154 



KNOWLEDGE. 



April, 1911. 



ORNITHOLOGY. 



By Hugh Bovd Watt. M.B.O.U. 



TH1-: BRITISH ORNITHOLOGISTS' UNION 

 EXPEDITION TO CENTRAL NEW GUINEA.— The 

 two members of this party invalided home, — Messrs. W. 

 Goodfellovv and G. C. Shortridsje — have recently safely 

 reached London, and the last-named has bronght with him a 

 large zoological collection, including about eleven hundred 

 birds. One Paradise-bird is stated to be certainly new to 

 science, and <^here are fine examples in the collection of the 

 scarlet and yellow Paradise-bird (Xatitlioiiiclas circlcns), 

 new to the National collection at South Kensington : the 

 female of the species was hitherto unUnovvn. King-birds, 

 rifle-birds, and manucodes are well represented; cat-birds, 

 grackles and starlings of se\'eral species are numerous, and 

 parrots of all si^es, from pygmy parrots to great black 

 cockatoos; also kingfishers, rollers and pittas. The cuckoos 

 include a rare and curious species {Microdyiiainis parva) 

 resembling a honey-guide. There are, further, many different 

 species of pigeons and fruit-pigeons, .and numerous smaller 

 birds, which are expected to yield the most interesting forms 

 of all, when they have been studied by the authorities. — 

 {Country Life, 4th March. 1911. page 291.) 



In Ethnology the important discovery has been made by 

 this expedition of a community of primitive people, wearing 

 no clothes, having still in use the implements and weapons of 

 the Stone Age, and unable to count beyond three. These 

 people occur up the Miniika Ki\ er. in the hitherto unknown 

 interior of Dutch New (juinea. Lantern slides from these 

 were shown at the March meeting of the British Ornithologists' 

 Club. 



WA'II'KFOWL IN THE ZOOLOGICAL GARDENS, 

 London. — .Amongst recent improvements at the "Zoo" is 

 a new lake for waterfowl, the stock of which is heavier now 

 than it has been for a long period. It is hoped that one result 

 may be a very full list of birds breeding this season. 



The geese include examples of the Orinoco, upland, 

 ruddy-headed, emperor, cereopsis. snow (blue and white), 

 black-headed, bar-headed, Hutchins, and spur- winged. On 

 the water may be found the conmion, ruddy and Argentine 

 flamingoes, mandarin, sunnner and Bahama ducks, spoonbills, 

 .American and Chiloe widgeon, China pintail, cinnamon, blue- 

 wing, green-wing, Japanese, chestnut-breasted, Andaman. 

 Brazilian, Chilian, and versicolour teal, rosy-bills, red-crested 

 pochards, white-eyes and maned geese. In the sea-lion's 

 pond is a recently arri\ed king penguin, about three feet in 

 height.— 1 77it' Field, 25th February, 1911, page 384.) 



CROSSBILLS IN THE BRITISH ISLES.— An account 

 of the exceptionally wide-spread visitation occurring in 

 1909-10, and the phenomenal nesting which followed, is 

 promised by Mr. H. F. Witherby, of Hritisli Birds, and the 

 subject was illustrated by exhibits made at a recent meeting of 

 the British Ornithologists' Club. Nests and eggs were shown, 

 most of the eggs being those of the Continental crossbill, 

 obtained last season in different parts of England and Ireland. 

 Eggs were also exhibited from the Continent, as well as those 

 of the resident Scottish race of this bird and of the parrot 

 crossbill, for comparison. The nests showed much divergence 

 in make and material. The Rev. F. C. R. Jourdain pointed out 

 that the material for study had hitherto been scanty, and that 

 there was no authentic record of a case of nesting in the same 

 locality in England for two consecutive seasons. 



