BRITISH CHEMICAL ABSTRACTS
PURE CHEMISTRY
SEPTEMBER, 1928.
General, P hysical, and
A b so rp tio n sp e c tr u m of th a lliu m vapour b etw een 7000 an d 1850 A. R . G. L o y a r t e and A. T . W i l l i a m s (J. Phys. R adium , 1928, [vi], 9,121—
126).—Observations on th e absorption spectrum of thallium vapour between 700° and 900° show, in agreement w ith G rotrian (A., 1923, ii, 106) and others, the lowest level to be 2P 1 an d all the corresponding lines of th e series 2P 1 —iS 1 an d 2P 1 —2D 2 have been observed. A t 700° an d below, some lines correspond
ing w ith th e level 2P 2 appear, b u t they are fewer th an in the case of alum inium , gallium, or indium. No trace of th e green line 5350-46 A . could be detected.
Sharp, fine lines between 2210 and 2105 A ., previously recorded as b a n d or diffuse lines b y earlier workers, have been observed. L . S. T h e o b a l d .
F iltra tio n of arc and sp a rk lin e s in a m a g n etic field b y u s in g d isr u p tiv e d isc h a r g e in a vacuum . H. Na g a o k a and T. Fu t a g a m i (Proc. Im p. Acad.
Tokyo, 1928, 4, 195— 197).—The m ethod of separat
ing arc and spark lines in a spectrum by using the disruptive discharge in a strong m agnetic field (cf.
this vol., 339) gives am biguous lines in some cases, due to the resistance of th e air to th e m otion of the ions.
This can be prevented b y using the discharge in a vacuum. An app aratu s is described by means of which this can be studied. A. J . Me e.
Influence of en er g y fa c to rs on th e structure of sp ectra. T. Ne g r e s c o (J. Chim. p h y s.,' 1928, 25,308—319).—The influence of tem perature on flame spectra and of th e n atu re of the electrodes, the sur
rounding atm osphere, th e potential gradient between the electrodes, an d th e n atu re of the current on arc and spark spectra is discussed, and also the effect of self-induction on th e spark discharge and its spectrum.
The emission of radiation of low potential is not due solely to the ho t envelope of metallic vapour, but is primarily an electrical effect. The effect of self- induction is due to th e lowering of the potential gradient in th e initial discharge, which causes an increase in th e intensity of the radiations due to the subsequent oscillations' W. A. Ric h a r d s o n.
S eries in th e sp a rk sp ectra of germ an iu m . Iv. R . Raoand A. L. Na r a y a n (Proc. Roy. Soc., 1928, A, 119; 607—627).-—The spark spectrum of german
ium has been investigated over the range 6484-32—
2099-98 A . A small q u a n tity of germanium was fused to the tips of pure tin rods, which were used as electrodes between which th e spark took place. The spark was studied in an atm osphere of hydrogen under varying conditions, th e spectra being photographed by a 5-foot concave grating and a large Hilger quartz
3 o 92
Inorganic C hem istry.
spectrograph. The region below 2400 A. was photo
graphed on Schum ann plates. Detailed descriptions and analyses are given of th e spectra of singly-ionised (G en ), doubly-ionised (G em ), and trebly-ionised (Ge iv) germ anium , an d the results are in complete agreem ent w ith the P auli-H eisenberg-H und theory.
The second ionisation potential is com puted to be ab o u t 15-88 volts, and the th ird abo ut 33-17 volts. A characteristic group of lines has been observed which appears more intensely under weaker stimuli. W hen th e excitation is a m axim um th e lines disappear, b u t th e inclusion of self-induction brings them o u t clearly.
As such, their behaviour is sim ilar to th a t of arc lines, b u t their presence has not been recorded by any previous investigator of the arc spectrum of germ an
ium . A table is given of all the lines of germanium which have been classified. L. L. Bir c u m s h a w.
In ten sity ra tio of th e d o u b lets of th e p rin cip al s e r ie s of th e alk a li m e ta ls . H . J a c o b (Ann.
Physik, 1928, [iv], 86,4 49 —493).—The in tensity ratio of the com ponents of th e second doublet of th e principal series of potassium , rubidium , and cæsium has been measured by means of M erton’s m ethod.
The lines were produced a t the highest possible tem perature (2600°) by th e use of an oxy-hydrogen flame. The values of K , th e intensity ratio, were found to v ary between 1-80 and 2-02. I n the case of rubidium an d of cæsium th e m ethod of Gouy was used in addition for the purpose of obtaining th e
“ tru e ” intensity ratio. The “ tru e ” intensity ratio for th e cæsium lines approxim ates to 4-0. F or rubidium the ratio is evidently greater th a n 2-3, b u t the value of the “ true ” intensity ratio was no t
reached. W. E. D o w n e y .
In ten sity of sp ectra l lin e s. A. K u p p e r (Ann.
Physik, 1928, [iv], 86, 511—529).—M athem atical, Calculations based on Schrôdinger’s wave equation lead to values for th e intensities of the lines of the Balm er, Paschen, B rackett, and 5th series.
W. E. Do w n e y. In te n sity r a tio of th e ortho- and p a ra -series in re la tio n to th e stru ctu re of th e h eliu m atom . J . S t a r k (Ann. Physik, 1928, [iv], 86, 530—540).—
A helium line arising from the Is state cannot be detected. The ratio of the intensity of the para- series of helium to th a t of the corresponding o rth o series decreases w ith increasing gas pressure. The ratio is greater, for a given pressure, when the excit
ation is due to fast cathode rays th an when slow cathode rays are used. The para-series correspond w ith th e singlet series of th e alkaline-earth m etals,
930 B R ITISH CHEMICAL ABSTRACTS.— A.
th e ortho-series to th e trip let ones. The spectral and structural sim ilarity of helium and the alkaline-earth m etals leads to th e view th a t a p ara-state is less stable and, therefore, less frequent th an the corresponding
ortho-state. W . E. Do w n e y.
S p e ctr u m of io n ise d so d iu m . F. H. Ne w m a n
(N ature, 1928, 122, 97).— The au th o r’s pairs of wave-num ber differences in the N a n spectrum do not appear to be accidental (cf. Laporte, this vol., 680).
A. A. El d r id g e. S p ark sp ectru m of p a lla d iu m (Pd I I ) . A. G.
Sh e n s t o n e (Physical Rev., 1928, [ii], 32, 30—38).—
The analysis of the spectrum of P d n differs from th a t of McLennan and Sm ith (A., 1926, 875). The term s include 4d2D(4d9); 5sik2 F , ik 2 P, ~B, 2G(4d85s) ; all the related triads from the stru ctu re 4d85p; 6si&2F, iP 3, 2G6(4d86s) ; and fragm ents of term s due to 4ds5d.
