258 



NA TURE 



\yan. 28, 1875 



Lasswitz, of Breslau, contributes an article on the decay of the 

 "kinetic atomic theory " in the seventeenth century. — Another 

 communication is by Dr. H. Streintz, of Vienna, on torsion- 

 oscillations of wires. It is followed by a paper on resistance in 

 galvanic conductors, by H. Herwig. This paper was accidentally 

 delayed, and should have been published before another one on 

 the same subject, which appeared in Part 1S74, No. 9, of these 

 Annals. — The ne.xt paper, on fluorescence, by O. Lubarsch, is 

 highly interesting. The author gives an account of elaborate 

 investigations he made on the subject, with special reference to 

 spectrum analysis ; his general results seem to show (i) that for 

 each fluorescent substance there are only certain rays of light 

 causing fluorescence ; (2) that the colour of the fluorescent light 

 depends on the rays of incidence, and follows Stolies's law ; and 

 (3) that the most refrangible fluorescent rays, produced by sun- 

 light, correspond to tliat jjlace in the spectrum where the liquid 

 shows its maximum of absorption, providing its fluorescence 

 proves a simple one, when examined by prismatic analysis of the 

 linear spectrum. In all three points Mr. Lubarsch differs from 

 Pierre and Lommel, who investigated the subject before him. — 

 On the expansion of mercury after Mr. Regnault's experiments, 

 is a valuable communication from Mr. A. Wiillner.— The 

 remaining papers are : On the influence of the temperature of 

 air on the index of refraction, by M. V. von Pang ; and on the 

 oblique passage of rays through lenses with reference to a pecu- 

 liarity of the crystalline lens, by L. Herman. — Besides these, 

 there is a short note by H. Schneebeli, on Hipp's machine for 

 determining the laws of motion. 



Dcr Natityforsclur (Nos. 49-52, Dec. 1S74.)— Among the 

 papers in this number we note the following : — On currents and 

 temperatures in the Atlantic Ocean ; observations made on board 

 the German corvette Gazelle, by the commander Herr von 

 Schleinitz, on a voyage to the Kerguelen Islands. — On carnivo- 

 rous plants ; researches made by Prof Ferd. Cohn, of Breslau, 

 with European species. — Note on the discovery of a new aste- 

 roid, 139, on Oct. 13, 1S74, by Mr. J. Palisa, at Pola. It ap- 

 peared of the nth magnitude, under R.A. 2h. 7m. I9'39s. ; Decl. 

 + 7° 29' 507". — On the native iron of Ovifak, Greenland ; dis- 

 cussing the question whether this native iron is of meteoric or 

 terrestrial origin. — On the influence of temperature upon the 

 respiration of plants ; researches made by Herren von Wolkoff 

 and Mayer at Heidelberg, showing that the influence is not 

 nearly so great as is generally accepted. — On the formation of 

 urea in the animal organism, by Herr von Knieriem. — On attrac- 

 tion and repulsion by heat and light, by A. Bergner; account of 

 experiments made, which led to difterent results than those 

 obtained by Mr. Crookes. — On the decrease of intensity in the 

 light of Jupiter's satellites when passing over the planet's disc. 

 This was explained by S. Alexander as resulting from inter- 

 ference and absorption of the rays of light ; H. J. Klein now 

 gives a much simpler explanation. — On the inorganic cell and 

 the phenomena of growth in the inorganic world, by M. Traabe ; 

 giving a purely physical explanation for the origm and growth of 

 the cell. — Besides many smaller notes of scientific inteie-t, tiielast 

 number contains a detailed account of the sledge journeys made 

 by Oberlieutnant Jul. Payer while in polar regions with the 

 Austrian Polar Expedition. 



SOCIETIES AND ACADEMIES 



London 



Royal Society, Jan. 21. — " On the Origin and Mechanism 

 of Production of the Prismatic (or columnar) Structure of 

 Basalt," by Robert Mallet, C.E., F.R.S., &c. 



