464 



NA TURE 



[September 6, 1900 



SOCIETIES AND ACADEMIES. 

 Paris. 



Academy of Sciences, August 27. — M. Faye in the chair. 

 — On Egyptian gold, by M. Berthelot. Analyses of specimens 

 of gold of different epochs show that at the time of the sixth 

 and twelfth Egyptian dynasties the art of separating the silver 

 from native gold was not known. Some gol4 leaf of the 

 Persian epoch was pure, the silver having been separated. As, 

 however, there is a period of about twelve centuries between the 

 dates of the last two specimens analysed, specimens of inter- 

 mediate dates must be examined if the date of this metallurgical 

 discovery is to be fixed. — Observations of the comet 1900 b 

 (Borelly-Brooks) made with the large equatorial of the Observa- 

 tory of Bordeaux, by MM. G. Rayet and A. Ferand. The 

 nucleus of the comet on July 31 was of about the 9th or loth 

 magnitude, the head having a diameter of 3' to 4' of 

 arc. — The apparent semi-diameter of the sun and its posi- 

 tion relative to the moon, deduced from the eclipse 

 of May 28, by MM. Ch. Andre and Ph. Lagrula. The final 

 lesult for the apparent semi-diameter of the sun is given as 

 15' 59"'24 + o""30. — On an anomaly of the dichotomous phase 

 of the planet Venus, by M. E. Antoniadi. The edge of the 

 planet is always more brilliant than the central regions ; thence 

 irradiation ought to produce the prolongations actually observed. 

 The phenomenon would thus appear to be of purely physio- 

 logical origin. — Dielectric cohesion and explosive fields, by M. 

 E. Bouty. The term explosive field is applied to the mini- 

 mum strength of field between two nearly plane electrodes 

 required to produce sparking. The curves relating to critical 

 fields, as described in a preceding note, show many analogies 

 with those of explosive fields. Thus both the critical and 

 explosive fields are linear functions of the pressure of the gas, 

 and the constants for the gases hydrogen, air and carbonic 

 acid are arranged in the same order of magnitude. — On 

 the comp isition of the combinations obtained with fuchsine 

 and the sulphonated azo-colouring matters, by M. Seyewetz. — 

 — On ligiiting by the cold physiological light called living light, 

 by M. Raphael Dubois. By the growth of certain micro- 

 organisms in suitable media, details of which are given, a room 

 may be illuminated with an intensity about equal to moonlight. 

 -^Action of the total pressure upon the assimilation by chloro- 

 phyll, by M. Jean Friedel. Although the influence of the 

 partial pressure of the carbon dioxide in the atmosphere upon 

 chlorophyll assimilation has been well investigated, the effect of 

 changing the total pressure of the air has not yet been examined. 

 It was found that the lowering of the total pressure, even to 

 \ atmosphere, does not modify the nature of the chlorophyll 

 assimilation, but that its intensity diminishes in a regular manner 

 with the pressure. Four species of plants were used, and the 

 numbers obtained for the variations were of the same order in 

 all of them. — ^On the ancient extent of the glaciers in the region 

 discovered by the Belgian Antarctic Expedition, by M. Henryk 

 Arctowski. 



Cape Town. 



South African Philosophical Society, August i. — L. 

 Peringuey, President, in the chair. — The secretary read a 

 second report on the mud island which appeared off Pelican 

 Point at the beginning of June, from Mr. Cleverly, R.M., 

 Walfish Bay, and showed the photographs taken by Mr. 

 Waldron, Public Works Department. Mr. Cleverly reported 

 that the island no longer existed on June 7, it having then entirely 

 subsided, as, on steaming over the site, soundings of six and 

 seven fathoms were obtained. The sea was much discoloured, 

 and a distinct odour of sulphur was still to be distinguished. 

 Small quantities of dead fish were found on Pelican Point, but 

 this is a not unusual occurrence. About the time of the island's 

 appearance heavy rollers set in along the coast, and though these 

 did not affect Walfish Bay, thirty yards of the new breakwater 

 at Swakop Mouth were totally destroyed, a derrick carried 

 away, and two men drowned. Though these rollers are usually 

 experienced on this coast in the winter months, Mr. Cleverly 

 understands that the engineer in charge at Swakop Mouth had 

 set up a theory that the damage to his works resulted from an 

 earthquake wave, and that he pointed to the appearance of the 

 mud island at Walfish Bay in support of his theory, but in Mr. 