Zeeman effects for m ost of the lines have been measured. The ionisation potential is calculated as 19-8 volts from 4dP to 4d8. A. A. El d r id g e.
S tru ctu re of th e re so n a n ce lin e, 6708 A ., of th e lith iu m arc sp ectru m ; iso to p e effect w ith lith iu m . H. Sc h ü l e r and K . Wu r m (Naturwiss.,
1927, 15, 971—972; Chem. Zentr., 1928, i, 644).—
A weak th ird com ponent, situated tow ards th e red, of th e lithium resonance line 6708 A . is recorded, and is considered to be a com ponent of the Li6 doublet.
A. A. El d r id g e. P o la r isa tio n of reso n a n ce ra d ia tio n of ca d m iu m . P. So l e il l e t (Compt. rend., 1928, 187, 212—214).—The effect of a m agnetic field on the hnes 3261 and 2288 A. in th e resonance spectrum of cadm ium has been investigated, th e exciting radiation being unpolarised. In a zero field, or one in the same direction as th e incident light, the m axim um polaris
ation is 85% for 3261 A. and 60% for 2288 Ä. The two orbits of the 2 ’P 1 level have different stabilities, and durations of about 2 x l 0 " 6 sec. and 10-9 sec.,
respectively. C. W. Gib b y.
O p tically ex c ited iod in e b a n d s w ith altern a te m is s in g lin e s. R . W . Wo o d and F . W . Lo o m is
(Phil. Mag., 1928, [vii], 6, 231—238).-—The fluores
cence spectrum of iodine enhanced by th e presence of helium a t 0-5 mm. pressure has been examined and the fluorescence lines have been found to correspond exactly w ith the absorption lines w ith even initial rotational quantum numbers, and th e altern ate lines to be missing in the fluorescence bands. I t then follows th a t, since the original excited iodine molecules after absorbing light and im m ediately before colliding w ith helium atom s had the rotational quantum num ber 34, during collisions in which the electronic q u an t um num ber is unchanged the rotational quantum num ber of an iodine molecule can change only by an even number. This conclusion is no t in accordance w ith th e selection principle, b u t is in agreem ent w ith th e theory of H und (A., 1927, 809) th a t the ro tation al states of sym m etrical molecules are divided into two classes, characterised by eigen-functions sym m etrical and unsym m etrieal, respectively, in th e position co-ordinates of th e nuclei, betw een which transitions do n o t occur. A. E . Mit c h e l l.
A fterg lo w in m ix tu r e s of n itro g en and o xyg en . B. Le w is (N ature, 1928, 122, 241).—Using an elec-
trodeless discharge w ith a spark gap, a t 1-8—0-01 mm., there is for a given m ixture, e.g., air, a sharp m inim al afterglow a t 0-53 mm. separating the yellow
ish-green oxygen afterglow (at higher pressures) from the orange-yellow nitrogen afterglow (at lower pressures). I n a certain pressure region near this m inimum a long discharge gives a blue afterglow ; the nitrogen bands also appear a t a suitable pressure.
W ith a very short discharge only th e yellowish-green afterglow is visible. Thus, different types of after
glows m ay be excited in the same gas m ixture a t the same pressure m erely by altering th e period of dis
charging. A. A. El d r id g e.
S p e ctr u m of tr eb ly -io n ised an tim on y , Sb iv.
J . 13. G r e e n and R. J . L a n g (N ature, 1928, 122, 242).—A 3P 3S m ultiplet between 805 and 861 A ., a very strong 3P 3D m ultiplet between 873 and 940 A ., a 3D 3F m ultiplet between 2077 and 2113 A ., and a possible 3P 3P ' group between 1051 an d 1193 A . have been identified. The ionisation p otential is computed as 42 volts. A. A. E l d r i d g e .
A n a ly sis of th e fir s t sp a rk sp ectru m of sulphur (S+). D. K . Bh a t t a c h a r y y a (N ature, 1928, 122, 241—242).
In flu en ce of m a g n e tic fie ld s on th e bands of th e th ird p o sitiv e grou p in n itro g en . B. Pogany a n d R . Sc h m id (Z. P h y s ili, 1928, 49, 162—166).—
D a t a a r e g iv e n fo r t h e b ro a d e n in g of th e lines of the (0,1) a n d (0,2) b a n d s of th e t h i r d p o s itiv e group of n itr o g e n in a field of 26 k ilo g a u ss. R.. W. Lunt.
C la ssifica tio n of th e b a n d sp ectra associated w ith th e n eu tra l o x y g en m o lec u le . W. Os s e n- b r u g e n (Z. Physik, 1928, 49, 617—216).—The classi
fication of th e oscillation an d rotatio nal terms in the Schum ann bands of th e n eutral oxygen molecule is discussed in d e ta il; by adopting the value 6'54x 10~"' for h, th e following values are derived for the moment of in ertia in a motioidess unexcited state and for the effective atom ic radius respectively, 19-20 X l0 '40 g. cm.2, 0-6005 x l0 ~ 8 cm. R. W. Ltjnt.
V a riatio n of th e in te n s ity of the lin e s of the m e rcu ry sp e c tr u m ex c ite d b y different ty p es of d isc h a r g e. T. Ho r i (Z. Physik, 49 , 259—26S).—
Q ualitative d a ta are given for th e intensity of mercury lines excited by arc discharges w ith and without the presence of hydrogen, by low-velocity electrons from an oxide-coated cathode, and by a Geissler tube discharge. These results, which are preliminary to a q u an titativ e investigation, indicate th a t the observed variations cannot be traced solely to variations in a b so rp tio n ; it is tho ug ht th a t the emission of HgH bands in th e presence of hydrogen indicates th a t the reaction H g*+ H ,==H g H + H takes place.
R . W. Lu n t. R e la tiv e in te n s itie s of th e H a and Z)3(He) lines in p ro tu b era n ces of th e s u n ’s chrom osphere.
E. J. Pe r e p e l k in (Z. P h y s ik , 1928, 49, 295—305).—
A stro n o m ic a l. R . W. Lu n t.
In te n sity d istrib u tio n in th e n eg a tiv e nitrogen b an d sp ectru m . L. S. O r n s t e i n an d W. R. yam W ijk (Z. Physik, 1928,49, 315—322).—Measurements have been m ade of th e in tensity distribution in the bands 3914, 4278, 3884, an d 4237 A . The intensity
GENERAL, PH YSICAL, AND INORGANIC CHEMISTRY. 931 distributioncan berepresented by a Boltzm ann function
of the rotational quantum num ber p of the form exp[—h2p (p + l)l8 r:2Ik T ], where h is the Planck constant, I th e m om ent of inertia, k the Boltzmann constant, and T the absolute tem perature.
