February 24, 1898J 



NA rURE 



405 



Kant's fame as a metaphysician has completely overshadowed 

 his reputation as a physicist ; but all his earlier papers were on 

 physical subjects, such as the theory of winds, the earth's rotation 

 period, the rings of Saturn, and, best-known, the nebular hypo- 

 thesis of the universe. His great object in life was to dis- 

 courage visionary speculation and to reduce all subjects to the 

 confines of reason. Where Newton had in some cases to pos- 

 tulate the direct intervention of the Creator, Kant based his 

 explanation upon known physical laws. If he had known the 

 laws of thermodynamics, his nebular hypothesis, which only fell 

 short in that respect, would have completely anticipated La- 

 place. — The islands and coral reefs of the Fiji group, by A. 

 Agassiz. This is an extract from a letter dated Suva, Fiji 

 Islands, December 15, 1897, describing a cruise in the Austra- 

 lasian twin-screw steamer Yaralla. The writer says : The 

 great variety of causes which have been active in shaping the 

 present physiognomy of the reefs and atolls of Fiji shows the 

 impossibility of assigning any one factor, like subsidence for 

 instance, as is done by Dana and Darwin, as the single cause for 

 the formation of the many different kinds of atolls and barrier 

 reefs to be found in the Fiji group. The formation of the great 

 barrier reef of the southern shores of Viti Levu is due to causes 

 very similar to those which have given to the northern coast of 

 Cuba between Nuevitas and Matanzas its present physiognomy. 



Syinovs's Monthly Meteorological Magazine, February. — 

 Meteorological observations at Camden Square, London, N.W. 

 There are few records day and night for forty years without a 

 break, and no station with suitable exposure in London which 

 has been at work so long. We are glad to see that Mr. 

 Symons intends to give a series of tables showing the results 

 of his observations for each month, and the present number, 

 being the first of a new volume, contains those for January 

 1858-97.— Warmth, dryness, and high barometer in January 

 1898. A number of notes are quoted upon the above subjects ; 

 the table above referred to shows that, for London, the features 

 of 1898 are : barometer almost unprecedently high ; mean dry 

 bulb temperature, 0'05° above 1884, and therefore the highest 

 on record ; minimum in air and on grass, o'6° and o"5°, re- 

 spectively, above the highest previous records, which were in 

 1875 and 1884 ; rain, only about a third of the average, but 

 more than twice that of 1880. — In the Conway Valley geraniums 

 were found in blossom out of doors. 



SOCIETIES AND ACADEMIES. 

 London. 



Royal Society, February 3. — " Comparison of Oxygen with 

 the extra Lines in the Spectra of the Helium Stars, jS Crucis, 

 &c. ; also Summary of the Spectra of Southern Stars to the 

 3^ Magnitude and their Distribution." By Frank McClean, 

 F.R.S. 



In a previous paper read before the Society on April 8, 1897, it 

 was suggested that the special lines present in spectra of the first 

 division of helium stars (Type I., Division la) might possibly 

 be due to oxygen. 



The indications in the spectra of the northern stars that these 

 extra lines are due to oxygen are slight, as the lines at best are 

 indistinct. Among the southern stars, however, there are 

 several in the spectra of which these lines are, better defined, 

 and there is one, viz. j8 Crucis, in which they are very fairly 

 defined. 



Upon the plate which accompanies the paper a series of photo- 

 graphs of stellar spectra are reproduced. The lines are drawn 

 out by themselves below the spectrum of ^ Crucis. They are 

 then compared directly by juxtaposition with a drawing of the 

 spectrum of oxygen. The close similarity of the whole grouping 

 of the two spectra as they appear on the plate admits of little 

 doubt that the extra lines actually constitute the spectrum of 

 oxygen. 



The spectrum of 7 Argus is given on the plate in order to 

 identify it as a helium star. It contains two crucial lines of 

 helium. The Wolf-Rayet stars, of which it is the principal 

 example, are thus classified as helium stars. 



A summary of the spectra of 1 16 stars to the'^i magnitude in 

 the Southern Hemisphere is given. They were photographed 

 between May and October last with an object-glass prism, 

 mounted in front of the Cape astrographic telescope. The 

 photographic spectra are classified on the same system as in the 



NO. 1478, VOL. 57] 



previous paper. The table of distribution for the whole sphere 

 by areas and classes is given. 



