June 25, 1891] 



NATURE 



191 



ammonia, it energetically converts nitrites into nitrates ; the 

 presence of ammonia is apparently a great hindrance to its 

 action. An attempt to isolate the organism failed. The nitri- 

 fication performed by soil thus appears to be the work of two 

 organisms, one of which oxidizes ammonia to nitrite, while the 

 olher oxidizes nitrite to nitrate. 



Geological Society, June lo.— Sir Archibald Geikie, F.R.S.- 

 President, in the chair. — Before the commencement of the 

 general business, Prof. Blake rose on behalf of those present 

 .: the meeting to congratulate the President on the honour 

 !iat it had pleased Her Majesty to confer upon him. No 

 ne who knew him could fail to appreciate how thoroughly it 

 u as deserved ; and the Geological Society would doubtless feel 

 \\%o the honour conferred on their science in the person of their 

 President and the head of the Geological Survey of the United 

 Kingdom. — The following communications were read : — Note on 

 some recent excavations in the Wellington College districf,' by 

 the Rev. A. Irving. — Notes on some post-Tertiary mar ne 

 deposits on the south coast of England, by Mr. Alfred Bell. 

 Communicated by Mr. R. Etheridge, F.R.S. The author's 

 object in this paper is to trace the successive stages in the 

 development of the present coast of the north side of the 

 English Channel, and to ascertain the sources of the diversified 

 faunas. The first traces of marine action on the south coast in 

 post-Tertiary times, are found on the foreshore in Brack lesham 

 Bay. The author's reading of the section is somewhat different 

 from that of the late Mr. Godwin- Austen ; and he divides the 

 marine series into (i) an estuarine clay with Mollusca common 

 to estuarine flats ; (2) a compact hard mud ; and (3) a bed of 

 fine sandy silt with many organisms. These beds indicate a 

 change from estuarine to deep-water conditions. A full list of 

 the Selsey fossils is given, including, amongst other animals, 

 upwards of 200 Mollusca. Of 35 species of Mollusca not now 

 living in Britain, the majority exist in Lusitanian, Mediterra- 

 nean, or African waters ; furthermore, nearly 45 per cent, of the 

 Mollusca are common to the older Crags of the eastern counties. 

 The author considers the fauna of the Portland Bill shell-beds to 

 indicate the further openinjj of the Channel subsequent to the 

 formation of the Severn Straits, and believes that this fauna 

 represents the deposits wanting between the Selsey mud-deposits 

 and the erratic blocks which, according to him, overlie the 

 mud ; these Portland shells indicate an intermediate tempera- 

 ture, *• rather southern than northern," according to Dr. Gwyn 

 Jeffreys. In conclusion, details concerning still newer beds are 

 ;;iven, and lists of fossils found therein ; and the author observes 

 that there is no evidence to show when iTie English Channel 

 finally opened up, beyond the suggestion of Mr. Godwin-Austen 

 that, if the Sangatte beds and the Coombe Rock are of the 

 same period, it must have taken place after their formation. 

 After the reading of this paper some remarks were made by Mr. 

 Etheridge, Mr. C. Reid, Prof. Hull, and the author. 



Mathematical Society, June 11.— Prof. Greei\hill, F.R.S., 

 President, in the chair. — The following communications were 

 made : — Systems of spherical harmonics, by E. W. Hobson. — 

 On the motion of a liquid ellipsoid under its own attraction, by 

 Dr. M. J. M. Hill. — On certain properties of symmetric, skew- 

 symmetric, and orthogonal matrices, by Dr. H. Taber. — An 

 application of the method of images to the conduction of 

 heat, by G. H. Bryan.— A property of the circum-circle, by R. 

 Tucker. 



Cambridge. 



Philosophical Society, June i.— Prof. G. H. Darwin, 

 President, in the chair. — The following communications were 

 made :— On the part of the parallactic series of inequalities in 

 the moon's motion which is a function of the ratio of^ the mean 

 motions of the sun and moon, by Mr. Ernest W. Brown. — On 

 Pascal's hexagram, by Mr. H. W. Richmond. The author 

 applies Cremona's method of deriving the hexagram by pro- 

 jection of the lines on a nodal cubic surface from the node. By 

 use of a new form of the equation to this surface the equations 

 of the lines are obtained in a perfectly symmetrical form, and 

 their properties thence developed. — ^A linkage for describing 

 lemniscates and other inverses of conic sections, by Mr. R. S. 

