Dec. 24, 1874] 



NA TURE 



157 



Prof. Williamson's contributions to biological science were 

 commenced forty years ago, and embrace investigations into the 

 structure of the Foraminifera, the Rotifera, the scales and bones 

 of fishes, and the fossil plants of the Carboniferous and Oolitic 

 periods. These comprise works of great merit and value, not 

 only on account of their accuracy and the extent and novelty of 

 the observations which they contain, but by reason of the 

 breadth of view and the philosophical spirit which pervade 

 them. 



His labours in Vegetable Paleontology are above all remark- 

 able, being alike laborious, searching, and productive of im- 

 portant results. These are embodied in sbc contributions (of 

 which the last will soon appear) to the Philosophical Transac- 

 tions upon the organisation of the fossil plants of the coal- 

 measures — and one on the restoration of a Cycadeous tree (Zaiiiia 

 gii>as) from the Yorkshire Oolite, published in the Transactions 

 of the Linnean .Society. These are not only models of laborious 

 research and exact description, but they are illustrated by more 

 than fifty plates, devoted to microscopic analyses of vegetable 

 tissues, obtained by making transparent slices of the fossils. 

 Both the slices and the drawmgs are made by Prof. Williamson 

 himself, who thus, to his reputation as a biologist, unites those 

 of an accomplished artist and a skilful lapidary, qualifications 

 which should be namel along with those fur which the medal is 

 awarded, because no unscientific lapidary could have obtained 

 equally illustrative sections, and no common artist could have 

 depicted them with equal exactitude. The more important 

 results thus obtained refer to the structure, affinities, and repro- 

 ductive organs of Calamites and its allies, to Lepidodendron, 

 Sigillaria, Lepidostrobus, Asterophyllites, and to other genera 

 of the Carboniferous epoch. 



In addition to these contributions to the history of previously 

 known genera of that epoch. Prof. Williamson has been able to 

 show, on the one hand, that groups of now living plants which 

 were not previously supposed to have a great geological anti- 

 quity, actually flourished during the Carboniferous period, and, 

 on the other, that plants of that period which had been previously 

 referred with confidence to groups now living, have in reality 

 other and widely different affinities. 



The medal was received by Prof. Williamson. 



SCIENTIFIC SERIALS 



Astronoviisihe Nachrichien, No. 2014. — In this number 

 appear some interesting observations made by Nicolaus V. 

 Konkoly onthe spectrum of meteorites. Some 130 of the August 

 meteors were examined, and it was observed that the nucleus 

 gave a continuous spectrum, the apparent colour of the naked 

 eye predominating in the spectrum. The tail of the yellow meteors 

 gave the sodium lines only, the green one gave magnesium lines, 

 and the red ones strontium or lithium. The sodium lines were 

 present in all. In some of the larger meteors the author suspects 

 thespectiuni of iron is present. — Position observations of Coggia's 

 comet are given by Argelander and by Tebbutt, of the Windsor 

 Objervatory, N.S. Wales. — Dr. Kleim writes objecting to the 

 explanation of variation of brigntness of Jupiter's moons during 

 tiansit, given by HerrS. Ale-xander. — Dr. Luther gives position 

 observations of Peilho (118) and elements of Danae (61). — The 

 elements of Botrelly's comet are given by Griitzmacher, and those 

 of Sylvia by Tieijcn. — F. Anderson sends an opposition ephc- 

 merisof the planet Undina for November and December. — Prof. 

 Spterer gives observations of sun-spots and protuberauces ; and 

 observations of the occidtation of Venus by the moon, taken at 

 Kiel, are given. 



Zdtschrift dcr Oiskrrdchischen Gcsellschaft fiir Mdcorologie. — 

 Dec. I. — In an article on the non-periodic movements of the 

 barometer and the baric windiose, Dr. Koppen, taking into con- 

 sideration the almost constant cyclonic movement of the air in 

 Europe, asks how it is, while gradients are steepest with west 

 and south-west winds, that when the barometer is observed 

 at equal distances round a minimum centre, it is not found to be 

 highest where the south-west wind is blowing. The mean height 

 of the barometer is on the contrary considerably higher with 

 north and east winds. The explanation lies in the difference 

 between northern and southern Europe with respect to the 

 magnitude of non-periodic oscillations of the barometer. 

