NATURE 



[Jan. 17, 1889 



four hours. This circumstance may be taken as supporting 

 Sihncke's theory of aerial electricity, according to which the 

 electricity during a storm results from the friction of drops of ice 

 and water, and this can only take place when cold currents of 

 air at comparatively low levels flow over warm, moist masses of 

 air. 



Physical Society, December 14, 1888.— Prof, von Helm- 

 holtz. President, in the chair. —Dr. Thiessen gave an account of 

 experiments which he had carried out in order to measure the 

 amount by which gravity varies at different heights. The method 

 he employed was that of Jolly, but with the introduction of a 

 modification, in order to eliminate the irregularities due to dif- 

 ferences of temperature at the higher and lower stations. Scale- 

 pans were attached to each arm of the balance — one close up to 

 the beam, the other some distance below it — and the weight was 

 interchanged between the pans, both at the upper and lower 

 stations, thus eliminating the influence of differences of temper- 

 ature and of any inequality of the balance. The upward force 

 of the air had no influence on the results, notwithstanding the 

 varying volumes of the weights used. The distance between 

 the upper and lower scale-pans was 11 '5 metres, and the weight 

 used was i kilogramme. Twenty-four determinations were made, 

 which gave as a result that the kilogramme, when in the lower 

 pan, weighed 2 "8 milligrammes more than when it was weighed 

 in the upper pan. After making some corrections, and, among 

 these, one necessitated by the fact that the weight in its lower 

 position was 4 metres below the general surface of the earth, it 

 was found that the weight of i kilogramme varies by 0*28 milli- 

 gramme for each i metre of difference in altitude. — The Presi- 

 dent gave an account of a paper by Prof. Hertz, which he had 

 yesterday communicated to the Berlin Academy. It contained 

 a description of further experiments on electrodynamic waves, 

 and their analogy with waves of light. Weak induction dis- 

 charges between small metallic cylinders with rounded ends 

 were employed, and a similar apparatus for the detection of the 

 electrodynamic waves. The action was not propagated more 

 than 2 or 3 metres through space ; when it fell on a metallic 

 surface it was reflected, interference phenomena were observed, 

 and from these the length of half a wave was found to be 30 

 centimetres. When a metallic parabolic mirror, i metre across 

 its opening, was placed behind the apparatus used to produce 

 the discharge, the action was propagated to a distance of 

 8 metres ; and the action was greatly increased when a second 

 concave mirror was placed behind the receiving apparatus. 

 When a conductor was interposed, the action ceased, while non- 

 conductors allowed the waves to pass. By interposing perforated 

 metallic screens, it was found that the waves are propagated in 

 straight lines ; the waves passed through a dry wooden partition. 

 Polarization of the waves could be determined in several ways. 

 When the receiver was placed at right angles to the apparatus 

 producing the waves, no action between them could be detected, 

 the vertically-produced waves not being picked up by the hori- 

 zontally-placed receiver. When the two pieces of apparatus 

 were placed parallel to each other, and a wooden cube, with a 

 number of insulated metallic wire rings wrapped round it, was 

 placed in the path of the electrodynamic waves, it produced the 

 same effect as does a tourmaline plate on polarized light. When 

 the wires were vertical — that is to say, parallel to the exciting 

 apparatus — the action was not propagated through the cube ; but 

 it was, on the other hand, when the wires were horizontal. 

 When the receiver with its mirror was placed horizontally, so 

 that it did not record any action as reaching it, and the wire 

 arrangement, described above, was placed in the path of the 

 waves, no change took place in the receiver when the wires on 

 the cube were either vertical or horizontal, but the receiver was 

 affected when the wires were placed at an angle of 45°. The laws 

 of reflection of electrodynamic waves at metallic surfaces were 

 found to be the same as those for the reflection of light at plane 

 mirrors. Finally, Prof. Henz has determined the refraction 

 which the waves undergo in a prit.m made of pitch, and finds 

 that the refractive index of this substance for electric waves is 

 I '68. — Dr. Ritter demonstrated by experiments the action of 

 the ultra-violet rays of light on electric discharges in accordance 

 with the experiments of Hertz, Wiedemann, and Eberts. 



Stockholm, 



Royal Academy of Sciences, January 9. — On the re- 

 searches and studies made at the zoological station of the 

 Academy at Christineberg in Bohuslan, during the past year. 



by Prof. S. Loven. He gave an account of papers by Dr. 

