November 22, 1900] 



NATURE 



99 



of pottery glazes, by William Jackson and Edmond M, Rich, 

 was read. The paper described experiments carried out to 

 determine what factors, apart from chemical composition, affect 

 the amount of lead oxide yielded to dilute hydrochloric acid by 

 lead fritts as used by potters. It was found that the solubility 

 is increased in a very marked manner by increase of fineness, so 

 that it appears that if details are given of the solubility of fritts 

 they should be accompanied by particulars of its degree of fine- 

 nesb. The solubility of the same fritt reduced to diiTerent 

 degrees of fineness varied from i to 15 per cent, of the material 

 used. It was found also that after the action of the acid has pro- 

 ceeded for a short time it appears that the whole of the soluble 

 lead has been extracted. This, however, was due, not to the 

 absolute insolubility of the remainder, but to the formation of 

 an insoluble layer on the surfaces exposed to the action of acid 

 which protects the particles from further action. By removing 

 this layer by chemical or physical means it was found possible 

 to extract more lead oxide from the fritt, and by continually re- 

 moving this insoluble layer it was possible to extract continually 

 more lead oxide, until practically the whole of the lead oxide 

 passed into solution. — A paper on the phloem of Lepidophloios' 

 and Lepidodendron was read by Prof. F. E. Weiss. The author 

 had examined sections of these two nearly allied fossil plants in 

 which the tissues have been exceptionally well preserved. The 

 examination of these specimens led him to the conclusion that the 

 phloem region is not occupied by large secretory sacs, and that 

 the tissue is not partially disorganised during the life of the 

 plant, as has been suggested, but that it consists of cells not 

 fundamentally different from those composing the phloem of 

 living lycopods. In those stems, however, in which secondary 

 thickening is found to have taken place, an active division of 

 some of the phloem cells can be observed. The author dis- 

 cussed the possible reasons for the usual destruction of the 

 phloem elements, and considered that it must take place previous 

 to mineralisation, but after the death of the plant. He attri- 

 buted the more ready destruction of the phloem cells to the 

 peculiar nature of the cell walls, which he thought were probably 

 composed — as in the case of the nearly allied lycopods — of 

 amyloid, a semihydrate of cellulose. This substance is more 

 easily acted upon by water than cellulose, and consequently the 

 phloem would be more liable to rapid decay than the rest of 

 the tissues. 



November 13. — Prof. Horace Lamb, F.R.S., President, in 

 the chair. — Prof. Reynolds mentioned a curious phenomenon 

 observed at sunset during the summer, in the form of a 

 narrow beam of light proceeding vertically from the sun 

 and persisting for about half an hour after sunset. A similar 

 appearance was seen by Mr. Thorp when crossing the 

 Mediterranean in the early summer. — Dr. Lees called atten- 

 tion to a useful expression for calculating the circumference 

 of an ellipse to a close degree of approximation, more 

 simple than those ordinarily given in engineers' text-books. 

 — Mr. Thorp described a method by which he had succeeded in 

 silvering his diffraction films, and he referred to a device by 

 which he expects to obtain similar films from concave surfaces. — 

 Prof. Dixon discussed the reversal of lines of the spectrum of an 

 explosion wave observed by Profs. Dewar and Liveing, and gave 

 an alternative explanation to that olTered by them. He also 

 discussed MendeleefFs theory as to the nature of the action which 

 takes place when hydrogen and oxygen or other pairs of gases 

 combine, and suggested an alternative view of the nature of the 

 reaction. 



Edinburgh. 

 Royal Society, November 5. — Sir Arthur Mitchell, Vice- 

 President, in the Chair. — As usual at the first meeting of the 

 session, the chairman gave a short review of the work of the pre- 

 ceding session. In particular, attention was drawn to the be- 

 quest to the Society made by the Inte Prof. Piazzi Smythe ; to the 

 representation which the Society had made to the Geological 

 Survey Committee as to the advisability of completing the survey 

 of Scotland on the six-inch scale ; and to the Scottish Antarctic 

 Expedition now being organised by Mr. W. S. Bruce.— A paper 

 was read by Drs. O. Noel Paton, J. C. Dunlop and Elsie Inglis 

 on dietary studies of the poorer classes in Edinburgh. The diets 

 of fifteen families, including ninety-five individuals belonging to 

 the labouring classes, were studied by the method employed by 

 Atwater in America. It was found that the average diet of the 

 thrifty poor contained 108 grms. of proteid and 3275 large 

 calories of energy per man per diem ; but among the thriftless 

 and ignorant very defective diets were observed. Such a 



NO. 1621. VOL. 63] 



deficient diet cost, for an average family of father, mother and 

 four or five children, about \^s. 67. per week, which leaves out 

 of a labourer's wage of 20J. to 2.2s. a sum too small for the other 

 necessaries of life and nothing for recreation. — In a note on the 

 relations amongst the thermo- and electro-magnetic effects, Dr. 