 ^The low pressure in the north and north-west during the 

 prevalence of south-west winds is not compensated by an ade- 

 quately high pressure in the south and south-east. Air flows 



thence either to form a maximum over a small space in high 

 latitudes, or southwards over a large space without causing high 

 pressures. Similarly, but conversely, with north and east winds. 

 — Among the " Kleinere Mittheilungeu " we have a notice of 

 Prof. Dove's article on cool Mays after mild Januarys, publislied 

 in the magazine of the Berlin Academy. Ilerr Dove regards as 

 proved a tendency to low temperatures in spring after warm winters. 

 It appears that a mild January is generally followed in the 

 interior of continents by a mild May, on the north and east 

 coasts by a cool May, on the Atlantic Ocean again by a May 

 milder than usual. 



SOCIETIES AND ACADEMIES 

 London 



Royal Society, Dec. 10.— "On the Development of the 

 Teeth of the Newt, the Frog, and certain Lizards, and on the 

 Structure and Development of the Teeth of Ophidia." By 

 Charles J. Tomes, M.A. 



The descriptions given by Arnold and Goodsir of the develop- 

 ment of the human teeth have been already demonstrated to be 

 in material respects inaccurate as applied to man and other Mam- 

 malia; and the present paper shows that the accounts propounded 

 by I'rof. Owen, of the process in Batrachia and Reptilia, which 

 are practically an extension of the theories of Goodsir to these 

 classes, are even more at variance with the facts of the case. 



There is in no Batracliian or Reptile any open groove or fissure 

 (" primitive dental groove ") ; there are, at no period of develop, 

 ment, free papilloe ; consequently the whole process of " encap- 

 sulation " has not any existence, but is purely hypothetical. 

 From first to last the whole process of tooth development takes 

 place in solid tissue, beneath an even and unbroken surface ; 

 with which, however, the young tooth sacs have a connection 

 through a band of epithelial cells. The first process is a dif. 

 ping down of a narrow process of the oral epithelium, the ex- 

 tremity of which, after it has penetrated in some, as the snake, 

 to a great depth, becomes dilated, and is transformed into the 

 enamel organ ; and this is the case wheiher a recognisable coat 

 of enamel is or is not to be found on the perfect tooth. Subse- 

 quently to the dipping in of the band of epithelium, and con- 

 comitantly with the dilatation of its end, a dentine pulp is formed 

 opposite to it. This may constitute the entire tooth sac, which 

 is then wholly cellular, as in the newt ; or it may go on further 

 to the formation of a connective-tissue tooth capsule. The ex- 

 ternal thin structureless coating of the teeth of Ophidia is derived 

 from an unmistakeable enamel organ, developed as above de- 

 scribed ; it is therefore enamel, and not cementum, as it is deno- 

 minated by Prof. Owen. The successional tooth sacs, very 

 numerous m the snakes, are located in a sort of capsule : this 

 char.icter, peculiar to the Ophidia, and most marked in the lower 

 jaw, is of obvious service during the extreme dilatation which 

 the mouth undergoes, as is also the tortuosity of the process 

 of tpitheiium, before it reaches the collection of tooth sacs. 

 '1 he epithelial band may be traced winding by the side of the 

 older tooth sacs till it reaches the position of the youngest, where 

 it ends in a ccecal extremity, to be transformed into the enamel 

 organ next developed. In fine, the stages of open groove, free 

 papilla;, and encapsulation of the samehave no existence what- 

 ever in Batrachia and Reptilia, their existence having been 

 previously disproved in Mammalia. 



"Experiments showing the Paramagnetic condition of Arteria 

 Blood, as compared v/ith the Dtamagnetic condition of Venous 

 Blood." By Richard C. Shettle, M.D. 



The experiments consist in suspending between the poles of a 

 powerful electro-magnet arterial blood, hermetically sealed in a 

 glass tube, in a medium of venous blood, and venous blood in 

 the same tube, previously well emptied of its contents, in a 

 medium of arterial blood, care being taken to avoid as far as 

 pohsible any exposure of the blood to the atmosphere ; thus 

 preventing any alteration in its physical characteristics as regards 

 the gases which it contains. 



In the former of the two cases the testing tube was found to 

 take an a.xial, and in the latter an equatorial position. 



Dec. 17. — "Note on the Vertical Distribution of Tempera- 

 ture in the Ocean." By J. Y. Buchanan, chemist on board 

 H.M.S. Challenger. Communicated by Prof. A. W. Williamson, 

 For. Sec. R.S. 



From newspapers and other reports which have been received 



