504 



NA TURE 



[September 14, 1905 



tudes near the source of various great sounds, eg. Sunder 

 cannon firing, and volcanic explosions. He g.ves reasons 



source therefore may not be very great. 



lune 16.-" The Absorption Spectrum and Fluorescence 

 of Mercury Vapour." By W. N. Hartley, F.R.S. 



The aut'hor having undertaken the '"vesfgat.on of the 

 absorption spectra of _metals m ^a state ^of ^vapour, the first 



side tube to the 



substance examined was mercury 



flask of Heraeus's quartz glass, with 



neck ? cm which the metal may be d.sflled and con^ 



densed. The ravs from a condensed spark were passed 



through the flask and on to a cylindncal -ndensmg len 



of quartz which focused the rays on to the slit of a quartz 



spectrograph 



T/ie -\hsorbtion S/.«(r..»..-The whole rays were trans- 

 mi ted from the red to a point in the ultra-violet where 

 there is a tin line at X 257. -67. From there to ^ 2526^ 

 there is a very sharplv defined and intense absorption band 

 somewhat degraded on the side towards the red, beyond 

 that the rays are transmitted with full intensity to a wave- 

 length about 2000. T,„;i:„rt 

 The f/uorMccnce.— When the mercury was boiling 

 briskly the whole side of the flask nearest to the spark 

 was lighted up with a green fluorescence; this Penetrated 

 about one-third of the space within the flask, and lighted 

 up the interior. The quartz glass itself was not fluorescent 

 in the slightest degree. Solutions of mercuric chloride 

 showed no absorption band. 



The absorption band in the vapour of mercury belongs 

 to the vapour, and is accompanied by strong fluorescence 

 between a certain maximum and minimum of temperature 

 lying verv near to the boiling point. It is a question still 

 Jndecided whether the ravs absorbed by mercury vapour 

 as shown by the band measured, reappear with a lowered 

 refrangibility as yellowish-green light in accordance with 

 the law of Stokes. 



New South Wales. 

 Royal Society, June 7.— Mr. H. A. Lenehan, president, 

 in the chair.— On the so-called gold-coated teeth in sheep : 

 Prof .\. Liversidge. Paragraphs in some of the London 

 and Sydney newspapers have stated that gold-coated teeth 

 have been found in Australian sheep. The author recently 

 received the lower half of a sheep's jawbone from Uubbo 

 the teeth of which are more or less completely incrusted 

 with a yellow metallic substance, but more like iron 

 pvrites (marcassite) or brass than gold. The deposit is 

 about I 32 of an inch, or less than i mm. in thickness. 

 Under a half-inch objective it is seen to be made up of 

 thin translucent lavers, but there is no recognisable organic 

 structure. The metallic lustre is due to the way in which 

 the light is reflected from the surface of the superimposed 

 films. The scale partly dissolves in dilute acids. The 

 residue consists of filmv organic matter, still possessing a 

 metallic sheen, although white in colour instead of yellow. 

 The chemical examination shows that the incrustation on 

 the teeth is merely a tartar-like deposit, made up principally 

 of calcium phosphate and organic matter. 



julv I.— Mr. H. A. Lenehan, president, in the chair.— 

 Observations on the illustrations of the Banks and Solander 

 plants : J. H. Maiden. 



Paris. 

 Academy of Sciences, September 4.— M. Troost in the 



pl^.,|r Researches on the insoluble alkaline substances 



formed bv humic substances of organic origin, and their 

 role in plant phvsiology and in agriculture : M. Berthelot. 

 The e.xperimcnts were' made with fresh and old specimens 

 of humic acid prepared from sugar, with dead leaves, and 

 with soil. The substances extracted by maceration with 

 water and bv distillation with water in presence of 

 potassium and calcium salts were analysed. — The eclipse 

 of the sun of .August 30 observed at Paris : M. Loewy' 

 In spite of the interference caused by cloud, the partial 

 eclipse was observed at Paris under good conditions. The 

 times of first and second contacts were obtained, and 



NO. 1872, VOL. 72] 



numerous photographs were f,=^ken.-.Actinometric measure- 

 ments carried out during the eclipse of August 30. J. 

