5S8 



NA TURE 



[October 6, 1904 



Among recent contributions to aeronautics, considerable 

 interest attaches to Mr. A. F. Zahm's paper on atmo- 

 splieric friction, published in the Bulletin of the Philo- 

 sophical Society of Washington, xiv., pp. 247-276. It is 

 commonly assumed by experimenters that skin friction in 

 ordinary gliding models is a negligible quantity, but Mr, 

 Zahm finds that the frictional resistance is not improbably 

 as great for air as for water in proportion to their densities, 

 and, indeed, that it constitutes one of the chief obstacles to 

 bodies and aerosurfaces gliding at high speeds. By plotting 

 the relations between velocity and resistance on logarithmic 

 squared paper, the author found for plane surfaces that the 

 frictional resistance varied as the power of the velocity with 

 index 1-85. Prof. M. Smoluchowski-Smolan, in his paper in 

 the Philosophical Magazine for June on the principles 

 of aerodynamics, discusses the equations of motion of a 

 compressible fluid when account is taken of thermodynamical 

 effects, and he applies the principle of dynamical similarity 

 to certain physical problems. The Scientific American for 

 September 10 contains two illustrations of gliding machines. 

 The idea of attaching a machine to a bicycle in order to 

 attain the requisite speed has doubtless frequently suggested 

 itself to experimenters, and Mr. S. V. Winslow contributes 

 a photograph of a "bicycle aeroplane," which he alleges 

 " has proven perfectly successful so far as balancing is 

 concerned." The figure of Prof. Botts's circular aeroplane, 

 furnished with vertical screws in the centre, reminds one 

 of the illustrations in the well known " Histoire des 

 Ballons " of Tissandier, and it may be safe to predict that 

 a small model of this pattern would constitute a pretty 

 toy, and would sail well through a room. 



In the Journal of the Royal Microscopical Society for 

 August, a simple direct proof of Abbe's theorems on the 

 microscopic resolution of gratings is given by the late Prof. 

 J. D. Everett, F.R.S. 



In the Physical Review for July Mr. N. A. Dubois de- 

 scribes a simple method of employing allotropic silver for 

 the preparation of conducting fibres for quadrant electro- 

 meters and other similar apparatus. The author finds that 

 dried films of allotropic silver, although poor conductors, 

 become very good conductors on being treated with gaseous 

 hydrochloric acid, and that (he method can be applied to 

 the most delicate apparatus in a few minutes without risk 

 of injury. 



Messrs. E. L. Nichols and E. Merritt describe some 

 interesting studies on fluorescence in the Physical Review, 

 xix., I (July). The authors found that eosin, naphthalin 

 roth, fluorescein, quinine sulphate, chlorophyll, canary glass, 

 green and white fluorspars, and other substances exhibited 

 the same types of fluorescence, the spectrum consisting of 

 a single band near the infra edge of the corresponding 

 absorption band. The position of the maximum and the 

 distribution of intensity was independent of the wave-length 

 or composition of the e.xciting light. Fluorescence near 

 the red or violet ends was traceable further towards the 

 opposite end than is the case with bands near the middle 

 of the spectrum, because of the increased luminosity in 

 these directions. In no case did Stokes's law hold. 

 Fluorescent substances having absorption bands of shorter 

 wave-length than that with which fluorescence was 

 associated were excited by light in that band, but the same 

 was not the case when the wave-length was longer. 

 Finally, where more than one fluorescence band existed, it 

 was considered probable that each was due to a different 

 fluorescent material, as no case of multiple fluorescence 

 occurred where only one fluorescent substance was present. 



NO. i8?3. VOL. yd] 



The first two numbers (July and August) of a new 

 magazine — Lc Radium, La Radioactivity et Ics Radiations — ■' 

 received from MM. Masson and Co., Paris, contain many 

 useful and interesting articles on radio-activity and allied 

 subjects. These articles are not original contributions, but 

 are readable and well illustrated accounts of very recent 

 original work. Several deal with recent attempts to use 

 radio-active bodies for therapeutic purposes. There are in 

 addition reviews of recent papers, notices of new books, and 

 a correspondence column. While such a magazine may not 

 be essential to those who are able to keep in touch with the 

 recognised scientific journals, it will probably be found useful 

 by many interested in the subject. 



The meteorological observations and results relating to 

 the Bremen Observatory for 1903 have been published by 

 Dr. Paul Bergholz. The volume forms one of the series of 

 the Deutsches meteorologisches Jahrbuch ; it therefore 

 follows that the work leaves nothing to be desired. The 

 tables show the actual readings at three hours daily, with 

 monthly and yearly means, and daily means for each hour. 

 In addition, there are phenological and other observations 

 for Bremen, and rainfall summaries for several stations in 

 connection with the observatory. 



We have received the report on rainfall registration in 

 Mysore for 1903, by Mr. J. Cook, director of meteorology 

 in that province. The number of Government stations is 

 194. In addition to the tables, the report includes useful 

 maps showing average monthly, yearly, and geographical 

 rainfall for thirty-four years (1870-1903). During 1903 

 some heavy falls in twenty-four hours are recorded ; — 

 II inches in the district of Shimoga, in July; 11-5 inches in 

 Kolar, in November; 1265 inches in Kadur, in July. Mr. 

 Cook states that a station which escapes inspection even for 

 a single year is most likely to be defective in some par- 

 ticular ; a yearly inspection would obviously entail a large 

 amount of expense in travelling, and its necessity would 

 seem to point to want of interest by the observers in their 

 work. 



We have received a copy of a second edition of Mr. 

 Conway Belfield's " Handbook of the Federated Malay 

 States," which has just been published. The book has been 

 thoroughly revised, and the statistics brought down to the 

 end of the year 1902. 



Prof. J. C\ijic contributes to the Mitteilungen of the 

 \'ienna Geographical Society an important paper summar- 

 ising the results of recent research on the glacial pheno- 

 mena of the Balkan peninsula, and correlating them with 

 the results of similar investigation in the Alps and 

 Carpathians. 



We have received the third Bulletin of the International 

 Council for the Study of the Sea, containing the observi 

 ations made during the cruises of the different vessels in 

 February, 1904; also No. 14 of the council's Publications 

 de Circonstance, on surface temperature observations io 

 the North Sea, by Dr. Evan Everdingen and Dr. C. H, 

 Wind. 



A SERIES of gazetteers of the States is being published 

 by the U.S. Geological Survey. During the last few weeks 

 gazetteers of Virginia, Maryland, Delaware, and Texas 

 have appeared, each giving a general description and an 

 account of special features. .-Xnother valuable publication 

 of the same department is a third edition of the Bulletin 

 on the " Boundaries of the United States and of the Several 

 States and Tewitories. " 



The Central Meteorological Observatory of Japan has 

 issued the first of a new series of Bulletins, in which it is 



