. S. Th e o b a l d.
R a d ia tio n -le s s c o llis io n p ro c e s s e s a t s m a ll velocity. P . M. Mo r s e and E . C. G. St u e c k e l b e r g
(Ann. Physik, 1931, [v], 9, 579—600).—The theory of inelastic collisions between at. and mol. particles is considered and com pared w ith th e experim ental facts.
A . J . Me e. F i r s t r e p o r t of th e C o m m itte e of a t. w ts . of th e I n te r n a tio n a l U n io n of C h e m is tr y . G. P. Ba x t e r, (Mm e.) M. Cu r i e, O. Ho n ig s c h m t d, P. Le Be a u, and R. J . Me y e r (J. Amer. Chem. Soc., 1931, 53, 1627—
1639; cf. A., 1930, 269).—The following revised a t.
wts. are adopted : R e, 186-31 ; Ta, 181-4 ; As, 74-93 ; C'a, 40-08. J . G. A. Gr i f f i t h s.
M a s s e s of O 17. H . C. Ur e y (Physical Rev., 1931, [ii], 37, 923—929).—Calc, values of th e rest mass of 0 17 are not in agreem ent w ith experim ental d a ta ; various explanations are discussed. N. M. Bl ig h.
A t. w t. of c æ s iu m : u s e of th e w o r d ‘ ‘ m a s s - s p e c tr o g ra p h . " F . W. As t o n (N ature, 1931, 127, S13).—M ass-spectra of X e an d Cs, obtained during the same exposure, give a packing fraction of —5-0M2-0 for Cs, and an at.w t. 132-91 ±0-02. The w ord “ mass- spectrograph ’’ should no t be applied to D em pster’s
apparatus. L. S. Th e o b a l d;
-Y-Ray s e a r c h fo r e le m e n t 61. S . Ta k v o r i a n
(Compt. rend., 1931, 192, 1220— 1223).—By fraction
ation of th e double Mg n itrates from m onazite sands from India, 500 g. of th e m ixed N d-S m double nitrates was obtained. X -R ay exam ination, both absorption and emission, showed th a t th e am ount of element 61 therein could not exceed 1 p a rt in 10'1.
C . A . SlL B ER R A D .
N u c le a r im p u ls e r o ta t io n of le a d is o to p e s . H. Ko p f e r m a n n (Naturwiss., 1931, 19, 400).—The spectra of neutral and singly-ionised Pb were investig
ated for ordinary and U-Pb. W hilst th e lines of wave-lengths 4058, 4242, 4245, an d 5373 À. show hyperfine stru ctu re in the ordinary P b spectrum , th ey are simple for U -Pb. The U -Pb line does not agree with the strongest lino in the hyperfine structure, bu t with the second strongest. There is well-marked
■ -otopic displacement between the lines of P b 206 and
P b288. A . J . Me e.
L u m in e sc e n c e d u e to r a d io a c tiv ity . D. H.
Ra b a k j ia n (Physical Rev., 1 9 3 1 , [ii], 3 7 , 1 1 2 0—
1Î28).—General observations and results cannot be
explained b y any form of R u th erfo rd ’s active-centre theory, b u t can be in terp reted qu alitatively by assum ing th a t a-, (3-, an d y-rays produce excited mols., which, returning to th eir in itial state, em it luminous energy. O ther aspects of th e problem are discussed.
N. M. Bl ig h. T h e re c o il p h e n o m e n o n a n d c o n s e rv a tio n of m o m e n tu m . F . Jo l io t (Compt. rend., 1931, 192, 1105— 1107).—The experim ents of A kiyam a (cf. A., 1924, ii, 814) on th e direction of th e recoil atom s of actinon and a c tin iu n w l have been repeated w ith an im proved ap paratus giving recoil tracks up to 7 mm.
long. There are no grounds for assum ing th e emission of y-rays sim ultaneously w ith th a t of the recoil atom . C. A. Si l b e r r a d.
C o m p le x ity of th e a - r a d ia tio n of r a d io a c tin iu m . (Mme.) I. Cu r i e (Compt. rend., 1 9 3 1 , 192, 11 0 2 — 1 1 0 4 ).—M easurem ents of the range of a-particles of radioactinium b y m eans of th e Wilson expansion cham ber show th a t these fall in about equal am ounts into two groups w ith ranges in air, a t 7 6 0 m m . an d 15°, of 4 -6 8 and 4 -4 8 cm. Absence of aetinium -X from th e radioactinium used was definitely proved, as also th e im possibility of the particles of less range being due to re ta rd atio n a t th e source. C. A. Si l b e r r a d.
