192 



NA TURE 



[December 26, 1901 



stellar atmospheres, gave further illustrations, from the conditions 

 holding in our own atmosphere, of the distinction between 

 thermostatic cquililjrium and convective equilibrium, the former 

 being characteristic of the upper strata and the latter of the 

 lower strata, ^becially in the neighbourhood of mountains. 

 Passing to the case of the sun, he found it necessary to assume 

 (in order to explain the height of the chromosphere) that hydrogen 

 gas contains an appreciable amount of potential energy, latent 

 heat, as it were, stored up by the dissociation of its molecules 

 into smaller molecular groups. A comparison of the deviations 

 from Dulong and Petit's well-known law led to a division of the 

 elements into two groups, of which iron and carbon might be 

 taken as the types. In the one group the molecular potential 

 energy increases with the temperature, in the other it 

 diminishes. Hydrogen belongs to the former group. These 

 considerations also gave a clue to the comparative smallness of 

 the layer of metallic vapours in the sun, and, moreover, ex- 

 plained why the spectra of the hottest stars were characterised 

 by a broadening of the hydrogen lines and a narrowing of the 

 lines of the metallic vapours. Finally, it was shown how a 

 change of temperature in part of the sun's photosphere would, 

 on the principles developed in the paper, at once cause violent 

 outbursts of hydrogen gas, such as are observed in the solar 

 protuberances. — Lord Kelvin exhibited a model of the diatomic 

 equilateral crystalline assemblage described in his paper on 

 molecular constitution of matter, Roy. Soc. Edin., July, 1889. 

 By means of this model any relation between the rigidity and the 

 resistance to compression could be obtained, thereby completely 

 disposing of the reasoning of the older French elasticians, who 

 believed that there must be a definite relation between the two 

 elastic constants in an isotropic elastic solid. 



Dublin. 

 Royal Irish Academy, December 9. — Prof. R. Atkinson, 

 president, in the chair. — Prof. J. P. O'Reilly read a paper on 

 the waste of the coast of Ireland. In this paper the author dis- 

 cussed the different .stages of change that the country had gone 

 through following the work of Prof Boyd Dawkins, " Early Man 

 in Britain and his Place in the Tertiary Period." Taking the state 

 of the country at the end of the Pleistocene period, when the 

 great forests covered the surface of the upraised drift surface, he 

 pointed out how this has been taken to indicate the then existence 

 of land extending off to the west either as a continental plateau 

 or as a series of islands which sheltered this forest growth, now 

 impossible owing to the harsh winds which come in directly 

 from the ocean. He directed attention to the report of Messrs. 

 Newton and Teall, referred to in Nature, vol. Ivii. p. 324, on 

 the lava sheets of Franz Josef Land, which tends to admit 

 the former existence of an immense basaltic plateau of which 

 the islands Spitsbergen, Jan Mayen, Iceland, Greenland, the 

 Faroes, Hebrides and N. Ireland formed part, the subse- 

 quent break-up of this plateau giving rise to islands and to the 

 present state of those mentioned. Explaining how meagre the 

 details are concerning the changes undergone by the coast of 

 Ireland in past times, he pointed out how these might be supple- 

 'mented by examining what the coasts of the northern islands, 

 Scotland, Cornwall and of I'rance had suffered in loss from the 

 continual beat and wear of the Atlantic storms and waves. The 

 loss and waste he showed to be far greater than is generally 

 imagined, and that Ireland and the islands which once bordered 

 it to the west, .south-west and north-west must have undergone, 

 and be actually suffering, very great and serious waste and change. 

 Considering the great scientific importance of the question, it 

 was submitted that it would be becoming on the part of the 

 Royal Irish Academy to promote a survey of the coast line as it 

 actually stands at this commencement of the twentieth century, 

 and to have points fixed as h.as been done for the coast of 

 Scandinavia, so that hereafter it may be possible accurately (o 

 fix the rale at which the island is being wasted away by the 

 Atlantic waves, and in this manner to allow of a determination 

 being made of what was its former extent in prehistoric and 

 early historic times. — Prof Charles J. Joly read a paper on the 

 .point representations of screws. The reciprocal of the quadric 

 in six variables representing screws of a given pilch plus /, taken 

 with respect to the quadric of zero pitch, is shown to be the 

 quadric of pitch minus p. From this property the remarkable 

 relations detailed by Sir Robert Ball in his recent memoir, 

 "Further Developments of the Geometrical Theory of Six 

 Screws," are easily deducible. In the second part of the paper 

 ^ method is explained of representing a screw by a pair of 



NO. 1678, VOL. 65] 



weighted points in a given plane — the five numbers required 

 consisting of the ratio of the weights and the two coordinates 

 of each point of the pair. 



