288 



NATURE 



\yan. 19, I 



twenty-eight Pegwell Bay species, ten are cojamon to the 

 Lower Landenian, and five to the Bracheux Sands, which 

 present a marked analogy with the Woolwich series. These 

 Sands of Bracheux are replaced in the neighbourhood of Paris 

 by red and mottled clays. Out of forty-five species at Beauvais, 

 only six are common to the Thanet Sands, and ten to the 

 Woolwich series. Out of seventy-five species in the Woolwich 

 and Reading Beds, nineteen occur in the Bracheux Beds, if 

 we add to these latter the sands of Chalon-sur-Vesles. 

 Respecting the Basement Bed of the London Clay (Oldhaven 

 Beds in part), the author would exclude the Sundridge and 

 Charlton fossils, which should be placed on a level with the 

 Upper Marine Beds of Woolwich. He allowed that the former 

 were deposited on an eroded surface, but this involves no real 

 imconformity, whilst the palasontological evidence is in favour 

 of this view, since, out of fifty-seven species in the Sundridge 

 and associated beds, only sixteen are common to the London 

 Clay. He therefore objected to the quadruple division. Either 

 the Oldhaven should go with the Woolwich or with the 

 Basement Bed. He admitted that the term " Basement Bed" 

 is objectionable, and preferred Mr. Whitaker's term for the 

 series, as he would limit it. The Lower Bagshot Sands the 

 author would call "London Sands," whose Belgian equivalent 

 is the Upper Ypresian, and the French the Sands of Cuise-de la- 

 Motte, forming the uppermost series of the Lower Eocene. A 

 group of fossils has been discovered in the Upper Ypresian 

 sands of Belgium, which leaves no doubt of their being of Lower 

 Eocene age, and consequently the Lower Bagshots must t)e 

 placed upon the same horizon. There is no separating line of 

 erosion between the Lohdon Clay and the Lower Bagshots, the 

 upper part of the former is sandy, and the lower part of the latter 

 frequently argillaceous. Similarly no definite line can be drawn 

 between the Upper and Lower Ypresian ; but in both countries 

 this series is separated from overlying beds by a well-marked 

 line of erosion. So also in France the base of the Calcaire 

 Grossier (Bracklesham Beds) is a pebbly greensand resting on i 

 an eroded surface of the Sands of the Cuise-de-la-Motte. In 

 Belgium, in Whitecliff Bay, and in the Bagshot district the 

 Upper Eocene rests upon an eroded surface of the Lower 

 Eocene. The reading of this paper was followed by a discussion 

 in which the President, Mr. Whitaker, Dr. Evans, Dr. Geikie, 

 and others took part. — On the Cambrian and associated rocks 

 in North- West Caernarvonshire, by Prof. J. F. Blake. 



PARIS. 



Academy of Sciences, January 9. — M. Janssen, President, 

 in the chair. — Remarks on M. Cornu's last note regarding the 

 synchronizing of time-pieces, by M. C. Wolf, The author points 

 out that M. Cornu has misunderstood the language of the English 

 physicist, Mr. Everett, whose theory is shown to be perfectly 

 applicable to the Verite method of synchronization. The 

 efficiency of this system has received a remarkable confirmation 

 from the circumstances attending an accident by which the 

 synchronizing apparatus was recently put out of order in the 

 city of Paris. — Researches on ruthenium, by MM. H. Debray 

 and A. Joly. In continuation of previous studies of this rare 

 metal, the authors here deal with its oxidation and the dissocia- 

 tion of its bioxide. From these researches it appears that 

 hyperruthenic acid must now be added to the list of compounds 

 which are easily destroyed by heat, although obtained at such 

 high temperatures' that their existence was long considered pro- 

 blematical. Their formation at these temperatures is analogous 

 to the dissociation of bodies that were supposed to be incapable 

 of decomposition before H. Sainte-Claire's discovery. — Re- 

 searches on the breath of man and other mammals, by MM. 