THE WOOD-PIGEON PEST.— The number of resident 

 birds of this species in Wilts, Hants, and other Southern 

 Counties this winter has been enormousl)- swollen by arrivals 

 from other quarters. Many of these are smaller in size, and 

 recognisable as innnigrants from Scandinavia. The birds 

 were abnormally prevalent and persistent, doing havoc to 

 clovers and catch-crops, which are specially cultivated in the 

 counties named for ewes and lambs in the spring months. .A 

 flock-master at Cholderton. near Andovcr, with four thousand 

 .acres of ground, estimated th.at .some six tlioiisand to seven 

 thousand pigeons frecjuented it. In Wiltshire alone the 



damage done by the middle of February was said to mount 

 up to about ;i 30,000. Ordinary methods of scaring and 

 trapping having proved quite insufficient, a vigorous shooting 

 campaign was organised. One, two, or three days in each 

 week have been given to shooting the birds in each neigh- 

 bourhood simultaneously, as far as possible, following them to 

 their roosting-places. .A Government Inquiry is being asked 

 to investigate the extraordinary increase in the species, and 

 how to deal with this plague to agriculturists. 



A GOOD LOCAL LIST.— " The Birds of East Renfrew- 

 shire," by Mr. John Robertson {Glasgow Naturalist, 

 February. 1911, pages 41-59; 207. Bath Street, Glasgow. 1,3), 

 is one of those somewhat notable little works which show how 

 rich a result follows continuous and careful observation, even 

 in a not too favourable locality. The district covered is a 

 limited inland one, encroached upon further and further each 

 year, by the southern suburbs of Glasgow. Yet Mr. Robertson 

 records one hundred and fifty - one species, eighty -three of 

 which ha%e bred. The number of kinds of ducks and waders 

 which occur, season after season, is remarkable. 



THE LATE PROFESSOR ALFRED NEWTON.— Those 

 who only knew this great English ornithologist by his own 

 writings and the eulogistic accounts which have been given 

 of him in scientific and ornithological publications will turn, 

 with great interest to an article in the March number of 

 the Coriihill (pages 334-349), by Mr. .Arthur C. Benson, who 

 was a contemporary of the Professor at Magdalene, Cambridge, 

 from 1904 to 1907. Mr. Benson's chapter is, of course, not 

 ornithology, but is an intimate and personal narrative, revealing 

 a character of a type probably not anticipated by those who 

 had not personal acquaintance with the man. From this 

 personal point of view, Mr. Benson's own feelings are thus 

 expressed; — "I began by fearing him. I went on to admire 

 him, and I ended by lining him." 



■• PHOTOGRAPHY FOR BIRD - LOVERS."— Messrs. 

 Witherby & Co. have in the press .n illustrated volume 

 entitled " Photography for Bird - Lovers," by Mr. Bentley 

 Beetham, a well-known and successful bird photographer. 

 The book is an essentially practical guide to the pursuit of 

 bird-photography in all its branches, and Mr. Beetham gives 

 ungrudgingly- from the store of knowledge gained by his own 

 personal experience in the field. 



PHOTOGRAPHY. 



By C. E. Kenneth Mees, D.Sc, F.C.S., F.R.P.S. 



THE RELATION BETWEEN THE COLOUR OF 

 SIL\'ER IMAGES, AND THE SIZE OFTHE PARTICLES 

 WHICH COMPOSE THEM. — In a former number of 

 " Knowledge " (December, 1910), I referred to the investiga- 

 tion of this subject by Schaum and Schloemann, in which 

 they came to the conclusion that the colours were due to 

 optical resonance. 



At the Royal Photographic Society, on March 7th, Mr. 

 Chapman Jones ga\e an account of an in\estigation undertaken 

 by him with a view to the examination of the accuracy of 

 Zsigmondy's view that it was not possible to deduce the size 

 of the particles from the colour of a colloidal solution, and 

 that the colour was dependent to a considerable extent upon 

 the separation between the particles. 



.As the subject of this investigation, bromide of silver, 

 chloride of silver and phosphate of silver lantern plates were 

 used, developed by means of developers containing ammonium 

 carbonate and ammonium bromide, so as to produce carmine 

 and yellow tones ; while in one series of experiments the 

 phosphate plates were printed out. 



Mr. Chapman Jones adopted a most ingenious method of 

 measuring the size of the particles. If a silver image be 

 treated with mercuric chloride and. after washing, developed 

 with ferrous o.xalate, it adds mercury in the proportion of one 

 atom of mercury to one atom of silver. A second intensifica- 

 tion produces an image consisting of one atom of silver and 

 three atoms of mercury ; a third, one atom of silver and se\en 



