96 



NATURE 



[May 27, 1897 



the result of experiments made by Mr. P. G. Tiddens, of 

 Grriningen, is founded upon the fact that a perfectly identical 

 deflection image is produced by rays of, very different wave- 

 length, by varying the distance between the source, the diffract- 

 ing slit, and the screen in a definite manner. Starting from a 

 diffraction image of light rays, provisional experiments were 

 made to determine whether the wave-length of X-rays was equal 

 to, or one-quarter or one-fifteenth of, that of light rays. In the 

 last-mentioned case, the image resembled that obtained from 

 light rays more than the others did ; it was not, however, quite 

 identical with it — Prof. Haga read a paper, by Dr. C. H. 

 Wind, on the influence of the dimensions of the light beams 

 on Fresnel's diffraction phenomena, and on the diffraction of 

 X-rays. From experiments, made by Mr. Tiddens, it appeared 

 that the X-shadow figures obtained by Fomm and others, are not 

 ordinary Fresnel diffraction images. The author showed that the 

 shadow figures obtained are to be conceived as secondary dif- 

 fraction images (arising from ordinary ones on the slit serving 

 as a source of light being widened), and he developed the main 

 points of the theory of these secondary diffraction images, and 

 pointed out the way it opens to determining the wave-length. 

 The existence of secondary diffraction phenomena, analogous to 

 those observed when employing X-rays, can easily be ascertained 

 when ordinary light is used. This, in the author's opinion, as 

 good as proves the undulatory character of X-rays.— Mr. Ham- 

 burger communicated a new quantitative method of determining 

 the anti-bacterial action of blood and tissue fluid. This method 

 avoids the usual counting of microbes with the help of plate 

 cultures, because this occasions errors of 40 to 50 per cent. 

 Instead of counting the microbes, their total volume is determined 

 by centrifugal action. This method occasioned errors of only 

 6"S per cent. — Prof, van derWaals presented, for publication in 

 the Proceedings, a paper on the equilibrium of a compound 

 ■solid in the presence of a gas and a liquid. The author proves 

 that by adding to the i/^ surface for a mixture {Arch. Neerl., 

 t. xxiv.) a t// line for the solid, the laws of these phenomena 

 - can be deduced in a simple way by geometrical construction. 



DIARY OF SOCIETIES. 



THURSDAY, May 27. 

 ^Institution of Electrical Engineers, at 8. 

 FRIDAY, May 28. 

 ■Royal Institution, at 9. — The Isolation of Fluorine : Prof. H. Moissan. 

 'Physical Society, at 5. — The Perception of Difference of Phase by the 

 Two Ears : Dr. A. A. Gray. — The Isothermals of Isopentane : Mr. Rose- 

 Innes. 



SA TURDA F, May 29. 



London Geological Field Class. — Excursion to Sheerness. Drive to 



East Church, Hensbrook. London Clay. Leave Holborn Viaduct, 1.25. 



MONDAY, May 31. 



. Royal Geographical Society, at 8.30.— Nupe and Ilorin (Nigeria): 



Lieut. Seymour Vandeleur. 



TUESDAY, June i. 

 Royal Institution, at 3. — The Heart and its Work : Dr. E. H. Starling. 

 .. Zoological Society, at 8.30.— On the Structure of the Skull in the 

 Paraguayan Lepidosiren : Prof. T. W. Bridge. — On the Classification of 

 the ThyrididiE, a Family of the Lepidoptera Phalaenae : Sir George F. 

 Hampson, Bart. — On a Collection of Lepidoptera obtained at Shoa in 

 1894 by Mr. F. Gillett : Dr. A. G. Butler. 



WEDNESDAY, June 2. 

 \ Entomological Society, at 8. 

 Victoria Institute, at 4.30. — Annual Meeting. — Address by Lord 

 Kelvin. 



THURSDAY, June 3. 



.iRoYAL Society, at 4. — Election of Fellows. At 4.30. — /"wi^aW^ Papers : 



The Sensitiveness of the Retina to Light and Colour : Captain Abney, 



F.R.S.— On the Mechanism by which the First Sound of the Heart is 



..produced: Sir R. Quain, F.R.S. — Mathematical Contributions to the 



"Theory of Evolution. On the Relative Variation and Correlation in 



■iCivilised and Uncivilised Races : Miss Alice Lee and Prof. K. Pearson, 



F.R.S.— An Investigation on the Variability of the Human Skeleton, 



-with especial reference to the Naquada Race, discovered by Prof. Flinders 



Petrie in his Explorations in Egypt : E. Warren. — On the Brains of Two 



Sub-Fossil Malagasy Lemuroids : C. I. Forsyth Major. — (i) On the Di- 



' electric Constants of certain Frozen Electrolytes, at and above the 



Temperature of Liquid Air ; (2) On the Dielectric Constants of Pure Ice, 



Glycerine, Nitrobenzol, and Ethylene Dibromide, at and above the 



Temperature of Liquid Air : Prof. Fleming, F.R.S., and Prof. Dewar, 



F.R.S.— Preliminary Communication on the Nature of the Contagium of 



Rinderpest : A. Edington. 



Linnean Society, at 8.— Observations on Termites : Dr. G. D. Haviland. 



—On the Genus Ramulina : Prof. T. Rupert Jones, F.R.S., and F. 



Chapman. 



