200 



NATURE 



[October 7, 1920 



Smithton discovery the authors deal with a mass of 

 data relating to the evolutionary trend of the Noto- 

 theria and the structure of the skull. They also deal 

 with a reclassification of the genus. The N'ototheria 

 are a group of animals that in Tasmania became 

 extinct late in Pleistocene times. They were 

 generalised, and yet in part specialised. They retained 

 the racial characteristics that can be relegated to five 

 geological periods — that is, from the pre-Locene to the 

 latest Pleistocene. They show similar developments 

 to those of the perissodactyl ungulates, and, without 

 leaving a single modern representative to carry on 

 their race in totality, they left many characters scat- 

 tered through their rnarsupial allies, the kangaroos, 

 wombats, and native bears, which still grace our wood- 

 lands to-day. In dealing with the taxonomic data 

 relating to the skull the authors recognise two well- 

 marked groups, namely : Group i., Megacerathine, 

 and group ii., Leptocerathine. — H. T. Parker : Mental 

 efficiency. .\ study of the results obtained by testing 

 children bv the Binet-Simon scale. 



Books Received. 



The Cactaceae : Descriptions and Illustrations of 

 Plants of the Cactus Family. By N. L. Britton and 

 J. N. Rose. Vol. ii. Pp. 'vii-l-23g+xl plates. (Pub- 

 lication No. 248.) (Washington : Carnegie Institu- 

 tion.) 



Geometrical Investigation of the Formation of 

 Images in Optical Instruments. Embodying the 

 Results of Scientific Researches Conducted in German 

 Optical Workshops. Edited by M. von Rohr. 

 (Forming vol. i. of "The Theory of Optical Instru- 

 ments.") Translated by R. Kanthack. Pp. xxiii + 

 612. (London : H.M. Stationery Office.) iX. 55. net. 



Technical Handbook of Oils, Fats, and Waxes. Bv 

 P. J. Fryer and F.. E. Weston. Vol. i. : Chemical 

 and General. Third edition. Pp. xii+280+xxxvi 

 plates. (Cambridge: At the University Press.) 155. 

 net. 



Commonwealth of Australia. Papua. Annual 

 Report for the Year igiS-ig. Pp. 119. (London: 

 Australia House, Strand.) 



The Human .Atmosphere (The Aura). Bv W. J. 

 Kilner. Pp. vii+300. (London : Kegan Paul and 

 Co., Ltd.) los. 6i. net. 



Mathematical Papers for .\dmission into the Royal 

 Military .'\cademy and the Royal Militarv College and 

 Papers in Elementary Engineering for \aval Cadet- 

 ships and Royal Xvc Force. November, 19 19, and 

 July, 1920. Edited by R. M. Milne. Pp. 34. 

 (London : Macmillan and Co., Ltd.) \s. <)d. net. 



Diary of Societies. 



THmSDAT, OcrOBEE 7 



RorAL Aebonaoticai, Societi (at Ro.val Society of Arts), at 5.30.— 

 Major-General Sir F. H. Sykes : Civil Aviation. 



CHlLD-STtlDr SociETr (at Koyal Sanitary Institute), at 6.— Dr. 

 C. W. Kimmins: The Handwriting of the Future. 



KoTAL SociETt OF Medicink (Obstetrics and G.vn»col(>gv Section), 

 at 8.— The President: Spoon-shnpcd Deprtssed Birtii Fracture 

 of the Frontal Bone treated by Elevation. — Dr. il. Kerr; (11 

 The Surgery of the Uterus Bicornis t'nicollis, . with a case of 

 Resection of the Uterus foUowt-d by two Normal Pregnancies: 

 (2) The Intrn-vesical Repair of Inaccessible Vesico-vaginal 

 Fi.stula.— Dr. A J. McNnir: A Case of Placenta Prievia with 

 Vasa Pnevio,— H. Bripgs : (Presidential .\ddrc8s), The Female 

 Pelvic Floor. (Neurology Section), at 8.45.— Dr. H. Head: 

 (Hughling3 Jackson Lecture), A New Conception of Aphasia. 



FRIDAY, OCTOBER 8. 

 RotAt SOCIETT or Medicine (Clinical Section), at 5.30.— Z. Cope: 

 The Clinical Significance of Shonlderpain in Upper .Ibdominnl 

 ■ Lesions. 



RoTAt Photoorvphic Societi or Gbeat Beitaix, at ".— R. A. 

 Mnlby : A Miniature Alpine Garden. 



