;S8 



NATURE 



[February 14, 190T 



and a half, it slowly darkens to a nearly normal shade, as the 

 details come out more sharply. If the exposure has been 

 correctly made, there will be no trace of fofj. With stronger 

 baths the picture comes out in the normal time, and has 

 the normal shade. If the pictures are too dense, the 

 remedy is to reduce the strength of the sodium carbonate 

 solution, or to increase the amount of hypo in the bath. 

 Very fine results are obtained with the sodium carbonate 

 solution at half tlie strength given in Cramer's formula. 

 When the plate has been sufficiently exposed, a negative of the 

 object can usually be seen upon the plate before development. 

 With long exposure this image is very distinct. It fades out in 

 the bath, and the plate becomes clear. The shadows appear 

 strongly, but indistinctly at first, and of a pink colour, and the 

 highlights still appear white. The solution remains clear. 

 Too much hypo will cause turbidity and a loss of detail. When 

 the plate is exposed in a printing frame under either a negative 

 or a positive, an exposure of half a minute to diffuse daylight is 

 ample with an ordinary negative. The plate may be over- 

 exposed by placing it for a long time in direct sunlight, and it 

 will then appear on development somewhat like an over-exposed 

 negative. This has not yet been tried with hypo in the bath. 

 Prof. Nipher showed a preliminary diagram, in which exposure 

 and ilhimination of the developing bath were taken as co- 

 ordinates. Tne zero condition was represented by a line, and 

 the conditions for producing direct and inverted pictures were 

 represented by areas. He also exposed and developed, in a 

 common bath, in the lighted audience room, negatives printed 

 from negatives, and positives printed from positives. The pos- 

 sible value of radio-active substances acting upon the developing 

 plate in place of, or in addition to, light, was referred to as a 

 most promising field for study. 



DIARY OF SOCIETIES. 



THURSDA K, Femruarv 14. 



Royal Societv, at 4.30. — Some Additional Notes on the Orientation of 

 Gresk Temples , being the Result of a Journey to Greece and Sicily in 

 April and May, 1900 ; F. C. Penrose, F.R.S. — The Transmission of the 

 Trypanosoma Evansi by Horse Flies, and other Experiments pointing to 

 the Probable Identity of Surra of India and Nagana or Tsetse Fly 

 Disease of Africa: Dr. Leonard Rogers. — On the Influence: of Ozone on 

 the Vitality of some Pathogenic and other Bacteria : Dr. A. Ransome, 

 F.R.S., and A. G. R. Foulerton. — On the Functions of the Bile as a 



Solvent: B. Moore and W. H. Parker. To be read in title only: 



On the Application of the Kinetic Theory of Gases to the Electiic, Mag- 

 netic and Optical Properties of Diatomic Gases: G W. Walker. — 

 Heredity, Differentiation, and other Con ceptions of Biology ; a Con- 

 sideration of Prof. Karl Pearson's paper " On the Principle of Homoty- 

 posis" : W. Bateson, F.R.S. 



Mathematical Society, at 5.30. — The Distribution of Velocity and the 

 Equations of the Stream Lines, Hue to the Motion of an Ellipsoid in 

 Fluid Frictionless and Viscous : T. Stuart. — On Factorisable Twin Bi- 

 nomials : Lieut. -Colonel Cunningham, RE. — Concerning the Abelian 

 and Related Linear Groups: Prof. L. E. Dickson. — A Geometrical 

 Theory of Differential Equations of ihe First and Second Orders: 

 R. W. Hudson. — Brocardal Properties of some Associated Triangles: R. 

 Tucker. — A Note on Stability, with a Hydrodynamical Application : T. 

 J. la. Bromwich. 



Society OF Arts (Indian Section), at 4.30. — The Greek Reireatfrum 

 India : Colonel Sir Thomas H. Holdich, K.C.I.E. 



Institutidn OP ElectkicalEnginkk.ps, ai b.— Capacity in Alternate 

 Current Working : W. M. Mordey. (Adjourned Discussion.) 

 FRIDAY^ February 15. 



RoYAi, Institution, at 9.— Electric Waves : Right Rev. Monsignor 

 Gerald Molloy. 



Geological Society, at 3. — Annual General Meeting. 



Institution of Mechanical Engineers, at 8.— Light Lathes and 

 Screw Machines : J. Ashford. 



Epidemiological Society, at 8.30 — The Epidemiological Aspects of 

 Isolation Hospitals : Dr. Arthur Newsholme. 



MONDA y, February 18. 



Royal Institution, at 3,— Origin of Vertebrate Animals : Dr. Arthur 

 Willey. 



SociErY of Arts, at 8.— The Bearings of Geometry on the Chemistry 

 of Fermentation : W.J. Pope. 



Sjcieiy of Chemical Industry, at 8. — Discussion on the Occurrence 

 and Detection of Arsenic in Manufactured Products. 



Victoria Institute, at 4.30.— The Wahabies : S. M. Zwemer. 

 TUESDAY, Fkbruary 19. 



Royal Institution, at 3.— Practical AKchanics : Prof. J. A. Ewing, 

 F.R.S. 



Zoological Society, at 8.30. 



Institution of Civil Engineers, at 8.— The Nilgiri Mountain-Rail- 

 way : W. f. Weightman. 



Royal Statistical Society (St. Martin's Town Hall, W.C), at .s-so.— 

 The Growth of Municipal and National Expenditure : The Riglit Hon. 

 Lord Avebury, F.R.S. 



