August, 1905. 



KNOWLEDGE & SCIENTIFIC NEWS. 



207 



Uintacrinus in the Croydon Chalk. 



Dr. G. J. Hinde has found .ivery close resemblance to some 

 of the higher zDuesof the chalk of the coast near Margate in the 

 chalk of'the tract between Russell Hill and Beddington, in 

 Surrey. Hitherto the chalk hereabouts had been thought to 

 belong to the zone of Micyaster cor-aiit^uiiium, although when 

 last year the third volume of the " Cretaceous Rocks of Great 

 Britain" was published by the Geological Survey, it was 

 anticipated that the zone of Maisii/^ilcs was present. Doubts 

 have now been set at rest by the discovery by Dr. Hinde of 

 some test-plates of free-swimming crinoid Mai-supitcs, with 

 Echinocoiys scutatiis ; and at the same time he discovered 

 some smaller inconspicuous test-plates, which, on close ex- 

 amination, were found to belong to the unstalked free- 

 swimming crinoid known now as Uintacrinus. These show the 

 existence", near the place where the chalk disappears beneath 

 the tertiaries, to reappear on the north of London, of the 

 lower portion of the Marsupitcs-zone, called by Dr. Rowe the 

 " Band of Uintacrinus." The fossils found by Dr. Rowe in 

 this band in coast-sections near Margate agree almost identi- 

 cally with those found by Dr. Hinde near Beddington. 



O R.NITHOLOGICAL. 



By W. P. Pycraft, A.L.S., F.Z.S., M.B.O.U., &c. 

 The Scent of Sitting Birds. 



Mr. Tegetmeier, at the last meeting of the British Ornitho- 

 logists' Club, made some interesting observations on the scent- 

 less nature of birds when sitting on their eggs. He contended 

 that the physiological explanation of this was well known, and 

 that the "vicarious secretions" causing the scent were re- 

 tained within the body in sitting birds, and passed into the 

 cloaca, to be eventually voided with the faeces. The odour of 

 the f;eces dropped by a silting bird was, he said, totally 

 different from that passed at other times, and their particularly 

 offensive smell was caused by these secretions. 



We venture to think that this explanation will not stand the 

 test of investigation. Birds are unique in the glandless nature 

 of their skin, even sweat glands being absent. Whatever smell 

 escapes is probably exuded by the feet ; hence the care taken 

 by many birds to fly straight off from the nest, and so prevent 

 the tell-tale traces, which would otherwise be left, of the 

 whereabouts of their eggs. The unusual offensiveness of the 

 faeces may be explained by their long retention in the cloaca. 



The Eggs of the Knot. 



Dr. Bianchi, of the St. Petersburg Museum, brought with 

 him, on his recent visit to London, a collection of twelve eggs 

 of the Knot (Tringa canittus), and a few nestlings, and these 

 he exhibited at the last meeting of the British Ornithologists' 

 Club. 



The nestlings of this bird were discovered by Colonel 

 Fielden when in the Arctic expedition of 1876; but the eggs 

 remained unknown till discovered by the late Dr. Walters on 

 an expedition to the Taimyr Peninsula in igoi. To allay all 

 doubt as to the identity of these eggs the parent birds were 

 also taken. The eggs are remarkable for the great variability 

 which they show in size, form, and colour. The ground-colour 

 ranged from " pale clay " to pale yellowish white, and pale 

 green. The markings took the form of dirty-brown and violet- 

 grey spots, tending to cluster at the blunt end of the egg, and 

 varying much in size. 



Dr. Walters was the medical attendant and ornithologist of 

 the expedition, and died before it returned, at Kotelny Island, 

 December 21, 1902. 



Nesting of the Scoter in Ireland. 



The Field, July 15, contains a most interesting account 

 by Major Trevelyan of his discovery of the breeding of the 

 Common Scoter (CEdcmia nigra) " on one of the loughs in 

 Ireland " during this summer. He had the good fortune to 

 discover the female sitting on a nest of eight eggs in June last. 