A rtific ia l d is in te g r a tio n b y a -p a rtic le s . J.
Ch a d w i c k, J . E . R . Co n s t a b l e, an d E . C. Po l l a r d
(Proc. R oy. Soc., 1 9 3 1 , A , 130, 4 6 3 — 4 8 9 ).—An exam ination has been m ade of th e protons em itte d by a num ber of elem ents when bom barded by a-particles from a Po source. Definite effects were found for B, N 2, F, N a, Al, an d P. E xcept in th e cases of F and N a, th e results suggest th e presence of d istin ct groups in th e protons released in disintegration, which are explained on the assum ption of definite levels for th e protons and a-particles in a nucleus. I t is assumed t h a t all th e a-particles of a stable nucleus are in the sam e energy level and th a t no t more th a n tw o protons can be p u t into th e same proton level. Of th e two possible types of disintegration, (1) in which the a-particle is captu red by th e nucleus, (2) in which a p roton is ejected w ith ou t capture of th e a-particle, the first explains th e present results.
L . L . Bir c u m s h a w. S tr u c t u r e of t h e a -p a rtic le . O. K . Ri c e (J.
Amer. Chem. Soc., 1 9 3 1 , 53, 2 0 1 1—2 0 1 2 ; cf. th is vol., 5 4 4 ).—Theoretical. J . G . A. Gr i f f i t h s.
A b s o rp tio n of ¡3-rays b y m a t t e r . G . Fo u r n i e r
and M. Gu il l o t (Compt. rend., 1 9 3 1 , 192, 1 1 0 0— 1102 ; cf. th is vol., 5 4 3 ).—I f th e source of ¡3-rays and the absorbent m etal are placed so th a t varying p ro portions of th e rad iatio n reach th e ionisation chamber, g/p m ay be calc, from th e slope of th e log. curve, provided th a t th e superficial density is sufficient.
C. A. Si l b e r r a d. W e ak lin e s in th e n a t u r a l [3-ray s p e c tr u m of r a d iu m -C . C. D. El l is and H . H . El l io t t (Proc.
Camb. Phil. Soc., 1 9 3 1 , 27, 2 7 7 — 2 7 9 ; cf. A., 1 9 3 0 , 1 3 3 9 ).—To overcome th e difficulty of distinguishing very faint lines from defects in th e p late several photo
graphs were com pared. E igh t new lines w ith their estim ated intensities are tab ulated, and previously reported lines are elim inated or corrected.
N. M. Bl ig h.
7 8 4 B R ITISH CHEMICAL A BSTRACTS.— A .
E lim in a tio n of th e (3-w ave-length f r o m th e c h a r a c te r is tic r a d ia tio n of iro n . W. A. Wood
(Proc. Phys. Soc., 1931, 43, 275—278).—A th in film of Mn, prepared by electrolytic deposition on A1 foil, removes the (3-wave-length by selective absorption.
C. W. Gl b b y. E v e ’s c o n s ta n t. A. W . R e i t z (Z. Physik, 1931, 69, 259—286).—A stu d y of th e secondary electrons em itted by Ra-G y-radiation from Al, Zn, an d P b has led to a redeterm ination of E v e’s const, for air, which a t 0° and 760 mm. is 4-3 x 10°. The significance of the const, in cosmic-ray m easurem ents is discussed.
A. 13. D. Ca s s i e. E x is te n c e of a n o d e sp u tte rin g '. M. Ba r e i s s
(Z. Physik, 1931, 68, 5S5—590).—Anode sputtering of Ba and Au m ay occur, b u t th e effect is very small.
R . W. Lu n t. A c tio n of r a d ia tio n o n a to m ic n u c le i. G. I.
Po k r o v s k i (Ann. Physik, 1931, [v], 9, 505—512).—
I t is deduced generally th a t exotherm ic at. dis
integration m ust be accelerated by radiation. The effect observed m ust always be positive, b u t its abs.
magnitude cannot be calc, w ithout closer knowledge of th e nuclear structure. J . W . Sm i t h.
O p a c ity a n d s t e l l a r s t r u c t u r e . D. S. Ko t h a r i
(Nature, 1931,127, 740—741).
O rig in of c o ro n a lin e s . E . A. Hy l l e r a a s (Z.
Physik, 1931, 69, 361—365).—Theoretical.
A. B. D . Ca s s i e. Q u a n tu m th e o r y of r a d ia tio n . L. Ro s e n f e l d
and J . So l o m o n (J. P hys. R adium , 1931, [vii], 2, 139— 147).
A p p lic a tio n of s o m e th e r m o d y n a m ic la w s to th e e x p la n a tio n of a to m ic n u c le a r p ro c e s s e s . G. I.