 VioMe. The observations at Trappes, Bordeaux, and on 

 the Pic du Midi were spoilt by the weather, but satisfac- 

 tory results details of which will be communicated later, 

 were obtained at Bagnires and Sfax.-On the existence 

 in certain gooseberry trees of a compound furnishing 

 hydrocyanic acid: L. Guignard. I" *e case of the 

 common red gooseberry, hydrocyanic acid has been obtained 

 from the leaves at all 'stages of their growth, but is absent 

 from the fruit. The leaves of several other species have 

 been examined for prussic acid with negative results.-- 

 On the glvcuronic acid of the blood : R. Lepine and M. 

 Boulud.— The secretary read telegrams from various 

 observers relating to the solar eclipse of August 30, from 

 which it would appear that satisfactory observations were 

 obtained at Alcasebre, Sfax, Guelma, and Philippeville, 

 clouds interfering at Cistierna, Burgos, Tortosa, and 

 Alcald de Chisbert.— Observation of the eclipse of 

 August 30 at Alcald de Chisbert (Spain) : Marcel Moye. 

 The brilliant corona was the most marked feature of the 

 eclipse.— On the same : R. Mailhat. Remarks on some 

 photographs taken at Paris.— On the envelopes of spheres 

 of which the two sheets correspond with conservation of 

 the angles ; A. Demoulin. — On the importance of the 

 effect of irradiation in spectrophotography : .'\drien 

 Guebhard. — The constitution of the copper aluminium 

 alloys : LiJ-on Quillet.— On the origin of lactose. The 

 effects of injection of glucose into females during lactation : 

 Ch. Porcher. — The geology of the southern Carpathians : 

 G. M. Murgoci. — The influence of the solar eclipse of 

 .August 30 on the earth's magnetic field at Paris: Th. 

 Moureaux. The oscillations observed during the eclipse 

 were much greater than the regular diurnal variations, — 

 On the polarisation of the sky during the eclipse of the 

 sun : M. Piltschikoff. 



CONTENTS. P.4GE 



Astronomy for Travellers 4S1 



The Evolution of Human Society. By F. W. H. . 482 

 Our Book Shelf :— 



Ward ; "Trees " 4S2 



Frost : " A Laboratory Guide in Elementary Bacteri- 

 ology."— Prof. R. T. Hewlett 4S3 



McMurry : " Nature-study Lessons for Primary 



Grades."— R. L 4S3 



Gans: "Einflihrung in die Vekloranaly.sis mit Anwend- 



ungen auf die malhematische Physik" 4S3 



Letters to the Editor : — 



Observations of the Total Solar Eclipse in Tiipoli, 



Barbary. {Illustrated.)— Viai. David Todd . . 484 

 On the Class of Cubic Surfaces.— A. B. Basset, 



F.R.S . 484 



Ben Nevis Observatory and the Argentine Republic. — 



William S. Bruce 4S5 



Properties of Photographic Plates Exposed to Light. — 



L. H. Winn 4S5 



Cause and Prevention of Dust from Automobiles. 



(Illustrated.) By W. R. Cooper 4S5 



The International Union for Cooperation in Solar 



Research . 49° 



Notes 49° 



Our Astronomical Column : — 



Nova Aquilce No. 2 494 



Variation of a Newly Discovered Asteroid 494 



Interpretation of Spectroheliograph Pictures .... 495 



The Observatory of Paris 495 



An Electric Micrometer. {Illustrated.) By Dr. P. E. 



Shaw 495 



The British Association :^ 



Section I. — Physiology. — Opening Address by 

 Colonel D. Bruce, M.B., ' F.R.S., C.B., 



President of the Section 49^ 



University and Educational Intelligence 503 



Societies and Academies 503 



