542 



NATURE 



[January 22, 1920 



Over is an extremely variable phenomenon. The re- 

 duplication hypothesis is regarded as definitely dis- 

 proved, and all detailed interpretations are based upon 

 the structure of the chromosomes. Crossing-over 

 between two fixed points on a chromosome is found 

 to be highly variable. It is also found that a change 

 in genes between two fixed points in the third 

 chromosome slightly disturbs the ratios of crossing- 

 over between those points. Biometric analysis shows 

 that the results are all in harmony with the hypothesis 

 that the factors are represented by particles arranged 

 along the chromosomes. A cross-over in one region 

 of the chromosome is more likely to be accompanied 

 by a cross-over 25-35 units away than elsewhere. 



Vol. ix. of the Bulletin Statistique has just been 

 published by the International Council for Fishery 

 Investigations. Particular interest attaches to this 

 report, as it deals with the year 1913, the last 

 of a long series during which there has been a con- 

 tinuous, progressive development of the sea-fishing 

 industry in North European countries, and vol. ix. is 

 likely to remain a standard of comparison of two 

 periods, in the interval between which many conditions 

 will be found greatly to have changed. The council 

 has in preparation a Bulletin describing the effect 

 of the war upon the fisheries, and this, it is hoped, 

 will soon be ready. Several changes have been 

 made in the arrangement of the present volume ; 

 the use of two languages has been dropped, 

 and the results are now published onlv in English. 

 There are many useful diagrams. A feature of ex- 

 ceedingly great interest, the estimation of the capital 

 employed industrially, in factories, curing works, etc., 

 in 1913, as well as in the vessels, might be included 

 in the next volume as a help to the understanding of 

 the great change in economic conditions that is now 

 taking place. 



The T6hoku Imperial University, Sendai, Japan, 

 continues to publish beautifully illustrated memoirs on 

 fossils in the geological series of its Science Reports. 

 In the latest part received (vol. v.. No. i), Mr. I. 

 Hayasaka describes the microscopical structure of 

 three Permian species of the remarkable sponge 

 Amblysiphonella from Japan and China. Prof. H. 

 Yabe also illustrates in three fine plates the micro- 

 scopical structure of a Tertiary foraminiferal lime- 

 stone from Borneo. ' . 



The United States Geological Survey has published 

 Professional Papers Nos. 112 and 120, dealing respec- 

 tively with Cretaceous plant-remains from Tennessee, 

 Mississippi, Alabama, .nnd Georgia, and Cretaceous 

 fish-scales from various .American localities. The 

 plant-remains, described by Dr. E. W. Berry, are 

 chiefly leaves of dicotyledons, and represent a lowland 

 coast flora. The sudden appearance of dicotyledons 

 as the dominant plants in Middle Cretaceous times 

 is still a mysterv', and Dr. Berry thinks this modern 

 flora may have originated in the Arctic regions. The 

 description of the fish-scales by Prof. T. D. A. 

 Cockerell is a bold attempt to use fragmentary fossils 

 in stratigraphical geology. 



NO. 2621, VOL. 104] 



Part iii. of vol. iv. of the Records of the Geological 

 Survey of India, which has just reached us, contains 

 a review of the mineral production of India during 

 19 18. Upon the whole the position is satisfactory, 

 most of the important minerals showing an in- 

 creased production. Thus the coal output rose from 

 18,212,918 to 20,721,543 tons; it is worth noting 

 that the most substantial increases are shown in the 

 important coalfields of Jharia and Raniganj, which 

 produced respectively 52-85 per cent, and 3074 per cent, 

 of the total Indian output. The output of iron ore, 

 too, increased, namely, from 413,273 to 492,484 

 tons, most of which was smelted in the works of the 

 Tata Iron and Steel Co. and the Bengal Iron and 

 Steel Co.; the latter produced also 12,114 tons of 

 ferro-manganese during the year under review. 

 There was a large increase in the production of 

 chromite, mainly through the development of some 

 recent discoveries in the State of Mysore. The output 

 of manganese ore, on the other hand, fell from 

 591,000 to 518,000 tons, the falling off being probably 

 caused by the difficulties of procuring the neces- 

 sary shipping facilities. The Bawdwin mine in the 

 Northern Shan States again shows an increase of out- 

 put, namely, 19,074 tons of lead and 1,970,614 oz. of 

 silver, as against 16,962 tons of lead and 1,580,557 oz. 

 of silver. Gold, on the other hand, declined some- 

 what, namely, from 574,293 oz. to 536,118 oz. The 

 falling off under this head has, of course, a far 

 less effect upon the prosperity of India than has the 

 increase noted under such minerals as coal and iron, 

 which contribute essentially to the industrial develop- 

 ment of the country. 



The oscillations in the luminosity of incandescent 

 electric lamps illuminated by alternating currents 

 forms the subject of a short report by Dr. Luigiio 

 Fabaro in the Atti dei Lincei (xxviii. (i), 7, 8). The 

 phenomena had been previously studied by Prof. 

 Corbino, and the present experiments refer mainly 

 to certain recent types of lamp. Diagrams are drawn 

 showing the relation between the fluctuations of 

 intensity and those of the electromotive force, and, at 

 the same time, the difference of phase between the 

 luminosity and the exciting electromotive force. These 

 are in conformity with the theory that the effect can 

 be reduced by increasing the mass of the filament, j 



From the Laboratorio di Ottica pratica e Me 

 canica di Precisione we have received the first 

 numbers of a new periodical, Rivista d'Ottica e Mec- 

 canicd di Precisione. Hitherto Italy has not had a 

 technical periodical on the lines of the German Zeit- 

 schrift fiir Instrumentenkunde , and the new journal 

 is a modest attempt to fill the want. Like other 

 countries, Italy has made great progress in the con- 

 struction of optical and other scientific instruments 

 during the war, and the need for a medium in which 

 matters of interest to practical optical workers can be 

 discussed is now being felt. The November-December 

 number contains articles on Galileo and the pendulum 

 clock, the application of interference methods over 

 simple observations with the naked eye, the first instal- 

 ment of a paper by P. G. Nutting on " Dispersion 