Royal Photographic Society, at 8.— Imitative 7w.r/« Creative— a 

 Comparison : W. Edwin '1 indall. 



WEDNESDA V, February 20. 



Society of Arts, at 8.— Some Features of Railway Travelling, Pjst and 

 Present : Frederick McDermott. 



Geological Society, at 8. — Submerged Valleys oppo.site the Mouth of 

 the River Congo and of Western Europe : Prof. E. Hull, F.R.S.— The 

 Geological Succession of the Beds below the Millstone Grit Series of 

 Pendle Hill and their Equivalents in other Districts in England : Dr. 

 Wheelton Hind and J. Allen Howe. 



Royal Meteorological Society, at 7.30. — Report on the Phenological 

 Ob-ervations for 1900 : E. Mawley. — A Review of Past Severe Winters 

 in England, with Deductions therefrom : Albert E. Watson. 



Royal Microscopical Society, »at 7.30. — Exhibition of Bacteria and 

 Blood Parasites : C. Beck. 



TfiURSDAY, February 21. 



Royal Society, at 4.30. 



Linnean Society, at 8. — On the Affinities of ^linopus melanoleucus, 

 Alph. Milne-Edw. : Prof. E. Ray Lankester, F.R.S., and R. Lydekker, 

 F.R.S. — Etude d'une espece nouvelle de Lipapedes : M. A. Gruvel. 



Institution OF Electrical Engineers, at 8. — If the discussion on Mr. 

 Mordey's paper is closed, the following paper will be read :— The Elec- 

 trical Power Bill of 1900 : Before and After : W. L. Madgen. 



Chemical Society, at %.—{i) Isomeric Hydrindamine Mandelates and 

 Phenylchloracethydrindamides ; (2) Isomeric Benzylhydrindamine bromo- 

 camphorsulphonates and some Salts of (/-/-Hydrindamine : F. Stanley 

 Kipping and H. Hall. — Condensation of Phenols with Esters of the 

 Acetylene Series. IV. Benzo-y-pyrone and its Homologues : S. Ruhe- 

 mann and H. W. Bausor. — Constitution of Bromocamphoric Anhydride 

 and Camphanic Acid : A. Lapworth and W. H. Lenton — The Action of 

 Acetylchlor- and Acetylbrom-aminobenzenes on Amines and Phenyl 

 hydrazine : F. D. Chattaway and K. J. P. Orton. 



FRIDA V, February 22. 



Royal Institution, at 9. — Metals as Fuel : Sir W. Roberts-Austen, 

 F.R.S. 



Physical Society, at 5. — How Air subjected to X-Rays los;s its Dis- 

 charging Property, and how it Discharges Electricity : Prof. Emilio 

 Villari. — (i) On the Propagation of Cusped Waves and their Relation to 

 the Primary and Secondary Focal Lines; (2) On Cyanine Prisms, and a 

 New Method of Exhibiting Anomalous Dispersion : Prof. R. W. Wood. 



Institution of Civil Engineers, at 8. — Automatic Coupling: J. L. 

 Cridlan. 



SATURDAY, February 23. 



Royal Institution, at 3. — Sound and Vibrations : Lord Rayleigh, F.R.S. 



Essex Field Club (Essex Museum of Natural History Stratford), at 6 30. 

 — Recent Work in Molluscan Morphology: Prof. G. B. Howes, F.R.S. 



AO. 1633. VOL. 63] 



CONTENTS. PAGE 



Darwinism and Lamarckism, Old and New. By 



E. B. P 365 



The Rational Teaching of Mathematics. By 



Prof. John Perry, F.R.S 367 



Human Origins 368 



Our Book Shelf:— 



' ' Atti 'della Fondazione scientifica Cagnola " . . . . 369 

 Sellers: "An Elementary Treatise on Qualitative 



Chemical Analysis." — ^J. B. C 369 



Levy: " Microbes et Distillerie." — A. J. B 370 



"The Filth Report upon the Fauna of Liverpool 



Bay and the Neighbouring Seas " 370 



" Analytical Tables for Complex Inorganic Mixtures " 370 

 Letters to the Editor:— 



Mathematics and Physics in Public Schools. — G. H.J. 



Hurst 370 



The Use of Mosquito Curtains as Protection against 



Malaria.— D. E. Hutchins 371 



Audibility of the Sound of Firing on February i. — 



H. D. G 372 



Sensational Newspaper Reports as to Physiological 



Action of Common Salt.— Prof. Jacques Loeb . 372 

 The Publication of Books without Dates.— Prof. O. 



Henrici, F.R.S 372 



Optical Illusion.— W. Larden 372 



Some Animals Exterminated during the Nineteenth 



Century. — Dr. Henry de Varigny ; R. L. . . . 372 

 The Preservation of Photographic Records. By 



Chapman Jones 373 



A Lancashire College. (Illustrated.) By R. T. G. . 374 



Lord Lilford's Life. {Illustrated.) By R. L. ... 376 



Prof. J. G. Agardh. By E. S. B 377 



Prof Elisha Gray 378 



The Indian Engineering College, Coopers Hill . . 378 



Notes. [Illustrated.) 380 



Our Astronomical Column : — 



Variability of Eros 383 



Catalogue of Principal Stars in Coma Berenices 



Cluster 383 



United States Naval Observatory 383 



Double Star Measures . . 383 



Science at Sheffield University College 383 



University and Educational intelligence 385 



Societies and Academies 386 



Diary of Societies 388 