 Brown- Sequard and d'Arsonval, These researches make it 

 evident that the air exhaled by mammals, even in a healthy state, 

 contains a very powerful toxic element, to which should probably 

 if not certainly be attributed the bad effects caused by breathing 

 a close atmosphere. — Variation of temperature of a condensed 

 or expanded vapour while preserving the same quantity of heat, 

 by M. Ch. Antoine. An easy method is given for calculating the 

 final tension that results from the variation of a given temperature, 

 and the final temperature that results from a given degree of 

 condensation or expansion.' — On the influence of temperature on 

 the magnetic state of iron, by M. P. Ledeboer. Although it 

 has long been known that a magnet raised to a red heat loses its 

 magnetic properties, no successful attempt had hitherto been 

 made to determine by direct measurement the actual degree of 

 temperature at which iron ceases to be a magnetic body. The 

 experiments here described now show that iron remains magnetic 



up to 650° C. , after which a rapid variation is observed in its 

 magnetic condition. At 750° the magnetic properties are scarcely 

 perceptible, and at 770° they disappear altogether, returning in 

 the same way as the metal cools down. This presents a remark- 

 able analogy to the conclusions of !M. Pionchon, who, in his 

 recent paper on the specific heat of iron at high temperatures, 

 has shown that this metal undergoes a sudden change of state 

 between 660° and 720°. — On the present value of the magnetic 

 elements at the Observatory of the Pare Saint-Maur, by M. Th. 

 Moureaux. The absolute values, as deduced from the mean of 

 horary observations recorded by the magnetograph are as fol- 

 low : declination, 15° 52''!; inclination, 65° 14''7 ; horizontal 

 component, o ' 19480 ; vertical, 0"42245 ; total force, 0'4652O; 

 longitude of the Observatory, 0° 9' 23" E. of Paris ; N. lat., 

 48° 48' 34". — On the employment of sulphureted hydrogen for 

 purifying the salts of cobalt and nickel, by M. H. Baubigny. 

 The experiments here described clearly show that from a mix- 

 ture of the salts of these two metals it is impossible to obtain a 

 pure sulphuret either of nickel or of cobalt by the action of sul- 

 phureted hydrogen. Dellfs' statements regarding the action of 

 hydrogen on the salts of the heavy metals are thits shown to be 

 groundless.' — On a new method of quantitative analysis for the 

 nitrites, by M. A. Vivier. This method consists in using the 

 reaction discovered by Millon for the analysis of urea, but with 

 absorption of carbonic acid and measurement of the nitrogen 

 liberated in the process. 



BOOKS, PAMPHLETS, and SERIALS RECEIVED. 



A Treatise on Algebra : Charles Smith (Macmillan). — The Nervous 

 System and the Mind : C. Mercier (Macmillan). — Reports on the Mining 

 Industries of New Zealand, 1887 (Wellington). — The lithic of Freethought : 

 K. Pearson (Unwin). — Year-book of Pharmacy, 1887 (Churchill). — An Ele- 

 mentary Text-book of Physiology : J. M'Gregor Robertson (Blackie). — 

 Bergens Museums Aarsberetning for 1886 (Griegs, Bergen). — Zoological 

 Record, vol. 23, 1886 (Gurney and Jackson). — A Course of Lectures on 

 Electricity : G. Forbes (Longmans). — Report on Indian Fibres and Fibrous 

 Substances (Spon). 



CONTENTS. PAGE 



The Teaching of Elementary Chemistry 265 



Chinese Civilization 26S 



The Method of Creation 270 



Our Book Shelf :— 



Langley and Phillips :" The Harpur Euclid " . . . 271 

 Hartley : "A Course of Quantitative Analysis for 



Students" 271 



Letters to the Editor : — 



" A Conspiracy of Silence." — Prof. John W. Judd, 



F.R.S 272 



On the Constant P in Observations of Terrestrial 

 Magnetism. — Prof. Wm. Harkness ; Prof. 



Arthur W. Rucker, F.R.S 272 



The Mist-Bow.— Albert Bonus; Thomas Kay; 



C. O. Budd 273 



Atmospheric Effects at Sunset. — Charles Croft . . f 273 



Newton's " Principia." — Prof. A. Stoletow . . . 273 



Meteors. — W. F. Denning ; Prof, Charles Carpmael 273 



The Electrification of the Air. — C. Michie Smith . 274 



Wind Force at Sea. — Capt. David Wilson- Barker 274 

 A Troublesome Parasite of a Brittle-Starfish. — ^J. 



Walter Fewkes 274 



Raised Beaches versus High-Level Beaches. — A. R. 



Hunt 275 



Vegetation and Moonlight.— D. E. Hutchins ... 275 



Centre of Water Pressure. — George M. Minchin . 275 



A New Magnetic Survey of France. — T. M 275 



Timber, and some of its Diseases. V. {Illustrated.') 



By Prof. H. Marshall Ward 275 



Science in Elementary Schools 279 



Notes 282 



Our Astronomical Column : — 



The Mauritius Observatory 284 



Occultations of Stars by Planets 284 



Olbers' Comet 285 



Astronomical Phenomena for the Week 1888 



January 22-28 285 



Geographical Notes 285 



The Total Eclipse of the Moon, January 28 ... . 286 



University and Educational Intelligence 287 



Societies and Academies 287 



Books, Pamphlets, and Serials Received 288 



