December 9, 1909] 



NA TURE 



16- 



in the latter Prof. O. Drude discourses on the theory of 

 the origin of species, and especially the publication of the 

 famous volume bearing that title, as a land-mark in the 

 life of Darwin. 



According to a paper by Mr. L. B. Taylor, published 

 in the October number of the Journal of the South African 

 Ornithologists' Union, Verreaux's eagle (.4q«i7a verrcauxi) 

 constructs its nest in Cape Colony entirely of the green 

 boughs of a rough bush, which must be very difficult to 

 break o(T. The only other instance of the use of similar 

 material for nest-making occurs in the case of the African 

 .4. waiilbergi, where it is used as lining. A. verreauxi 

 preys, to a great extent, on hyraxes, numerous remains 

 of which were found in the nest examined by Mr. Taylor, 

 but also hunts and kills a certain number of klipspringers. 



The latest issue (vol. vi., anno 3) of Rhista di Scienza 

 contains three articles on geological subjects. Prof. L. de 

 Marchi dealing with mountain-formation, Prof. F. E. 

 Mess contributing the second instalment of an interesting 

 article on modern theories of volcanic action, and Messrs. 

 P. Enriques and M. Gortani discussing the succession of 

 geological periods. The last-named article is of a some- 

 what remarkable»character, as the authors deny the exist- 

 ence of any such definite periods. They do not, however, 

 propose to abolish the generally accepted geological classifi- 

 cation, which they consider necessary for the convenience 

 of study, but content themselves with pointing out its 

 purely artificial character. 



The important subject of the working of teak forests 

 comes in for discussion in the Indian Forester (October). 

 Mr. J. F. Troup, tlie imperial superintendent of forest 

 svorklng-plans, recommends measures for improvement 

 fellings in the Burma forests associated with burning of 

 undergrowth to help natural reproduction and produce even- 

 aged crops. With reference to the mixed teak forests in 

 the Central Provinces, where the system is coppice with 

 standard, Mr. C. M. McCrie points out that information 

 is wanting as to the longevity of coppiced stools and 

 coppice shoots, also as to the fertility of seed produced by 

 the latter. 



For many years coffee plantations in Central America 

 have suffered from the attacks of a parasitic fungus which 

 is said to be almost as dangerous as its better known 

 eastern congener, Hemileia vastatrix. Little information 

 has been available concerning the life-history of the fungus 

 except the production of a conidial stage on diseased 

 leaves, shoots, and fruits, to which Cooke gave the name 

 Stilbum flavidtim. Mr. G. Massee now records in the 

 Kew Bulletin (No. 8) that he has obtained an ascus-forming 

 (Nectria) stage, which transfers the fungus to the genus 

 SphEerostilbe. Unlike the conidia, the ascospores readily 

 produce infection in healthy leaves, leading to the forma- 

 tion of the customary white spots and conldiophores. 



A STUDY of the phytoplankton gathered in the North 

 Atlantic Ocean affords a great deal of variation, as will 

 be realised from the results published by Mr. W. Stuwe 

 in Engler's Botanische Jahrhiicher (vol. xliii., part iv.). 

 From Dover to Brest the plankton is coastal, and consists 

 almost entirely of diatoms, with a preponderance of species 

 of Coscinodlscus and BIddulphla. Thence to the Azores 

 species of Ceratium abound in the deeper waters, but in 

 the neighbourhood of the Canaries the increase of 

 Bacillariacea; betokens an influx of coastal forms. Around 

 the Cape Verde Islands Trichodesmium is dominant in the 

 equatorial currents. Another type of vegetation is met 

 with in the Sargasso Sea, in which species of Ceratium, 

 nctably Ceratium tripos protuberans, are common. With 

 SO. 2093, VOL. 82] 



regard to vertical distribution, in the colder waters the 

 Bacillariace.-E predominate at the surface, while the 

 Peridinea^ occur in the next zone ; in the warm seas the 

 Perldlneas lie at the surface, and the diatoms are found 

 below. 



The results of manurlal experiments on the sugar-cane, 

 carried out at the Experiment Station of the Hawaiian 

 Sugar-planters' Association, have just been issued 

 (Bulletin No. 29). The results could not be correlated with 

 the chemical composition of the soil as determined by 

 the ordinary methods of analysis or by the aspartic acid 

 method first used in Hawaii, and the author concludes 

 that the profit resulting from the application of manures 

 will depend largely upon other factors than the chemical 

 composition of the soil. The greatest loss from the use 

 of improper mixtures of fertilisers was found to occur in 

 acid soils. 



We learn from the Journal of Agriculture of South 

 Australia that the Irish potato blight (caused bv the 

 fungus Phytophthora infestans) has made its appearance in 

 several of the Australian States. It does not appear that 

 the disease is yet very widespread, and by mapping out 

 the affected areas and adopting suitable precautions within 

 those areas it should be possible to prevent great damage 

 being done. A well-illustrated account of the disease is 

 given, so that the practical man may readily recognise 

 it, and methods of treatment are fully described. Spray- 

 ing with Bordeaux mixture is a well-recognised preventive 

 measure, and is discussed at some length. 



A SUMMARY has recently been issued from the New Jersey 

 Agricultural Experiment Station of the investigations 

 carried out by Messrs. Voorhees and Lipman on various 

 nitrogenous manures. Out of a hundred parts of nitrogen 

 supplied as nitrate of soda, sixty-two parts were recovered 

 in the crop over a period of ten years, and in the case of 

 ammonium sulphate forty-three parts were recovered ; 

 these results agree almost exactly with those obtained by 

 Wagner at Darmstadt. The relative availability of the 

 various fertilisers tested was : — ■ 



Sodium nitrate ... 



Ammonium sulphate 



Dried blood 



Solid manure (fresh) ... 



Solid and liquid manure (fresh) 



Solid and liquid manure (leached) 



Solid manure (leached) 



100 

 697 

 64-4 

 35-9 

 S3-0 

 43-1 

 38-9 



The fundamental importance of irrigation and of methods 

 of dry-farming In South Africa is well brought out in a 

 series of articles In recent issues of the Agricultural 

 Journal of the Cape of Good Hope. Throughout consider- 

 able areas of South Africa the rainfall is either insufficient 

 or is too irregularly distributed for the best crop returns 

 to be obtained, and the chief problem in arable farming 

 becomes the provision of proper water supply. Recourse 

 may be had either to irrigation or to "dry farming," the 

 former being more generally applicable than the latter. 

 A delegate was sent to the National Irrigation Congress 

 at Albuquerqu, New Mexico, U.S.A., and his report con- 

 tains many suggestions likely to be of value in evolving 

 methods suited to South Africa. There is also a report 

 on the possibilities of irrigation in Bechuanaland. By way 

 o' encouraging dry farming, the De Beers Company is 

 offering at the next Bloemfontein show a prize of 20Z. for 

 the best exhibit of maize grown on " dry lands " without 

 irrigation. 



In Man for November Mr. W. G. Aston raises the ques- 

 tion of the origin of sexual antipathy among near relations. 



