Aprh, 1911. 



KNOWLEDGE. 



149 



has shewn that Ephedra cainpylopoda. found in the south of 

 Europe, is not only adapted for msect-pollination, but is 

 regularly \isited by insects. In his intei-esting memoir on 

 this the first established case of insect pollination among the 

 Gymnospernis. Forsch shows that the yellowish-red colour of the 

 inflorescences attracts insects, which feed on the sticky pollen, 

 and that nectar is provided in the form of drops which ooze 

 from the micropj-le. The insect-visitors included thirteen 

 species of Hymenoptera and Diptera, which were found to 

 carry the pollen on the underside of their bodies. Since 

 secretion of sugary liquid occurs in the flowers of Gncttiin 

 and Wcht'itschia, it is very likely that these genera also 

 are insect-polhnated, though, until now, it has been supposed 

 that the function of the liquid which oozes from the 

 micropyle, is simply that of catching pollen blown by the 

 wind, in much the same way as in the female cones of pines. 

 Pearson {Phil. Trans. Roy. Soc, 1909) had already suggested 

 that the flowers of Wclicifschia are insect-pollinated, and in 

 this plant there are glandular outgrowths below the anthers 

 which doubtless act as honey-glands. Pearson has also 

 described, though not fully, the development of the ovule of 

 this remarkable genus. The endosperm begins, as usual, in 

 Gymnospernis. with free nuclear division, forming an embryo- 

 .sac with appro.ximately one thousand and twenty-four free 

 nuclei, representing ten successive divisions. These nuclei 

 are distributed through the sac, so that when cell-walls are 

 formed the sac is divided into multinucleate cells ; those in 

 the micropylar (upper) region contain fewer nuclei than the 

 others, and they become the nuclei of free eg.gs. The cells of 

 the lower three-fourths of the endosperm contain many nuclei, 

 and these fuse and form a uninucleate tissue — the primary 

 endosperm, which continues to grow both before and after 

 fertilisation. The multinucleate cells of the micropylar region 

 send out tubes into the overlying nucellar tissue, into which 

 the free nuclei pass, and these prothallial tubes meet the 

 pollen-tubes in the lower half of the nucellar cap. 



CHEMISTRY. 



By C. .AiNswoRTH Mitchell. R..\. (C_).\on.). F.I.C. 



COMBUSTION OF G.'\SES WITHOUT FLAME.— .\ 

 new property of copper is described by M. J. Meunier in the 

 Coinptcs Rcndiis (1911, clii. 194). On heating a wire of pure 

 copper in the luminous flame of a Bunsen burner until all sur- 

 face oxide has been reduced to metallic copper, and then 

 admitting air the wire will begin to glow. On now lowering 

 the hot copper into the tube of the burner, the steady glow 

 will continue without igniting the mixture of air and gas in the 

 tube. The maximum intensity of glow is obtained when the 

 proportion of gas in the mixture is about 30 per cent. During 

 this slow combustion the copper is rendered exceedingly brittle 

 and may readily be reduced to a powder of crystalline 

 appearance. 



CELTIUM: A NEW ELEMENT.— M. G. Urbain des- 

 cribes in the Comptcs Rcndits (1911, clii. 141). a new element 

 for which he suggests the name Ccltinin and the symbol Ct. 

 It was found accompanying the elements lutecium and 

 scandium in gadolinite earth, and was isolated from the mother 

 liquor obtained in the separation of lutecium. In its .general 

 properties it is intermediate between these two metals, and 

 differs from both in its magnetic permeability and in its 

 spectrum. Its chloride is more volatile than that of lutecium, 

 but less volatile than that of scandium, while its hydroxide is 

 a stronger base than scandium hydroxide, but is weaker than 

 lutecium hydroxide. Its atomic weight has not yet been 

 determined. 



HELIUM IN THE AIR OF VESUVIUS.— In the only 

 recently published proceedings of Section II of the Seventh 

 International Congress of Applied Chemistry of 1909 (pages 

 83-86). Mr. A. Piutti gives an account of his investigation 

 of different incrustations from Vesuvius which at various 

 periods he has tested for helium. In each case the substance 

 was heated and the gas emitted was absorbed by cooled 

 charcoal. A specimen of sanidinite from Vesuvius yielded 



0-106 c.c. of gas per granmie. Its radio-activity was found 

 to be principally due to the presence of zircon crystals, and 

 these, like the gas, contained helium. 



