Aprjl 15, 1916] 



NATURE 



155 



unusual type of wing from the Northumberland Coal- 

 field is very suggestive of the Protodonata, and is 

 described as a representative of a new genus and 

 I species. 



Aristotelian Society, March 8. — Dr. H. Wildon Carr, 

 ' president, in the chair. — T. Percy Nunn : Sense data 

 and the physical object. A criticism of the view that 

 physical objects are revealed in perception as exist- 

 ences of which we have immediate knowledge that 

 they are the "sources " of our sense data. The author 

 contended that the "source" is not in truth an 

 "existence" beyond. the sense data, but includes the 

 whole collection of such sense data as can be directly 

 ; apprehended bv perceiving subjects under different con- 

 ditions. Nothing is gained in simplicity and natural- 

 ness by invoking admittedly hypothetical " sources " 

 in order to say about them something formally iden- 

 tical with what must in any case be said about indubit- 

 able sense data. For instance, the assumption of a 

 "source" in order to explain why we attribute real 

 shape to an object creates more embarrassment than 

 I it removes, for, while it miay account for the sense 

 : data which resembled the " source " in shape, it 

 •affords no help in accounting for those that do not. 

 iThe contention that sense data carry- with them a 

 '- rence to a " source," or always indicate a reality 

 >nd themselves, breaks down when the attempt 

 nade to deal with the problem of hallucination and 

 r. The physical theory of matter does not necessi- 

 L tic the assumption of a "source"; for the mole- 

 [cules (and atoms) of matter are simply the molar 

 j bodies of everyday experience conceptually reduced in 

 I size. Whatever belongs to the latter may belong to the 

 former also. 



Edinburgh. 

 Royal Society, March 6. — Dr. J. Home, president, 

 in the chair.- — Prof. F. O. Bower : Leaf architecture 

 as illuminated by a study of the Pteridophyta. A 

 knowledge of leaf architecture may be gained (i) by 

 a comparative study of adult leaves in a large number 

 of different types; (2) by a study of the juvenile leaves 

 and of their development towards the adult form ; (3) 

 by a further comparison with the fossil record. The 

 jfirst of these avenues has had priority, especially in 

 relation to the higher flowering plants, leading unfor- 

 tunately to an interpretation of the lower in terms 

 of the higher. A careful study of the juvenile leaves 

 of the Pteridophyta show that all the varied forms 

 of leaf can be explained as a modification through 

 growth of an original simple dichotomy. The dicho- 

 tomy in juvenile leaves may be equal or unequal. 

 In the latter case the system is commonly developed 

 sympodially, and all gradations may be observed. 

 This is well illustrated in Pteridium and Osmunda. 

 The order of ontogenetic development is normally 

 from equal dichotomy to sympodial dichotomy, and 

 when the development of the leaf is strong there may 

 bs transition to monopodial branching. In higher 

 v'ascular plants, after the arrest of apical growth, the 

 most prominent factor is intercalary growth. This is 

 effective in producing the petiole. A numBer of com- 

 3arisons were instituted which indicated, as a general 

 Statement for vascular plants, that their leaf archi- 

 recture is throughout referable to modifications of a 

 branch system originating phvleticallv in a simple 

 t-af subject to dichotomy. 



Paris. 

 Academy of Sciences, March 27.— M. Ed. Perrier in 

 [jhe chair. — The president announced the death of Leon 

 Labb^, free member of the academy, at the age of 

 Mghty-four, and gave an account of his work in 

 ;urgery.— A. Blondel : Remarks on the use of high 

 NO. 2424, VOL. 97] 



potential continuous current for wireless telegraphy 

 and telephony. With reference to a recent communi- 

 cation to the academy on this subject by MM. Girardeau 

 and B^thenod, it is pointed out that the energy losses 

 are greater than those calculated from the equations 

 employed by Fracque. There are also practical diffi- 

 culiies connected with the use of high-tension con- 

 tinuous current, not present to the same extent when 

 alternating current is used. — Lester R. Ford : The 

 approximation of irrational complex quantities. — A. 

 BunI : Geometrical applications of Abel's theorem and 

 Stokes's formula. — G. H. Hardy : The summation of 

 Dirichlet's series. — J. Guillaume : Observations of the 

 sun made at the Lyons Observatory during the fourth 

 quarter of 19 15. Observations were made on sixty 

 days, the results being given in three tables showing 

 the number of spots, their distribution in latitude, and 

 the distribution of the faculae in latitude. — Louis Roy : 

 The electrodynamics of absorbent media. — L. Reutter : 

 The analysis of a Roman pomade. This pomade was 

 found in a Roman amphora excavated near Lugano, 

 and was found to consist of a mixture of beeswax and 

 other fats, added to styrax and turpentine macerated 

 in wine, with some henna. — Paul Gaubert : The growth 

 of crystals. Remarks on a recent communication of 

 C. Dauzere. The crystallisation of thymol under the 

 microscope is periodic. — M. Deprat : Cycles of erosion 

 and recent epeirogenic movements in south-western 

 China. — Adrien Guebhard : The extension north of the 

 department of Var of the tectonic formula of the 

 neighbourhood of Castellane (Basses-Alpes), and the 

 generalisation of its principle. — A. Brives : The rela- 

 tions of the Trias and metalliferous deposits in 

 Algeria. — P. Chausse : Researches on the persistence 

 of Botal's cleft in some domestic animals. This mal- 

 formation was found in 30 per cent, of the three 

 months old calves examined, and was also common 

 in grown cattle and in pigs. It was exceptional in 

 the horse and dog. — A. Lecaillon : The existence of 

 two annual generations in Galeruca luteola, and on 

 the manner in which they succeed each other. — A. 

 Magnan : Vaccination against parat3phoid fevers A 

 and B. — A. Trillat : A calorimetric method utilised by 

 the Romans for characterising soft waters. The Romans 

 attached considerable importance to the quality of 

 their drinking water, and appear to have chosen the 

 softest water when more than one supply was avail- 

 able. From a remark by Hippocrates it seems that 

 the bleaching of small quantities of red wine by the 

 water was the test employed. It is shown that a 

 series of nine waters is arranged in the same order 

 of hardness by testing with wine or by the ordinary 

 alkali-metric method. 



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