R. W. Lu n t. B an d s of th e th ird p o sitiv e grou p in n itrogen . R. Sc h m id (Z. Physik, 1928, 49, 428— 462).—The classification of th e bands (0,2), (0,3), (0,4), (1,4) by Guillery has been extended to include the bands (0,0), (0,1), (1,0), (1,1), (2,3), and (3,4).
R. W. Lunt. E n ergy d istrib u tio n in b and sp ectra, e sp ec i
ally in n itro g en b an d s. G. He r z b e r g (Z. Physik, 1928, 49, 761—773).—I t is pointed out th a t the parabolic energy distribution in a band spectrum required by Condon’s theory (A., 1927, 89) is attained only when th e distribution of th e molecules over the various vibration states in th e initial condition is uniform. Generally this is no t the case. From the theory developed by F ranck (A., 1926, 583) consider
able deviations would be expected, although a t great activations approxim ations to th e Condon distribution law can be attained. This has been shown experi
mentally w ith th e nitrogen bands. This fact is explained b y supposing th a t in th e case of collisions between high-velocity electrons, F ran ck ’s rule is broken and vibrations of higher quantum num ber can be stim ulated to a greater extent. J . W. Sm it h.
S p ectro sco p ic d ata r e la tin g to th e afterglow in n itrog en . G. He r z b e r g (Z. Physik, 1928, 49, 512—533).—The spectrum of th e afterglow in nitrogen excited by th e electrodeless discharge under u n specified electrical conditions has been examined with reference to th e shift of the m axim a of intensity in the green, yellow, and red group of bands produced by quenching th e afterglow w ith liquid air and by alteration of th e pressure. The d ata obtained are reviewed a t length an d are though t to support the hypothesis th a t th e afterglow is due to collisions between m etastable atom s despite the difficulty of interpreting Bonhoeffer’s d a ta (cf. A., 1927, 801) on
this view. R. W. Lu n t.
Inverse S ta rk effect in th e p rin cip a l ser ie s of sodium. W. Gr o t r ia n (Z. Physik, 1928, 49, 541—
545).—The inverse S tark effect in absorption in sodium vapour a t 280—320° has been measured for the doublets of th e 2nd and 3rd term s of the principal in fields up to 102 kv. cm.-1 In th e case of the doublets 3302-94 an d 3320-34 A. th e displacements are equal and linearly related w ith the square of the field strength; a sim ilar relationship holds for the doublets 2852-851 and 2853-038 except th a t th e former has a slightly greater displacement coefficient than the
latter. R . W. Lu n t.
S ta tistica l d eriv a tio n of th e R yd b erg correction for s-te rm s. E . F e r m i (Z. Physik, 1928, 49, 550—554).
Ion isation of m e rcu ry a to m s b y reaction w ith helium io n s. J . S t a r k (Ann. Physik, 1928, [iv], 86, 541—546).—The emission of m ercury spark fines is much stronger in comparison w ith th e emission of mercury arc lines for a m ixture of m ercury vapour
and helium in the negative glow of a discharge tube th a n for a m ixture of m ercury vapour an d neon. The sam e intense emission of the spark lines should apply in th e case of th e alkaline-earth and alkali metals.
W. E . Do w n e y. D istr ib u tio n in d irection of p h o to -electro n s fr o m a lk a li m e ta l su rfaces. I I . E . Iv e s, A. R.
Ol p i n, and A. L . Jo h n s r u d (Physical Rev., 1928, [ii], 32, 57—80).—A stu dy of the distribution in direction of photo-elcctrons em itted from surfaces of liquid alloys of sodium and potassium, and th in films of potassium or rubidium on platinum , irradiated by light incident a t various angles and polarised in different planes. Some form of surface anisotropy appears to exist. A. A. El d r id g e.
C om p lete p h o to -electric e m is s io n fr o m p o ta s s iu m . (Miss) J . Bu t t e r w o r t h (Phil. Mag., 1928, [vii], 6, 1— 16).—E xam ination of the photo-electric emission from potassium has produced no evidence for the existence of a positive emission. If such does occur it is less th an 10~7 times th e negative emission or a t least a thousand times smaller th an the apparent positive emission reported by Dember (Ann. Physik, 1910, 30, 142). The photo-electric threshold of potassium has two work-functions corresponding with the wave-lengths 9700 and 60,000 A., th e results indicating th a t th e “ patches ” (Richardson and Young, A., 1925, ii, 343) of lower work-function form a very small p a rt of th e to ta l surface and under pro
longed illum ination are able to acquire th e greater work-function. A. E . Mit c h e l l.
T h e n o r m a l p h o to -electric effect. P . Lu k i r- s k y and S. Pr il e z a e v (Z. Physik, 192S, 49, 236—
258).—The photo-electric effect in alum inium , zinc, tin, nickel, silver, cadmium, lead, copper, and platinum has been investigated by measuring the currents flowing from a small sphere of the m etal under investigation, when illum inated by m ono
chrom atic light in th e range 2302—3130 A., to a surrounding m etal sphere, as a function of the P.D . between the two spheres. U nder such conditions th e m axim um electron energy |m >2max. is related to the potential V2 producing satu ratio n current by the equation i7nv2max_==e{V2+ K ) = h i —p l —p 2, where K is th e contact P.D . between the spheres, p 1 the work of removing an electron from an atom , and p 2 the work associated with th e m otion of th e released electron to th e m etal surface. The d a ta obtained lead to th e following values respectively for the critical excitation wave-lengths : 4132, 4009, 3411, 3364, 3364, 3302, 3110, 3033, an d 3018 A .; and the m ean value obtained for P lanck’s constant is 6-543 x 10~27 e rg x sec., in good agreem ent with the accepted value from optical data, 6-545 X10-27. I t is also shown th a t th e contact P.D . between aluminium and th e other m etals examined is equal to the difference between the m inim um qu an ta necessary for the excitation of photo-electrons. From this it is con
cluded th a t th e electrons em itted under the influence of light are identical with those associated w ith electrical conduction. The velocity distribution of photo-electrons where corrected to the same maxim um velocity and photo-electric current varies somewhat in th e m etals examined, which is thought to be due
932 B R ITISH CHEMICAL ABSTRACTS.— A.
to the different light penetration and corresponding differences in th e work term s, p 2. The velocities of th e photo-electrons become more uniform and approxim ate closely to th e m axim um velocity as the thickness of th e irradiated m etal layer is reduced.
R . W. Le n t. P h o to -e le c tr ic effec t w ith su b -m ic r o sc o p ic d ro p s. K . S c h a r f (Z . Physik, 1928, 49, 827—•
857).—The photo-electric properties of m ercury, bism uth, selenium, and sulphur particles, produced b y vaporisation of th e elem ent in an atm osphere of pure nitrogen, have been investigated by Ehren- h a ft’s condenser m ethod. These substances show a predom inant norm al photo-electric effect. Inverse charging appears only rarely in single particles, b u t to a m uch greater ex ten t in the clouds of very small particles produced by strong heating of the substance.
