262 



NATURE 



[July i6, 1903 



the velocity of travel, and concluded by making some re- 

 marks on self-recording instruments and their management. 

 — A paper by Mr. J. Baxendell, on the Dines-Baxendell 

 anemograph and the dial pattern non-oscillating pressure- 

 plate anemometer, was read by the secretary. The Dines 

 pressure-tube anemometer is now the accepted standard 

 instrument for recording wind movement, but it does not 

 record the direction of the wind. Mr. Baxendell has 

 endeavoured to overcome this drawback, and in this paper 

 he gives a description of the combined velocity and direc- 

 tion anemometer which he has designed for the Fernley 

 Observatory at Southport. In addition, he has designed 

 a non-oscillating pressure-plate for showing on a dial the 

 maximum pressure of the wind. By using a combined 

 " head " or vane for the Dines anemometer, Mr. Baxendell 

 has been able to arrange for the new instrument to record 

 (i) the velocity, (2) the direction, and (3) the maximum 

 pressure of the wind. 



Linnean Society, June 18.— Prof. S. H. Vines, F.R.S., 

 president, in the chair. — New Chinese plants, by Mr. S. T. 

 Dunn. In this, descriptions of more than seventy new 

 species are given, founded on specimens collected chiefly in 

 Yunnan by Dr. A. Henry and Mr. E. H. Wilson. — The 

 germination of the seeds of Davidia involucrata, by Mr. 

 W. Botting Hemsley, F.R.S. The fruit has an exceedingly 

 hard, bony endocarp or " stone," enclosing usually a number 

 of seeds, and causing wonder how they can free themselves 

 for germination. Under the influence of moisture, a portion 

 of the back of each cell (carpel) separates and falls away in 

 the form of a valve or shutter, revealing a portion of the 

 seed. The radicle soon begins to grow, and in due time 

 reaches the ground, when the upper part of the plantlet 

 frees itself and commences an independent existence. — • 

 Rudimentary horns in horses, by Dr. G. W. Eustace. Two 

 thoroughbred horses showed bilateral osseous prominences, 

 casts of which were shown ; in both the left or near boss 

 is the larger. The occurrence of these is extremely rare, 

 but the pedigree of all known instances being traced back, 

 it is found that they are all descended from the Darly 

 Arabian, bought at Aleppo, and shipped to England in 1705 ; 

 further, all are descended from Eclipse. The only refer- 

 ence to this phenomenon is that noted by Darwin, " Varia- 

 tion of Animals and Plants," vol. i. p. 52. The author 

 shows that these bosses are not mere exostoses due to dis- 

 ease, and draws the conclusion that they are instances of 

 the reappearance, in a rudimentary condition, of structures 

 which once existed in a functionally perfect condition. — 

 Scottish fresh-water plankton, part i., by Mr. W. West 

 and Prof. G. S. West. The paper deals with plankton- 

 material from lochs in different parts of Scotland and the 

 Outer Hebrides. The Scottish plankton is found to differ 

 considerably from that of the western part of continental 

 Europe ; it is remarkably rich in Desmids, which are of 

 a distinctly western type, and the most abundant are species 

 of Staurastrum. The scarcity of free-swimming Proto- 

 coccoideae is striking, but Diatoms are fairly represented. 

 A noteworthy feature is that both Diatoms and Desmids 

 display long spines or processes ; this excessive develop- 

 ment is ascribed by the authors to the assumption of a 

 purely free-swimming habit. — On the anatomy of the leaves 

 of British grasses, by Mr. L. Lewton-Brain. The paper 

 is the result of testing the classification of leaf-structure 

 devised by Prof. Marshall Ward. Four main types are 

 recognised : — (i) leaves in which the upper surface is flat 

 or nearly so ; (2) the upper surface marked by distinct 

 though not very high ribs ; (3) the upper surface marked 

 by very distinct and high ribs ; and (4) the upper surface 

 reduced to a mere fold in an almost solid leaf. 



Geological Society, June 24.— Sir Archibald Geikie, 

 F.R.S., vice-president, in the chair. — On a transported 

 mass of Ampthill Clay in the Boulder-clay at Biggleswade 

 (Bedfordshire), by Mr. Henry Home. Under 10^ feet of 

 soil and Boulder-clay, the Ampthill Clay was penetrated 

 for 67 feet, resting on Chalky Boulder-clay, fine silty clay, 

 disturbed Gault, and Lower Greensand. The clay is litho- 

 logically identical with the Ampthill Clay with its selenite- 

 crystals, and contains Ammonites excavatus, often covered 

 with Serpula;, but no abundant examples of Ostrea deltoidea. 

