;76 



NATURE 



[July 31, 1913 



female of Diphlebia hybridoides , Tillyard, to the list 

 of Australian Odonata. — H. Maiden and E. Betche : 

 Notes from the Botanic Gardens, Sydney. No. 18. 

 Seven new species are proposed. Notes on proposed 

 new varieties, plants new for New South Wales, and 

 plants with interesting- new localities are given. — 

 Mr. Tillyard : Study of zoo-geographical distribution 

 by means of specific contoursT In this method, 

 instead of attempting to subdivide the recognised zoo- 

 geographical regions into distinctly marked-off sub- 

 regions and lower divisions, it is proposed to study 

 the various groups of plants or animals occurring 

 over the whole region, by constructing "specific con- 

 tours " by the following rules :— (i) The group selected 

 must be a natural group, i.e. a genus, tribe, or family 

 which forms a homogeneous whole, and not merely 

 a group separated off for convenience of classification. 

 (2) The records available must be sufficiently numerous 

 to give the general form of the contour, but absolute 

 accuracy is neither attainable (without infinite labour) 

 nor necessary. (3) Each species of the selected group 

 is reckoned as a unit. On the map of the region 

 under study, against each locality which has been 

 " worked," the number of units occurring there is 

 to be put down. Then contour lines, in the form of 

 free_ curves, are to be drawn so that all localities 

 having an equal number of units shall be between 

 anv two successive contour lines. 



BOOKS RECEIVED. 



Department of Applied Statistics, University Col- 

 lege, University of London. Drapers' Company 

 Research Memoirs. Biometric Series VIII. : — A 

 Monograph on Albinism in Man. Bv K. Pearson, 

 E. Nettleship, and C. H. Usher. Part ii., Text. 

 p P- 265-524. Part ii., Atlas. Plates a.-w. and 

 a.a.-n.n. (London : Dulau and Co., Ltd.) Text and 

 Atlas, 30s. net. 



Smithsonian Institution. U.S. National Museum. 

 Bulletin 81 : — Synopsis of the Rotatoria. By H. K. 

 Harring. Pp. 226. (Washington : Government 

 Printing Office.) 



Memoirs of the Geological Survey of India. 

 Vol. xli. :— The Coalfields of India. By the late 

 Prof. V. Ball. Entirely revised and largely rewritten 

 by R. R. Simpson. Pp. i47 + xliv+2o~pIates + map. 

 (Calcutta : Geological Survey of India ; London : 

 Kegan Paul and Co., Ltd.) 5 rupees, or 6s. 8d. 



Transactions of the Royal Society of Edinburgh. 

 Vol. xlix. Part 1. Session 1(512-13. Vol. xlviii. 

 Part 3. Session 1912-13. Vol. xlviii. Part 4. 

 Session 1912-13. (Edinburgh: R. Grant and Son; 

 London : Williams and Norgate.) Js. 6d., 31s., and 

 1 6s. 8<L respectively. 



The Standard of Value. Bv W. L. Jordan. Eighth 

 edition. Pp. vi + 287. (London: Simpkin and Co., 

 Ltd.) 7s. 6d. net. 



Practical Physics for Secondary Schools. By N. H. 

 Black and Dr. H. N. Davis. Pp. viii + 487. (Lon- 

 don : Macmillan and Co., Ltd.) 55. 6d. net. 



British Pharmaceutical Conference. A Presidential 

 Survey. 186^ to 1913. Pp. 96. (London : The 

 Chemist and Druggist?) 



On the Circulation of Energy and Matter. Bv 

 E. M. Darken. Pp. 27. (Wellington, N.Z. : P.O. 

 Box 266.) 



Report on Scottish Ornithology in 1912, including 

 Migration. By L. J. Rintoul and E. V. Baxter. Pp. 

 96. (Edinburgh : Oliver and Boyd.) 



The National Phvsical Laboratory. Report for the 

 Year 1912. Pp. 123. (Teddington : W. F. Parrott.) 

 NO. 2283, VOL. 91] 



The National Physical Laboratory. Collected Re- 

 searches. Vol. ix., 1913. Pp. iv + 245 + plates. 

 Vol x., 1913. Pp. iv + 253 + plates. (Teddington: 

 National Physical Laboratory.) 



Merck's Reagenzien-Verzeichnis. Dritte Auflage. 

 Pp. 446. (Berlin: J. Springer; London: E. Merck.) 

 6s. 6d. 



Organic Chemistry for Advanced Students. Vol. ii. 

 By Prof. J. B. Cohen. Pp. vii + 427. (London. E. 

 Arnold.) 16s. net. 



Die chemische Verwandtschaft und ihre Bezieh- 

 ungen zu den ubrigen Energieformen. By Dr. Max 

 Speter. Pp. 134. (Leipzig : P. Reclam, jun.) 2 

 marks. 



Phonetic Spelling : a Proposed Universal Alphabet 

 for the Rendering of English, French, German, and 

 all other Forms of Speech. By Sir H. Johnston. 

 Pp. 92. (Cambridge University Press.) 3s. 6d. net. 



CONTENTS. page 



Prof. Perry's Practical Mathematics. By Prof 



G. H. Bryan, F.R.S 55, 



An Egyptian Desert. By J. W.J 553 



The Problem of a Pure Milk Supply. By Prof. R. T. 



Hewlett jr^ 



Our Bookshelf 555 



Letters to the Editor: — 



Pianoforte Touch. — Spencer Pickering, F.R.S. . 555 

 A Danger of so-called " Automatic Stability." (With 



Diagram.)— Prof. G. H. Bryan, F.R.S. . . 556 

 The Structure of the Diamond. — Prof. W. H. Bragg, 



• F.R.S. ; W. L. Bragg 557 



Artificial Hiss.— Fred J. Hillig : Lord Rayleigh, 



O.M , F.R.S 557 



Prof. Armstrong and Atomic Constitution. — Sir Oliver 



Lodge, F.R.S 558 



Distribution of Amphidinium. — Prof. W. A. Herd- 

 man, F.R.S 5158 



Gramophone Improvements. {Illustrated.) — A. A. 



Campbell Swinton 558 



The Maximum Density of Water. — Dr. John Aitken, 



F.R.S 558 



The Unpublished Papers of J. J. Lister. By A. E. 



Conrady 559 



The Ancient Artists of South-Western Europe. 



(Illustrated.) By Dr. A. C. Haddon, F.R.S 560 



Experimental Cancer Research 363 



Notes 564 



Our Astronomical Column: — 



Astronomical Occurrences for August 568 



Nova Geminorum No. 2 568 



Variation of Latitude 56S 



The Intensity Distribution of Individual Lines in 



Stellar Spectra 56S 



Recent Work of the Geological Survey of Great 



Britain. (Illustrated.) By G. A. J. C 568 



Ornithological Notes 570 



Blood-Parasites. By H. G. Plimmer, F.R.S. ... 571 



University and Educational Intelligence 574 



Societies and Academies 575 



Books Received 576 



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Editorial Communications to the Editor. 

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