Po k r o v s k i (Physikal. Z„ 1931, 32, 374—377).—The Boltzmann principle is applied to at. nuclear processes w ith results agreeing satisfactorily with experiment.
A. J . Mee. R e la tio n c o n c e rn in g a to m ic n u c le i. W. D.
Ha r k i n s (J. Amer. Chem. Soc., 1931, 53, 2009—2011).
—Concerning the au th o r’s and L atim er’s theories (this vol., 5 4 4 ). J . G . A. Gr i f f i t h s.
Q u a n tis e d r o ta t io n of th e p o ta s s iu m a to m . R . G. Lo y a r t e and R . Gr i n f e l d (Univ. Nac. La P la ta , E stud. Cienc., 1929, No. 89, 103—10S).
Ch e m ic a l Ab s t r a c t s. D is c h a rg e in p u r e w a te r v a p o u r. S. Fr a n c k
(Z. Physik, 1931, 69, 409— 417).—In itial and spark discharges in w ater vapour a t atm . pressure were studied w ith plane, spherical, and pointed electrodes opposed to a plane electrode. A. B. D. Ca s s i e.
A b s o r p tio n of lig h t b y s im p le io n ic c r y s ta ls a n d e le c tric a l d e te c tio n of l a t e n t im a g e s . R . Hi l s c h and R . W. Po i i l (Z. Physik, 1931, 68, 721—
734).—W ork on form ation of laten t images in K B r crystals is sum m arised and experim ents showing th a t there is no m easurable m otion of electricity during form ation of a la te n t image are described; a m ovem ent of electricity occurs during irreversible bleaching of
the image. A. B. D. Ca s s i e.
C ry s ta l s t r u c t u r e o f n i tr a te s . C. Sc h a e f e r
(Z. Physik, 1931, 68, 766—767).—Differences in the reflexion m axim a of calcspar an d N a N 0 3, observed by
Schaefer and others (A., 1 9 2 8 , 3 4 9 ), could not be detected w ith a new specimen. A. B. D. Ca s s i e.
R o ta tio n a l c o n s ta n ts of th e io d in e m o n o c h lo rid e m o le c u le . W. E. C u r t i s and J . P a t - k o w s k i (Nature, 19 3 1 , 127, 7 0 7 ).—D etails of the ro tatio n stru ctu re in th e region 6 4 8 2 — 6 8 3 7
A.
and the ro tatio n al constants obtained are recorded.L. S. Th e o b a l d. B a n d s p e c tr a of a lk a lin e - e a r th h a lid e s . K.
He d f e l d (Z . Physik, 1 9 3 1 , 68, 6 1 0 — 6 3 1 ).—The band spectra of CaCl2, SrCl2, BaCl2, CaBr2, SrB r2, B aB r2, and C al2 have been investigated for th e visible spectral region. Photographs of th e spectra were obtained by incorporating a q u a n tity of th e appropriate salt in a C arc and in an oxy-acetylene flame. I n practically all th e substances th e stric t isotope separations were
obtained. W. R. An g u s.
V alen cy. XV. A b s o rp tio n s p e c tr a of p o ly h a lid e io n s . F . L. Gi l b e r t, (Mr s.) R . R . Go l d
s t e i n, and T. M. Lo w r y (J.C.S., 1 9 3 1 , 1 0 9 2 — 1 1 0 3 ; cf. A., 1 9 2 6 , 4 5 4 ).—Mol. extinction coeffs. were ob
tained for 7 arom atic polyhalides of th e series BrCGH (;NMe3+ in E tO H , for 8 Cs polyhalides in EtO H and in w ater, and for a series of aq. K polyhalides prepared b y adding free halogens to th e K halides.
The polyhalide ions from I 3' to B rC l/ gave charac
teristic absorption spectra n o t attrib u tab le to hydrolysis, dissociation, reduction, or double decomp.
Dissociation, especially m arked in aq. solutions, dim inishes th e in ten sity of the strong selective absorp
tion of th e ions, w ithout changing th e form of the absorption curves. N. M. Bl i g h.
A b s o rp tio n of [lig h t b y ] a c e to n e v a p o u r in th e S c h u m a n n re g io n . G. S c h e i b e and C. F . L i n - s t r o m (Z . physikal. Chem., 1 9 3 1 , B , 12, 3 8 7—3 8 8 ).— Three narrow bands, separated by the sam e intervals as in th e Me halides, have been observed between X 19 0 0 and 1 8 6 0
A.