 The boulder was probably an outlier, situated in Oxford 



Clay at a level high enough to be ploughed into by the 

 agent which form^ the Glacial Drift. — ^The Rhaetic and 

 Lower Lias of Sedbury Cliff, near Chepstow, by Mr. 

 Linsdall Richardson. The chief portion of the cliff- 

 section described has a direction north-east and south-west ; 

 the dip of the beds does not exceed 3° to the south-south- 

 east. — Notes on the lowest beds of the Lower Lias at Sed- 

 bury Cliff, by Mr. Arthur Vaughan. The two chief points ' 

 of interest of this section are, the relation of the basal 

 conglomerate to the Cotham Marble and White Lias of 

 neighbouring districts, and the examination of the faunal 

 sequence, with a view of testing the absolute value of 

 ammonite-zones. A diagram is given showing the times 

 of appearance and disappearance, the abundance or rarity, 

 of several fossils within and below the zone of Ammonites 

 psilonotus, and on account of the beginning of five forms 

 at a given horizon and the disappearance of several forms 

 immediately below it, this level is chosen as the base of 

 the zone of A. psilonotus, rather than the point of appear- 

 ance of A. planorbis, 4 feet higher up. It is hoped that the 

 construction of similar diagrams will be of use in testing 

 the value of a series of ammonite-ages as divisions of 

 relative time. 



Dublin. 

 Royal Dublin Society, June 16.— Prox. J. M. Purser in 

 the chair. — Prof. T, Johnson and Miss M. C. Knowles 

 gave an account of the contents of the British herbarium 

 of the late H. C. Levinge, which had been given to the 

 National Museum in Dublin. The collection contains 

 specimens of nearly all the species of flowering plants and 

 ferns recorded for Ireland ; it is especially rich in West- 

 meath plants, and supplies many additions to the records 

 of Irish topographical botany. Mr. Levinge's herbarium 

 of ferns, British and foreign — 4000 sheets — had been 

 previously given to the museum. — Prof. J. A. McClelland 

 read a paper on ionisation in atmospheric air. This paper 

 deals with the amount of ionisation in free atmospheric 

 air. and the variations of the ionisation at different times. 

 The largest values have been obtained after several hours' 

 continuous rain, which would agree with the known radio- 

 activity of freshly fallen rain. On the other hand, very 

 small values of the ionisation have been found after slight 

 showers, probably because the ions have been removed 

 fiom the atmosphere by the condensation on them of water 

 vapour. — Dr. Henry H. Dixon showed a model for illus- 

 trating the part played by the mesophyll cells in transpira- 

 tion. The model consists of a funnel closed above by two 

 membranes, between which is a lenticular space containing 

 a sugar solution. The funnel and its stem are filled with 

 water, and, when set in an upright position, are supplied 

 with water through a capillary tube. The motion of water 

 in this tube is made apparent by microscopically observing 

 a precipitate suspended in it. In the paper the working 

 of the model is explained, and it is pointed out that the 

 tension set up by evaporation from the surface of the leaf- 

 cells is transmitted, through the solvent in them, to the 

 water in the conducting tracts of the plant, while at the 

 same time the dissolved substances exert an osmotic pressure 

 and keep the cells turgid. The paper also contains the 

 description of an experiment by which the solvent of osmotic 

 cells may be subjected to tension while at the same time 

 the pressure exerted by the solute is apparent. — Prof. A. W. 

 Conway read a paper on a new foundation for electro- 

 dynamics ; a modification of the scheme of Helmholtz was 

 proposed in it, the scalar and vector potentials being multi- 

 plied by a factor showing Doppler effect. — Mr. J. T. 

 Jackson described a new method of producing tension in 

 liquids ; how ordinary tap water, just as drawn from the 

 city supply mains, had been subjected to a tension of 381b. 

 per square inch. Advantage was taken of the principle 

 underlying the working of the common filter pump, Venturi 

 water-meter, spray distributor, &c. The water was forced 

 through a glass tube constricted at one point, and the 

 pressure at the constriction was estimated to fall below two 

 and a half atmospheres negative. 



Royal Irish Academy, June 22. — Prof. R. Atkinson, presi- 

 dent, in the chair. — On the synthesis of glycosides — some 

 derivatives of arabinose, by Prof. Hugh Ryan and Mr. 

 George Ebrill. Following the method employed by Ryan 



NO. 1759. VOL. 68] 