In like manner a specimen of pink tourmaline, which yielded 

 0-511 c.c. of gas per gramme was found to contain helium, and 

 this element was also identified in the air of Naples as well as 

 of \'esuvius. 



Its presence was also proved in the zircons from many other 

 localities, and in the case of large tourmalines from 

 Madagascar the green outer portion was more radioactive and 

 contained more heHum than the inner light pink part. In 

 general, though not invariably so, the proportion of helium 

 corresponded with the degree of radio-activity. 



SPONTANEOUS IGNITION OF COAL.— The results 

 of a bacteriological investigation of the spontaneous com- 

 bustion of coal, by Mr. E. Galle, an outline of which is 

 given in the Cheiii. Zcntralhl. (1911, I. 48), have suggested 

 several interesting conclusions. Cultivations were made both 

 in the presence and absence of air, and seven species of 

 bacteria were isolated from coal. Of these, four species 

 {B. nacraceus, B. siibtilis. B. mcscntcricus. and 

 B. pseudosuhtiUs\ were found to be capable, when grown 

 on suitable nutrient media in the presence of coal dust, of 

 producing combustible mixtures of gas containing from 5-4 to 

 27-3 per cent, of carbon dioxide, and 71-5 to 84-8 per cent, 

 of methane, together with traces (less than three per cent.) of 

 carbon monoxide, oxygen, and hea\-y hydrocarbons. Onlv 

 B. nacraceus and B. pseudosuhtilis produced these latter 

 gases. The conditions under which these mixtures of com- 

 bustible gases were produced were perfectly comparable with 

 those that would occur in nature, and there is therefore every 

 reason for assuming the possibility of their production by 

 bacteria in coal measures. 



Hence, while the spontaneous ignition of coal cannot be 

 .attributed exclusively to bacteriological activity, it is not 

 improbable that bacteria may be an important factor in its 

 occurrence. 



FIRE-PROOF AND SUBMARINE PAINTS.— .An 

 abstract of a paper read before the Seventh International 

 Congress of Applied Chemistry of 1909, by M. Coflignier, is 

 published in the Jonrn. Soc. Cheni. Ind. (1911, xxx., 223). 

 In fire-proof paints the principle adopted is to incorporate 

 with the other ingredients of the paint an ammonium salt, which 

 under the influence of heat, will give oft' ammonia, and so 

 produce an atmosphere unfavourable for combustion. The 

 solubility of most ammonium salts renders them unsuitable for 

 this purpose, but good results have been obtained by mixing 

 the pigment with insoluble ammonium magnesium phosphate 

 and a special medium consisting of linoleate of lead in oil of 

 turpentine. 



In 1895. a special submarine paint was prepared by 

 Holzapfel, the object being first coated with an anti-corrosive 

 deposit, and then with a second layer containing toxic 

 substances. Owing to the reactions which occurred between 

 the two layers, however, the paints were liable to crack, and 

 would not last for more than about six months. 



Recently this drawback has been remedied by the production 

 of a paint in which the outer coating consists of an amalgam 

 of copper incorporated with an earthy pigment and a water- 

 proof medium. 



.As soon as marine organisms attack this coat the amalgam 

 is exposed, and voltaic currents are produced which set free 

 poisonous compounds of copper and mercury and destroy the 

 intruders. Thus the action is only brought about in places 

 where it is necessary, and the life of the paint is doubled. 



GEOLOGY. 



By Russell F. Gwinnell, B.Sc, A.R.C.S., F.G.S. 



THE GEOLOGICAL SURVEY OF SCOTLAND.— Three 



colour-printed sheets of the one-inch map of Scotland have 

 recently been issued, together with memoirs on the same districts. 

 Two of these (Edinburgh and Haddington) are new editions ; 

 the third is the long-exptcted Glenelg sheet, which includes 



