532 



NATURE 



[June 30, 19 10 



tion. It is not clear that either nitrogen, potash, or phos- 

 phoric acid is present in sufficient quantity to account for 

 the increased crops, and the simplest explanation appears 

 to be that the carbohydrate furnishes additional supplies of 

 energy for the nitrogen-fixing bacteria in the soil, and thus 

 leads to a gain in the soil nitrogen. 



The methods of picking, drying, and packing hops in 

 Kent are described in some detail by Mr. Arthur Amos in 

 the Journal of the Board of Agriculture (No. 2). Mr. 

 Amos writes with a complete knowledge of the subject as 

 a hop-grower, and is also a trained botanist ; the article 

 is therefore one of considerable interest. Hop production 

 is a highly specialised branch of farming, requiring much 

 more capital per acre than wheat or cattle production, and 

 it includes not only hop growing, but also drying. The 

 oasts, or drying ovens, are familiar objects to all who have 

 travelled across Kent. The drying is managed by a skilled 

 workman, who remains in charge during the whole time 

 of hop-picking, and even sleeps on the spot so that he 

 may be at hand in case of need. A good hop-dryer is a 

 person of distinction in the village community, and rightly 

 so, since he can by his efforts materially influence the 

 value of the product. 



The extraordinary interest shown by the public in poultry 

 production at the present time is discussed in the April 

 number of the Journal of the National Poultry Organisation 

 Societ}-. To a certain extent a section of the daily Press 

 is responsible for this outburst, but the popular interest 

 alwaj's existed even before it was recognised by the Press. 

 The society is proposing to take as full advantage as 

 possible of the present favourable opportunities for the 

 introduction of cooperative methods in egg production. It 

 will be interesting to see how far cooperation may become 

 a factor in English rural life. 



The Field of June 25 contains a summary of an 

 important paper read by Mr. Pocock at the meeting of the 

 Zoological Society on June 21 on the scent-glands of deer 

 and antelopes, and their bearing on the classification of 

 those groups. The author gave reasons for regarding the 

 Indian four-horned antelope as related to the bushbucks 

 rather than to the duikers, while the beira antelope of 

 Somaliland is classed with the dik-diks instead of with 

 the gazelles, and the saiga, the chiru, and the palla are 

 removed from the latter group to independent positions. 

 In the deer it is considered that the form of the antlers 

 does not constitute a trustworthy guide to affinity. 



In the Ma}' number of the National Geographic 

 Magazine Mr. H. M. Smith, the Deputy Commissioner, 

 tells some of the wonderful results which have been 

 accomplished by the Fisheries Commission in re-stocking 

 the depleted waters of the United States with food-fishes, 

 lobsters, oj'sters, &c. Nearly forty years ago the Govern- 

 ment realised the urgent necessity for measures of this 

 nature, and at the present day the official system of fish- 

 culture is stated to surpass in importance and extent that 

 of all other countries collectively. A few States did not 

 join in the movement, with the result that there has been 

 a shortage in the supply of the eggs of certain species. 

 The obvious remedy for this is the assumption by the 

 Federal Government of supreme power in regard to 

 fisheries. For the first ten years of its existence the 

 energies of the commission were concentrated on the 

 culture of the eight commonest and most valuable food- 

 fishes. Nowadays the list is six times as large, and 

 includes shad, whitefish. Pacific salmon, white perch, 

 yellow perch, cod, various kinds of flat fish, and lobsters. 



NO. 2 122, VOL. 83] 



The hatcheries also rear numerous kinds of fresh-water 

 species. The only permanent marine hatcheries are in 

 Maine and Massachusetts, where, to use the author's own 

 words, such species as cod, pollock, flat-fish, and lobsters 

 are reared and distributed by the billion. Special atten- 

 tion is likewise directed to the diseases of fishes, particu- 

 larly cancer, for which new laboratories are in course o! 

 erection. The article concludes with an account of new 

 fisheries and new methods of fishing discovered by the 

 commission. 



In an article in the June number of the Zoologist Mr. 

 F. J. Stubbs endeavours to explain the mechanism by 

 which aquatic birds are enabled to maintain themselves at 

 different levels in the water. Moorhens, it is well known, 

 will not unfrequently maintain themselves at a consider- 

 able depth below the surface by grasping plants with their 

 toes, and it is suggested that the same means are some- 

 times employed by dabchicks. It is obvious, however, 

 that such a method will not hold good for divers, in which 

 grasping power is lacking. The mechanism, in the 

 author's opinion, is afforded by the presence of a layer of 

 air held between the " feather-film " — or mesh of barbules 

 and cilia formed by the outer layer of the plumage — and 

 the skin. " Each of the contour-feathers is provided with 

 a separate apparatus of muscles, whereby it can be held 

 out at right angles or pressed close to the body. In the 

 first case the bird would appear round and fat, in th 

 second very slim, and there would be a correspondin. 

 change in the extent of the air-envelope, and consequent! 

 of the buoyancy of the bird. By adjusting the thickne? 

 of this layer of air between the ' feather-film ' and the 

 epidermis the bird can alter its specific gravity." It is 

 further considered that the water-repelling property of the 

 plumage of a duck is due to the feather-film, and not to 

 the natural oiliness of the feathers. 



We have received a series of contributions from the 

 Palaeontological Laboratory of Yale University, reprinted 

 chiefly from the American Journal of Science. This depart- 

 ment of the Peabody Museum, which became famous 

 through the researches of the late Profs. O. C. Marsh and 

 C. E. Beecher, well maintains its reputation under the 

 direction of Prof. Charles Schuchert. The most important 

 paper is one by Dr. G. R. Wieland describing in detail the 

 remarkable Cretaceous turtle, Archelon ischyros, which has 

 now been mounted for exhibition and measures consider- 

 ably more than three metres in length. A discussion of 

 this and allied Cretaceous fossils seems to show that the 

 curious leathery turtles are the degenerate descendants of 

 ordinary turtles. Baron F. von Huene and Dr. R. S. Lull 

 publish a photograph and sketch of the original specimen 

 of the small Triassic Dinosaur, Nanosaurus agilis, showing 

 that it is much less satisfactory than might be supposed 

 from Prof. Marsh's description. Prof. T. D. A. Cockerell 

 and Dr. H. F. Wickham describe many insects and plant- 

 remains from the Miocene of Florissant, Colorado ; while 

 Prof. Schuchert himself discusses a series of Silurian fossils 

 from Arisaig, Nova Scotia, carefully collected by Mr. W. H. 

 Twenhofel. 



The " Extracts from Narrative Reports of Officers of 

 the Survey of India," for the season 1907-8, contain an 

 interesting account of precise levelling carried out with the 

 American binocular level. This instrument differs from 

 levels of the ordinary form in several important particulars. 

 It is provided with a second telescope, through which the 

 bubble can be viewed and the scale reading at each end 

 of the bubble observed at the same time as the staff read- 

 ing is taken. The advantage of this is obvious, as the 