Chemical Society, at 8.— On the Thermo-chemistry of Carbohydrate 



Hydrolysis ; On the Thermal Phenomena attending the Change in 



Rotatory Power of Freshly-prepared Solution of certain Carbohydrates, 



with some Remarks on the Cause of Multirotation : Horace J. Brown, 



' F.R.S., and Spencer Pickering, F.R.S.— Optical Inversion of Camphor; 



Derivatives of Camphoric Acid. Part II. Optically Inactive Derivaiives ; 



Racemism and P.seudo-racemism : Dr. F. S. Kipping and W. T. Pope. — 



On some New Gold Salts of the Solanaceous Alkaloids : Dr. H. A. D. 



Jowett. 



FRIDA Y, June 4. 

 Royal Institution, at 9.— Signalling through Space without Wires : W. 



H. Preece, C.B., F.R.S. 

 Geologists' Association, at 8.— The Origin of the High-Level Gravel 



with Triassic Debris adjoining the Valley of the Upper Thames : H. I. 



Osborne White. 



SATURDAY, June 5. 

 Geologists' Association — Excursion to Cheltenham and Stroud. Leave 



Paddington at 10.^2 a.m. 



BOOKS, PAMPHLETS, and SERIALS RECEIVED, 



Books. — A Ride through Western Asia : Clive Bigham (Macmillan). — 

 A Text-Book of Geology : W. J. Harrison, new edition (Blackie).— A 

 Handbook to the Order Lepidoptera : W. F. Kirby. Vol. v. Moths, Part 

 3 (Allen). — Uber Verwachsungsversuche : Prof. G. Born (Leipzig, Engel- 

 mann). — Vear-Book of the Scientific and Learned Societies, 14th annual 

 issue (Griffin).— Catalogue of Tertiary MoUusca in the Department of 

 Geology, British Museum (Natural History) : G. F. Harris, Part i 

 (London). — Catalogue of the Fossil Cephalopoda in the British Museum 

 (Natural History) : Dr. A. H. Foord and G. C. Crick, Part- 3 (London). 

 — The Concise Knowledge Natural History (Hutchinson). — Harrow 

 Butterflies and Moths : J. L. Bonhote and Hon. N. C. Rothschild, Vol. 2 

 (Harrow, Wilbee). — L'Evolution Regressive en Biologic et en Sociologie : 

 J. Demoor, J. Massart, and E. Vandervelde (Paris, Alcan). 



Pamphlets. — Annual Report of the Geological Survey of the United 

 Kingdom : Sir A. Geikie (Eyre). — Vergleichende Studien uber das Seelen- 

 leben der Ameisen und der Hohern Thiere : E. Wasmann (Freiburg in 

 Bresgau, Herder). 



Serials. — Zeitschrift fiir Physikalische Chemie, xxii. Band. 4 Heft 

 (Leipzig, Engelmann). — Geological and Natural History Survey of Minne- 

 sota, 22nd and 23rd Annual Reports (Minneapolis). — Proceedings of the 

 Academy of Natural Sciences of Philadelphia, 1896, Part 3 (Philadelphia.) 

 —Maori Art, Part i (Wellington, N.Z.).— Good Words, June (Isbister).— 

 Sunday Magazine, June (Isbister). — L'Anthropologie, Tome viii. No. 2 

 (Paris, Masson. — Essex Institute Historical Collections, Vol. xxxii. (Salem, 

 Mass.). — Longman's Magazine, June (Longmans). 



CONTENTS. PAGE 



The Collected Papers of Professor Adams 73 



A Cyclopaedia of Biological Theory. By Prof. E. 



Ray Lankester, F.R.S 75 



Comparative Mythology 77 



Our Book Shelf:— 



Archibald : " The Story of the Earth's Atmosphere." — 



W. E. P 78 



Masefield : " Wild Bird Protection and Nesting- Boxes, 



&c."— R. L 78 



" Reports from the Laboratory of the Royal College of 



Physicians, Edinburgh " 78 



Dolbear : " First Principles of Natural Philosophy " . 78 

 Letters to the Editor: — 



Adjustable X-Ray Tubes. {Illustrated.)— Pi.. A. C. 



Swinton 79 



Boomerangs without Twist. — W. F. Sinclair .... 79 



Scorpion carrying Flower. — A. Newnham 79 



The Utility of Specific Characters.— Dr. Samuel 



Wilks, F.R.S 79 



I^uminous Phenomena observed on Mountains. — Prof. 



J. M. Pernter 80 



The Effect of Wind and Atmospheric Pressure on the 



Tides.— F. L. Ortt 80 



Contact Electricity and Electrolysis according to 

 Father Boscovich [With Diagram.) By the Right 



Hon. Lord Kelvin, G.C.V.O., F.R.S 84 



New Observations on the Larva of the Common 

 Eel. [Illustrated.) By Prof. G. B. Grassi and Dr. 



S. Calandruccio 85 



Toronto Meeting of the British Association. II. By 



Prof. A. B. Macallum .85 



Notes 86 



Our Astronomical Column: — 



The Origin of Solar and Stellar Light 89 



The Nebula of Orion 90 



The Parallax of 61^ Cygni 90 



The Royal Society Conversazione 90 



Influence of Rontgen Rays upon Electrical Con- 

 ductivity. By Prof. Villari 91 



The Chemistry of the Hottest Stars. By J. Norman 



Lockyer, C.B., F.R.S 91 



University and Educational Intelligence 92 



Scientific Serials ■ • • 93 



Societies and Academies 93 



Diary of Societies 96 



Books, Pamphlets, and Serials Received 96 



NO. 1439, VOL. 56] 



