62S 



jVA TURE 



[October 27, 1892 



means of a Cornu photo-polarimeter. The eye-end of this instru- 

 finent is covered with a cobalt glass, the quantity of polarized 

 light from the chosen point in the sky is measured, the blue glass 

 replaced by a ruby glass, and the determination repeated for the 

 latter. Generally, the intensity of polarization for blue light is 

 sensibly greater than that of the red. This is not favourable to 

 Lallemand's theory of the blue colour of the sky as a phenomenon 

 of fluorescence. The difference of polarization is, however, not 

 constant, but depends upon the direction of the wind. A series 

 of observations made at Kharkoff between April and September, 

 181' \ hvjvy a maximu.Ti di leie'r.^ with a south-easterly wind, 

 diir t' •' SV1 metric<i;iy on ' it}; ti te,> and even becoming 

 negcL...^ vv. N. W. The amount of ^ '"rization of the 



blue shows the opposite distribution, so that \^ ' '-' 



tion of the atmosphere rises or falls, the elTect'is grc. 

 less refrangible radiations than in the riher^; There is .iso a 

 notable relation between polarizatio;, and atmospheric moisture. 

 Th«.3.E. brings thegreatestam'/riL of precipitation, the northerly 

 winds the least. It is a!sr. probable that dust and dry fogs 

 exert a considerable in R. -nee., as shown by the circumstance 

 that the greatest difF .icts have been obtained in high winds, 

 when the whole !o.! .^ was covered with dust. — On a new way of 

 preparing ac;tyi'.ne, by M. L. Maquenne (see Notes). — On the 

 analysis of mixtures of ammonia and methylamines, by M. H. 

 Quantin. — On the nervous tissues of some invertebrates, by M. 

 A. B. Griffiths. — Examination of some rocks collected by Prince 

 Henry ol Orleans on the lower Black River in Tonkin, by M. 

 Stanislas Meunier. — Note on the miocene formations of western 

 Algeria, by M. Jules Welsch. The miocene formations occur 

 in normal succession near Hamman Riva, where they rest on the 

 Cretaceous. It appears certain that the last upheaval of the 

 Atlas did not take place at the end of the Helvetian epoch 

 (middle miocene), as hitherto believed. It was post-Tortonian, 

 and took place at the end of the upper miocene. For the forma- 

 tions of Gontas, Ben Chicao, Mascara, &c., are Tort onian ; they 

 are within the block of the Atlas Mountains, and have been 

 lifted to heights of 800, 1000, and even 1700 metres. This 

 result tends to confirm the general idea worked out within the 

 last few years that the zones of folding are nearer the equator in 

 proportion as they are more recent. 



Amsterdam. 

 Royal Academy of Sciences, September 24, Prof. Van 

 de Sande Bakhuysen in the chair. — Mr. H. A. Lorentz dealt 

 with the refltction of light by moving bodies. In a former 

 paper ("Arch, neerlandaises," t. xxv. p. 363) the author con- 

 sidered the propagation of light through a ponderable dielectric 

 which has a movement of translation, but leaves at rest the 

 inclosed ether. The equations then arrived at may be written 

 in the form — 



div. D = o. div. H = o, 



curlE 



H, curl 



pH + -L vect. (E/) l4,rr), 



47rV2D = «2E + vect. (H/), 

 the vectors H, D, E, and / representing the magnetic force, the 

 dielectric displacement, the electric force, and the velocity of 

 the pmderable matter. The signs "div." and "curl" have 

 the same meaning as in Heaviside's formulas {Phil. Mag., 

 5th ser. vol. xxii. p. 118), and Vect. (E/) indicates the vector 

 product. Finally, V is the velocity of light in vacuum, and n 

 the index of refraction. At the boundary of two media, 

 possessing a common translation, there will be continui'y of the 

 normal components of D and H, and of the tangential com- 

 ponents of E and H -f -L vect. (E/) 1. If i and r are the 



angles of incidence and refraction for the relative rays (" Arch, 

 neerlan .aises," t. 21, pp. 129-134), Fresnel's expressions for 

 the amplitude of the reflected ray — 



sin a - r) _^ t g[i - r) 



r) 



sin (?■ -t- r) 

 have to be multiplied by 



_ 2py COS i 



where Wj relates to the first medium, and p-^ is the velocity, in 

 the direction of the normal, with which the reflecting surface 

 recedes. This result may be shown to be consistent with the 

 conservation of energy, provided that the pressure exerted, 

 according to Maxwell, by the vibratory motion, be taken into 

 account. — M. van Bemmelen made a second communication on 



NO. 1200, VOL. 46] 



the existence of the crystalline hydrate of FcoOj. He obtained 

 the ferrite of sodium (FejOgNagO) in different crystal forms. 

 Under certain circumstances this form was a hexagonal plate. 

 These crystals could be metamorphosed by the action of water 

 in the hydrate of FejO^, without loss of their optical properties. 



BOOKS, PAMPHLETS, and SERIALS RECEIVED. 



