i6S 



NA TURE 



[June 15, 1893 



of degeneration found to go together with multiplicity of homo- 

 logous parts, and is illustrated by corresponding gradati n in 

 the animal kingdom, where the m)riapod is classed below the 

 hexapod insect. — On the repeated application of Bernouilli's 

 theorem, by M. Jules Andrade. — On problems of dynamics 

 reducible to quadratures, by M. Paul Staeckel. — Sketch of a 

 new theory of electrostatics, by M. Vaschy. — On some phe- 

 nomena exhibited by Natterer's tubes, by M. Gouy. — Absorption 

 of seleniuretted hydrogen by liquid selenium at high tempera 

 tures, by M. H. Pelabon. If selenium be melted in a tube 

 containing hydrogen and then cooled, it is found to contain a 

 large number of bubbles with a brilliant internal surface, which 

 are absent in selenium fused in air. On reducing the mass to 

 powder the characteristic smell of seleniuretted hydrogen is 

 observed, and if the mass is broken up under water the latter 

 is coloured red by the finely divided selenium liberated from 

 the seleniuretted hydrogen by the oxygen of the air. — Organo- 

 metallic combinations belonging to the aromatic series, by M. 

 G. Perrier. — On the coccidia of the birds, by M. Alphonse 

 Labbe. — On the Plankton of the Polar Sea, by M. G. 

 Pouchet. — On pseudo-fecundation in the Uredinei and accom- 

 panying phenomena, by M. Sappin-TroufTy. — On two cases of 

 parasitic castration observed in Knautia arvensis. Coulter, by 

 M. MoUiard. — On the sedimentary strata of Servia, by M. J. 

 M. Lugovic. — On the eclogites of Mont Blanc, by MM. L. 

 Duparc and L. Mrazec. — On the employment of vine leaves for 

 feeding cattle, by M. A. Muntz. In the south of France sheep 

 are often let into the vineyards after the vintage and allowed to 

 strip the vines of their leaves. The vines do not appear to 

 suffer thereby in the least. Fresh vine-leaves contain 67 'O per 

 cent, water, i8'5 extractive matter, 3 8 nitrogenous matter, and 

 2'3 per cent, fatty matter. When dried, the proportions are : 

 extractive matter, 51 percent. ; water, 15; nitrogenous matter, 

 II ; cellulose, 8 '5 ; and fatty matter, 55 per cent. In the 

 various vineyards of southern France the amount of leaves per 

 hectare (2 47 acres) varies from 2500 to 9500 kgr., or about the 

 average yield of hay for the same area. Moreover, the leaves, 

 instead of getting blown away by the wind and lost, are con- 

 verted into manure by the cattle, and, in addition, the vine is 

 much less sensitive to drought than the ordinary fodder crops. — 

 On the effects of inoculation of human cancer or cancerous pro- 

 ducts upon animals ; positive result in one case, by M. Mayet. — 

 On the amplitude and mean duration of the extreme oscilla- 

 tions of the barometer at Paris, by M. Leon Descroix. — On the 

 density and alkalinity of the waters of the Atlantic and the 

 Mediterranean, by M. J. Y. Buchanan. Along the entire south 

 coast of Spain the water was of the same density as the Atlantic. 

 Eastwards of Cape Gata, where the eastward current is no 

 linger active, the denser water of the Mediterranean set in. 

 The mean ratio of salinity and alkalinity was 0*50 for the 

 Atlantic, and 04875 for the Mediterranean, the difference being 

 probab'y due to the abundance of calcareous rocks on the 

 latter. 



Amsterdam. 

 Royal Academy of Sciences, May 27. — Prof, van de 

 Sande Bakhuysen in the chair. — Mr. Hubrecht gave a descrip- 

 tion of phagocytic and vasifactive processes by which the tropho- 

 blast of 7 upaja javanica attacks the maternal uterine epithelium 

 and prepares congested surfaces against which the area vascu- 

 losa and afterwards the allantois are applied. The placenta of 

 Tupaja is double, and situated right and left of the foetus. The 

 trophohlast of Tupaja was furthermore compared to that of 

 Sorex and of Erinaceus, in all of which it displays a considerable 

 degree of activity. It was more rigorously defined as being the 

 epiblast of the mammalian blastocyst, after deduction of what 

 is intended for the formation of the embryo and for the internal 

 coating of the amnion. In conclusion, certain phylogenetic 

 speculations concerning the trophohlast were brought forward. 

 — -Mr. Schoute exhibited three new thread-models of devel jp- 

 ables related to higher algebraical equations. The first is the 

 discriminant of the general cubic «' -f- 3.V!<2 + t^u ■\- z = o. 