NO. 2658, VOL. 106] 



llOXDAi', Oc-ioi™ 11. \ 



BiocRKUicAL Society (at King'» College), at 5. \ 



RoiAL SociCTT or Medicixe (War Section), at S 30.— Wing-Corn- ; 



roander Martin Flack : Medical Requirement* for Air Navigatioa. 

 Meoioai. SocKTr or I.ondox (at 11 Cbandot Street. W.l), at 8. — 

 Annual General Meeting. At 8.30.— Sir William Hale-White: (Pre- 

 sidential Addrefcs), Then and Now. 



TUESDAY, Ocioeni 12. 

 SociETT FOB THI Stciit Or IXEBBiETi (at Medical Society of London), 



at 4.— Dr. J. A. D«vid>on, and others: Discussion on Special 



Clinics for Inebriates. 

 RoTAi, PHOTooBArBic SociiTi OF OirjtT BxiTiiK, at 7. — (Annual 



Traill Taylor Memorial lecture). Prof. A. E. Conrady: The 



Present State of Photographic Optics. 



WEDSF.SDAY. OcTOBHi 13. 

 IiraTiTBTiOK Of ACTOHOBII.E ExoiNiXBs (at Royal Society of .\rt»), 



at 8, — Sir Henry Fowler : Presidential .\ddress. 

 HoNTEBiAK SociETT (at Sion College), at 9.— Sir George Newman: 



The Ministry of Health as an Instrument in Prcwntive Medicine. 



THURSDAY, Octobee 14. 

 OmcAi SOCIETT (at Imperial College of Science and Technology), 



at 7.30.— H. A. Hughes and P. F. Everitt: The Field of View 



of « Galilean Telescope. — B. K. Johnson : The Calibration of th« 



Divided Circle of a Large Spectrometer. 

 iNSTiTCTioN or AvTOMOBiLE EsoiNEEBS (at 28 Victoria Street), at 



8.— Graduates Meeting. Messrs. Chatterton and Wat«on: Factors 



affecting Power Output. 

 RoTAt SociETT OF MEDICINE (Neurology Section), at 8.30. — Dr. E. 8. 



Reynolds; (Presidential .Address), The Causes of Nervous Disease. 



FRIDAY, OcTOBEK 15. 

 RoTAi Socirrr op .^rts (Indian Section), at 4.30. — T. M. Ainscoogli: 



British Trade with India. 

 HoTAt College of Stbgeons of England, at S — Prof. A. Keith: 



Demonstration on the Contents of the Museum. 

 RotAi Photoobaphic Society of Gbeat Britain, at 7. — A. KeigUey: 



An Evening in Lakeland. 

 Royal Societt of Medicine (Eleotro-Therapentics Section), ^t 8.30 — 



8. Gilbert Scott: Presidential Address. 

 SociETT OF Tropical Medicine and Hygiene, at 8.30. 



SATIRDAY, October 16. 



Physiological Society (at Guy's Hospital), at 4. 



CONTENTS. PAGE 



The Metric System and International Trade. By 



Harry AUcock 169 



The Study of Live Embryos 170 



Two Books for the Country 171 



Principles of Aeronautics 173 



Text -books on Chemistry 174 



Our Bookshelf 176 



Letters to the Editor: — 



The Briti.sh Association. — Sir Napier Shaw, F.R.S. ; 



Sir Edward Brabrook, C.B 178 



The Exaniin.ition System. — Oxford M.A 179 



An Awkward Unit. —Prof. Alexander McAdie . . 179 

 Absorption Spectrumof Hydrogen Chloride. — F. W. 



Loomis 179 



A New Visu.il Illusion.— J. E, Turner 180 



Plant-life in the Cheddar Caves.— Edith Bolton . . 180 

 Old Maps,— T. Sheppard ; The Writer of the 



Note 180 



The Iridescent Colours of Insects. II. (Illustrated.) 



By H. Onslow 181 



Physical Anthropology of Ancient and Modern 



Greeks. (Illustrated.) By L. H. Dudley Buxton . 183 

 Obituary : — 



Alfred E. Fletcher. -^J. B. C 185 



D. H. Nagel.— Prof. H. B. Dixon, F.R.S. . . . 186 



Notes 187 



Our Astronomical Column : — 



Prof. Pickering's Lunar Observations 191 



The Sun's Magnetic Field 191 



Fossils and Life. II. By F. A. Bather, M.A., D.Sc, 



F.R.S . 192 



International Catalogue of Scientific Literature . . 195 

 The International Congress of Mathematicians. 



By H. B. H 196 



Disorders of Symbolic Thinking 197 



University and Educational Intelligence .... 198 



Societies and Academies 199 



Books Received 200 



Diary of Societies 200 



(Index.) 



