164 



NATURE 



\June 15, 1876 



dry season is between 70" and 80'' F. and that at the summit of 

 the peak is 30° or 40° F. ; consequently the low strata of air are 

 rnuch the less dense, and an almost horizontal ray of light pass- 

 ing over the summit must be refracted upwards and suffer total 

 internal reflexion, as in ordinary mirage. On this supposition 

 the veil must become more and move vertical, as the rays fall 

 less horizontally, and this will continue until they reach the cri- 

 tical angle, when total internal reflexion ceases and it suddenly 

 disappears. Its apparent tilting over on the spectator is pro- 

 bibly an illusion, produced by the rapid approach and the rising 

 of the dark veil withoi\t any gradual disappearance which can 

 be watched and, Citimated. It will be evident that the illumina- 

 tion of the innumerable particles floating in the atmosphere 

 causes the aerial shadow to be visible by contrast. Another in- 

 teresting phenomenon visible in the mountain districts admits of 

 an equally simple explanation. At times broad beams appar- 

 ently of bluish light may be seen extending from the zenith 

 downwards, converging as they approach the horizon. The 

 spaces between them have the ordinary illumination of the rest 

 of the sky. If we suppose, as is frequently the case, that the 

 lower strata of air are colder than the upper, the reflexion i-pokea 

 of in the case of Adam's Peak will be downwards instead of up- 

 wards. If several isolated masses of clouds partially obscure the 

 sun, we may have several corresponding inverted veils of dark- 

 ness like blue rays in the sky all appareiitly converging towards 

 the same point below the horizon. This latter phenomenon is 

 called by the natives "Buddha's Rays." — Prof. Dr. Forel of 

 Morges, Switzerland, then give, in French, an account of some 

 interesting observations which he has recently made on the 

 periodic waves which take place on the S wiss lakes and are there 

 called "Seiches." It was long since observed that the waters 

 of most of these lakes are subject to a more or less regular rise 

 and fall, which at times have been found to be as much as one or 

 two metres. M. Forel has studied this phenomenon in nine dif- 

 ferent lakes, and finds that it varies with the length and depth 

 of the lake and that the waves are in every way analogous to 

 those already studied by Prof. Guthrie in artificial troughs, and 

 follow the laws which he has deduced from his experiments. 

 Most of -the observations in Switzerland were made on the lake 

 of Geneva, but that of Neucha.el was found to be best fitted for 

 the study of the subject, possessing as it does an extremely regu- 

 lar geometric form. The apparatus he employed was very sen- 

 sitive to the motion of the water, being capable of registering 

 the waves caused by a steamboat half an hour after it had passed, 

 and five minutes before its arrival, and was so constructed as to 

 eliminate the effect of common waves, and to register the motion 

 side by side with a record of the state of the barometer, on paper 

 kept in continuous motion. While he found the duration of 

 waves to be ten minutes at Morges it was seventy minutes at 

 Geneva, and this is explained by the narrowness of the neck of 

 the lake at the latter place. This period he proved to be inde- 

 pendent of the amplitude, and to be least in the shortest lakes. 

 For shallow lakes the period is lengthened and his observations 

 show that the period is a function of the length and depth and 

 that longitudinal and transverse waves may coexist, just as Prof. 

 Guthrie has shown to be the case in troughs. 



Stockholm 



Academy of Sciences, March 12. — Ilerr' Rubenson com* 

 municated a paper entitled " Monthly and yearly averages of 

 Temperature at the State Meteorological Stations during the 

 Years 1859-1872." — Herr Smitt gave an account of a visit paid 

 by Herr P. Olsson, assisted by a grant from the Academy, to Norr« 

 land for zoological research. — Herr Th. M. Fries gave an 

 account of two reports made to the Academy — one by Docent 

 Berggren, who had gone to New Zealand for the purpose of 

 studying its flora, and the other by Dr. Hellbom, who had 

 made a lichenological visit to Norrland. — The following papers 

 were communicated ;— On the Influence of inequalities with long 

 p,:riod on the expression for the absolute perturbations of periodic 

 comets, by Herr Gylden. — Narrative of an expedition to Novaya 

 Zemlya and the mouth of the Jenesei in 1875, with map, by 

 Prof. Nordenskjold. — On the simultaneous covariants of the 

 fourth order and fourth class of two conic sections, by Prof. 

 Bjorling. — On sulphonaphtholid, by Prof. Cleve, — On the action 

 of pentachloride of phosphorus on /3 naphthol, by Prof. Cleve 

 and Candidate Julin-Dannfclt. — On the estimation of nickel 

 in nickeliferous magnetic pyrites, by Herr Ekelund. — Contribu- 

 tions to the knowledge of the development of Rajae, by Intendent 

 Malm.— Contributions to the Orthopttr-fauna of South Africa, 

 b/ Prof. Stal. 



