June 8, 1893J 



NA TURE 



143 



Drift. In the Willoughby hiring, bineith th? Drift, a b-o vn 

 sand was obtained, apparently the "Roach" division of the 

 Lower Cretaceous, and below it the Tealby Clays (lo8 feet), 

 onliiic ferruginous beds (l8 feet), and sandstone and sand 

 regarded as the Spilsby Sandstone. In the Alford boring the 

 highest solid rock appears to belong to the basal beds of the Red 

 Chalk, and below it is Carstone, and then clay. The axis of 

 the anticlinal appears to pass between Alford and the border of 

 I the wolds, and is probably continued in a north-westerly direc- 

 1 tion beyond the village of Claythorpe. The result of the in- | 

 I formation now obtained makes it probable that the Chalk tract 

 ; which lies to the south-east of the Calceby valley is completely 

 . isolated from the rest of the Chalk area. The President said 

 I that the lesson of the paper was that it was never safe to take 

 I anything for granted when one had to deal with Boulder Clay, 

 and Mr. Strahan remarked that he agreed with Mr. Jukes- 

 Browne's interpretation of the structure of the district. 



Linnean Society, May 24. — Anniversary meeting. -^Prof. 

 Stewart, President, in the chair. — The treasurer presented the 

 accounts duly audited, and the secretary having announced 

 the elections and deaths during the past twelve months, the 

 usual ballot took place for new members of Council, when the 

 followin!;were elected : — VIessrs. J. G. Biker, A.C.L. Giinther, 

 G. R. Murray, R. C. A. Prior, and Howard Saunders. The 

 President and officers were re-elected. The librarian's report 

 having been read and certain formal business disposed of, the 

 President delivered his annual address, taking for his subject 

 "The various mo-les in which animal sounds are produced." 

 On the motion of Dr. Braithwaite, seconded by Sir James 

 Gibson Maitland, Bart., a unanimous vole of thanks was 

 accorded to the President for his address, with a request 

 that he would allow it to be printed. The Society's gold medal 

 was then formally presented to Prof. Daniel Oliver, m recogni- 

 tion of the services rendered by him to botanical science, 

 and having been acknowledged by Prof. Oliver, the proceedings 

 terminated. 



Cambridge. 



Philosophical Society, May 15. — Prof. T. McK. Hughes, 

 president, in the chair. — ("he following com nunications were 

 iii<de to the Society : — Exhibition of abnormal forms of 3'/i;V;yif/-a 

 /(WM/a (Martin) from the Carboniferous Limestone, by F. R. 

 Cowper Reel. This species, as defined by Davidson, is nor- 

 mally suliject to great variation of form and ornamentation, as it 

 includes Sp. imbriccUa and Sp. elUptica. Specimens with inter- 

 mediate characters are however common. The series of abnor- 

 mal forms exhibited showed the gradual development of a sharp 

 median groove both in the dorsal and ventral valves so as 

 ultimately to produce a bilobed shell. From the nature of these 

 groves interruption of the shell-secreting action of the mantle 

 seems to have occurred along a definite line : and the cause may 

 have been disease, the presence of a parasite or foreign body, 

 or pressure during life, oimilar malformation is seen in some 

 Terebratulas, &c. The normal and regular bilobation of some 

 species of Ortkis, Terebratula, Alc, is comparable. — Exhibition 

 of Posl-Glacial Mammalian bones from Barrington recently ac- 

 quired by the Museum of Zoology, by Mr. .S. F. Harmer. — 

 Exhihiiion of a specimen showing Karyokinelic division of the 

 nuclei in a plasinodium of one of the Mycetozoa, by Mr. J. J. 

 Lister. — Observations on the Flora of the Pollard Willows near 

 Cambridge, by Mr. J. C. Willis and I. H. Burkill.— The plants 

 occurring in the tops of willows near Cambridge have been recorded 

 during the last few years, and amount to 80 species, occurring 

 3951 times altogether in about 4500 trees. Of these 80, only 18 

 form more than i percent, of the total number of records. The 

 rest have only a small number of records. As Loew has pointed 

 out in a recent paper, these plants are of interest from the points 

 of view of distribution of seeds and of epiphytism. Classifying 

 them according to means of distribution, we find that 19 species 

 have fleshy fruits ; 1763 records (44 6 per cent.) of these occur. 

