632 



NATURE 



[Oct. 25, 1888 



needed. In genera], solar or diffused light, not containing all the 

 visible coloured radiations, is incapable always of showing us the 

 true colour of bodies ; further, the light given by incandescent 

 bodies containing all the visible radiations is insufficient to dis- 

 close this true colour, which can be discovered only by means of 

 a complete continuous spectrum without absorption bands or 

 rays, or by simple radiations from incandescent gases. In such 

 lights the true colour is that which is diffused or transmitted 

 with greatest intensity, or else the blend of those so diffused or 

 transmitted. This is somewhat analogous to the dichroism or 

 polychroisrn of certain substances, as, for instance, the alcoholic 

 solution of chlorophyll, which may seem green, brown, or red, 

 according to its degree of concentration or its thickness on the 

 path of the white light traversing it. — On the observations of 

 stars by reflection, and on the measurement of the flexion of 

 Gambey's circle, by M. Peiigaud. The experiments here 

 described with the modified form of Villarceau's mercury bath, 

 lately submitted to the Academy, have enabled the author, as 

 he anticipated, to obtain good images of reflected stars. Thus 

 have been easily obtained within a period of five or six weeks 

 about three direct and six reflected observations of about a hundred 

 stars of all altitudes from 25 above the southern to 25 above 

 the northern horizon. A calculation of the flexion of Gambey's 

 circle yields a value practically identical with that given by 

 Villarceau. — On the luminous ligament in the transits and 

 occultations of Jupiter's satellites, by M. Ch. Andre. In a 

 recent communication {Coviptes rendus, cvii. p. 216) the author 

 showed that one of the chief causes of uncertainty in these 

 observations was due to the formation in the focal plane of the 

 telescope, and, within a certain distance of the geometrical con- 

 tact, to a luminous connection or "ligament" between the 

 images of the satellite and the planet. A method is here 

 explained by means of which the possible errors due to this 

 phenomenon may be avoided. — Observations of Brewster's 

 neutral point, by MM. J. L. Soret and Ch. Soret. The neutral 

 point of atmospheric polarization situated below the sun has 

 rarely been observed since its existence was first determined by 

 Brewster. The authors have now been able accurately to 

 observe it on the summit of Rigi (1800 metres) on the mornings 

 of September 23 and 24, the height of the sun above the horizon 

 being from 20° to 35 . They were able at the same time to 

 determine the distance of the neutral point above the sun 

 (Babinet's neutral point). — On some double phosphates of 

 yttria and of potassa or soda, by M. A. Dubois. These phos- 

 phates have been obtained by causing the amorphous phosphate 

 of yttria to react, by the dry process, on the sulphate of potassa 

 (H. Debray's process, extended by Grandeau to the chief groups 

 of metallic oxides) ; and also by making the pure yttria react at 

 a high temperature on the metaphosphates and pyrophosphates 

 of potassa and soda. — On the alkaloids of cod liver oil (con- 

 tinued), by MM. Arm. Gautier and L. Morgues. Having 

 already determined the volatile alkaloids, butylamine, amylamine, 

 hexylamine, and hydrodimethylpyridine, the authors here de- 

 scribe the two fixed bases accompanying them. These are 

 named aselline, from Asellus major, the large cod ; and 

 morrhuine, from Gadus morrhua, the common cod ; the latter 

 being especially remarkable for its physiological properties. The 

 respective formulas are, C 25 H 32 N 4 and C 19 H 27 N 3 .— - On pro- 

 pylphycite, by M. Ad. Fauconnier. Under this name, Carius 

 described, in 1865, a body with the formula C 3 H 8 4 , which 

 Claus afterwards declared to be the glyceric aldehyde, unknown 

 in a pure state. From the author's further researches it now 

 appears that propylphycite is nothing but glycerine itself. 



Stockholm. 

 Royal Academy of Sciences, October 10. — Species Sar- 

 gassorum Australia; descriptse et dispositse a Prof. T. G. 

 Ayardh. — On persulphocyanacid and dithiocyanacid, by Dr. 

 Klason. — On a scientific tour in Russia, Germany, and Holland, 

 by Dr. S. Arrhenius. — On a magnetic field balance, by Dr. 

 Angstrom. — Baron Nordenskiold exhibited an edition, from 1560, 

 of Mercator's large map of the world, lately discovered by 

 himself. — On a new arseniate mineral from Mossgrufvan, in 

 Nordmark, by Hr. Sjogren.- — On the anatomical structure of 

 Desmarestia aculeata, Lam., by Miss E. Soderstrom. — On a 

 class of transcendents, which originate through iterated integra- 

 tion of rational functions, by M. A. Jonquiere, of Bern. — On 

 aceto-propyl-benzol and aceto-kumol and their derivatives, by 

 Prof. Widman. — The electrical and thermic conductibility of 

 specular iron, by Hr. H. Backstrom. — Contributions to the 



knowledge of the thermo-electricity of crystals, by the same. 

