4IO 



KNOWLEDGE & SCIENTIFIC NEWS. 



[April, 1906. 



mass of a jjas when these change, are all unanimous in 

 indicating that for each pressure of a gas there are two 

 inversion temperatures (if any), but that above a certain 

 pres>ure there will be none. The last statement is equiva- 

 lent to asserting that if hydrogen be sufficiently compressed, 

 it will undergo warming in passing through a porous plug, 

 whatever its tempenifure may be. Further experiments 

 are badly wanted on this subject ; and if it should turn out 

 that the above prognostications are not realised, it will 

 merely show that the true equation connecting pressure, 

 volume, and temperature, is not the one upon which the 

 conclusions are based; and we have here, indeed, a most 

 sensitive means of obtaining information about this equa- 

 tion. 



ZOOLOGICAL. 



By R. Lydekkek. 

 A New British Fish. 



.'\mong British freshwater fishes few are of greater interest 

 than the group repiesented by the Lochmaben vendace 

 (Corcijonus I'andesius), the Irish pollan (C. poUan), and 

 several other more or less closely allied forms, each confined 

 to a single lake or group of lakes. All these fishes are 

 members of the salmon tribe, and are near akin to a marine 

 species ; the latter fact indicating that they were at one time 

 in all probability migratory, but have now become confined 

 to the lakes they respectively inhabit. This isolation is 

 doubtless the main factor which has led to the distinctness 

 of the various species. A further illustration of this 

 tendency to differentiation is afforded by the recent dis- 

 covery (detailed in the February issue of the Annals and 

 Magazine of Natural History) that the vendace of Derwent- 

 water is distinct from, although nearly allied to, the Loch- 

 maben species. In allusion to its slender build, it has been 

 named Coregoaus (jiaciliur. 



The White Winter Coat of Mammals. 



Much ink has been spent in diseu>^ing tlu- question as 

 to whether animals like the stoat, which in high northern 

 latitudes turn white in winter, do so by changing their 

 coats, or by the bleaching of the hairs of the dark summer 

 dress. It has been demonstrated that the senile whitening 

 of human hair is due to the presence of phagocytes, which 

 devour the pigment-bodies ; and from microscopic observa- 

 tions recently made by the well-known French naturalist, 

 Dr. F,. Troue-~sart, it appears that much the same kind of 

 action takes place in the hairs of mammals that turn white 

 in winter. Cold, by some means or other, causes the pig- 

 ment bodies to shift from the normal positions, and to trans- 

 fer themselves to other layers of the hair, where they are 

 attacked and devoured by phagocytes. The winter whiten- 

 ing of mammals is, therefore, precisely similar to the senile 

 bleaching of human hair, no shift of the coat taking place. 

 Under the influence of exposure to intense cold a small 

 mammal has been observed to turn white in a single night, 

 just as the human hair has been known to blanch suddenly 

 under the influence of intense emotion, and in both cases 

 extreme activity of the phagocytes is apparently the inducing 

 cause. Dr. Trouessart's paper is published in the Comptes- 

 rhulus of the French Biological .Society for February. 



A Dw&rf Elephant. 



As the heart of Congo-land is the home of dwarf repre- 

 sentatives of the human race, so, according to a German 

 naturalist, it is the abode of a diminutive race of the African 

 elephant, which probably does not exceed five feet in height. 

 The interest of this dwarf elephant centres in its relation 

 to the extinct pigmy species of Malta and Cyprus, whose 

 teeth indicate that they were nearly allied to the African 

 animal. 



The Horns of the Wild Sheep. 



It is a well-known fact that the horns of several species 

 of wild sheep arc always more or less damaged at the tips. 



This has been explained by some as due to the animals 

 fighting, or to their raking up the snow and ground in 

 search of food ; the latter theory not accounting for the fact 

 that it is only the horns of old rams which are thus 

 damaged. In a recent issue of Shields' Maqazinc Captain 

 C. E. Radclyffe offers the following explanation : — 



" My own opinion is that the tips are worn down in- 

 tentionally, and that this is done by rubbing the ])oints of 

 the horns against rocks. On inspection we find that the 

 tips are worn away, as if rubbed with a coarse file, and 

 are not broken off. If the latter were the case the remain- 

 ing ends of the horns would be more split and fractured 

 than they are." ... It seems that when the horns 

 attain a certain size and shape their points interfere with 

 vision, and in some cases also with feeding; for occasion- 

 ally they grow into such a shape that when the rams are 

 grazing their points, unless reduced in length, would come 

 into contact with the ground. Somewhat remarkable 

 powers of reasoning ;ire thus attributed by the author to 

 wild sheep. 



The editor is indebted to the author, Mr. C. O. Esterby, 

 for a copy of a paper on the nervous system of the copepod 

 crustaceans, recently issued by the University of California 

 at Berkeley. 



Papers R.ead. 



At the meeting of the Zoological .Society on February 6, 

 Dr. J. W. Jenkinsoii read a paper on the Ungulate placenta, 

 Mr. E. S. Russell described a new hydroid polyp, and Miss 

 Ricardo a new horse-fly; while Mr. H. Schwann com- 

 municated notes on a collection of African mammals, and 

 Mr. Lydekker described others collected by Major Powell- 

 Cotton. The most important paper was, however, one by 

 Mr. 11. G. F. Spurred on the modes of articulation of the 

 vertebrate lower jaw. At the meeting of the same Society 

 on February ^o, Messrs. Doncaster and Raynor described 

 experiments in breeding Lepidoptera, Mr. W. P. Pycraft 

 read a paper on certain passerine birds, Messrs. Thomas 

 and Schwann gave notes on African mam,mals, and Dr. B. 

 Dean discussed the habits of the Australian lung-fish. 



Protection of Birds. 



It is pleasing to note in the annual report of the Society 

 for the Protection of Birds, that some humane restric- 

 tive laws are having good results. For example. Lord 

 Curzon's order in India prohibiting the export of 

 plumage, an order which had the support of native 

 religious sentiment in India, has considerably reduced 

 the output, though Indian bird skins and feathers still 

 offered at the London plumage sales show tliat the 

 order is evaded. Tlie stationing of watchers at Dun- 

 geness and on Lundy Island for the protection of sea 

 birds has done good also; and peregrines and buzzards 

 are now nesting on Lundy. The gannets of the Bass 

 Rock are now secure from the guns of idiot trippers; 

 and it is hoped that the St. Kilda wren will be rescued 

 from threatened extinction by tlie Inverness order of 

 last summer. On the other hand, the decrease of swal- 

 lows is still unaccounted for, and there is little hope 

 of saving goldfinches from the imprisonment in the 

 cages of London slums and birdshops to which the 

 Sunday birdcatcher dooms him, unless Sunday were 

 made a close day. That the goldfinch and the king- 

 fisher will recover tlieir number if protected has been 

 shown. 



Messrs. Newton, scientific instrument makers, have taken 

 into partnership !\Ir. Russell L. Wright (son of the late 

 Mr. Lewis Wright, the author of " Light " •' Optical Pro- 

 jection," S:c.), who has been for some years tfieir works 

 manager and head of their electrical department. 