The num ber of negatively-charged particles in a cloud was found to be inversely proportional to the norm al sensitivity of th e element, which decreases w ith the different elements in th e order given above.
J . W. Sm it h. N a tu re of g a se o u s io n s. L. B. Lo e b (Physical R ev., 1928, [ii], 32, 81—96).—F or pure gases th e dielectric a ttra ctio n of the molecules by th e charged ion can account for th e order of m agnitude of th e m obility on either the cluster or th e small ion theory.
B lanc’s law is n o t universally valid. M obility curves in m ixtures indicate three types of e ffe c t:
absence of clustering, labile clustering, and stable clustering. Clusters approaching in th eir stab ility and n atu re definite chemical com binations are
postulated. A. A. El d r id g e.
E n e rg y of ra d ia tio n ex c ited b y electro n ic b o m b a rd m en t. P. Br ic o u t (J. Pliys. R adium , 1928, [vi], 9, 88— 119).—An apparatus is described for th e determ ination of th e relation between th e energy of th e electrons em itted from a ho t filam ent and th e intensity of th e radiation excited by them , and a m ethod of m easuring th e absolute value of th e energy em itted is developed. A theoretical explanation of th e results is discussed, an d a calculation m ade of th e probability of th e emission of a quantum of energy due to a collision between an electron and a n eu tral
atom . W. A. Ric h a r d s o n.
N e w m e th o d of d e te r m in in g th e m o b ility of io n s or elec tro n s in g a se s. R. J. v a n d e Graajtf (Phil. Mag., 1928, [vii], 6, 210—217).—The results of m ost m easurem ents of th e velocity of ions or electrons in th e direction of an electric force represent th e upper or lower limits of th e m ean velocities due to variable conditions. A m ethod for measuring th e m ean velocity of a group of ions moving in a gas under a steady electric force is described.
The m ethod involves th e superposition, on a p late an d grid com bination in th e gas under exam ination, of th e shutterin g effect of an oscillating poten tial of know n frequency which allows th e transference of ions during definite tim e intervals. M easurements of the distances an d the m axim um currents in th e gas then provide all th e necessary data. The m obility of th e positive ions of hydrogen a t 760mm. has been found to be 5-8 cm./Sec., which is approxim ately th e m ean of values given b y o th er workers. A. E. Mit c h e l l.
R eflex io n of electro n s. S. Sz c z e n ie w s k i (Compt.
rend., 1928,1 8 7 ,106— 109).—The reflexion of cathode rays from th e cleavage surface of a bism uth crystal has been m easured for different angles of incidence an d accelerating potentials of 62, 139, and 240 volts.
The results are in agreem ent w ith th e theoretical form ula X=12-22/y'v, where X is th e wave-length (in A.) associated w ith the beam of cathode rays, and v is th e fall of potential in volts. C. W. Gi b b y.
C o n stitu tio n of g er m a n iu m . F. W . Ast o n
(N ature, 19 28 ,122, 167).—Experim ents w ith germ an
ium tetra eth y l and tetrafluoride indicate th at germ anium has th e following isotopes, in order of descending in te n s ity : 74, 72, 70, 73, 75, 76, 71, 77.
I t is unlikely th a t a n y of these lines is due to hydrogen compounds, b u t the in ten sity of Ge76 is in doubt. Of these m ass num bers only 72 and 73 are peculiar to
germanium. A . A. El d r id g e.
A t. w t. of p ro to -a ctin iu m . F . Lo t z e (Natur- wiss., 1928, 16, 558).—Since 6 a-particles are lost in th e degeneration of proto-actinium to actinium-Z), an d since at. w t. determ inations on lead of radio
active origin lead to the m ean value of 207-42 for the at. w t. of actinium-Z), it is suggested th a t the most probable value for the at. w t. of protoactiniiun is 231.
R . W. Lu n t. D ep en d en ce of th e p h o to g ra p h ic action of p-rays on th e ir v elo city . C. D. E l l i s and G. H.
A s t o n (Proc. R oy. Soc., 1928, A, 119, 645—650).—
In recent work b y Ellis and W ooster (A ., 1927, 393) on the relative intensities of th e (3-ray groups of ra d iu m -5 and -C, it was assum ed th a t p h o to g ra p h ic action ra n parallel w ith the to ta l ionisation per cm., i.e., varied as 1/|32. T h is assum ption has now been tested b y com paring the distribution of intensity m easured photographically w ith G urney’s data for th e v ariation of th e num ber of electrons with the velocity (A., 1926, 5), an d it is found th a t photo
graphic action varies on the whole more rapidly than l/ p 2 in th e region 200,000 volts and upwards. Ilford X -ray emulsion plates were used, and the r e s u lts are expressed by a curve showing how to reduce photo
graphic densities due to electrons of different speeds to a common basis of tru e exposure.
L. L. Bir c u m s h a w. M eth od of d e te r m in in g th e v o lu m e of 1 curie of ra d on . L . We r t e n s t e i n (Phil. Mag., 1928, [vii], 6, 17—33).— Pressure m easurem ents on samples of radon of known radioactive power have been made by m eans of a K nudsen gauge, whilst th e corresponding p u rity has been determ ined sim ultaneously by means of a quartz fibre gauge, th e m ain im purity having been shown previously (this vol., 684) to be carbon dioxide. The volume of 1 curie of radon a t N.T.P.
is thu s shown to be 6-39 X 10-1± 5 % c.c. Measure
m ents in capillary tubes gave confirm atory results which were, however, rendered variable by th e effect of rarefied radon in prom oting gas evolution from th e glass, w hilst concentrated radon acts as a “ clean
up ” agent. The first effect is a ttrib u te d to a-particle bom bardm ent of th e glass, whilst the second is explained by the bom bardm ent of th e gas molecules by a-particles an d their subsequent adsorption. The considerably larger volumes obtained b y Rutherford
GENERAL, PHYSICAL, AND INORGANIC CHEMISTRY. 933 and others are attrib u ted to lack of sufficient in
formation as to th e purity of their m aterial.
A. E . Mi t c h e l l. E ffects p rod uced b y p o sitiv e -io n b o m b a rd m e n t of so lid s : m e ta llic io n s. M . L . Ol ip h a n t
(Proc. Camb. Phil. Soc., 1928, 24, 451—469).—
Experim ents have been m ade to determ ine the relation between the energy of a positive ion and the effect produced on a surface which i t bombards.
Considerable secondary emission occurs due to layers of adsorbed gas over th e target. The deposition of metal from th e positive ions causes changes of the surface bom barded which are difficult to allow for.
