546 



NATURE 



[November 27, 1919 



has been considered, and an aeroplane photographic 

 survey of the country between the two rivers indicates 

 that the Jordan probably originated in northern Syria 

 in earlier times. The Syrian portion of the stream 

 has been captured by the younger Orontes, and this 

 has had a very important effect on the whole topo- 

 graphy of the Jordan Valley. 



Linnean Society, November 6.— Dr. .\. Smith Wood- 

 ward, president, in the chair. — Col. H. E. Rawson : 

 Plant-sports produced at will. The author had ob- 

 served near Cape Town that shrubs of Kei-apple 

 (Aberia caffra) died when they were deprived of the 

 full sun up to a certain altitude in the early morning. 

 This led to experiments in screening plants about this 

 hour for various periods. "Selective screening" 

 resulted in various sports in form and modifications 

 of colour in Tropacolum ma jus. A special form of 

 Papaver rhoeas was obtained and fixed, and other 

 experiments were detailed. The author sums up 

 thus : — The intensity of the light regulates and 

 modifies the coloured bands upon all parts of the 

 plant which have been excited by interference. In 

 Nature selective screening prevails universally, and 

 these experiments suggest that it is deserving of study 

 to bring out its latent potentialities. — L. Hogben 

 Nuclear phenomena in the oocytes of Neuroterus, a 

 gall-flv. The atypical separation of polar bodies in 

 the Hymenoptera parasitica is a consequence of the 

 interruption of the first polar metaphase which 

 appears precociously before the egg is laid. There 

 is no evidence for " amitosis " in the germ-cells of 

 Hymenoptera. — L. V. Lester-Garland : A revision of 

 the genus Baphia, Afzel. The author had studied the 

 rich material in the herbaria of the British Museum 

 and at Kew, the number of known species having 

 increased from six (Bentham and Hooker fil. in 1865) 

 to sixty in the present enumeration. The genus is 

 practically confined to tropical .\frica, one outlier 

 reaching as far south as Natal, and another as far 

 east as Borneo. 



Royal Meteorological Society, November 7. — Sir Napier 

 Shaw, president, in the chair. — Prof. Vilhelm Bjerknes : 

 The structure of the atmosphere when rain is falling. 

 Though a comprehensive mathematical analysis of 

 atmospheric movements might be slow in yielding a 

 general solution of the problem of weather forecasting, 

 yet results of practical value were likely to be obtained 

 during the course of the analysis. Such results had 

 been applied to the forecasting of rain in Norway 

 with a fair measure of success. The basis of the 

 method consisted in drawing " lines of flow " of the 

 air and noting where these showed regions of con- 

 vergence or divergence. Such lines of flow indicated 

 two lines of convergence in a typical depression : 

 (i) where a warm south-westerlv wind blows almost 

 normally against the flank of a relativelv cold south- 

 easterly current (the warm air rising over the cold here 

 leads to steady rain over a belt some hundreds of 

 kilometres in breadth); and (2) where the cold south- 

 easterly current, curving round the north side of the 

 centre of depression, cuts under the warm south- 

 westerly wind. This causes a region of squally and 

 showery weather along a second narrower belt. 

 .\nother important application of the lines of flow lies 

 in the forecasting of thunderstorms. Experience 

 show'ed that in quiet weather in Norway under the 

 system of diurnal breezes certain points regularly 

 become centres of convergence, and it was at these 

 points that thunderstorms first developed, spreading 

 later to surrounding regions. 



Royal Anthropological Institute, November 11. — Sir 

 Everard im Thurn, president, in the chair. — S. H. 

 Warren : .\ stone-axe factory at Graig-lwyd, Pen- 



NO. 2613, VOL. 104] 



maenmawr. Stone axes of Neolithic types were 

 extensively manufactured out of the fine-grained 

 (andesitic) margin of the Penmaenmawr intrusion of 

 igneous rock. Blocks of scree, many of them of 

 large size, which fell from the crags were gradually 

 flaked down in successive stages until a satisfactory 

 stone-axe blade, ready for polishing, was obtained. 

 There are examples showing everv stage of the 

 process, arrested unfinished through accidental break, 

 age, or because the sha[3e being produced was un- 

 satisfactory. Under the last heading it was excessive 

 thickness of the blade which was the greatest source 

 of trouble. Many of the unfinislied "wasters" are 

 broken in half, producing the segmental form to varia- 

 tions of which the unfortunate names of "tea-cosy" 

 and " toe-cap " have been applied. Among the waste 

 of the axe-making industry, which is found in great 

 profusion on the mountain-side, the resemblances to 

 Mousterian flake industries are very striking. Equally 

 instructive parallels are to be observed among the 

 " wasters " with characteristic examples of the earlier 

 Palaeolithic industries, notably with the earliest of all, 

 or the pre-Chelles. Axes made of the Graig-lwyd rock 

 are being identified from other localities, and further 

 research along these lines is expected to give interest- 

 ing results. 



Manxhester. 

 Literary and Philosophical Society (Chemical Section), 

 October 24. — Su- Henry A. Miers in the chair. — Sir 

 William J. Pope : The photography of coloured objects. 

 Previous to the war all the various methods of colour 

 photography — the first of which was devised by Prof. 

 Joly, of Dublin — the modern processes of photographic 

 colour-printing, and the present-dav panchromatic 

 photographic methods for obtaining a correct rendering 

 in monochrome of parti-coloured objects, were based 

 upon the success which has been attained in impart- 

 ing sensitiveness throughout the visual spectrum to 

 the ordinary blue-sensitive photographic plate. By 

 staining the plate with erythrosine it becomes sensitive 

 to green and orange ; plates so treated are termed 

 orthochromatic. A number of dyestuft's belonging to 

 the class of cyanine dyes discovered by Greville Wil- 

 liams in 1856 are capable, however, of sensitising a 

 photographic plate throughout the whole range of the 

 visible^ spectrum. Experimental investigation of sensi- 

 tising dyestuffs was instituted in the chemical labora- 

 tories of the University of Cambridge by Dr. W^ H. 

 Mills and Sir William J. Pope at the end of 1914. 

 Methods for producing the ordinary sensitising dye- 

 stuffs on a technical scale were devised, and all the 

 sensitisers used by the .Mlies have been |)repared in 

 the Cambridge laboratories since the German im- 

 portation ceased. The best panchromatic plate made 

 in pre-war davs possessed about one-third the sensi- 

 tiveness to red as to blue light. .-\t the present time 

 a very rapid panchromatic plate is on the market 

 which is much faster to red than to blue light ; the 

 rapidity of the plate to red light has been thus 

 increased about fourfold. 



DuisLIN. 



Royal Irish Academy, November 11.— Prof. G. H. 

 Carpenter in the chair. — Mrs. Lilian Porter : Floral 

 development in Tricuspidaria lanceolaia. Both penta- 

 merous and hexamerous flowers occur. The calyx is 

 quincuncial or irregularly imbricated ; the corolla is 

 usually induplicate-valvate, but shows a tendency to 

 contortion ; the stamens arise on an enlargement of 

 the receptacle in groups of three alternating with the 

 petals; one stamen is terminal and two are lateral, as 

 in early stages of Tilia, thus emphasising the relation- 

 ship between EL-eocarpaceae and Tiliacea\ 