Books. — The Student's Hand-book of Physical Geology : A. J. Jukes' 

 Browne, 2nd Edition (Bell). --The Beauties of Nature: Sir John Lubbock 

 (Macmillan). — Notes on Qualitative Chemical Analysis : P. L. N. Nayudu 

 (Madras, Chetty).— Amherst Trees: J. E. Humphrey (Amherst, Mass., 

 Carpenter). — Magnetical and Meteorological Observations made at the 

 Government Observatory, Bombay, 1890 (Bombay). — Explosives and their 

 Power: M. Berthel^t, translated by C. N. Hake and W. Macnab (Murray). 

 — Domestic Electric Lighting, treated from the Consumer's Point of View : 

 E, C. de Segundo (Alabater).— Introduction to Physiological Psychology: 

 ■"Jr. T. Ziehen, translated by C. C. van Liew and Dr. O. Beyer (Sonnen- 

 schein). — Notes by a Naturalist : H. N. Moseley, New Editiofl (Murray). — 

 The Science and Practice of Lighting; W. H. Y. Webber (W- King).— 

 Commercial Organic Analysis, vol. 3, Part 2, 2nd Edition : A. H. Allen 

 (Churchill). — Comitd International des Poids et Mesures. Proces Verbaux 

 des Stances de 1891 (Paris, Gauthier-Villars). — The Keliquary, vol. 6, New 

 Series (Bemro.se). — Vergleichende Morphologic der Pi ze : Dr. F. v. Tavel 

 (Jena, Fischer) — Beitrage zur Biologie und Anatoniie der Lianen : Erster 

 'Iheil ; Beitrage zur Biologie der Lianen : Dr. H. Schenck (Jena, Fischer). 

 —Dissections Illustrated, Part i, the Upper Limb: C. J. Br.)die(WhiLia;ker). 

 — Science Instruments (Newcastle-on-Tyne, Brady and Martin).— Tfireatisc 

 on 1 hermodynamics : P Alexander (Longmans). — Vegetable Wasps and 

 Plant-Worms: Dr. M. C. Cooke (S. P. C.K.).— Text-book of Petrology: 

 I >r. F. H. Hatch, and Edition (Sonnensch'-in). — Meteorological Service 

 Report, 1888 : C. Carrmael (Ottawa. Dawson), 



Pamphlets.— The Inaugural Robert B .yle Lecture : Sir H. W. Acland 

 (Frowrie). — Astronomical Observations made at the University Observatory, 

 Oxford, No. 4, Researches in Stellar Parallax by the Aid of Photography, 

 Part 2 : Prof. PrUchard (i )xford. Clarendon Press). 



Serials. — Records of the Ausirahan Museum, vol 2, Nos. 2 and 3 

 (Sydney). - Journal of State Medicine, vol. i, No. 2 (Griffin).— Journal of the 

 Chemical Society, October (Gurney and Jackson). — Zeitschrift fiir Wissen- 

 schaftliche Z jologie, 54 Band, 3 Heft (Williams and Norgate). — Journal of 

 the Royal Microscopical Society, October (W^illiams and Norgate). — 

 I ournal of Anatomy and Physiology, vol. 27, New Series, vol. 7, Part i 

 (Griffin). 



CONTENTS. PAGE 



Poland's " Fur-Bearing Animals " 605 



Spinal Nerve — Impulses and Electromotive Changes. 



By A. D. W 606 



Electrotechnical Training. By P. D 60S 



Hygiene and Public Health 609 



Our Book Shelf:— 



Frank : '"' Lehrbuch der Botanik nach dem gegen- 



wartigen Stand d'=r Wissenschaft" 610 



Woodward: " Arithmetical Chemistry."— J. W. R. 610 



Jones: " Lessons in Heat and Light " 610 



Angell : " Elements of Magnetism and Electricity " . 610 

 Letters to the Editor : — 



Further Notes on a Recent Volcanic Island in the 



Pacific— Captain W.J. L. Wharton, F.R S. . 611 

 Earth- Fractures and Mars "Canals." {Illustrated.) 



—Prof. G. A. Lebour 611 



A Wave of Wasp-Life.— G. W. Peckham .... 611 

 Note on the Occurrence of a Freshwater Nemertine in 



England. — W. Blaxland Benham 611 



Protective Mimicry. — Rose Haig Thomas .... 612 



Stellar Parallax 612 



Contributions to the Study of Disinfection. By 



Mrs. Percy Frankland 613 



An Ethnographical Survey of the United Kingdom 615 



Notes 615 



Our Astronomical Column : — 



C.-met Barnard (October 12) 619 



Discovery of Three New Planets by Photography . . 619 



Kutherfurd Measures of Stars about iSCygni .... 619 



A New Variable Star 620 



Jupiter's Fifth Satellite 620 



The Spectrum of Nova Aurigse 620 



"Jupiter and His System" 620 



Geograptiical Notes 620 



Geikielite and Baddeleyite, Two New. Mineral 



Species. By L. Fletcher, F.R.S 620 



New British Earthworms. {Illustrated.) By Rev. 



Hilderic Friend 621 



The Problem of Marine Biology. By George W. 



Field 623 



Optical Projection. By Sir David Salomons . . . 625 



University and Educational Intelligence 627 



Scientific Serials . 627 



Societies and Academies 627 



Books, Pamphlets, and Serials Received 628 