 W. Peddie showed how the Hall, the Nernst, the Ettingshausen 

 and the Leduc effects may be represented in mutual relation, so 

 that when, say, the Leduc effect is known, the others may be 

 predicted. For this purpose consideration is taken of the direc- ' 

 tion of the resultant heat flow induced in consequence of the 

 changes of temperature gradient evidenced in the Thomson 

 effect. The Leduc effect is known only in the case of bismuth, 

 yet, in the case of other metals, the possible signs of the remain- 

 ing effects can be deduced ; and the actual signs are found to be 

 included in these in ail cases except those of cobalt and zinc. 



Mathematical Society, Nov. 9. — Mr. R. F. Muirhead in 

 the chair. — The following papers were read : Euclidian proof 

 of Pascal's theorem, by Mr. R. F. Davis. — Note on the 

 expression for the area of a triangle, by Mr. C. Tweedie. — 

 Proof of a theorem in co-ordinate geometry, by Mr. J. 

 Jack (communicated by Mr. A. Milne). — The following were 

 elected office-bearers for the current session : President, J. W. 

 Butters ; Vice-President, Geo. Duthie ; Hon. Secretary, D. 

 C. Mcintosh ; Hon. Treasurer, James Archibald. 



Paris. 

 Academy of Sciences, November 12. ^M. Maurice Levy 

 in the chair. — On the next appearance of the Leonids, and their 

 aerostatic observation, by M. J. Janssen. In order to prevent 

 the interference of clouds with the observations of the Leonids, 

 arrangements had been made for a balloon ascent on each of 

 the three nights, November 13-14, 14-15, and 15-16, during 

 which Leonids may be expected. — On the conditions affecting 

 chemical activity under the action of silent electrical discharges, 

 by M. Berthelot. The effects of silent electrical discharges 

 ("effluve") and of atmospheric electricity are compared, the 

 production of oxides of nitrogen, ozone and nitric acid being 

 possible in this way without actual lightning. Some of the 

 effects produced in Deville's hot and cold tube experiments, 

 and ascribed by him to dissociation, are also ascribed by the 

 author to similar electrical effects. — On the order of formation 

 of the elements of the central cylinder in the root and stem, by 

 M. Gaston Bonnier. The central cylinder presents the sam 

 general structure in both root and stem, the constitution and the 

 order of development of the tissues being the same in both 

 cases, except as regards the position of the ligneous poles. The 

 paper is illustrated by six diagrams showing sections of Thalic- 

 trum silvaticutn, Chenopodium polyspervium, Ricinus com- 

 munis, Pulmonaria officinalis and Rannnculus acris. — The 

 Perpetual Secretary announced to the Academy the death of 

 M. I'Abbe Armand David, Correspondent for the Section 

 of Geography and Navigation. — On surfaces which possess a 

 non-linear series of rational curves, by M. S. Kantor. — 

 On the series analogous to Lagrange's series, by M. A. Bougaiev. 

 — Superficial lines appearing in the sawing of metals, by M. Ch. 

 Fremont. Six photographs are given of sections of different 

 shapes cut by sawing. A series of lines, differing from the saw 

 markings, are produced, which vary with the shape of the piece 

 cut, the systems of lines being parallel to the edges cut by the 

 saw. They differ from Liider's lines. — On the experiments of 

 Prof. Rowland relating to the magnetic effect of "electrical 

 convection," by M. V. Cremieu. In previous communications 

 the author has described experiments which led him to the con- 

 clusion that the so-called " electrical convection " produced no 

 magnetic effect. Further experiments are now described, cor- 

 responding exactly to those of Rowland and of Himstedt, in 

 which a charged disc rotates round a magnetised needle. In 

 the first experiment no deviation of the needle was observed, 

 although the effect should have been from 12 to 175 mm. In 

 other experiments a deviation was obtained, but it is shown that 

 these deviations are not due to the magnetic effect of the elec- 

 trical convection, since they can be suppressed by the interven- 

 tion of a metallic plate. The whole work tends to show that, 

 contrary to the experiments of Rowland, electrical convection 

 produces no magnetic effect. — On the splitting-up by alkalis of 

 acetylenic ketones, by MM. Ch. Moureu and R. Delange. 

 Ketones of the type R - C = C - CO.R' are split up by heating 

 with alkalis. An acid and a ketone would, in general, appear 

 to be produced simultaneously, thus benzoylphenylacetylene, 

 CjHs.CiC.CO.CeHj, gives benzoic acid and acetophenone. 