W . E . Do w n e y. R ecoil v e lo c itie s in 8-p article e m iss io n in th o riu m -B . L . We r t e n s t e i n (Z. Physik, 1928, 49, 463).—Polemical against D onat and Philipp (this
vol., 343). R . W. Le n t.
V ap orisa tion of p o lo n iu m in a vacu u m . P. Bo n ê t-Ma u r y (Compt. rend., 1928, 187, 115—
117).—A m ethod is described for m easuring the rate of vaporisation of polonium in a vacuum .
C. W. Gibb y. K in em a to grap h ic sk etc h of elec tric a lly ex ploded w ir e s. H . Na g a o k a and T. Fu ta g a m i
(Proc. Im p. Acad. Tokyo, 1928, 4, 198—200).—
Instead of photographing exploding wires on films rotating in a plane a t rig h t angles to th e line of sight, as had been done previously, photographs were taken on a film m oving round an axis parallel to the wire.
Photographs are given of th e explosion of copper and iron vires, an d of magnesium ribbon. Luminous particles are expelled a t rig h t angles to th e direction of flow of th e current, not continuously, b u t in
masses. A. J . Me e.
V elocity of p a r tic le s sp u ttered b y d isrup tive d ischarge. H . Na g a o k a and T. Fu t a g a m i (Proc.
Imp. Acad. Tokyo, 1928, 4, 201—204; cf. A., 1927, 1117; this vol., 97, 339, 683).—By photographing the sputtered particles on a film rotatin g with known velocity an d m easuring th e tracks, the velocity of the particles can be found. The m ean velocities (in m./sec.) found are, for tungsten, 43, for magnesium, 37, and for cerium, 90, b u t as the speed depends on voltage, cu rrent strength, an d the form of the elec
trodes, these values are indicative only of its order of
magnitude. ' A. J . Me e.
D ecom p osition of th e lea d atom . A. S m its and W. A. F r e d e r i k s e (Z. Elektrochem ., 1928, 34, 350—
360).—A ttem pts have been m ade to effect artificial disintegration of lead, employing quartz-m ercury lamps, high-tension spark discharges and low-tension arcs through gaseous and liquid dielectrics, and irradiation. The spark and arc experiments yielded definitely negative results, b u t some indications of breakdown were observed by X -ray irradiation of lead for long periods of tim e. Difficultly reproducible positive results were obtained by using quartz- mercury vapour lam ps, and th e quartz-lead lamp remains th e only m ethod which has yielded definite results. The possibility th a t th e result is in this case due to contam ination and n o t to transm utation is, however, recognised. H. F . G i l l b e .
G en eralisa tio n of th e K ra m ers—H eisen b erg d isp e r sio n fo r m u la for sh o rt w a v e s in th e m u lti- electro n p ro b lem . I. Wa l l e r (Naturwiss., 1927, 15, 969; Chem. Zentr., 1928, i, 643).—A new disper
sion form ula is advanced. A. A. El d r id g e. C on traction of h yd rog en u nd er elec tric d is ch arge. R . De l a p l a c e (Compt. rend., 1928, 187, 225—227).— Electrolytic hydrogen, subm itted to a high-tension discharge a t pressures below 11 mm., undergoes an irreversible contraction, n o t due to the form ation of H 3. Carbon monoxide and m ethane are found after the discharge. C. W. Gi b b y.
S ta tis tic a l d ed uction of so m e p ro p ertie s of th e a to m . C alcu lation s of R y d b erg 's correction.
E . Fe r m i (A tti R . Accad. Lincei, 1928, [vi], 7, 726—
730).—M athem atical.
T h eo ry of elec tric con d uction. W. H. McCrba
(Proc. Camb. Phil. Soc., 1928, 24, 438—444).—
M athem atical (cf. Sommerfeld, this vol., 681).
W . E . Do w n e y. E lectro n ic th eo ry of m e ta ls a ccord in g to w a v e -m ec h a n ica l s t a t i s t i c s ; V olta effect. A.
So m m e r f e l d (Ber., 1928, 61, [B], 1171— 1180).—A
lecture. H . Wr e n.
W av e-m ech an ica l th eo ry of m e ta llic co n d u ctiv ity. J . Fr e n k e l and N. Mir o l u b o w (Z.
Physik, 1928, 49, 885—893).—M athem atical (cf.
Frenkel, this vol., 577). J . W . Sm t h. U n d u la tin g th e o r y of tw o -elec tro n orb its.
A. W . Co n w a y (Proc. R oy. Irish Acad., 1928, 38 A, 18—28).—M athematical.
E lectro n in a g ra v ita tio n a l field . J . M. Wh i t t a k e r (Proc. Camb. Phil. Soc., 1928, 24, 414— 420).—
M athem atical. W . E. Do w n e y. W ave m e ch a n ics of an a to m w ith a n o n - C oulom b cen tra l field . III. T e r m v a lu e s and in te n sitie s in s e r ie s in op tica l sp ectra . D . R.
Ha r t r e e (Proc. Camb. Phil. Soc., 1928, 24, 426— 437).—M athem atical. W . E. Do w n e y.
In v ersio n p o in t of th e seco n d order. W . Ja z y n a (Z. Physik, 49, 270—278).—M athem atical.
R . W. Lu n t. Im p u lse -en er g y -ju m p in D ir a c ’s q ua n tu m th eo r y of electro n s. H . Te t r o d e (Z. Physik, 1928,4 9 , 858—864).—M athem atical. J . W . Sm it h.
M e a su rem en t of lig h t a b so rp tio n . H . v o n Ha l b a n and J . Eis e n b r a n d (Z. wiss. P ho t., 1928, 25, 138— 152; cf. A., 1927, 1017).—The factors for carrying ou t m easurem ents of light absorption are critically discussed. The advantages and disadvan
tages of th e photographic and th e photo-electric m ethods are considered. W ith a sufficiently high extinction, th e extinction coefficient can be determ ined photographically with an accuracy of a few per cent.
The photographic m ethod is not suitable for determ in
ing small differences of extinction or of concentration of absorbing m aterial, or for the absolute m easurem ent of sm all extin ction s; it is, however, very suitable for th e complete q u antitative determ ination of absorption spectra, and for this it is more useful th a n th e photo
electric m ethod owing to its rapidity. The pho to electric m ethod shows no lower lim it of differential
934 B R IT ISH CHEMICAL ABSTRACTS.----A.
sensitiveness in regard to extinction, an d is therefore em inently suitable for estim ating low values of extinction and small differences, of extinction. In absolute m easurem ents its sensitiveness cannot be fully utilised. I n determ ining complete absorption spectra the lim ited num ber of lines utilisable is a disadvantage.