 — Determination of the magnetic inclination in Stockholm, 

 Sundsvall, and Ostersund, by Hr. P. A. Siljestrom. 



Amsterdam. 



Royal Academy of Sciences, September 29. — M. de 

 Vries read a paper on sterile plants of maize or Indian corn. — 

 M. Van Bemmelen discussed the contents of a paper of M. 

 Bakhuis Rozeboom, on the combinations of calcium chloride 

 with water in solid and fluid condition. — M. J. A. C. Oudemans 

 read a paper on levels becoming unfit for use by the diminished 

 mobility of the bubble, in consequence of the precipitation of 

 granular corpuscles against the interior surface of the g'.ass. He 

 demonstrated that this evil could be obviated by (1) constructing 

 the levels of kali-glass, and not of natron-glass ; (2) taking care 

 that no water should be able to penetrate into the interior of 

 the instrument ; and (3) employing, instead of sulphuric ether, 

 petroleum ether for the filling. 



BOOKS, PAMPHLETS, and SERIALS RECEIVED. 



The Fatal Illness of Frederick the Noble : Sir M. Mackenzie (Sampson 

 Low). — The Senses, Instincts, and Intelligence of Animals: Sir John 

 Lubbock (Kegan Paul). — Lectures on the Ikosahedron and the Solution .j{ 

 Equations of the Fifth Degree : F. Klein, translated by G. G. Morrice 

 (Triibner). — Text-book of Practical Logarithms and Trigonometry : J. H. 

 Palmer (Macmillan). — Experimental Mechanics, 2nd edition : Sir R. S. Kail 

 (Macmillan). — Examples for Practice in the use of Seven-figureLogarithms : 

 J. Wolstenholme (Macmillan). — The History of Australian Exploration, 

 1788-1888 : E. Favenc (Turner and Henderson, Sydney). — A Manual of the 

 Vertebrate Animals of the Northern United States, 5th edition : D. S. Jordan 

 (McClurg, Chicago). — Outlines of Natural Philosophy, enlarged edition : J. 

 D. Everett (Blackie).— The British Moss Flora, Part xi. : K. Braithwaite 

 (published by author). — The Theory and Practice of Absolute Measurements 

 in Electricity and Magnetism, Vol. i. : A. Gray (Macmillan). — Mathematical 

 Examples : J. M. Dyer and P. Prowde-Smith (Bell). — The Student's Pesta- 

 lozzi : J. Russell (Sonnenschein). — Journal of the Royal Microscopical 

 Society, October (Williams and Norgate).— Journal of the Royal Statistical 

 Society, September (Stanford). — Annalen der Physik und Chemie, 1888, No. 

 10; Beiblatterzu den Annalen der Physik und Chemie, 18S8, No. 9 (Barth, 

 Leipzig). — Bulletin of the American Geographical Society, vol. xx. No. 3 

 (New York), — Bulletins de la Societe d' Anthropologic de Paris, Tome xi. (3 

 Serie) Fasc. 1 and 2 (Masson, Paris). 



CONTENTS. page 



Empiricism versus Science 609 



The Mesozoic Mammalia 611 



Earth Sculpture 61+ 



Our Book Shelf :— 



Hinman : " Eclectic Physical Geography " 615 



Letters to the Editor : — 



Prophetic Germs.— The Duke of Argyll, F.R.S. . 615 

 Definition of the Theory of Natural Selection. — Prof. 



George J. Romanes, F.R.S 616 



How Sea-Birds Dine. — Earl Compton 618 



The Zodiacal Light. — Dr. Henry Muirhead . . . 618 

 The Geometric Interpretation of Monge's Differential 



Equation to all Conies. — R. B. H 619 



A Shadow and a Halo. — Rev. Edward Geoghegan ; 



Charles Cave 619 



On the Grass Minimum Thermometer. — Dr. W. 



Doberck 619 



On the Electromotive Variations which accompany 

 the Beat of the Human Heart. {Illustrated.) By 



Dr. Augustus D. Waller 619 



The Maximum of Mira Ceti. {Illustrated.) By J. 



Norman Lockyer, F.R.S 621 



Flora of the Kermadec Islands. By W. Botting 



Hemsley 622 



Digiti Minimi Decessus 622 



Notes 623 



Our Astronomical Column : — 



The Ring Nebula in Lyra 626 



Comets Brooks and Faye 626 



Comet 1888 e (Barnard) 626 



American Observatories 626 



Astronomical Phenomena for the Week 1888 



October 28— November 3 626 



On the Origin and the Causation of Vital Movement. 



I. {Illustrated.) By Dr. W. Kuhne 627 



The Hemenway Expedition in Arizona. By Thomas 



Wilson 629 



Self-reproducing Food for Young Fishj 631 



University and Educational Intelligence 631 



Societies and Academies 631 



Books, Pamphlets, and Serials Received 632 