 Three species with burrs have 651 lecords (l6'4 per cent.) ; 34 

 species >vith winged or feathered fruit or seed have 996 records 

 (aS'l per cent.); 7 with very light seeds have 421 (io'6 per 

 cent.) ; and finally of plants whose means of distribution is poor 

 or somewhat doubtful, we have 17 species with 120 records (2'9 

 per cen'.). It is thus shown very strikingly how the various 

 listribution mechanisms succeed, only the better ones showing 

 in the list any numbers. The bird-distribu'ed plants figure much 

 higher here than in such cases as e.g. the lloraof the churches of 



NO. 1232, VOL. 48] 



Poitiers (Richard), because birds visit the trees to such an extent , 

 The observations show clearly the fact that a seed is only car 

 ried a short distance by its distribution mechanism. Plants were 

 always found upon the soil, within 250 yards at most, of those 

 found in the trees. An analysis was taken as far as possible of 

 the birds' nests found in the tree-, and pieces, often with ripe 

 fruits, of many plants in the list were discovered in them, so 

 that probably this means of distribution is of some importance. 

 With regard to epiphytism, Loew considers ihrse plants as ex- 

 hibiting a commencement of this mode of life, and this seems 

 probable enough. Like the regular epiphytes, they possess good 

 methods of seed distribution. Their position does not call for 

 any special means of supporting themselves, and the supply of 

 humus is plentiful. Mycorhiza, which Loew found on msny, 

 was not observed in the few examined. The size of many of the 

 shrubs, e.g. Elder, Kibes, Roses, &c. , was very remarkable ; 

 some elders were three inches thick or more, and as much as 12 

 feet high. Experiments are in progress upon the growth of 

 plants in willow humus. — Note on the plants distributed by the 

 Cambridge dust-catts, by I. H. Burkill. — The street-sweepings 

 of Cambridge have of late been spread on Coe Fen for the pur- 

 pose of raising the level. From this material spring the plan's 

 whose seeds have been scttered in the dust of the roads. Of 

 these, 99 species and one variety have ^een collected. No less 

 than 39 per cent, are species whose dissemination has been 

 effected directly or indirectly by Man, being either used for food 

 or maintained in the gardens. The other species are almost all 

 such as seed freely on roadsides, and have for the most part very 

 light seeds. 



Dublin. 



Royal Dublin Society, May 17. — Prof. G. F. Fitzgerald, 

 F.R.S., in the chair. — Dr. G. Johnstone Stoney, F.R.S., read 

 a paper on the cause of sun-spots. In this communication the 

 author recalled attention to the explanation of sun-spols which 

 he had offered in 1867, in a paper on the physical constitution 

 of the sun and stars, published in the Proceedings of the Royal 

 Snciety, No. 105, 1868. He pointed out that the discoveries 

 since made through the spectroscope, and the details of the 

 photosphere revealed to us in the photographs taken by Prof. 

 Janssen at Meudon, have brought to light striking confirmations 

 of this explanation. The photosphere, according to the author's 

 view, consists of incandescent sooty clouds, and the cjoudy 

 regions constitute the bright patches seen in Prof. Janssen's 

 photographs, each of which is in general some hundreds of 

 miles broad and several hundreds of miles long. Inasmuch as 

 the greater part of the radiation emanates from them, they must 

 form a stratum of minimum temperature. In the interstices 

 between the patches and in those larger openings which are 

 known as sun-spots, a less luminous background is brought into 

 view. This is either a second layer of cloud which is of trans- 

 parent material like terrestrial clouds, or it is a position in which 

 both the density suddenly becomes greater and at which there 

 isasudden transition from transparent atmosphere above to 

 opacity beneath. This would present the appearance of the 

 reflecting surface of a molten ocean. Now, by the "Law of 

 Exchanges," such an ocean as is supposed by the second 

 hypothesi-, being capable of reflecting incident light abundantly, 

 or such a cloud of transparent material as is supposed by the 

 first hypothesis, being capable of scattering incident light 

 abundantly, would either of them radiate much less abundantly 

 than the sooty clouds which constitute the photosphere, and 

 would therefore appear black in comparison, whether at the 

 same temperature, or at higher temperatures up to a certain limit. 

 One or other of these, then, appears to be that dark background 

 seen in sun-spotsand in the intervals between thepatches of photo- 

 sphere. The appearance of penumbra seen in most sun-spots 

 and in many of the intervals between the patches of photosphere 

 would be presented wherever the sooty clouds are thin, and not 

 sending down the abundant showers which seem elsewhere to 

 prevail, and which in faculse are continuous over immense spaces. 

 — Mr. Thomas Preston attracted the attention of the Society to 

 a simple, direct, and perfectly general method of expressing 

 the efficiency of a reversible engine in terms of the temperatures 

 of the source and refrigerator. He also mentioned that the 

 cycle originally described by Carnot requires no correction, and 

 depends on no theory of heat. Carnot begins with an adiabatic 

 transformation, and his cycle consequently possesses all the 

 advantages of the "corrected" cycle proposed by Maxwell. 