In this paper the author shows that all the salient phenomena of 

 prismatic basalt as observed in nature can be accounted for as 

 results of contraction by cooling in a homogeneous body pos- 

 sessing the properties of basalt, and that the theories hitherto 

 advanced and repeated in text-books of the production of ba- 

 saltic prisms are alike untenable and unnecessary. If a large 

 level and tabular mass of homogeneous basalt cool slowly 

 by loss of heat from one or more of its surfaces, the contraction 

 of the mass while plastic will be met by internal movements 

 of its particles ; but when the temperature has fallen to a 

 certain point of rigidity reached at between 900° and 600° F., 

 splitting up commences, and that surface will begin to divide 

 itself into similar geometric figures of equal area, which on 

 mechanical principles must be hexagons, the diameter of which 

 is shown to depend upon the relation that subsists between the 



coefficients'of extensibility of the material and of its contraction 

 by cooling down to the splitting temperature. These hexagons 

 are the (irst formed ends of the future prisms, which split deeper 

 into the mass as cooling down to the splitting temperature 

 reaches deeper into it. When the prisms have split down to a 

 certain distance, further cooling proceeds, not only from the ends 

 of the prisms, which formed the surface of original cooling, but 

 from the sides of the prisms. Now, as each prism is coldest at 

 the end, and hottest where in the act of splitting, and is also 

 hotter along the axis than at the exterior of each prism, so, by 

 contraction, differential strains are produced in each prism, both 

 parallel to the axis and transverse to it, which result in cross 

 fractures at intervals along the length of the prism, the distances 

 between which the author has assigned. Transverse fracture 

 round the prism must commence in the outer coiiche in a plane 

 normal to the resultant of the contractile strains longitudinal 

 to and transverse to the axis of the prism ; the fracture com- 

 mences, therefore, oblique to the prismatic axis. This obliquity 

 diminishes as the transverse contractile force diminishes, as the 

 circumferential coiuhe of cooling reaches nearer to the axis of the 

 prism ; the result is chat the transverse fracture when completed 

 is lenticu'ar or cup-shaped, the convex surface always pointing 

 in the same direction in which the cooling is progressing within 

 the mass. 



If the mass cool from the top surface only, the convex 

 surfaces of the cup-shaped joints will all point downwards ; if 

 cooled from the bottom only, they will point upwards ; and if 

 from both surfaces, the convexity of the joints will be found point- 

 ing both upwards and downwards in the mass. As the splitting 

 always takes place normal to the surface of cooling, so, if that 

 surface be level and cool, uniformly, the prisms must be vertical 

 and straight ; also, if the cooling surface be a vertical or inclined 

 one, the [direction of the prisms will be normal thereto. If, 

 however, the mass cool from its upper or lower surface, but 

 of much greater thickness in one direction than in the opposite 

 one, the prisms formed will not be straight, but have their axes 

 curved, because the successive couches reaching the splitting 

 temperature successively within the mass, and normal to which 

 the splitting takes place, are themselves curved planes. These 

 are a few of the principal points of this paper, which the author 

 believes renders, for the first time, a complete and consistent 

 account of all the phenomena observed in prismatic basalt. A 

 considerable number of these phenomena were referred to and ex- 

 plained by the author. At the conclusion of his paper the author 

 submits to rigid examination the notions whicl-' from 1804, the 

 period of Mr. Gregory Watts's paper (Phil. Trans. ), to the present 

 time, have continued to occupy the text -books of geologists, and 

 he poi-nts out how entirely these fail to account for the 

 phenomena. 



Linnean Society, Jan. 21.— Dr. G. J. AUman, F.R.S., pre- 

 sident, in the chair. — Dr. HoUis read a paper on the pathology of 

 oak-galls. Oak-galls may be divided into two classes, the unilo- 

 cular or one-celled, which include the woody marbled oak-galls, 

 the ligneous galls of Reaumur, and the currant leaf-galls ; and the 

 multilocular or many-celled, including the spongy oak-apple and 

 the oak-spangles of the leaves. The author went with some 

 detail into the structure and history of development of each of 

 these kinds, taking a few examples of each. With the exception 

 of the oak-spangles, all the different kinds appear to be formed 

 during the growth of the leaf. The pathological differs from the 

 healthy development in the more rapid growth of its cellular 

 elements and in the larger size they attain ; this is gained at the 

 expense of the differentiation of the matrix of the bud. The 

 author traced the origin of the different layers of the gall itself 

 to the different Layers of the leaf from Avhich it is produced. A 

 discussion followed, in which the President, Mr. Murray, Mr. 

 Howard, Prof Dyer, and others took part. — The following papers 

 were then read :— Reports of the Challenger Expedition ; On the 

 Lichens, chiefly of Tristan d'Acunha, by the Rev. Dr. Stirton. — 

 On the Lichen Flora of New Zealand and Chatham Island, by 

 the Rev. Dr. Stirton. 



Mathematical Society, Jan. 14. — Prof. H. J. S. Smith, 

 F.R.S., president, in the chair.— Mr. J. W. L. Glaisher gave 

 an abstract of a paper by Prof. Cayley, on the potentials of 

 ellipses and circles. The potential of an ellipse of uniform den- 

 sity (in regard to a point not in the plane of the ellipse) was 

 found by a process similar to that made use of in Gauss' memoir, 

 " Determinatio attractionis quam e.xerceret Planeta,'' &c. (1818) ; 

 the final result resembled in a remarkable manner the formula 

 for the potential of an ellipsoid. The author then deduces a 