 Cleverly's opinion the cause of the upheaval must have been 

 extremely local as no disturbance whatsoever was felt at the 

 settlement or in the confined waters of Walfish Bay. Mr. 

 Waldron, on the invitation of the president, gave an account of 



his visits to the island. It was visited on Tune i, 2 and 4. At 

 the next visit, on June 7, there was no island. On June i one 

 member of the party landed and noticed a small basin-shaped : 

 hollovv containing water and emitting gas bubbles. The odnur- 

 was distinctly that of sulphuretted hydrogen. Dr. Corstophine- 

 agreed with Dr. Marloth as to there being no need for volcanic 

 activity to explain the phenomenon ; nor was there any evidence 

 of such. He compared the appearance of the island at Walfish 

 Bay with the "mud lumps" known to arise in the Gulf of 

 Mexico, and quoted Sir Charles Lyell's account of these. The 

 Walfish Bay island was evidently a quite similar phenomenon. 

 As to the gas, the Gulf of Mexico " mud lumps " usually gave 

 off marsh-gas, and the sulphuretted hydrogen perceived as being 

 emitted at Walfish Bay, was probably due to ihe decomposition 

 of animal as against plant material. The fine mud from 

 Walfish Bay, under the microscope, was found to contain 

 diatoms, fish scales, bones, and other remnants of animal 

 matter. — Notes on stone implements of palEcolithic type 

 found at Stellenbosch and the vicinity, by L. Peringuey and 

 G. S. Corstophine. The discovery of stone implements of 

 a particularly ancient type at Bosman's Crossing, Paarl and 

 Malmesbury, was described. From the rude character of the 

 chipped stones, Mr. Peringuey was disposed to regard them as 

 being equal in age to the palaeolithic implements of Europe, but 

 Dr. Corstophine had shown him the difficulty of accepting this 

 theory owing to the geological deposits in or on which the 

 stones are found. So far no implements have been found in any 

 deposit that can be regarded as of great antiquity. In the 

 Stellenbosch district the implements are found imbedded either 

 in the rain-wash of weathered granite or in the laterite, or 

 simply on the surface, so that no geological evidence has yet 

 been discovered as to the presumable antiquity of the 

 implements. One feature of this occurrence, which Dr. 

 Corstophine pointed out, is that as yet no implements have 

 been found on the recent alluvial terraces of the Eerste River, 

 but only on the hill slopes round about. The implements are 

 formed from water.worn boulders of Table Mountain Sandstone, 

 and often retain a considerable portion of the water-worn 

 surface. 



CONTENTS. PAGE 



A New Departure in the Teaching of Zoology . . 433 



Colour Photography. By C. J 434 



Our Book Shelf:— 



Schoeler : " Probleme Kritische Studien iiber den 



Monismus."— H. W. B 435 



Denny: "Diamond Drilling for Gold and other 



Minerals."— B. H. B. . 435 



"Symons's British Rainfall, 1899 " 435 



Letters to the Editor: — 



Railways and Moving Platforms. — Lieut.-Colonel 



W. Sedgwick 436 



The Migration of Swifts — William Andrews . . . 436 

 The Reform of Mathematical Teaching. — Henry 



■ Woollen 436 



The Trembling of the Aspen Leaf.— Henry J. 



Colbourn . . . 436 



Electricity direct from Coal.— E. F. Bamber ... 437 

 Artificial Deformations of Heads, and some Customs 



connected with Polyandry. — Kumagusu Minakata 437 

 Huxley and his Work.— F. W. Henkel .... 437 

 The Causes of Fracture of Steel Rails. (Ilhcsirated.) 437 

 The Bradford Meeting of the British Association. 



By Ramsden Bacchus 439 



Inaugural Address by Prof. Sir William Turner, 



F. K.S., President of the Association .... . 440 

 Section A. — Mathematics and Physics. — Opening 

 Address by Dr. Joseph Larmor, F.R.S., Presi- 

 dent of the Section 449 



Notes 456 



Our Astronomical Column:— 



Ephemeris for Observations of Eros 459 



Comet Swift C1894 IV) 459 



The New Spectrographs for the Potsdam Great 



Refractor 459 



Structure and Constitution of Two New Meteorites . 459 

 Latitude-Variation, Earth-Magnetism and Solar 

 Activity {With Diagrams.) By Dr. J. Halm . . . 460 



University and Educational Intelligence 463 



Societies and Academies 464 



NO. 16 ID, VOL. 62] 