New South WAt,ES, 

 Royal Society, October 3. — Prof Liversidge, F.R.S., 

 president, in the chair. — Marriage and descent among the Aus- 

 tralian aborigines, by R. II. Mathews. In this short paper the 

 author dealt with thesocial laws of some tribes in New South Wales, 

 Queensland and elsewhere. Tables and genealogies were supplied 

 illustrating the marriage restrictions, and the descent of the re- 

 sulting progeny. A brief description was given of certain in- 

 augural ceremonies through which the youths have to graduate 

 in order to reach the status of aboriginal manhood. — On the 

 constituent of peppermint odour occurring in many Eucalyptus 

 oils — part i., by Henry (!. Smith. The first Eucalyptus oil 

 was distilled by Dr. While in 1788, at Sydney, and owing to 

 the great resemblance between this oil and that obtained from 

 the peppermint Mentha piperita, he named the tree from which 

 he had obtained the oil the " Peppermint Tree." Its botanical 

 name is Eucalyptus piperita. .Since then many other species of 

 Eucalyptus have been found to have this peppermint odour, and 

 are generally known as " peppermints." The constituent giving 

 this odour has now been isolated. It occurs in greatest amount 

 in the oil obtained from the leaves of E. dives, next in that oi E. 

 radiata, and in fair amount in the oils of several other species. 

 It is usually found in those Eucalyptus oils in which the principal 

 terpene is phellandrene, although this is not always so, but 

 generally there is an almost entire absenceofEucalyptol in those 

 oils in which it occurs most abundantly. The crude oil of E. 

 dives was taken for the preparation of this peppermint con- 

 stituent. This constituent is not menthone, and is probably a 

 new ketone; a molecular determination gave 1 55, so that probably 

 its formula may eventually be found to be CmHijO. — On the 

 crystalline structure of gold nuggets from Klondyke, Victoria 

 and New Zealand, by Prof. Liversidge, F. R.S. Sections of 

 three nuggets from Klondyke were shown. The crystal faces 

 are comparatively small, and the nuggets have a granular struc- 

 ture, as if built up of separate grains, of one or two millimetres 

 in diameter. They are also more fissured and contain more 

 cavities than usual. The sections of Victorian (Australian) and 

 New Zealand nuggets are also made up of small crystals, and 

 they present numerous small cavities after the removal of the 

 quartz and iron oxide by treatment with hydrofluoric and hydro- 

 chloric acids, so that the sections present quite a different ap- 

 pearance from the very compact and largely crystallised nuggets 

 from West Australia. 



CONTENTS. PACK 



Fire Prevention. By Emeritus 169 



Cuneiform Decipherment 170 



Elementary Histology at Cambridge 171 



Our Book Shelf:— 



Kane : " A Catalogue of the Lepidoptera of Ireland." 172 

 Sabin : " An Atlas of the Medulla and Midbrain." — 



G. E. S 172 



Rabot : " Les Variations de Longeur des Glaciers." . 172 



Simmons and Stenhouse : " Experimental Hygiene." 173 

 Baldwin : " Dictionary of Philosophyand Psychology." 



—A. E. T 173 



Goeldi : " Die Vogelwelt des Amazonenstrdmes ; 

 Enstanden als Atlas zu dem Werke ' Aves do 



Brazil.'" 173 



Bourne: "The Bettesworth Book. Talks with a 



Surrey Peasant." '73 



Letters to the Editor : — 



Relative Velocity in Streams. — Dr. D. T. Smith . 174 

 Change of Pitch of Certain Sounds with Distance. — 



Dr. D. van Gulik 174 



Chemical Instruction and Chemical Industries in 



Germany. By Dr. F. MoUwo Perkin 174 



The Geological Survey of the United States ... 176 



Notes 178 



Tycho Brahe in Prague 181 



Experimental Phonetics. (Illustrated.) By Prof. 



John G. M'Kendrick, F. R.S 182 



The Ancient Glaciers of Skye 189 



University and Educational Intelligence 190 



Scientific Serial 19° 



Societies and Academies 190 



