January 27, 1910] 



NA TURE 



365 



The usual classification of the major submarine 

 forms includes the shelf, the depression, and the 

 elevation. The shelf extends to about loo fathoms 

 below sea-level. As the lowest ground represented 

 in these maps, from o to 600 feet, is coloured green, 

 while the sea to the depth of 100 fathoms is tinted a 

 light blue, students will probably find it somewhat 

 difficult to compare these areas. The maps would 

 have gained considerably if both, these regions, from 

 600 feet to the loo-fathom line, had been left white, 

 and if the names, at any rate on the land, had been 

 omitted. It is surely quite unnecessary to print 

 "'.^FRic.4" across the continent in such large letters 

 as to obscure some of the details of the plateau' of 

 Abyssinia. 



On the oceans the names are fewer in number, and 

 do not interfere with the graphic effect of the deeper 

 blue which marks the depressions and elevations of 

 the ocean floor. 



Though, as regards graphic representation, more 

 suited for reference than school use, these maps have 

 one important advantage. The equal-area projection 

 employed is most,effecti\e for the oceans, when shown 

 separately, and the comparison of areas possible should 

 be useful in the study of the relative extent of land 

 and sea. 



The Practical Management of Sewage Disposal 



Worl;s. By \\'. C. Easdale. Pp. 60. (London : 



The Sanitary Publishing Co., Ltd., 1909.) Price 



2S. net. 

 :The author has endeavoured with considerable suc- 

 ■cess to deal, in the space of fifty-four small pages, 

 with the more important points arising in the manage- 

 ment of small sewage works and private-house instal- 

 lations, &c. 



When considering the question of tanks, the author 

 rather unfortunately states that in all types of tanks, 

 i.e. sedimentation, precipitation, and septic tanks, the 

 work to be done is the same, viz. the removal of 

 suspended matter. This expression is somewhat mis- 

 leading" and liable to misinterpretation. 



Apparently, in dealing with the removal of sludge 

 from tanks, septic tanks only are considered, as the 

 author's doctrine of "little and often" removal, with- 

 out emptying the tank, can only in general be pro- 

 perly applied to such tanks, and, it may be added, 

 only when the design of the tank allows of the re- 

 moval of the more or less thoroughly septicised sludge. 

 In the case of sedimentation and chemical precipita- 

 tion tanks, it is almost essential that the sludge should 

 be completely removed at each operation in order to 

 ■avoid fermentation taking place, with its consequent 

 ill-effect on the complete settlement of the suspended 

 solids. 



In connection with the design of contact beds, the 

 •author rightly directs attention to the e.xtreme import- 

 'ance of the thorough and complete drainage of the 

 bed, and also to the question of the size of the unit. 



It is evident that there is a limit to the applica- 

 tion of the maxim "little and often" advocated in 

 regard to the removal of accumulated suspended 

 matter from the surface of the contact beds. From 

 the point of view of economy, cleansing operations 

 should not be carried out too frequently, as it is 

 obvious that a certain amount of filtering media must 

 be removed at each operation, incurring additional 

 cost ; while so long as the accumulated suspended 

 matter is not sufficient to impede the drainage from 

 the surface and consequent ingress of air, no detri- 

 mental results may be anticipated. 



The author's remarks with regard to the attention 



to_ be given to distributing apparatus in connection 



with percolating filters are important, and should 



be carefully noted. In connection with the final 



NO. 2100, VOL. 82] 



chapter on tests and records, Spitta's methylene blue 

 test might with advantage be included, and possibly 

 a colour test for nitrates. 



The book can be thoroughly recommended for the 

 objects defined in the author's introductory remarksi. 



E. A. 

 Das Reich der Wolken und Niederschldge. By Prof. 



Dr. Carl Kassner. Pp. 160. (Leipzig : Quelle and 



Meyer, .1909.) Price 1.25 marks. 

 This work. No. 68 of the popular scientific manuals 

 published by Messrs. Quelle and Meyer, is to some 

 extent the outcome of lectures delivered by the author 

 at technical high schools, modified to meet the re- 

 quirements of general readers. In addition to sound 

 elementary information on the taking and reduction 

 of observations, it includes the results of the most re- 

 cent investigations, of the fundamental researches of 

 Hann, Hellmann, and others, and useful references 

 to the historical development of this branch of meteor- 

 ological science. Chapters i.-v. treat of aqueous 

 vapour, condensation, formation of fog and clouds, 

 sunshine and cloudiness. Chapters vi.-x. deal with 

 rainfall, snow and hail, exposure of gauges, calcula- 

 tion of results, &c. The remaining chapters, xi.-xiii., 

 refer to the rainfall over the globe, the causes of its 

 unequal distribution, to daily, yearly, and secular 

 periods. The whole will repay careful perusal ; among 

 some of the many points of special interest we may 

 note references to Goethe's appreciation of Howard's 

 classification of clouds, to various kinds of glazed 

 frost and hail, and to the effect of wind and exposure 

 on rainfall records. Hellmann's classification and re- 

 production of Neuhauss's photographs of snow crystals 

 are preferred to Glaisher's drawings, which the author 

 hints should now be omitted from text-books. On 

 p. 78 we notice that Chepstow is misprinted as 

 Chepston. 

 Astronomische Abhandlungen der Hamburg Stern- 



ivarte in Bcrgedorf. Edited by the director. Dr. R. 



Schorr. Band i. No. i, pp. 130, and 3 plates; 



No. 2, pp. 10, and 3 plates; No. 3, pp. 99. (Ham- 

 burg, 1909.) 

 Founded in 1825 by State-aided private means, the 

 Hamburg Observatory was taken over by the State 

 in 1833, and in 1906 was by decree transferred to the 

 new site at Bergedorf. This site and its equipment 

 are briefly described in Dr. Schorr's introduction to 

 the new series of " .-\bliandlungen " of which that 

 under review is the first volume. 



Part i. is by Dr. Dolberg, who describes, and dis- 

 cusses, the latitude determinations made at Hamburg 

 in 1904-6. The observations were made with a 

 Repsold portable transit instrument, and a great part 

 of the time was spent in determining and discussing 

 the instrumental errors. The actual latitude observa- 

 tions were made in 1905, and consisted of 426 com- 

 plete measures of 90 pairs of stars. These are dis- 

 cussed, with the reductions, at length, and a mean 

 latitude of 53° 33' 6'05"±o'oi5" is found for the posi- 

 tion of the circle. 



Dr. Graff is responsible for the work described in 

 parts ii. and iii., and in the former he describes his 

 observations, measures and drawings of Saturn dur- 

 ing 1907, when the ring system and the earth lay in 

 the same plane. The three plates carry twelve draw- 

 ings, and form an interesting record of the various 

 appearances of the edges of the rings from July 26 to 

 November 30, 1907. 



Part iii. is of less general interest, but is a useful 

 reference work. It contains the places of 580 variable 

 stars, lying between the North Pole and 23° south 

 declination, for the epoch i9oo'o. The objects are 

 given under their various constellations first, and are 

 then collected into a general catalogue showing the 



