July 17, 19 13] 



NATURE 



parasites of castor. The structure and life-history of 

 the fungus are fully described and illustrated by means 

 of ten excellent plates, one being coloured to show 

 the characteristic brown leaf spots which form the 

 first external indication of the disease. 



Technical Bulletin No. 16 of the Michigan Agri- 

 cultural College Experiment Station deals with the 

 grain-size and moisture content of soil in relation to 

 bacterial activity. Aeration and thickness of the mois- 

 ture film may be considered to be the important physical 

 factors of the soil in relation to the activity of aerobic 

 bacteria. Aeration increases as the square of the 

 grain-size, while the increase of the moisture film is 

 directly proportional to the grain-size. A coarse soil 

 is therefore of advantage to the aerobic bacteria. The 

 grain-size in cultivated soils is generally so small that 

 the optimum moisture film is reached only in the 

 waterlogged state. 



In the Bulletin of the Imperial Earthquake Inves- 

 tigation Committee (vol. v., pp. 109-37), Prof. Omori 

 again directs attention to the small slow movements 

 of the ground which he calls pulsatory oscillations. 

 The period of these oscillations ranges from about 

 four to about eight seconds, and Prof. Omori shows 

 that the period at a given moment is identical even 

 at Tokyo and Osaka, which are nearly 250 miles 

 apart, not only in its mean value, but also in its 

 variation from day to day. The amplitude of the 

 oscillations is much greater on soft than on hard 

 ground, and Prof. Omori suggests that the oscilla- 

 tions are produced at some depth in the solid crust 

 and magnified when transmitted to the soft soil of the 

 alluvial plains. A remarkable feature of pulsatory 

 oscillation is their complete dissimilarity at stations 

 only a few miles apart, it being impossible to identify 

 the different maximum groups even at two observa- 

 tories in Tokyo. This indicates that pulsatory oscilla- 

 tions are not the results of a progressive disturbance 

 like an earthquake. Prof. Omori regards them rather 

 as the results of underground disturbances originating 

 at an infinite number of points, due probably to 

 volcanic activity or to changes in the internal pressure 

 caused by the transit of a deep barometric depression 

 or by the existence of heavy ocean swells. 



Mr. R. C. Mossman (Argentine Meteorological 

 Office) has contributed to Symons's Meteorological 

 Magazine for June the third of his useful articles on 

 southern hemisphere seasonal correlations. During 

 the months January to March a remarkable parallel- 

 ism is pointed out since 1897 in the curves of mean 

 temperature at Alice Springs (Australia) and Cordoba 

 (Argentine Republic), both stations being located in a 

 continental situation. In eleven out of fourteen years 

 discussed (1897-1910) the departures from the means 

 for the period have the same sign. But previous 

 years (1879-96) show no definite agreement. During 

 the same months an opposition is generally shown 

 in the mean temperature curves at Perth (Western 

 Australia) on one hand, and at Valparaiso and San- 

 tiago (Chile) on the other ; for Valparaiso data for 

 only nine years (1901-9) were available. There is 

 also an opposition between the mean temperature at 

 SO. 228l. VOL. 91] 



Santiago and the thickness of the ice at Duluth 

 (Lake Superior). These results, as Mr. Mossman 

 remarks, are of interest as they indicate an inter- 

 relation between the action centres governing the 

 conditions during the period in question in Australia, 

 South America, and the United States. 



A well-illustrated article in the Journal of the 

 Franklin Institute for May reproduces an address 

 given before the institute in January by Mr. E. A. 

 Sperry, president of the Sperry Gyroscope Company, and 

 deals with the engineering applications of the gyrostat. 

 It appears that the gyroscope has been successfully 

 applied to the stabilising of the United States steamer 

 Worden, and that the application has enabled a more 

 complete study of the effects of rolling of vessels on 

 the power necessary to propel them to be made. To 

 the gyrostatic compass we have directed our readers' 

 attention previously. The application of the gyrostat 

 to the control of the wings and rudders of an aero- 

 plane has now been successfully carried out, and we 

 have, in addition, recorders of the rolling and pitch- 

 ing of vessels and artificial horizons depending on the 

 gyrostatic principle, all working satisfactorily. 



The report of the Advisory Committee for Aero- 

 nautics for the year 1912-13 gives a general account 

 of the work accomplished. The construction of the 

 new four-foot wind channel at the National Physical 

 Laboratory has been undertaken in the light of 

 numerous experiments, and the pulsations in the flow 

 which are the chief cause of difficulties in air-channel 

 experiments have been so much reduced that the 

 accuracy of individual measurements can be relied on 

 in general to within one-half per cent. This channel 

 replaces one of the same size, but a new 7-ft. channel 

 is projected, and the necessary sum for its construction 

 will be included in the estimates for 1913-14. In this 

 respect the laboratory will be provided with means 

 for experiments on fully rigged models of complete 

 aeroplanes, an acceptable addition to its resources too 

 long delayed. Amidst a number of interesting and 

 important researches carried on, the investigation of 

 the stability problem will command most attention, 

 alike from mathematicians, physicists, and from those 

 who have to trust themselves to their incessant 

 vigilance to keep their frail craft upon an "even 

 keel " in the air, and we therefore are glad to note 

 that great advance has been made in the study and 

 investigation of this problem, though sufficient time 

 has not elapsed to put the knowledge so derived to 

 the test of practical application. The close relation- 

 ship between the work carried on at the Royal Air- 

 craft Factory and that at the laboratory gives reason 

 to hope that the inevitable divergence between labora- 

 tory and full-scale experiments will be ascertained and 

 allowed for, and we are glad to note the cooperation 

 that exists to forw-ard the experiments. We hope to 

 return to the work of this department of the labora- 

 tory when the technical report of the committee is 

 ready. 



In a paper published in the Gazzctla Chimica Italiana 

 (vol. xliii., i., 38) Prof. F. Angelico and Mr. F. Catalano 



