July 29, 1922] 



NATURE 



167 



Societies and Academies. 



London. 

 Geological Society, June 28. — Prof. A. C. Seward, 

 president, in the chair. — C. E. Tilley : The petrology 

 of the metamorphosed rocks of the Start Area (South 

 Devon). The rocks of the Start area comprise a group 

 of mica- and quartz-mica-schists, together with a great 

 development of green schists of basic composition. 

 They can be divided into lower mica- and quartz-mica- 

 schists, green schists, and an upper group of mica- 

 and quartz-mica-schists. The field relations of these 

 rocks show that the dominant feature of the area 

 is an anticlinorium with an axis plunging westwards. 

 The rocks are sharply differentiated from the slates 

 and phyllites of Devonian age in the Kingsbridge 

 area immediately to the north ; the two areas are 

 probably separated by an important boundary of 

 dislocation. The aluminous sediments are typically 

 quartz-muscovite-chlorite types, the grade of meta- 

 morphism corresponding to the formation of biotite 

 not being reached. In the composite type of sedi- 

 ment, where tufaceous material is included, the highest 

 stage of metamorphism is reached in the muscovite- 

 chlorite-garnet-albite-schists. The garnet is rich in 

 the spessartine molecule, and the reversal of the 

 normal biotite-garnet order in an increasing grade 

 of metamorphism is ascribed to the presence of 

 manganese. — A. R. Dwerryhouse : The glaciation 

 of the counties of Antrim, Down, and parts of 

 Armagh, Londonderry, Tyrone, Monaghan, and Louth 

 in Ireland. The deposits consist of boulder-clay, 

 gravel, and sand, and are divided into two groups 

 according to their direction of transport : those 

 derived from the north-east and carried by a glacier 

 which flowed by way of the Firth of Clyde from Scot- 

 land ; and those the source of which lay to the west, 

 carried by an Irish ice-sheet having its origin in 

 Donegal. The former are characterised by the 

 riebeckite-bearing rock of Ailsa Crag with granites, 

 quartz-porphvry, and pitchstone from Arran ; the 



1 latter contain boulders of igneous rocks from County 

 Tyrone. Delta-terraces and overflow-channels show 

 that ice-dammed lakes existed in the district. 

 Moraines occur, the most conspicuous being those 

 near Armoy in Antrim and near Garvagh in London- 

 derry. The earlier glaciation was effected by the ice 

 from Scotland, which reached south-west to the town 

 of Monaghan and the eastern flank of Slieve Beagh. 

 The Scottish ice was then gradually replaced by that 



' from Donegal. The latest phase of the glaciation 

 was a second advance of the Scottish ice, which 

 formed definite frontal moraines in the neighbourhood 



I of Ballymoney and Armoy, and the establishment of 

 a small local centre of glaciation in the neighbour- 

 hood of Trostan, the highest mountain in County 

 Antrim. Glaciation was probably continuous. 



Dublin. 

 Royal Dublin Society, June 27. — Dr. J. A. Scott 

 in the chair. — H. H. Jeffcott : The electrical design 

 of A.C. high tension transmission lines. A method 

 is given for calculating the performance of high 

 tension transmission lines, based on direct evaluation 

 I by complex quantities. The process can be system- 

 atised into an arithmetical routine. Examples of 

 its application to specific problems are given. — 

 T. Dillon, Rosalind Clarke, and V. M. Hinchy : 

 Preliminary experiments on a chemical method of 

 separating the isotopes of lead. Lead chloride con- 

 taining thorite lead was treated with magnesium 

 ethiodide and the resulting lead tetraethyl and 

 metallic lead were re-converted into lead chloride. 

 This material was treated with magnesium ethiodide 

 and comparative atomic weight determinations of 



the lead from the two fractions of lead chloride 

 obtained showed a difference of atomic weight of 

 0-2 to 0'3. — T. Johnson and J. G. Gilmore : (1) The 

 lignite of Washing Bay, Co. Tyrone. Lignite was 

 found at various depths, but especially at 1000 ft., 

 in the Washing Bay core. It is all coniferous in 

 nature and is referred to Sequoia Couttsiae, Heer, 

 of which cones, seeds and foliage have been previously 

 described from the same beds. The Lough Neagh 

 lignite originally described by Unger as Pence Pritch- 

 ardi may prove to be a Sequoia also. (2) Libocedrus 

 and its cone in the Irish Tertiary. A foliage impres- 

 sion of Libocedrus salicornioides showing character- 

 istic stomata and epidermal papillas is described. 

 The specimen was found at a depth of 904 ft. in the 

 clay core of the coal-bore at Washing Bay, Lough 

 Neagh. The foliage shoots and cones of the same 

 species from the interbasaltic beds of Ballypalady, 

 Co. Antrim, are also described, the specimens being 

 preserved in the Belfast Museum. Restorations of 

 the wood show agreement between the Irish material 

 and that from Leoben in Styria and with recent 

 Libocedrus, of which L. decurrens (California) and L. 

 chilensis are the nearest living representatives. 

 Paris. 

 Academy of Sciences, June 26. — M. Emile Bertin 

 in the chair. — P. A. Dangeard : Researches on the 

 structure of the cell in the iris. In an earlier com- 

 munication the author has suggested that the term 

 chondriome really comprises three different types 

 of elements named vacuome, plastidome and 

 spherome. This is confirmed by a study of the 

 leaf of Iris germanica. The structure is best observed 

 on unstained specimens. Fixing and staining 

 methods are liable to cause distortion, and have, in 

 the author's opinion, led to erroneous interpretations 

 of the cell structure in the past. — J. Costantin : 

 Acquired heredity. The wild potato is a mountain 

 species, growing in the Andes up to 4000 metres, 

 and the formation of tubercles is caused by a fungus. 

 In the absence of this fungus, the hereditary characters 

 can be maintained intact only if the plant is main- 

 tained under the climatic conditions which it requires. 

 Thus the variety "Up to date " degenerates in 

 Algeria, but has been maintained without change 

 for twenty-five years in Scotland. — Pierre and Louis 

 Bazy : Vaccination before operation. Preventive 

 auto-vaccination is suggested as preferable, except 

 in cases requiring immediate operation, to preventive 

 serotherapy. — Maurice d'Ocagne: Transparent nomo- 

 grams. — A. Rateau : Calculation of the variations 

 of the level of an aeroplane due to a variation 

 of its weight or to the use of a turbo-compressor. — 

 Henri Jumelle : The group of Chrysalidocarpus 

 lutescens. — M. Ame Pictet was elected correspondant 

 for the section of chemistry in the place of the 

 late Prof. Ph. A. Guye. — H. Mineur : Certain 

 functional algebraical equations. — Torsten Carleman : 

 The problem of moments. — Paul Levy : The law of 

 Gauss. Correction of an error in an earlier note 

 (March 27). — W. Margoulis : Transparent abacus 

 with orientation. — Gaston Bertrand : The law of 

 Riemann, the perihelion of Mercury, and the devia- 

 tion of light. Measurements of high precision are 

 necessary to decide between the formula; of Einstein 

 and Riemann. — Charles Nordmann and Le Morvan : 

 Observations of stars of the N type and especially 

 of a star with a very low effective temperature, by 

 means of the heterochrome photometer of the 

 University (Paris). One of the three stars examined 

 (112, 559, Henry Draper Memorial Catalogue) has 

 an effective temperature of 2160° absolute (1887° C), 

 the lowest temperature of any star measured. — N. 

 Yasilesco Karpen : A new evaluation of the internal 



NO. 



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