The differences observed between the photo-electric and photographic m ethods a t wave-lengths below X 3000, and especially w ith n itrate solutions, are explained by system atic errors in the photo-electric m easurem ents. Photo-electric cells show unex
pectedly large differences in th e relation of sensi
tiv ity to wave-length. The exact knowledge of th e properties of the cell used is especially im p o rtan t if absolute m easurem ents are to be m ade w ith im pure
light. W . Cl a r k.
P le o c h r o is m of to u rm a lin e. P . L e R o u x (J.
Phys. R adium , 1928, [vi], 9, 142— 152).—A bsorption m easurem ents on two sections of tourm aline cut parallel an d perpendicular to th e optical axis have been m ade for the m ercury arc lines 5790—3655 A . using a photo-electric cell and q u ad ran t electrometer.
W hen absorption is no longer small, the coefficient of absorption varies w ith the direction of propagation of th e light, th e value being less in the direction parallel th a n in th a t perpendicular to the axis of the crystal. This has been confirmed w ith a second sample of yellow tourm aline. The different value obtained in this case for the. coefficient of absorption indicates th a t the coloration of tourm aline is due to an im purity. L. S. T h e o b a l d .
D ielec tric co n sta n ts and a b so rp tio n in d ic e s of eth y l a lco h o l for sh o r t e lec tric w a v e s. S. M izu-
shhua(Proc. Im p. Acad. Tokyo, 1928, 4, 205—207).—
The dielectric co nstant and absorption index of ethyl alcohol were determ ined a t various tem peratures between 60° and —60° by the resonance m ethod, using electric waves of wave-length 59 cm. The results so obtained, together w ith those published previously (cf. A., 1926, 560, 778, 886, 1082) for other w ave
lengths, show th a t th e region of anomalous dispersion is shifted tow ards longer wave-lengths as th e tem perature is lowered. This agrees w ith D ebye’s dipole theory. From th e experim ental values for the dielectric constant, and by m aking use of D ebye’s formula, the molecular radius can be calculated. I t is found to be 2-1 x lO-8 cm., which is in good agreem ent w ith the value obtained by other methods.
A. J . Me e. C athode p h o sp h orescen ce of er b iu m in ca lciu m ox id e. S. F a g e r b e r g (Ann. Pliysik, 1928, [iv], 86, 435— 446).—The emission spectrum of an. erbium sulphate phosphor has been observed over the range 6800—3100 A . and th e wave-lengths of some 150 lines and bands have been measured. J . W. S m ith .
M e ta llic re flex io n fr o m rock s a lt and sy lv ite in th e fa r u ltra -v io let. A. H . P f u n d (Physical R ev., 1928, [ii], 32, 39— 43).— The wave-lengths of th e tru e resonance frequencies are estim ated to be 1547 an d 1581 A . for sodium chloride and potassium chloride, respectively. A. A. E l d r i d g e .
R ela tio n b etw e en m o le c u la r co n stitu tio n and co lo u r. III. R ecip ro ca l in flu en ce of th e c o m
p on en t v alen cy field s of a m o lec u le . In v ersion of th e a b so rp tiv e ch ara cter of tw o ch ro m o g en s.
M. V. I o n e s c u (Bui. Soc. Stiinte Cluj, 1927, 3, 373—
380; Chem. Zentr., 1928, i, 696—697).—The phenyl, 2>-methoxyphenyl, and 3 : 4-m ethylenedioxyphenyl derivatives of benzofulvene absorb more strongly th an these derivatives of dibenzofulvene, b u t the absorption intervals are no t equal. “ The absorption interval of two substances w ith identical substituents b u t different chromogens diminishes as th e co- ordinatively un saturated character of the substituents increases.” In fact, bis-^-dim ethylam inophenyl- dibenzofulvene absorbs more strongly th a n bis-
£>-dimethylaminophenylbenzoiulvene, owing to the reciprocal influence of th e valency fields of the chromogen and th e substituents. If the co-ordinative u n saturation of the substituents disappears, e.g., by salt» form ation, th e norm al absorptive character of th e chromogen returns. A. A . E l d r i d g e .
A b so rp tio n sp ectru m of n itr ic oxid e. M.
La m b r e y (Compt. rend., 1928, 187, 210—212;
cf. A., 1927, 808).—The absorption spectrum of nitric oxide has been measured. The formula} representing th e composition of the doublet 2267-85, 2261-5 are, first com ponent, v = 4 4 0 8 2 -f 10-7iV+2-3-ZV2 and v=
44077 -j-2-3iV2, second com ponent, v=44196-5+
9-12iV+2-76iY2 and v=44200+2-76iV 2. The doublet 2153-75, 2148-15 is represented by, first component, v= 4 6 4 1 9 + 10-2iy+2-lJV2 and v=46413-5+2-liY2, second com ponent, v ==46536+8-72Ar+2-56Ar2 and v=46531-5+2-56iV2. C. W. Gib b y
L u m in escen ce of w a te r and carbon disulphide u n d er th e in flu en ce of y-ra ys. L . Ma l l e t (Compt.
rend., 1928, 187, 222—223).—U nder th e influence of y-rays w ater an d carbon disulphide give rise to continuous luminescence spectra. C. W. Gib b y.
P o la r isa tio n of in fra -red ra d ia tio n b y calcite.
A. M. Ta y l o r (Phil. Mag., 1928, [vii], 6, 88—97).—
Infra-red radiation has been shown to be p artly polarised by passage through th in plates of calcite- cu t parallel to th e optic axis. These polarisation effects have been used to differentiate between the absorption bands of th e calcite in the infra-red region due to real m axim a of absorption and those which are merely th e effect of interference. Six fundamental absorption bands over th e range 94—7 ¡x with a first and second harm onic have been verified. The frequencies m easured are in agreem ent with those- calculated by ignoring th e assum ption of Schaefer (A., 1927, 5) of an inactive frequency which is active in com bination. A. E . Mit c h e l l.
In fluence of d ifferen t n u c le i on th e ab sorp tion sp ectra of o rga n ic co m p ou n d s. J . E . Pur v is
(Proc. Camb. Phil. Soc., 1928, 24, 421—425).—In the phenyl derivatives of th e two naphthylam ines it is found th a t the introduction of the phenyl group produces an additional b an d ; in th e ar- and ac- hydrogen derivatives of these two compounds the- ty p e of absoiption is controlled by the saturated or u n satu rated condition of each constituent ring. In the cresols, th e introduction of a nitroso-group produces colour. In th e anilides, the position of the typical absorption of aniline is destroj^ed, and it is replaced by a band due to a phenyl group. W. E. Do w n e y.
G ENERAL, PHYSICA L, AND INORGANIC CHEMISTRY. 935 F lu o rescen ce of m e rcu ry vap ou r u n d er lo w
ex cita tio n . ( L o r d ) R a y l e i g h (N ature, 1928, 122, 242).—R adiation of wave-length 3125 A . excites the green band fluorescence of m ercury vapour.