 This was placed under a small bush on an island. On 

 July I, he found her with five young ones swimming about in 

 the lough. Tufted ducks were breeding here in some numbers. 



and in several casoi it would appear that more than one 

 female was laying in the same nest, since as many as twenty- 

 one eggs were found in one case and nineteen in another ! 

 Two other nests contained sixteen and eighteen eggs respec- 

 tively. Gulls seem to levy a heavy toll on the young of these 

 birds, as well as on the eggs. 



The exact locality of this new breeding-ground is very wisely 

 withheld. 



Waxwings in Berkshire. 



In the Bulletin of the last meeting of the British Ornitho- 

 logists' Club, Major F. W. Proctor records the occurrence of 

 a pair of Waxwings (Ampclis garrnliis) at Maidenhead Thicket 

 on April II. They were, we learn, unmolested, but whether 

 they remained to breed has so far not been ascertained. 



Marsh-Warbler Nesting in East Kent. 



Mr. CoUingwood Ingram at the meeting above referred to 

 exhibited an egg of the Marsh- Warbler (Aerouphalus p3,liislris) 

 taken from a nest of five. The remaining four eggs were left 

 and hatched out. This is believed to be the first authentic 

 instance of the breeding of this species in Kent. The nest 

 was placed in on the shoots of a young ash-tree about three 

 feet from the ground. It was composed of dried grass-stalks 

 and lined with horse-hair and cocoa-nut fibre, the latter 

 procured from a neighbouring hop-garden. 



The Western Bla.ck-Eared Cha^t at Hove. 



An example of the Black-eared Chat (S-ixicola albicoUis 

 cafi-riiiLr) was killed at Hove on May 22, 1905. This is the 

 second recorded instance of this bird in Sussex; the first 

 example having been killed three years ago. Both cases were 

 reported to the British Ornithologists' Union by Mr. R. 

 B'.itterfield, who saw each bird in the flesh. 



PHYSICAL. 



By Alfred W. Porter, B.Sc. 

 A Scientific Essentia.1. 



And above everything the scientist must foresee. Carlyle 

 wrote somewhere to this effect : " The fact alone matters ; 

 fuhn Sansterrc passed this place; there is a reality for which 

 I would give all the theories of the world ! " Carlyle was a 

 compatriot of Bacon, but Bacon would not have said that. 

 That is the language of the historian. The physicist would 

 say rather : John Sansterre passed this way ! That is 

 nothing to me, since he will not pass this way again. 



Poincarc, La Science ct Vhypothese. 



The Alpha Stream. 



Professor Rutherford is making an extended investigation 

 into the properties of the Alpha stream of particles emitted in 

 many of the stages of disintegration of radium. .A preliminary 

 account appears in the Philosophical Magazine for July. The 

 main object of the experiments is to obtain a more accurate 

 measure of the mass of each of these particles, and thence to 

 decide whether or not they are identical with helium. This 

 better value has not yet been obtained, but many facts of 

 importance have turned up in the course of the preliminary 

 observations. 



Previous measurements have been made on the particles 

 shot out from radium. But it is now known that radium in a 

 state of radio-active equilibrium is a very complex substance ; 

 and that the particles shot out at different stages do not leave 

 with the same velocity. The improvement now introduced is 

 to use one of the disintegration products alone, viz.. Radium 

 C. Radium A (the product of the disintegration of the ema- 

 nation) is deposited on a highly negatively charged wire. 

 This quickly breaks up successively into Radium B and C, 

 and the Alpha particles then shot out are taken as 

 arising from C because B does not emit any. This wire is 

 then placed behind a slit, and the stream that passes the slit 

 falls on a photographic plate, slit and plate being placed a few 

 centimetres apart. The whole is placed in a transverse mag- 

 netic field in a vacuum, and the field reversed every ten 

 minutes for about an hour. On development the plate shows 



