464 



NATURE 



{Sept. 6, 1888 



Brooks's comet made at the Observatory of Algiers with the 

 o'5o m. telescope, by MM. Trepied, Sy, and Renaux. The 

 observations are for the period from August 11 to August 15 in- 

 clusive. On the former date the brilliancy of the nucleus was 

 about equal to that of a star of the tenth magnitude ; diameter of 

 nebulosity about 1', with faint tail in the direction of the diurnal 

 movement.— Observations of Faye's comet made at the Observa- 

 tory of Nice, by M. Perrotin. These observations were made on 

 August 11, 14, and 17. — On some experiments with the marine 

 telephone, by M. A. Banare. These experiments were carried 

 out by order of the Minister of Marine, at Brest, by means of 

 the apparatus to which the author has given the name of 

 "hydrophone." Sounds emitted by various sonorous instru- 

 ments, such as bells, whistles, and trumpets, were distinctly 

 heard, that of a bell weighing 150 kilogrammes at a distance of 

 5200 metres. The experiment, with a ship under way also gave 

 favourable results, and here also the ringing of a bell was clearly 

 detected at a distance of 1400 metres simultaneously with the 

 noise of the engine and screw of the tug. — On the remains 

 and zoological affinities of Testudo pcrpiniana, a gigantic fossil 

 turtle of the Perpignan Pliocene epoch, by M. P. Fischer. This 

 magnificent specimen, discovered by M. A. Donnezan, and de- 

 scribed by M. Ch. Deperet, has recently been acquired by the 

 Palaeontological Department of the Paris Museum. A compara- 

 tive study of the remains (various parts of the carapace) leads to 

 the conclusion that it must have been a gigantic species of a 

 living African group {Testitdo partialis, sulcata). Its affinities 

 with the gigantic turtles at present confined to the Aldabra 

 Islands in the Indian Ocean, and the Galapagos in the Pacific, 

 do not appear to have been established. Its relations with the 

 Chersites of South Europe are also doubtful, so that it may be 

 considered as a Pliocene survival in the south of France of an 

 older land fauna of an African type. Its ancestors may perhaps 

 be found amongst the large turtles discovered by M. Gaudry in 

 the Mount Leberon beds, but which are known only by some 

 fragments of the carapace. — The Secretary announced the death 

 of Herr Rudolf Clausius, Corresponding Member of the Section 

 for Mathematics, who died at Bonn on August 24. 



Berlin. 



Physiological Society, August 3. — Prof, du Bois Reymond, 

 President, in the chair. — Dr. A. Konig gave an account of 

 researches which he had carried out, in conjunction with Dr. 

