February 23, 1911^ 



NATURE 



557 



Prof. Zenneck then describes the Pauling process. It 

 is a well-known fact that vigorous blowing will put out 

 the electric arc, consequently it is not an easy matter to 

 blow air through an arc so that the nitrogen may become 

 oxidised without blowing out the arc. In the process of 

 Pauling, air is blown through an arc. The arc, however, 

 is struck between horn-shaped conductors, such as are 

 used as lightning arresters. The two horns are closest 

 together near the bottom, and it is here that the arc is 

 struck. Owing to the ascending hot air, the arc rises 

 upwards, and is broken once for each period of the 

 alternating current. A new arc, however, is immediately 

 produced again at the bottom, and this goes on con- 

 tinuously. An air current is also driven at high speed 

 through the electrodes, and this further elongates the 

 flames, so that an arc of very considerable length is pro- 

 duced. This process is now in successful operation in 

 Switzerland and the south of France. 



Special attention is given to the interesting process of 

 the Badische Anilin- und Sodafabrik. This particular 

 process was illustrated experimentally at the International 

 Congress of Chemistry held in London in May, 1909. An 

 arc is caused to form throughout a long tube, and the 

 air fs blown in tangentially. In practice, arcs of 8 metres 

 long are employed. 



Which of these three processes will best stand the test 

 of time remains to be seen. The sine qua non in all cases 

 is, however, cheap power. In structional details each 

 plant is being continually improved, and at present each 

 of these processes is being commercially worked. The 

 Paulin process is, we believe, very well adapted for the 

 manufacture of concentrated nitric acid, which is so 

 important in the manufacture of explosives, and if suflRci- 

 enily cheap may readily be converted into a fertiliser. 

 The other two processes are certainly well adapted for the 

 manufacture of fertilisers, and there is no inherent reason 

 whv nitric acid should not also be produced in all cases. 



F. M. P. 



BIRD XOTES. 



T N a lecture on the birds of \'ictoria delivered to the 

 -*• local Field Naturalists' Club in September, 1910, and 

 published in vol. xxvii., No. 8, of the Victorian Saturalist, 

 Mr. J. A. Leach directed attention to the extraordinarv, 

 and apparently unique, richness of Australia in birds. 

 Net only, he remarks, has the country its own peculiar 

 typves of interesting birds such as emeus, malleebirds, 

 black swan, laughing jackass, cockatoos, many parrots, 

 lyre-birds, bower-birds, &c. (some of these being common 

 to New Guinea), but it likewise contains representatives 

 of every widely spread family of birds with the exception 

 of vultures and woodpeckers. 



To vol. vi., No. 2, of the Journal of the South African 

 Ornithologists' L'nion Messrs. Bucknill and Gronvold 

 contribute a paper on the eggs of certain South African 

 birds, which, for the most part, have not been previously 

 described or figured, the paper being illustrated by an 

 exquisite coloured plate. The largest egg figured is that 

 of the African hawk-eagle (Etitolmaetus spilogaster), one 

 of a pair taken in Matabeleland in 1904, and now in the 

 Transvaal Museum. Perhaps the most interesting of all 

 is the egg of Poliohierax semitorquatus, which, in its 

 uniform whiteness, corresponds with those of the nearly 

 related Indo-Malay falconets (Microhierax). In 1902. when 

 the second volume of the " Catak^ue of Birds' Eggs " 

 was published, the British Museum possessed one clutch 

 of eggs of Microhierax, birt none of the allied African 

 genus. 



The third part of vol. x. of the Emu (December, 1910) 

 contains a report of the tenth annual session of the Royal 

 Australian Ornithologists' Union, held at Brisbane in 

 October. Special attention was directed to the need for 

 protecting Australian birds, and it was decided to request 

 the Government of Tasmania to take action for protecting 

 the penguins on the Macquarie Islands. Mention was 

 made of the founding of a Gould League for the purpose 

 of encouraging a love of birds among the rising genera- 

 tion. At one of the meetings the State Governor, Sir 

 William Macgregor, expressed himself in favour of bird- 

 protection, but had doubts as to the feasibility of its 

 NO. 2156, VOL. 85] 



enforcement. His Excellency stated as an example of this 

 diflSculty that when in British New Guinea he passed 

 laws for the protection of birds-of-paradise, and that these 

 were nearly fatal to the red species. For during his 

 absence a visitor asked permission to obtain one or two 

 specimens for scientific purposes, and, having obtained it. 

 straightway proceeded to shoot all that were obtainable, 

 so that when the Governor, on his return, visited Fer- 

 guson Island he found not a single full-plumaged bird of 

 this species remaining. 