There are in all 89 helium stars (Division I.), distributed 71 

 in the galactic zones and 18 in the galactic polar areas, the 

 areas being equal. 



The 81 stars in Division II., the Sirian stars, and Division III., 

 the Procyon stars (which along with Division I. constitute 

 Secchi's Type I.) are rather irregularly distributed throughout 

 the sphere. To the extent of the observations there is no con- 

 densation of stars of Divisions II. and III. in the galactic 

 zones as there is in the case of stars of Division I. 



The 106 stars in Divisions IV. and V. (II. and III. of Secchi's 

 types) are fairly evenly distributed throughout the sphere. 



The general distribution of the types of spectra throughout the 

 sphere to the extent of the observations bears out generally the 

 conclusion that stars with spectra of the more advanced types, in 

 order of development, are evenly distributed in space. Also that 

 stars with spectra more recent in order of development are 

 mostly congregated in the galactic zones. The helium stars of 

 Division I. are predominant in the Southern Hemisphere, 

 being congregated in the lower or southerly halves of the 

 galactic zones. They include 48 stars out of a total of 94 

 stars in those areas. They are also more closely congregated 

 in the vicinity of the galaxy than is the case in the northerly 

 halves of the galactic zones. In the contiguous constellations 

 of Musca, Crux, Centaurus, Lupus, and Scorpio there are 27 

 helium stars out of a total of 36 stars included in the tables. 



February 17. — " Upon the Structure and Development of 

 the Enamel of Elasmobranch Fishes." By Charles S. Tomes, 

 M.A., F.R.S. 



The nature of the hard polished outer layer of the teeth of 

 this group of fishes has been from time to time a subject of dis- 

 cussion, some authors holding that it is enamel, whilst others 

 deny its claim to be so styled. 



The general conclusion arrived at by the author is that, just 

 as the whole teeth of the Elasmobranchs present the simplest 

 known form of tooth development, so do they also present the 

 first introduction of enamel as a separate tissue. 



In its first introduction it was a joint product, made under 

 circumstances which almost precluded any slow and gradual 

 formation of an outer layer upon the teeth ; but in the further 

 specialisation of teeth in reptiles and mammals the tooth germs 

 sink more deeply into the submucous tissue, and are protected 

 for a much longer time. 



The enamel organs become more specialised, and finally take 

 upon themselves the entire work of enamel building, manu- 

 facturing both the organic matrix and furnishing it with lime 

 salts, as unquestionably happens in mammals. 



And if these conclusions be correct, it would be quite 

 justifiable to call it enamel, even though the dentine papilla haSv 

 had a share in its production. 



Geological Society, February 2. — Dr. Henry Hicks,. 

 F.R.S., President, in the chair. — The President announced that 

 Dr. Charles Barrois, Secretary of the Organising Committee of 

 the Vlllth International Geological Congress, which will be 

 held in Paris in 1900, would shortly come to London to invite 

 the .Geological Society to the Congress, and to consult the- 

 Fellows with regard to the proposed excursions and the subjects, 

 of discussion. — " Contributions to the Glacial Geology of Spits- 

 bergen," by E. J. Garwood and Dr. J. W. Gregory. The 

 extent of glaciation of Spitsbergen has been exaggerated, for 

 there is no immense ice-plateau, but normal glaciers with some 

 inland sheets and Piedmont glaciers. These differ from Alpine 

 glaciers, as they are not always formed from snow-fields at the 

 head, and though some of the glaciers (as the Baldhead Glacier) 

 have tapering snouts in front, most have vertical cliffs. Cham- 

 berlin's explanation that the latter are due to the low angle of 

 the sun is insufficient, and they seem to be caused by the ad- 

 vance of the ice by a rapid forward movement of its upper 

 layers. The ice of these upper layers falls off and forms talus 

 in front, over which the glacier advances, carrying detritus up- 

 hill with it, and producing a series of thrusts. The Booming 

 Glacier illustrates cases of erratics carried in different directions 

 by the same mass of ice. The deposits of the Spitsbergen 

 glaciers are of four types: (i) moraines of Swiss type; (2) 

 those formed mainly of intraglacial material ; (3) those formed 

 of re-deposited beach-material ; (4) deposits of glacial rivers, 

 and re-assorted drifts. The materials of the second are sub- 

 angular and rounded ; scratched and polished pebbles and 