Paris 

 Academy of Sciences, May 29. — Vice-Admiral Paris in 

 the chair. — The following papers were read :— On the atomic 

 constitution of bodies, by M. de Saint- Vcnant. There is nothing 

 contradictory in regarding atoms as material points having all 

 the properties of visible and tangible bodies, less extension. — 

 New remarks on the real existence of a matter formed of isolated 

 atoms comparable to material points, by M. Berthelot. He gives 

 reasons for withholding assent to MM. Kundt and Warburg's 

 view. — On the salts formed by peroxide of manganese, by M. 

 PVemy, — Observations on a basking shark recently caught at 

 Concarneau, by MM, Gervais. This species {Squalus maximus) 

 is found but rarely in temperate waters. It has a number 

 of flexible, elastic filaments (of osseous nature) attached to the 

 branchiae ; these sift the water, retaining the small animals as 

 food. — Examination of the possible mechinical action of light. 

 Study of the radioscope of Mr. Crookes, by M. Ledieu. The 

 author's theory (implying a special action of polarised light) was 

 submitted to the test of experiment by M. Fizeau, but with negative 

 results. Further experiments are promised. — The Caucasus and 

 its mineral waters, by M. Franfois. — Intensity of gravity in the 

 island of St. Paul, by M. Cazin. The apparent acceleration of 

 gravity there exceeds the theoretical acceleration by -z^^ of its 

 value. May not this affect astronomical observations ? — On the 

 radiometer of Mr. Crookes, by M. de Fonvielle. He describes 

 experiments, whence he infers an impulsive action of light. M. 

 Fizeau says that if a bundle of solar rays fall on the instru- 

 ment, limited by a screen so that they strike only the pohshed 

 surfaces, the rotation is such that each vane comes to meet the 

 rays instead of escaping from them, as would be the case if the 

 light had impulsive force. — On the Phylloxeras of the leaves of 

 the French vine, by M. Delachanal. — On the laws of matter, by 

 M. de Marsilly. — On a compressed air filter for water, by MM. 

 Chanoit and Midoz. — On the transformation of elliptic functions, 

 by M. Laguerre, — On the development in series of the functions 

 Al(x), by M. Joubert. — On the charge taken by the disc of the 

 electrophorus, by M. Douliot. He describes an arrangement by 

 which he verified the theoretical conclusion that the charge of the 

 disc is proportioned to its radius. — Theory of spectra ; observations 

 on Mr. Lockyer's last communication, by M. Lecoqde Boisbaudran, 

 All spectral lines change in relative intensity when the temperature 

 is raised ; Mr, Lockyer's theory would imply that each element 

 is decomposed into as many more simple substances as its spec- 

 trum has lines. Considering the immense number of lines in 

 certain spectra, such a view seems little probable. — On the con- 

 stitution of prophylenic monochlorhydrines, and the law of 

 addition of hypochlorous acid, by M. Henry. — On a quino- 

 acetate of calcmm, by M. Gundelach. — Variations of the electric 

 state of the muscles in voluntary contraction and artificial tetanus, 

 studied with the aid of the galvanoscopic limb, by MM. Morat 

 and Toassaint. — Anaesthesia by the method of intravenous in- 

 jections of chloral ; amputation of the thigh ; absolute insensi- 

 bility ; consecutive sleep for six hours ; cure without any 

 accident ; by M. Ore. — On frauds met with in the points of 

 lightning conductors, by M. Francisque Michel. 



CONTENTS Page 



British Manufacturing Industries. 13y T 145 



Hutton's ''Geologvof Otago." 146 



Our Book Shelf : — 



Munn's " Elsmentary Algebra " 147 



Letters to the Editor : — 



The Early History of Magaetism. — Wm. Chai'PELL 147 



The Dry River-beds of the Riviera. — ^John Aitken 148 



Method of Distributing Astronomical Predictions. — Charles de 



Liitrow 149 



Acoustical Phenomena. — S. P. Thompson 149 



Giant Tortoises. — Dr. Samuel Haughton, F R.S i4y 



Photography of Loan Collection Apparatus. — L 13 149 



Abstract Report to "Nature" on Experimentation on Ani- 

 mals for the Advance of Practical Medicine. By Dr. 



Benjamin W. Richardson, F.R.S 149 



Our Astronomical Column : — 



The Comet of 1698 152 



The Binary Star « Leonis 152 



Variable Stars . 152 



The Double-star 7 Centauri 152 



The Mammals and Birds of Burma 153 



Meteorology at Melbourne 153 



American-Indian Stone Tubes and Tobaccb-pipes. By Dr. 



Charles C Abbott {With Illustrations) 154 



New Meteorological Observatories at Montsouris. By W. 



DE Fonvielle 156 



Notes 157 



Loan Collection of Scientific Apparatus— 



Section— Mechanics.— Prime Movers 159 



Scientific Serials i6i 



Societies and AcADBMiBS • i6s 