Country Life of January i contains two life-size illus- 

 trations of the newly named Irish coaltit, placed alongsid 

 those of its Bcitish representative, with descriptive not' 

 by Mr. W. R. Ogilvie-Grant. The Irish bird is chara 

 terised by the light patches on the sides of the head and. 

 neck, as well as the occipital spot, being pale mustard- 

 yellow, instead of white ; the back olive^rey washed with 

 yellowish cinnamon, in place of olive-grey ; the upper tail- 

 coverts cinnamon, in marked contrast with the rest of 

 the upper parts, instead of brownish-fawn, not decidedly 

 different from the back; the breast and belly whitish, 

 washed with mustard-yellow, in place of whitish or 

 greyish-white ; and the sides and flanks cinnamon, instead 

 of fawn. In freshly killed examples the mustard-yellov. 

 is bright and conspicuous, but fades a few days afte: 

 death. The British coaltit, which Mr. Grant regards a» 

 a subspecies {Parus ater britannicus), occurs in County 

 Down, a fact, in his opinion, affording additional evidence 

 in favour of regarding the Irish bird (P. hibernicus) as a 

 separate species. 



Considerable discussion, reported in various issues of 

 the Field, has taken place at the British Ornithologists'" 

 Club with regard to white-breasted British cormorants. 

 While some ornithologists regard all such birds as 

 immature, others maintain that certain examples are much 

 older, and consider that one particular skin belonged to 

 a bird of ir'om twelve to fifteen months old. It was also 

 suggested that white-breasted birds appeared sporadical!) 

 in certain colonies, where they might become th- 

 dominating type. 



Notes on the peregrine falcon in the Midlands and on 

 the habits of the crested grebe are contributed to the 

 Januani- number of the Zoologist by Mr. O. V. Aplin. 

 The former species, it appears, is still a regular visitor 

 to the southern Midland counties, but the birds seen- 

 there in autumn are, in most instances at anj- rate, 

 immature. 



Of a very different character from all the foregoing is a 

 paper by >ir. H. C. Tracy, issued in the Zoological Publi- 

 cations of the University of California, on the significance 

 of white markings in passerine birds. The object of the 

 inquiry on this subject undertaken by the author was to 

 endeavour to reconcile the old theory that white_ markings 

 in birds are recognition-signs, with the newer, and appar- 

 ently contradictor}.-, hypothesis that they are for protective 

 purposes. The result, in Mr. Tracy's opinion, is that both 

 theories are perfectly true and mutually supplement one 

 another. Markings which are displayed only or chiefly 

 when the birds are in flight, such as the white area at 

 the base of the tail-feathers common to many terrestriaf 

 birds — as in our own wheatear — are recognition-marks, 

 and it is noticeable that these are specially developed in 

 gregarious groups. On the other hand, in the case of 

 arboreal species, white markings at the base of the flight 

 feathers, which become specially conspicuous when their 

 owners are in flight, appear to serve for protection and 

 for recognition. The author took, for instance, specimens 

 of the green-backed goldfinch (AstragaUnus psaltria) and 

 black-headed grosbeak (ZameJodia melanocephala), in 

 which these particular markings are well developed, and, 

 after spreading the wings, " photographed them against 

 sunlit foliage and backgrounds of leaves with spaces of sky- 

 showing through. The birds were difficult to find in the 

 resulting prints. Urnloubtedly the photographs, by theii^ 

 lack of relief, exaggerated the concealing effect ; yet that 

 there is such an effect, in general, it is safe to admit."" 

 L^ter on, it is added that when the bird takes wing, a 

 different principle comes into play, and, as there is no 

 broken background, the markings stand out conspicuously. 

 " When we consider." continues the author, " the value 

 to all birds ranging in the open foliage of instant recogni- 

 tion at a distance and sight-clues for the purpose of keep- 



