868 

Castle, Denmark, which consisted originally of Red 
Danish dairy cattle and’ Jersey cattle, are discussed. 
The yield during the first r0-week period of milking 
appears to be the most trustworthy measure of a 
cow’s milk-yielding qualities. The records of the 
cross-bred cattle (F;) show no indication of any 
single Mendelian factor in the inheritance of milk 
characters.—A. R. Olson and G. Glockler: The 
critical and dissociation potentials of hydrogen. 
A heated platinum filament covered with calcium 
oxide in a vacuum tube containing purified dry 
hydrogen at o-1 mm. of mercury pressure was used 
as the source of electrons. The beam of electrons 
passed through platinum stops to which varying 
accelerating and retarding potentials could be given, 
and fell on an ionisation cylinder connected with 
a quadrant electrometer. The dissociation potential 
of hydrogen appears to be 3-16 volts; eight breaks 
occur in the current-potential curves, five of which 
correspond with lines of the Lyman series.—G. L. 
Clark and W. Duane: (1) The reflection by a crystal 
of X-rays characteristic of chemical elements in it. 
Crystals of the compounds KI, KI,, CsI, Csl;, and 
CsIBr have been investigated and X-rays character- 
istic of iodine, cesium, and bromine have been 
identified which obey the regular laws of crystal 
reflection. The method used is to determine the 
position of peaks in the ionisation curve by rotating 
the crystal (corresponding to reflections from the 
various planes), and, setting the ionisation chamber 
at one of these peaks, to move the crystal and the 
ionisation chamber, the latter at twice the rate of 
the former. A series of peaks are obtained referring 
to one set of planes alone. For KI, wave-lengths 
of these correspond with the Ka and Kf wave-lengths 
of iodine. The distance between the 100 planes is 
3°53 x1o"® cm. KI, is found to be a cube slightly 
distorted with the edge 4:70 x1o~® cm. long. Csl;, 
appears to be a rhombic crystal with cesium atoms at 
each corner and iodine atoms at the centre and at points 
equidistant from the centre along the body diagonals. 
CsIBr, is also a rhombic crystal. (2) On the abnormal 
reflection of X-rays by crystals. Reflections of X-rays 
have been obtained from potassium iodide which 
are not in accord with the usual laws of crystal- 
reflection. The peaks caused in the ionisation curve 
are termed ‘ X-peaks.’’ For small deviations of 
the X-ray beam, the X-peak is outside that due to 
the 130 planes; for larger deviations, it is between 
those due to the 100 and 130 planes. The X-peak 
does not appear unless the incident beam contains 
X-rays of shorter wave-length than those in the 
K-series of iodine-——G. L. Clark: The significance 
of the experimentally determined crystal structures 
of the alkali polyhalides. It appears from X-ray 
analysis of the polyhalides KI, CsI,, CsI Bry, CsICl, 
that the three halogen atoms lie a diagonal of the 
crystal lattice, the heaviest in the centre; the metal 
atoms are atthecorners. Other polyhalides are closely 
related chemically and _ crystallographically, and 
probably have similar structures, apparently closely 
related to the simple halide unit cubes, the halide 
group replacing a halogen atom. The size of the 
metal atom determines the dimensions of the unit 
cell and thus the relative stabilities of the polyhalides 
of the group.—E. B. Wilson: Electric conduction : 
Hall’s theory and Perkins’ phenomenon. Perkins 
has shown that the addition of a negative charge 
to a conducting strip of graphite decreases the 
conductivity. This is contrary to what might be 
expected on a free electron theory of conduction, 
but can be explained on Hall’s theory of conduction 
by streams of electrons and ions, the latter taking 
a predominant part. 
NO. 2799, VOL. T1I | 
NATURE 

[June 23, 1923 
Official Publications Received. 
Report cf the Director of the Royal Observatory, Hongkong, for the 
Year 1922. Pp. 17. (Hongkong.) 
Department of Commerce : U.S. Coast and Geodet’c Survey. Serial No. 
225 : Reconnaissance and Signal Building. By Jasper 8. Bilby. ( ial 
Publication No. 93.) Pp. v+77. (Washington: Government Pr nting 
Office.) 30 cents. 
Smithsonian Institution: United Statés National Museum. Bulletin 
100: Contributions to the Biology of the Philippine Archipel and 
Adjacent Regions: Ophiurans of the Philippine Seas «nd jacent 
Waters. By Prof, Rene Kehler. Pp. x+486+103 plates. Bulletin 
124: The Type Species of the Genera of Chalcidoidea or Chalcid-Flies. 
By A. B. Gahan and Margaret M. Fagan. Pp. iii+173. 15 cents. » 
(Washington : Government Printing Office.) 
Report of the Aeronautical Research Institute, Tokyd Imperial Uni- 
versity. No.1: Hikoki ni taisurn Kaze no H6k6 to Hayasa wo kiroku- 
suru Kikai (An Instrument to measure the Direction and Speed 0! Wind 
relative to an Aeroplane). By Tamaru-Takuré. Pp, 23. Y. 0.50. No. 2: 
A New Air Velocity Calculator. Ry Toyotaré Suhara.— Pp. 26-81. 
Y. 0.70, No.3: On the Diurnal Variations of Winds in different Coastal 
Stations of Japan. By Torahiko Terada and Tatno Kobayasi. Pp. 33-85. 
Y. 1.10. No, 4: On tlie Decay of Vortical Motion in a Viscous Fluid. By 
Kwan-ichi Terazawa. Pp. 87-185. Y. 0.90. No. 5: On the Distribution 
and Variation of Temperature in the Cylinder and Piston of an Aircraft 
Engine. By Toyotaré Suhara and Navzo Sato. Pp. 137-170. Y. 1,20, 
(T6ky6: Maruzen Kabusiki-Kwaisya.) 
Neue Denkschriften der Schweizerischen Naturforschenden Gesellschaft 
(Nouveaux Mémoires de la Société Helvétique des Sciences Naturelles). 
Band 53. Pp. xx+402+54. Band°54. Pp, iv+2v1+32 Tafeln. Band 
55. Pp. viiitl49. Band 56. Pp. vit+128+28 Tafeln. Band 57. Pp. 
Ghee Band 58. Pp. viii+251. (Basel, Genf and Lyon: Georg and 
0. 
Statens Meteorologisk-Hydrogratiska Anstalt, Arsbok, 4, 1922) 2: 
Nederbirden i Sverige. Pp. 173. (Stockholm.) 
- 