They are attrib u te d to oscillation of th e Me group. F. L. U s h e r .A b s o rp tio n s p e c tr a of o -c h lo ro p h e n o lin d o - p h e n o l a n d o -c re s o lin d o p h e n o l. M. M. Br o o k s
(J. Amer. Chem. Soc., 1931, 53, 1S26— 1830).—
o-Chlorophenolindophenol shows an absorption max.
a t 625 mu in solutions (0-00005—0-00021/) of p u 8-0—9-6; th e dye is alm ost com pletely dissociated at Pn 9-6. o-Cresolindophenol a t p a 8-0 shows a max. at 500 m;jt w ith a slight secondary m ax. a t 610 m u ; increase in p a causes a rise in the m ax. (610 mu).
H. Bu r t o n. U ltra - v io le t a b s o r p tio n s p e c tr a of b a r b it u r ic a c id , v e ro n a l, a n d o th e r h y p n o tic s . N. G 6 m ez (Anal. Fis. Quim., 1 9 3 1 , 29, 2 8 0 — 2 8 3 ).—The u ltra violet absorption spectra of veronal, luminal, and isopropylallylbarbituric acid are similar, and do not show a b a n d ; barbituric acid has a band m ax. about 2 5 0 0
A.
Benzylidenebarbituric acid has one band at 2 5 0 0A.
an d another a t about 3 3 0 0A.,
attrib u ted to the presence of conjugate'double linkings; reduction b y nascent H causes the disappearance of both bands, and the spectrum is like th a t of veronal.H. F. Gi l l b e. C o n s titu tio n a n d s p e c tr a of th e p o rp h y r in s . H . He l l s t r o m (Z . physikal. Chem., 1 9 3 1 , B , 1 2 ,
G ENERAL, PH Y SIC A L, A N D IN OR G A N IC CHEMISTRY'. 7S5 353—363).—The absorption and fluorescence spectra
of different porphyrins have been exam ined in neutral, acid, and alkaline solution. Certain broad bands are resolvable into groups, th e significance of which is
discussed. F . L . Us h e r.
R a m a n s p e c tr u m of s o lid n itr o g e n p e ro x id e . A. C. Me n z ie s and C. 0 . Pr in g l e (Nature, 1931,127, 707).—The R am an spectrum of solid N 0 2 a t approx.
—80° consists of one line w ith a shift of 275 cm .'1 L . S. Th e o b a l d. S m e k a l- R a m a n effect. K . W . F . Ko h l r a u s c h
(Physikal. Z., 1931, 32, 385— 406).—A review.
R a m a n effec t a n d m o le c u la r c o n s titu tio n . IV.
B. Tr u m p y (Z. Physik, 1931, 68, 675—682).—The R am an effects for SiBr4 have been m easured and com
pared w ith th e displacem ents for SnBr4 (cf. th is vol., 284). W ith an appropriate selection of mol. constants it is foimd th a t th e displacem ents calc, on th e basis of a tetrahedral mol. configuration agree very well with th e observed shifts. M ixtures of SiCl4 and SiBr4 exhibited no new R am an lines, indicating th a t no m ixed mois, are found.
PC13 an d P B r3 give four fundam ental R am an dis
placements which are in good agreem ent w ith the frequencies expected on th e assum ption of a pyram idal structure. F rom these fundam entals certain mol.
constants have been evaluated. The R am an spectra of m ixtures of PC13 and P B r3 indicate th e existence of two new mol. species in the m ixture. These are assumed to be PCl2Bi’ and PClBr2. The alternation of intensities, of th e R am an displacem ents according as th e ra tio PC13 : P B r3, is 2 :1 or 1 : 2 indicates th a t the m ixed halides are in chemical equilibrium w ith the simple halides. W . R . An g u s.
R a m a n effec t of c e r ta i n s u lp h u r c o m p o u n d s . F. Ma t o s s i and H . Ad e r h o l d (Z. Physik, 1931, 68, 683—695).—The R am an effect has been studied for liquid S2C12, S 0 2, CS2, SOCl2, S 0 2C12, C1S03H , Me2S 0 3, E t2S 0 3, Me2S, E t 2S, M eEtS, and cryst. S. Good agreement is found w ith results of other investigators.
Characteristic displacements are satisfactorily assigned to several groups, b u t there is some doub t as to the justification of assigning a particular displacem ent to other groups. I t is concluded th a t S2C12 and S0C12 are Y-shaped mois, w ith a S atom a t th e centre. Binding const, ratios (S—-S 0)/(S —Cl) and th e semi-angle of the Y are calc. The theory of valency and deform ation oscillations (A., 1930, 1236) is discussed.
W. R . An g u s. R a m a n effec t in o r g a n ic s u b s ta n c e s a n d its u se i n c h e m ic a l p r o b le m s . A. D a d i e uan d K . W. F.