A. A. El d r id g e. A b so rp tio n of lig h t b y so lid an d d isso lv ed sa lts and ab sorp tion b y io n s. H . Le y [with W.
He id b r in k] (Z. anorg. Chem., 1928,1 7 3 ,287—296).—
The absorptive power of copper sulphate solutions for ultra-violet light between 0-30 and 0-25 ¡x deviates appreciably from B eer’s law ; a sim ilar result is obtained w ith concentrated solutions of copper perchlorate. The absorptive power of the solid pentahydrate is appreciably less th a n th a t of the solution, showing th a t the hydrated ion [Cu4H20 ]"
is present in the crystal lattice and th a t this forms a more norm al and more optically satu ra te d system th an does the solution, th e deviations in the absorptive power of which are ascribed to the form ation of complex anions. The change in th e colour of solutions of nickel and copper sulphates produced by the addition of sulphuric acid is shown by examination of the absorption spectrum to be due to dehydration of the coloured cation. A. R. Po w e l l.
D istr ib u tio n of v e lo c ity of th e ex c ited sod iu m atom s p rod u ced in th e op tical d isso c ia tio n of sod iu m iod id e. A. C. G. Mit c h e l l (Z. Physik, 1928, 49, 228—235).—The Doppler effect for the ¿ -lig h t em itted by excited sodium atom s produced by passing the fight from cadm ium or zinc arcs through sodium iodide vapour a t 650° has been m easured in directions parallel an d perpendicular to the direction of the beam producing dissociation. Since the effect is sensibly the same in th e two directions, it follows th a t the velocities of the excited sodium atoms in these directions are also equal. R. W. Lu n t.
D evice for m e a su r in g sp ectru m photograp hs.
R. Fr is c h (Z. Physik, 1928,49, 608).—A simple device is described suitable for the rapid determ ination of distances separating lines in a spectrum photograph with an accuracy of 0-01 mm. R. W. Lu n t.
S tru ctu re an d a ctiv a tio n of th e form aldehyd e m olecule : a n a ly sis fr o m th e p o in t of v iew of the u ltr a -v io le t a b so rp tio n sp ectru m of the vapour. V. H e n r i and S. A. S c h o u (Z. Physik, 1928, 49, 774— 826).—The ultra-violet absorption spectrum of form aldehyde vapour has been investig
ated and 35— 40 bands have been located between 3700 and 2500 A . The absorption maximum is a t 2935, as for other aldehydes. The bands can be divided into 11 groups, the first 7 groups containing rotation bands, whilst the other groups are indefinite and continuous and are attrib u te d to the pre-dis- sociated molecule. A double fine structure was found in the first 7 bands and is explained by assuming a doubly-quantised ro tatio n of the molecule, corre
sponding with two m om ents of inertia J and K , the former about th e C— O axis of the molecule, and the latter a t righ t angles to it. The values deduced for the moments of in ertia of the norm al molecule are J 0= l '3 8 x l O - 40, K 0—‘2 3 x 10“10. From this the con
figuration of the molecule is deduced as of Y-form with the following inter-atom ic distances : H —H = l- 3 8 x
10~8 cm .; C— 0 = l - 0 9 x l 0 - 8; C—H = l - 3 x l 0 ‘8 cm.
Similarly, there are two vibration num bers a and (3, corresponding with C—0 vibrations and H —H vibrations, respectively. For the norm al molecule a0= 1572-3 and (30=441 cm.-1, whilst for the excited molecule a' = 1231-3 and p '= 3 9 8 cm.-1 The band stru ctu re shows a trip let system, and the lines in each band can be arranged very exactly according to nine parabolas. The separation of the bands in these triplets is independent of the sta te of vibration of th e atom s and is alm ost equal to the value calculated from th e emission spectrum of th e CO molecule. The carbon monoxide molecule is supposed to exist norm ally in the JS state, from which it was predicted th a t it would have a new absorption band a t 2060-6 arising from the bS'-— change. This was found a t 2060-8 Â. The deductions are draw n th a t th e form aldehyde molecule exists norm ally in th e 3P sta te and passes through seven successive stages of vibrational activation into a pre-dissociated sub
stance. A t higher tem peratures th e la tte r condition appears a t lower degrees of excitation than a t normal tem peratures.
Observations of the absorption spectrum of form aldehyde in solution showed th a t in w ater the form aldehyde molecule is completely hydrated, whilst in hexane a t —70° it remains in the unimolecular
state. J . W. Sm it h.
O p tical ex c ita tio n and d isso c ia tio n of m e ta llic h a lid es. K . Bu t k o v and A. Te r e n i n (Z. Physik, 1928, 49, 865—884).—In continuation of previous work (A., 1926, 776; 1927, 1009) th e optical dis
sociation of the cæsium iodide, thallous bromide and chloride, and cuprous iodide molecules into the excited metallic atom and neutral halogen atom has been investigated. The lim iting frequencies a t which th e lines characteristic of the metallic atom are em itted when the vapour of the halide is irradiated w ith an intense beam of short ultra-violet light were deter
mined, and th e heat of dissociation of th e molecules so deduced was found to be in satisfactory agreem ent w ith those calculated from therm ochem ical data. In th e case of thallous iodide vapour, optical excitation causes th e emission of a band spectrum of the T il molecule besides th e atom ic lines. From this, the various dissociation processes are related w ith the energy levels in th e molecules. The d a ta obtained are com pared w ith those found previously.
J . W. Sm it h. T ita n iu m ox id e b an d s. A. C h r i s t y and R. T.
B i r g e (Nature, 1928, 122, 205).—Each of th e blue- green titaniu m bands consists of three It and three P branches. The three heads of the 0—0 band lie a t 19,349,19,347, and 19,340 cm.-1 (approx.). The bands are ascribed to n eu tral TiO, and are probably due to a 3P — 3P tran sitio n ; th e lower level is assumed to be an excited level of the TiO molecule.
A. A. El d r id g e. D ielec tric p o la risa tio n of liq u id s. III. P o la r isa tio n of th e iso m e r id e s of heptane. C. P.
Sm y t h and W. N. St o o ps (J. Amer. Chem. Soc., 1928, 50, 1883— 1890).—The densities, refractive indices, and other physical constants of M-heptane, its isom
erides, an d pSS-trimethylpentane are recorded for 20°. The dielectric constants and densities of
936 B R IT ISH CHEMICAL ABSTRACTS.— A.
w-heptane, S[3-dimethylpentane, y-ethylpentane, and pp8-trim ethylpentane between —120° and + 10 0°
are also recorded. These molecules possess no m easurable electric mom ents. Atoms in satu rated hydrocarbons m ay be linked in every possible con
figuration w ithout causing m easurable lack of electric sym m etry, although slight differences in th e rigidity of the binding electrons can be detected. The electrical sym m etry of th e molecules gives no evidence of a difference in the electronegativities of the various constituent radicals. S. K . Tw e e d y.