 It divides space into two parts, corresponding to points with 

 3 or I real roots. The ordinary twisted cubic forms its cuspidal 

 edge. The discussion of the number of real roots situated 

 between two given limits is facilitated by means of a certain 

 tetrahedron. The second surface corresponds to the quartic 

 «* -t- 6jr«- 4- 4^» -t- z = o. It divides space into three parts, 

 containing points with 4, 2, or o real roots. By planes perpen- 

 dicular to the jr-axis it is cut in rational quartics with two cusps 

 and one node. It possesses a parabolic nodal curve. And the third 



NO. 1233, VOL. 48] 



model realises the surface corresponding to the sextic k' - I5«* 

 -f I'^xti'^ -^ dyu + z = o. It divides space into four parts, with 

 points admitting 6, 4, 2, or O real roots. Any plane perpendicular 

 to the jr axis meets it in a rational sextic curve with four cusps 

 and six nodes. The cusps of the cuspidal edge are very remark- 

 able points on this surface. In general the developable corre- 

 sponding to a likewise mutilated equation of the nth order with 

 three coefficients x, y, z, will show rational sections of the nth 

 order with the planes perpendicular to the x axis, admitting 

 n - 2 cusps and J(« - 2) (« - 3) nodes, &c. — Mr. van der 

 Waals gave a formula for the law of molecular force. By 

 putting 



r 



-' r 

 for the potential of two material points, all the known laws of 

 molecular action may be deduced. In this formula A is a line 

 equal to the quotient of La Place's H and K. This law may l>c 

 explained by supposing (i) that the action of the point itself 

 varies inversely as the square of the distance, (2) that the uni- 

 versal medium gradually does absorb the lines of force. 



BOOKS, PAMPHLETS, and SERIALS RECEIVED 



BroKS.^Mensuration of the Simpler Figures: W. Briggs and T. W. 

 Edmondson (Clive).— Science Teaching in Schools: H. Dyer (Bb.ckie).— 

 New South Wales Statistical Register for 1891 and Previous Years : T A. 

 Coghlan (Sydney, Potter).— Conquete du Monde V^giital : L. Bourdeaa 

 (Paris, Alcan) — A Popular History of Astronomy, ,3rd edition: A. M. 

 Gierke (Black).— Problemes et Calcu's Pratiques d'EIectricitrf : A. Wit« 

 (Haris, GauthierVillars). —Captain t'ook's Journal, edited by Captain 

 Whnrton (E. Stock). — Bionomie de.s Meeres; Erster Theil— Einleitung in 

 die Geologic als Historische Wisseni^chaft : J. Wallher O^na, Fischers- 

 Philosophical Transactions of the Royal Society of London, vol. 184 (1891), 

 A. pp 361-504), The Value of the Mechanical Equivalent of Heat: E. 

 H. Griffiths (Kegan Paul). 



Pamj'hi.ets.— The Life-saving Society Handbook, and edition (London). 

 — On the Early History of some Scottish Mammals and Birds : Prof. Duns. 

 — From Holborn to the Strand : W. Robinson {Garden Office).— Report on 

 Utilisation of the River Darling: H, J. McKinney and F. W. Ward 

 (Sydney, Potter), — Su Alcune Dlsposizinni Sperimentali per la Dimos 

 trazione lo Studio delle Ondulazioni Elettriche di Hertx : A. Righi 

 (Roma). 



Serials. — Gazzetta Chimica Italiana, Anno xxiii. 1893, vol. i. Fasc, 5 

 (Palermo).— Himmel und Erde, June (Berlin). — American Jotimat of 

 Science, June (New Haven).— Bulletin Astronomique, May (Paris).— 

 Bulletin de I'Acad^mie Royale des Sciences de Belgique, 1893, No. 4 

 (Bruxelles).— Botani^-al Gazette. May (Bloomington, Ind.)— Journal of ihe 

 Chemical Society, June (Gurney and Jackson). — Zeitschrift fur Wissen- 

 schaftliche Z- ologie, 56 Band, 2 Heft (Williams and Norgate). 



CONTENTS. PAGE 



Applied Chemistry. By Sir H. E. Roscoe, M.P., 



F.R.S 14S 



A Popular Atlas 147 



Our Book Shelf:— 



Mivart: "Types of Animal Life."— C. LI. M. . . . 148 



Dyer: " Science Teaching in Schools " 148 



Letters to the Editor: — 



Vectors and Quaternions. — Prof. C. G. Knott ... 149 

 The Fundamental Axioms of Dynamics. — Edward 



T. Dixon 149 



Chemical Change. — V. H. Veley 149 



Mr. H. O. Forbes's Discoveries in the Chatham 



Islands.— Prof. Alfred Newton, F.R.S 150 



Linnean Society Procedure. — F. H. P. C 150 



The German Mathematical Association 150 



Relations between the Surface-Tension and Rela- 

 tive Contamination of Water Surfaces. (With 



Diagrams.) By Agnes Pockels 152 



Notes 154 



Our Astronomical Column : — 



Finlay's Comet (1886 Vn.) 158 



Determinations of Gravity 158 



Solar Observations at the Royal College, Rome ... 15" 



V Astronomic for June '5° 



Geographical Notes I59 



The Royal Society Soiree 159 



Thermometer Soundings in the High Atmosphere. 



By W. de Fonvielle 160 



Disinfectants and Micro-Organisms l6l^ 



The New Flora and the Old in Australia. By A. G. 



Hamilton i6' 



Societies and Academies 1^4 



Books, Pamphlets, and Serials Received 168 