Ko h l r a u s c h (J. O pt. Soc. Amer., 1931, 21, 286—
322).—A review.
In flu e n c e of ty p e of c h e m ic a l c o m b in a tio n on th e p r o p e r tie s of p o l a r m o le c u le s in th e s t a t e of v a p o u r. K . Bu t k o v (Z. physikal. Chem., 1931, B , 12, 369—376).—The determ ining character of the ionisation potential of th e positive constituent of a binary mol. is illustrated by plotting heats of dissoci
ation into atom s, energy of dissociation in to ions, th e product of the exponents in th e expression for nuclear potential energy, and th e Rosen-M ecke const, severally against th e first-nam ed q u an tity , for th e halides of
Cs, R b, K , N a, Tl1, Ag, and Cu1. A system atic change in th e order nam ed is observed in each case, tending to th e value of th e respective p ro p erty of th e non-polar
halogen mol. F . L . Us h e r.
In flu e n c e of s e c o n d a ry e m is s io n on v alv e c h a r a c te r is tic s . H . Bi t t m a n n (Ann. Physik, 1931, [v], 8, 737— 776).—The system atic irregularities appearing in D yn atron characteristics have been experim entally investigated. W . Go o d.
P h o to - e le c tr ic p r o p e r t ie s of c o m p o s ite s u rfa c e s a t v a r io u s t e m p e r a t u r e s a n d p o te n tia ls . D.
Raa ly d a n o ff (Physical Rev., 1931, [ii], 37, 884—
896).—The variation of photo-electric current w ith tem p, and plate potential for B a photo-electric cells w ith steady an d in terru pted illum ination is plotted.
The variation in photo-electric sensitivity w ith tem p, for com posite surfaces of B a and 0 2 on P t can be explained b y th e diffusion of B a or 0 2 on th e surface.
N . M. Bl ig h. P h o to - e le c tr ic c e lls w ith s ilv e r /s ilv e r b r o m id e e le c tro d e s . I. B. Va n s e l o w and S. E . Sh e p p a r d
(Z. wiss. P hot., 1931, 30, 13—39).—The p.d. between A gBr-coated Ag electrodes in K B r solution was m easured by a vacuum -tube voltm eter. The small in itial negative effect in th e illum inated electrode was quickly superseded b y an increasing positive effect which reached a m ax. The voltage increased w ith th e thickness of the AgBr and also w ith th e con
centration of K B r. R eproducibility is difficult.
H alogen acceptors (e.g., N a N 0 2, MeCN) decrease th e positive effect, an d B r increases it. An explanation is advanced on th e basis of th e discharge of electrons from B r ions on illum ination, th e positive effect being produced on recom bination of B r atom s w ith Ag.
J . Le w k o w it s c h. P h o to - e le c tr ic effec t f r o m a b a r i u m o x id e- c o a te d p l a t i n u m fila m e n t. K . Ne w b u r y and F . Le m e r y (J. Opt. Soc. Amer., 1931, 21, 276—281).
—The current approaches a satu ratio n value a t a plate p otential of 13 volts. F o r const, voltage i t passes through a max. a t filam ent tem p, of 1000°. The long wave-length lim it of th e effect is not above
4046 A . C. W. Gi b b y.
C o n d u c tiv ity of d e fo rm e d a n d te m p e r e d ro c k - s a l t c r y s ta ls . F . Qu i t t n e r (Z. Physik, 1931, 68, 796—S02).—The tru e conductivity of rock salt obeys v an ’t Hoff’s law w ith constants dependent on the ex ten t of tem pering and deform ation.
A. B. D. Ca s s i e. T e m p e r a t u r e v a r ia tio n of th e c o n d u c tiv ity of le a d c h lo rid e w ith a d m ix e d p o t a s s i u m c h lo rid e . Z. Gy u l a i (Z. Physik, 1931, 67, 812— 816).—Temp, v ariation of th e conductivity of PbCl2 containing 0-005 p a rt of KC1 follows a v a n ’t Hoff law, as does pure PbCl2, except for changes in const, param eters.
A. B. D. Ca s s i e. C o n d u c tio n of t h i n g la s s p la te s w ith h ig h fie ld s t r e n g t h s . W. Hu b m a n n (Ann. Physik, 1931, [vj, 9, 733—755).—The conduction of an ordinary glass and Je n a glass using Hg and am algam electrodes is examined. J . Fa r q u h a r s o n.
E le c tr o n ic c o n d u c tiv ity of s o lid o x id e s of v a r io u s v a le n c ie s . M. Le Bl a n c an d H . Sa c h s k
