December 12, 1912] 



NATURE 



419 



Cretaceous fossil genus Cycadeoidea, a member of 

 the extinct family Bennettitales, which was in some 

 respects more primitive than the cycads, and formed 

 a link between this group and the Pteridospermse, or 

 fern-like seed-plants. In a second paper the author 

 describes the development and fertilisation of Ccrato- 

 zamia mexicana, and notes the curious fact tliat the 

 normally small and evanescent ventral canal nucleus 

 may enlarge and approach the egg, possibly fertilising 

 it. 



\\'e have received from Messrs. Flatters and Gar- 

 nett. Ltd., 32 Dover Street, Manchester, a copy of 

 their lantern slide catalogue " E," together with 

 specimen slides illustrating a large range of subjects 

 (biology, geology, astronomy, textile fibres and 

 machinery, scenery. Sec). The slides submitted for 

 inspection are remarkably fine reproductions from 

 photographs, and the prices appear very reasonable. 

 Of the series of slides listed in this very comprehen- 

 sive catalogue, those dealing with botanical subjects 

 are the most complete, and these include an extensive 

 set of slides illustrative of plant associations at home 

 and abroad. The list of slides in the section of British 

 plant associations is arranged in accordance with the 

 plan adopted in the recently published standard work 

 on British ecology — "Types of British Vegetation," 

 edited by Mr. A. G. Tansley — and may be warmly 

 commended to teachers and lecturers as the best and 

 most complete set of ecological slides available. One 

 of the most remarkable series of slides offered is that 

 consisting of no fewer than 130 photomicrographs 

 illustrating the development of Pinus sylvestris. 



-Although few details of scientific value have been 

 made known about the disastrous Turkish earthquake 

 of August 9 last, Dr. G. Agamennone has been able 

 to draw- some conclusions of interest. The shock, 

 which in places attained the intensity 10 of the Rossi- 

 Forel scale, was strong enough to damage buildings 

 over an area nearly 200 miles long and 125 miles wide, 

 and containing about 20,000 square miles. The epi- 

 centre cannot yet be located with accuracy, but it 

 must have been near the north-west coast of the Sea 

 of Marmora. As more than 3000 persons were killed, 

 the earthquake must rank as one of the most destruc- 

 tive European shocks of the last thirty years. 



The curious phenomenon known in Japan as Inada 

 no goko. or halo in the ricefield, forms the subject 

 of a discussion by Profs. Fuchino and Izu, of the 

 College of Agriculture and Forestry, Kagoshima, in 

 the Journal of the Meteorological Society of Japan 

 (October, 1912). In the early morning, when the dew 

 lies on the plants, and the sun is shining, the shadow 

 of the head of a person standing in the fields is sur- 

 rounded by a luminous halo, elliptic in form, its long 

 axis corresponding with that of the body-shadow. As 

 the sun rises higher in the sky and the dew evaporates 

 the halo vanishes, but reappears on sprinkling the 

 ground with water. The authors describe some ex- 

 periments which they carried out with blankets, 

 isolated drops of water, and bottles. They conclude 

 from their experiments that the phenomenon of the 

 halo is caused by the reflected light from the sun- 

 NO. 2250, VOL. 90] 



images formed on the green blades by the passage of 

 the sun's rays obliquely through the dewdrops. 



Estimates of the age of the earth based on the 

 ratio of the amounts of helium and uranium present 

 in the Carboniferous and older rocks have given 

 results of the order 400 to 1500 million years. Esti- 

 mates based on the quantity of sodium brought into 

 the oceans by the rivers of the world and the amount 

 in the ocean at the present time lead to 70 million 

 years. A possible explanation of this discrepancy is 

 offered by Dr. F. C. Brown, of the University of 

 Ithaca, in the October number of Le Radium. He 

 suggests that sodium is itself a radio-active element 

 with a parent which is insoluble in water. The 

 sodium of the soil would then be due to the decom- 

 position of the parent, and that of the ocean to the 

 solution of the sodium in the soil and its transport 

 by rivers. During the earliest periods the soil content 

 being small, the transport to the ocean would be 

 reduced, and the age calculated from the present con- 

 tent of the ocean would be correspondingly increased. 



The Journal of the Washington .'\cademy of Sciences 

 for November 19 contains an abstract of a paper on 

 the atomic weight of bromine by Mr. H. C. P. Weber, 

 of the Bureau of Standards, which is about to be 

 published in the bulletin of the Bureau. The method 

 adopted is that of Noyes and Weber, by the direct 

 synthesis of hydrobromic acid, and it was found 

 capable of giving results of high accuracy. The final 

 value obtained on the basis of o-xygen 16, hydrogen 

 roo779, is 79'924, as against the International Com- 

 mission value 79'92o. 



Two papers on agriculture are included in the 

 October issue of Science Progress. Dr. J. V. Eyre 

 gives an interesting account of Russian agriculture, 

 in which he presents a picture of a vast territory, of 

 which only a small part is under cultivation ; more- 

 over, on account of the poverty and indolence of the 

 peasants the agriculture is of a very low order, arti- 

 ficial manures and agricultural machinery being 

 almost unknown over vast areas of the country. The 

 writer suggests that a few good harvests would prob- 

 ably do more than anything else to enable the im- 

 poverished farmers to carry out the improvements in 

 method with which many of them are already fami- 

 liar as a result of the active work of instruction under- 

 taken by the Government. Dr. Spencer Pickering 

 contributes the first of a series of papers on horticul- 

 tural research, in which he describes the Woburn 

 experiments on the planting of trees. These experi- 

 ments have suggested that rough treatment in plant- 

 ing is often more effective than the careful handling 

 of root fibres, which is usually recognised as correct. 

 Both articles are illustrated by several pages of photo- 

 graphs. 



The 1913 issue of "The Scientists' Reference Book 

 and Diary," published by Messrs. James Woolley, Sons, 

 and Co., Ltd., dealers in scientific apparatus, chem- 

 ical reagents, &c., of Manchester, has all the useful 

 characters of the issues of previous years. The student 

 of science will find it very convenient to have together 

 in the- same compact pocket-book a small work of 