 Cole. — Some experiments on liquid electrodes in vacuum tubes, 

 by Mr. C. Chree. This paper describes some experiments 

 undertaken at the suggestion of Prof. J. J. Thomson on the 

 electric discbarge through vacuum tubes in which one or both of 

 the electrodes were liquid surfaces. The liquids employed were 

 mercury and sulphuric acid. The electrodes when solid were 



NO. I 1 30, VOL. 44] 



of platinum or aluminium. Observations were taken of the- 

 difterences presented by the discharge when the substance of an 

 electrode was altered. The experiments were mostly at low 

 gaseous pressures, and included observations on the character 



of the phosphorescence then accompanying the discharge. On 



gold-tin alloys, by Mr. A. P. Laurie.— Note on a problem in 

 the linear conduction of heat, by Mr. G. H. Bryan. 



Edinburgh. 

 Royal Society, June i.— Prof. Chrystal, Vice-President, in 

 the chair. — Prof. Tait communicated a paper, by Prof. Piazzi 

 Smyth, on two series of enlarged photographs, one in the 

 visible, the other in the invisible, of the violet of the solar 

 spectrum. The paper was accompanied by the photographs. 

 The observations include part of the spectrum as previously ob- 

 served by Mr. Smyth in the summer of 1884, and extend to an 

 extreme distance in the invisible violet. The previous observa- 

 tions were included in sixty plates ; in the present series, twelve 

 more plates are added in the violet region, and two independent 

 photographs of each part have been taken. The photographs 

 agree with those of Prof. Rowland in indicating that the Fraun- 

 hofer line, "little d" is either entirely absent now from the 

 solar spectrum, or has become very unimportant. — Mr. R. Kid- 

 ston read a paper on the fossil plants of the Kilmarnock, Galston, 

 and Kilsyinning coal-field in Ayrshire. All the species which 

 are described in the paper belong, with one exception, to the 

 Lower Coal-measures. — Prof. Tait communicated the second 

 and third parts of a paper, by Prof. C. G. Knott, on some rela- 

 tions between magnetism and twist in iron, nickel, and cobalt. 

 Part II. contains a continuation of former experiments on the 

 twists produced in the magnetic metals when they are under the 

 combined influence of circular and longitudinal magnetizations. 

 A rectangular rod of cobalt twists, like nickel, left-handedly, 

 when a current is passed along it in the direction of magnetiza- 

 tion. Iron twists right-handedly, unless strong fields are em- 

 ployed. There is no reversal of the twist in nickel when strong 

 fields are used, but a maximum can be reached. The magnitude 

 of the twist which is produced by a reversal of one force depends 

 upon which force is reversed. In general, reversal of the longi- 

 tudinal field produces the greater effect ; but iron and nickel, in 

 low fields, twist most when the current is reversed. Hysteresis 

 is very evident in all the phenomena. Evidence is given in this 

 part in confirmation of the truth of an expression, which was 

 given in Part I., for the twist in terms of the elongations in a 

 thin-walled tube of given radius. Part III. contains a discus- 

 sion of the magnetic consequences of twisting a magnetized wire 

 — more especially a circularly-magnetized wire. The peculiar 

 manner in which the magnetic change sometimes lags behind 

 the stress, sometimes shoots ahead of it, is fully investigated. 

 This effect is found to depend upon the strength of the current, 

 on the amount of the twist, and on the amount of vibration to 

 which the wire is subjected. The longitudinal polarity which 

 is acquired when a wire carrying a current is twisted appears 

 to be high in comparison with the intensity induced at the 

 circumference of the wire. This seems to indicate the existence 

 of molecular groupings which alter their configuration when 

 subjected to change of stress or of magnetic force. The effects 

 which are observed when an apparently demagnetized wire is 

 subjected to twist suggest that a magnetized wire may in certain 

 circumstances consist of alternate layers of opposite polarities. 

 Any stress which acts differently on these layers will produce 

 powerful magnetic effects. From his own experiments and 

 those of other observers. Dr. Knott concludes that the first 

 effect of a shearing stress on the molecular groupings is not only 

 to increase the average intensity in the direction of the mag- 

 netizing force, but also to bring into prominence a relatively high 

 intensity in directions at right angles to it. — Dr. Buchan 

 communicated a paper by Mr. R. T. Omond, Superintendent 

 of the Ben Nevis Observatory, and by Mr. A. Rankin, assistant 

 observer, on the winds of Ben Nevis. The exact determination 

 of northerly winds is not very easy, owing to the shape of 

 the hill. The cliff, 2000 feet in height, which forms the 

 northern face, breaks these winds up, and makes them 

 squally and uncertain. Some may be entered on the record 

 as north when they should really have been entered as north-east 

 or north-west. Southern winds are on the whole slightly more 

 frequent than northerly winds are. At sea-level the most 

 frequent wind is west ; and south-west, west, and north-west 

 include nearly half of the total observations — more than half if 

 calms are excluded. These low-level winds are in exact accord- 