 Brodhun, for the experimental testing of Fechner's psycho- 

 physical law in its relationship to the sense of sight. In the 

 case of lights whose brightness varied between the limits -j^and 

 200000 of the unit used, it was necessary to measure at six 

 different points of the spectrum — that is to say, for six different 

 kinds of monochromatic light — the minimum change of intensity 

 which could be appreciated as a change at all. The experiments 

 were carried out on the trichromatic eye of the speaker and the 

 dichromatic eye of Dr. Brodhun. The observer sat in a dark 

 chamber, into which the eye end of the observing telescope 

 projected, and was able, by the rotation of a handle, to vary the 

 relative b Tightness of the upper and lower half of the field of 

 vision until the difference was just perceptible. The field of 

 vision was illuminated by a double slit, through which the pure 

 spectral red, orange, yellow, green, blue, or violet light could be 

 admitted. The upper half of the slit was fixed, while the lower 

 half could be widened or narrowed by the observer, and the 

 amount of the alteration in width of the slit observed and 

 recorded by an assistant. The source of light used was a 

 gas-burner with zirconium light. Several thousand separate 

 observations were made, from which it was found that the 

 several colour-systems have no influence on the sensitiveness to 

 differences in brightness of lights ; the values obtained in the 

 case of Dr. Konig's eye were identical with those obtained for 

 Dr. Brodhun's. The shape of the curve which expressed the 

 percentage relationship of the lea c t possible perceptible change 

 in intensity (expressed as an ordinate) to the intensity of the 

 light itself (expressed as an abscissa) was the same for all the 

 above six colours, differing only in the case of lights of minimal 

 intensity. The curve was not a straight line for all intensities 

 of light which were investigated, as it should be according to 

 Fechner's law. In the case of the greatest and least intensities 

 of light it was found that the smallest increase of intensity which 

 was just perceptible was greater than in the case of medium 

 intensities of light. With weak illumination the curve for lights 

 of greater wave-length, such as red, orange, and yellow, was 

 steeper than for lights of shorter wave-length. From this the 



speaker pointed out that the divergence in the curves of sensi- 

 tiveness to varying intensities commences with that intensity at 

 which, according to Purkinje, the subjective sensitiveness to 

 lights of different kinds changes as their intensity is diminished, 

 and in the same way as does the sensitiveness to varying 

 intensities. The speaker concluded with some interesting 

 considerations respecting the zero-point of the curve and the 

 negative parts of the abscissae. — Dr. Uhthoff gave an account of 

 experiments made with a view to determining the amount of 

 change in wave-length of spectral lights which are necessary to 

 produce the least perceptible difference in their colour. The 

 object of the experiments was to subject the results obtained by 

 Drs. Konig and Dieterici to a renewed testing, in answer to 

 objections which had been raised against them. Using the 

 same apparatus, but a different method, he had confirmed their 

 results. He also found, as Pearce had clone in 1883, that the 

 sensitiveness to change of colours is greatest for yellow and blue, 

 and least for red and green. 



BOOKS, PAMPHLETS, and SERIALS RECEIVED. 



Beginner's Guide to Photography. 2nd edition (Perken). — A Bibliography 

 of the Foraminifera from 1565 to 1888 : C. D. Sherborn (Dulau). — Hand 

 buch der Palaeontologie, i. Abtheilung, Pala^ozoologie, iii. Band, 2 Liefg. 

 (Munchen). — Dr. H. G. Bronn's Klassen und Ordnungen des Thier-Reichs, 

 Erster Band. Protozoa, 47, 48, u. 49, Liefg. : Dr. O. Butschli (Leipzig).— A 

 Text-book of Euclid's Elements. Parts 1 and 2, containing Books i.-vi. : 

 H. S. Hall and F. H. Stevens (Macmillan). — Catalogue of the Fossil Rep- 

 tilia and Amphibia in the British Museum (Natural History), Part 1 : R. 

 Lydekker (London). — Forschungsreise S. M.S. Gazelle, iv. Theil, Kotanik 

 Algen: Prof. Dr. E. Askenasy (Berlin). — Journal of the Chemical Society, 

 September (Gurney and Jackson. 



CONTENTS. page 



Geological Nomenclature. By Prof. John W. Judd, 



F.R.S 433 



Letters to the Editor : — 



Lamarckism versus Darwinism. — Edward B. Poul- 



ton 434 



The Zodiacal Light and Meteors.— T. W. Back- 

 house 434 



The Services of Catholic Missionaries in the East 



to Natural Science 434 



The Australasian Association for the Advancement 



of Science 437 



Professor Rudolf Julius Emanuel Clausius. By G. 



W. de Tunzelmann 438 



The British Association 439 



Inaugural Address by Sir Frederick Bramwell, 



D.C.L., F.R.S., M.Inst.C.E., President ... 440 

 Section A. — Mathematical and Physical Science. — 

 Opening Address by Prof. G. F. Fitzgerald, 



M. A., F.R.S. , President of the Section 446 



Section C. — Geology. — Opening Address by W. 

 Boyd Dawkins, M.A., F.R.S., F.G.S., F.S.A., 

 Professor of Geology and Palaeontology in Owens 



College, President of the Section 449 



Notes 45 1 



Astronomical Phenomena for the Week 1888 



September 9-15 454 



Geographical Notes 455 



Notes on Meteorites. II. By J. Norman Lockyer, 



F.R.S 4S 6 



Molecular Physics : an Attempt at a Comprehensive 

 Dynamical Treatment of Physical and Chemical 



Forces. II. By Prof. F. Lindemann t 458 



The Forestry School in Spain 461 



Scientific Serials 462 



Societies and Academies 463 



Books, Pamphlets, and Serials Received . . . . • 4 6 4 