S p ecific h e a ts at lo w te m p era tu re s of m a n - g a n o u s oxid e, m a n g a n o so m a n g a n ic oxid e, and m a n g a n e se d io xid e. R . W. Mi l l a r (J. A m er.
Chem. Soc., 1928, 5 0 , 1875— 1883).—The specific heats Avere m easured from 70° to 300° Abs. The specific h eat-tem p eratu re curves for m anganous oxide and manganese dioxide exhibit discontinuities.
W ith the aid of the Debye and E instein specific heat functions and th e th ird law of therm odynam ics th e following entropies (in g.-cal./l°) a t 25° were calcu
lated : manganous oxide, 14-92; manganosom anganic oxide (M n30 4), 35-73; manganese dioxide, 13-93.
The respective free energies, AF, are a t 25° (g.-cal./
mol.) : —85,830, —302,800, and —112,600.
S. K . Tw e e d y. E lectr ic m o m e n t of p -a zo x y a n iso le . J . Er r e r a
(Physikal. Z., 1928, 2 9 , 426—429).—M easurements of th e electric m om ent are held to indicate th a t th e optical anisotropy of p-azoxyanisole is due, n o t to molecular aggregates, b u t to th e molecules themselves.
The value obtained for th e electric m om ent is ¡x=
2-3 x lO -18. J . W. Sm it h.
D e term in a tio n of d ip ole m o m e n ts fr o m cr itica l data. J . K . Sy r k i n (Z. anorg. Chem., 1928, 1 7 4 , 47— 56).—The equation m = l - 6 6 x 10rwTcP£ has been deduced from th e equation for th e m ean energy of tw o rigid dipoles; m is th e m om ent of th e dipole, T c an d P c are th e critical tem p eratu re an d pressure.
The m om ents of 79 substances have been calculated, a n d th e results are in agreem ent w ith th e values observed by other workers. R elationships between th e dipole m om ents of sim ilar compounds are dis
cussed; e.g., for homologous series th e m om ent decreases as th e num ber of carbon atom s in the molecule increases. A dditive relationships are observable in a num ber of cases. H . F. Gi l l b e.
M olecu lar and a to m ic v o lu m e s. XX. S p ace o ccu p ied b y h y d ro g en in m e ta llic h y d r id es. W.
Bil t z (Z. anorg. Chem., 1928, 1 7 4 , 42— 46).—
H ydride form ation by th e alkali, alkaline-earth, and rare-earth m etals is accompanied by a reduction to a b o u t half its value of the zero mol. volume. The mol. volumes of th e rare-earth hydrides class these elem ents w ith th e alkali an d alkaline-earth groups.
H . F . Gi l l b e. R a m a n effect. P . Pr in g s h e i m (Naturwiss., 1928, 16, 597—606).—Descriptive.
D ep en d en ce of refra ctiv e in d e x on tem p era tu re and d en sity . G. P e t e r s (Ann. Physik, 1928, [iv], 86,494—510).—An interferom eter m ethod of m easur
ing th e refractive index of liquids is described.
M easurem ents on liquid hydrogen cyanide have been
m ade, b u t th e results are n o t of sufficient accuracy to determ ine which of th e various theoretical form ula m ost accurately represents th e effect of tem perature an d density. W. E . Do w n e y.
R otation p o la r isa tio n of electro m a g n etic w a v e s due to te tra h ed ra l m o lec u le m o d els.
K . F. Lin d m a n (Acta Acad. Aboensis M ath, phys., 1927, 4 , No. 1, 1—22; Chem. Zentr., 1928, i, 1146).—
Experim ents were carried ou t w ith isotopic three- dim ensional system s of num erous small tetrahedral molecule models an d waves of length greater than those of the resonators and th e dimensions of the single models. I n accord w ith B io t’s corresponding law for optical activ ity , th e ro tatio n of th e plane of polarisation of th e electrom agnetic waves is propor
tion al to th e num ber of molecule models in their p ath , i.e., to th e cross-section of th e active substance.
A. A. El d r id g e. P o la r isa tio n of sca ttere d lig h t q uanta. C. V.
Ra m a n and Iv. S. Kr is h n a n (N ature, 1928, 122, 169).
N e w p h en om en on in th e s c a tte r in g of light b y c r y sta ls. G. La n d s b e r g and L . Me n d e l st a m
(Naturwiss., 1928, 1 6 , 557—558).—W hile investigat
ing th e scattering of light, using a m ercury arc source, from qu artz crystals, a dim inution in frequency of the scattered lines 2536, 3126, an d 3650 A. was observed.
I t is suggested th a t th e observed dim inution in frequency can be accounted for by th e emission of one q uan tu m of an infra-red frequency per quantum scattered, since in th e cases recorded th e diminution in frequency corresponds w ith emission a t the known absorption region X=20-7 p.. R . W. Lu n t.
R efra ctiv e in d e x fo r electro n w aves. L.
Ro s e n f e l d and E. E. Wi t h e r (Z. Physik, 1928, 4 9, 534—540).—A theoretical discussion of the relation
ship between th e values of u, th e “ refractive index of a m etal, e, th e p o ten tial in th e m etal, and V derived from th e equation e V — lm v 2, for various m etals.
V alen cy c h e m istr y of b oron , and the co n stitu tio n of th e s im p le s t b oron hydride. E . Wib e r g
(Z. anorg. Chem., 1928,1 7 3 ,199—221).—An electronic form ulation of boron hydride, B2H 6, is derived by po stulating th a t (1) th e o ctet rule is valid for boron compounds, (2) th e boron atom cannot combine by covalencies w ith m ore th a n 4 atom s, (3) hydrogen is com bined b y electrovalencies only in th e metallic hydrides, an d in all other cases b y covalencics. The conclusion is reached th a t in all electrovalency com
pounds boron is terv a len t and in all covalency com
pounds, quinquevalent. Q uadrivalent boron, in the sense of q uadrivalent carbon, does n o t exist. The form ula derived is consistent w ith addition of sodium an d am m onia to th e hydride, its reactions w ith water an d th e hydrogen halides, an d th e form ation of
hypoborates. H . F . Gil l b e.
P o la r co n cep tion of co -ord in a ted valen cies.
E. J . W . Ve r w e g (Chem. W eekblad, 1928, 25, 250—
254).—I t is contended th a t th e so-called co-ordinated valencies in complex com pounds are in fact polar in natu re, although “ deform ed ” to such a degree as to appear to some ex ten t non-polar. S. I. Le v y.