Diary of Societies. 
MONDAY, June 25. 
Socrery or BIOMETRICIANS AND MATHEMATICAL Statisticians (at 
University College), at 8.—Dr. T, H. C. Stevenson : The Social Distribu- 
tion of Causes of Death in England and Wales. 
Roya Society of Mepicrine (Odontology Section), at 8.—L. E_ Clare- 
mont: Case of Fibro-Cystic Disease of the Lower Jaw.—Dr. A. 
Hopewell-Smith: Two Odotomes ; Some Observations on the Histology 
and Pathology of the Dental Pulp. ; 
Roya. InstiTUTe or British ARCHITECTS, at 8.30.—Presentation of the 
Royal Gold Medal. 
TUESDAY, June 26. > 
ImperiaL Epucation ConrereNce (at Institution of Mechanica’ 
Engineers), at 8.--Miss L. De Lissa: Recent Developments in Infant 
Education and their Connexion with the Work of the Elementary 
Schools. 
RoyaL ANTHROPOLOGICAL INsTITUTE, at 8.15.—de Barri Crawshay: 
Exhibit of Eoliths from the South Ash Pit on the Kentish Chalk 
Plateau, and of Stone Implements from Mesopotamia.—S. Hazzledine 
Warren: The Paleolithic Succession of Stoke Newington. 
Socro.oeicat Society (at Royal Society), at 8.15.—Dr. EB. Jenks: The 
Function of Law in Society. 
WEDNESDAY, Jone 27. 
Roya Society oF Arts, at 4.—Annual General Meeting. 
Rovab Socirry or Mepicine (Surgery Section), at 5.30—Dr. W. Mayo, 
Sir Berkeley Moynihan, J. Sherren, G. Grey Turner, and A. J. Walton: 
Discussion on the Surgery of the Hepatic and Common Bile Ducts. 
ImpERIAL Epvucation Conrerence (at Institution of Mechanical 
Engineers), at 8.—L+t.-Gen. Sir Robert 8. 8. Baden-Powell, Bart. : 
The Boy Scont and Girl Guide Movement. 
THURSDAY, Jone 28. 
Roya. Soctery, at 4.30.—Prof. V. H. Blackman, A. T. Legg, and F. G. 
Gregory ; The Effect of a Direct Electric Current of very Low Intensity 
on the Rate of Growth of the Colcoptile of Barley.—Miss R, M. Tupper- 
Carey and Prof. J. H. Priestley: The Composition of the Cell Wall at 
the Apical Meristem of Stem and Root.—L. J. Harris: The Titration 
of Amino- and Carboxyl-Groups in Amino-Acids, Polypeptides, ete.— 
Dr. M.S. Pembrey, N. W. MacKeith, W. R. Spurroll, E. C. Warner, and — 
H. J. Westlake : Observations on the Adjustment of the Human Bod 
to Muscular Work.—F. A. E. Crew: Studies in Intersexuality. IL. 
Sex-Reversal in the Fowl.—Prof. W. Finkler: Analytical Studies on the 
Factors causing the Sexual Display in the Mountain Newt (7'riton 
alpestres).—Prof. G. A. Schott: The Scattering of X- and y-Rays by 
Rings of Blectrons—The Effect of Damping of the Incident Radiation.— 
Major P. A. MacMahon: A Class of Transcendents of which the Bessel 
Funetions are a Particular Case.—Dr. L. C. Martin: The Photometric 
Matching Field.—Prof. G. P. Thomson: Test of a Theory of Radiation. 
—Dr. A. Ll. Hughes and P. Lowe: Intensities in the Helium Spectruin. 
—A. A. Dee: The Effect of Quenching from above the Carbide Transi- 
tion Temperature upon the Magnetism of Steel.—T. 8. P. Strangeways 
and H. E. H. Oakley : The Immediate Changes observed in Tissue Cells 
after Exposure to Soft X-Rays while growing in vitro. 
Institution oF EvecrricaL Excixrers (at British Museum (Natural 
History)), at 8.30.—Annual Conversazione. \ 
Roya Society or Mepicixe (Urology Section), at §.80.—Prof. C. G. 
Cumston: Certain Points in Connexion with Nephritis. 
FRIDAY, June 29. 
Socréré pes IncéNieurS Crvits DE France (British Section) (at Institu- 
tion of Mechanical Engineers), at 8.30,—M. Barrillon: The Port of — 
Rouen and the Lower Seine. 
a 
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