 Aurivillius on the disguise amongst the Oxyrhynchous Crabs, 

 by Dr. Viren on a Nereid Annelid (Nereis ftieata, forma inqui- 

 tina), by Herr Lonnberg on cestodes in marine fishes and birds. 

 — Researches on the periodic system of the elements, by Dr. T. 

 R. Rydberg. — Baron Nordenskiold exhibited some uncommonly 

 large crystals of magnetic iron from the Nordstjerne mine near 

 Vestanfors, and gave an account of some remarkable Swedish 

 localities with crystallized magnetite. He also showed four 

 meteorites, for the collection of the State Museum, received from 

 the British Museum. Amongst these were (i) a sample of a 

 small, highly-interesting block of iron, which fell near Rowton, 

 in Shropshire, August 20, 1S76 ; (2) a fragment' of a meteor- 

 ite which fell in Hisen, in Japan. — On some transcendents, 

 which appear at the repeated integration of rational functions, by 

 Dr. A. Jonquiere, of Bern. — On natural etching figures and other 

 phenomena of solution on beryllium, from Muovinsk, by Herr 

 W. Peterson. — Researches on minerals from Fiskernses, in Green- 

 land, by Herr N. V. Ussing. — Mineralogical notes, II., 3-4, by 

 Herr G. Flink. — Anatomical studies on Echidna, by Miss C. 

 Westling. — On the dimorphism of the Rhizopoda retindata, by 

 Dr. A. Goes. — The insect fauna of Greenland ; I. Lepidoptera 

 and Hymenoptera, by Prof. Chr. Aurivillius. 



BOOKS, PAMPHLETS, and SERIALS RECEIVED. 



Memoirs and [Memoranda in Anatomy, vol. i. : Cleland, Mackay, and 

 Young (Williams and Norgate). — Mnlekularphysik, Erster Band : Dr. O. 

 Lehmann (Williams and Norgate).— Thomas Jefferson and the University 

 of Virginia : H. B Adams (Washington). — Transactions of the Sanitary 

 Institute of Great Britain, vol. i.K. (Stanford). — Life Register (West, New- 

 man). — Essai d'une Theorie du Soleil et des Etoiles Variables : A. Brester 

 (Delft). — Industrial Education in the South : Rev. A. D. Mayo (Washing- 

 ton). — Kew Observ.-itory, Richmond, Report for the year ending December 

 31, 1888 (Harrisjn). — L Ecoulement des Glaciers: Dr. A. A. Odin (Lau- 

 sanne). — Arnold Toynbee : F. C. Montague (Baltimore). — Journal of 

 Physiology, December (Cambridge). — Journal of Chemical Society, Decem- 

 ber (Supplementary Number) and January (Gurney and Jackson). — Himmel 

 und Erde, i Jahrg. Heft 2, 3, 4 (Berlin, Pactel). — Annalen der Physik und 

 Chemie, 1889, No. i (Leipzig, Barth). 



CONTENTS. Page 



The History of Mathematics 265 



The Building of the British Isles. By Prof. A. H. 



Green, F.R.S 268 



Our Book Shelf:— 



Montelius : " The Civilization of Sweden in Heathen 



Times" 270 



Welford and Sturmey : "The 'Indispensable' Hand- 

 book to the Optical Lantern " 270 



Letters to the Editor: — 



Alpine Haze. — Rev. W. Clement Ley 270 



A Remarkable Rime. — Miss Annie Ley 270 



Mass and Inertia. — Prof. Oliver J. Lodge, F.R.S. 270 



A Hare at Sea. — W.J. Beaumont ,...,.. 271 

 The Artificial Reproduction of Volcanic Rocks. By 



Alphonse Renard . 271 J 



Some Recent Advances in the Theory of Crystal- 1 



Structure. {Illustrated.) By H. A. Miers .... 277 

 The Earthquake at Ban-dai-san, Japan. ByVaughan 



Harley , 279 



Notes 280 



A&tronomical Phenomena for the Week 1889 



January 20-26 283 i 



Geographical Notes 283 m 



The Strassburg Botanical Institute. By William R. ^ 



Dudley 284 



Industrial Education. By Prof. John Perry, F.R.S. 284 

 Zoological Notes from Torres Straits. By Alfred 



C. Haddon 285 



University and Educational Intelligence 286 



Scientific Serials 286 



Societies and Academies 2S6 



Books, Pamphlets, and Serials Received 288 



