Feb. 1 8, 1875] 



NATURE 



317 



producing a refrigeration of the crast equal to that which wculd 

 ht effected in a certain longer time of the pre-glacial or post- 

 glacial periods, then for a certain term of time — of length bearing 

 some proportion to the difference between the two — succeeding 

 the glacial epoch, the earth would, with its outer crust so much 

 below the normal, lose little or no heat by radiation, so that 

 during that subsequent period the thermo-dynamical effects due 

 to cooling would be reduced to a minimum or cease altogether, 

 and a period of nearly staple equilibrium, such as now prevails, 

 obtain. 



" This last great change in the long geological record is one of 

 so exceptional a nature that, as I have observed elsewhere,* it 

 deeply impresses me with the belief of great purpose and all-wise 

 design, in staying that progressive refrigeration and contraction 

 on which the movements of the crast of the earth depend and 

 which has thus had imparted to it that rigidity and stability which 

 now render it so fit and suitable for the habitation of civilised 

 man ; for, without that immobility, the slow and constantly 

 recurring changes would, apart from the rarer and greater cata- 

 strophes, have rendered our rivers unnavigable, our harbours 

 inaccessible, our edifices insecure, our springs ever-varying, and 

 our climates ever-changing ; and whde somejdistricts might have 

 been gradually uplifted, other whole countries must have been 

 gradually submerged ; and against this inevitable destiny no 

 human foresight could have prevailed." 



SCIENTIFIC SERIALS 



The youriial of Botany for December 1874 and January and 

 February 1S75 contain quite the average of papers of general 

 interest. Among the original papers may be mentioned in par- 

 ticular one on the critical species Tritunnt piiiigcns, and another 

 on Riitncx maximus, by the Hon. J. Leicester Warren ; descrip- 

 tions of new species of Scille^e and other Liliacea", by Mr. J. 

 G. Baker ; a list of the wild flora of Kew Gardens and pleasure- 

 grounds, by G. Nicholson ; Antluwanthuiii puclii, by F. Towns- 

 end ; and the continuation of the paper on the Botany of the 

 Maltese Islands, by Mr. J. F. Duthie. A larger proportion of the 

 space than usual is filled by reviews of botanical works, English 

 and foreign. The plates include two of new species of Asco- 

 bo! IIS, to illustrate a paper by Mr. James Renny ; A nthox- 

 aiil/iuni puiiii, recently discovered in the south of England ; and 

 Carex frigida and Salix Sadlcri, the two, recent additions to the 

 Scottish flora made by Mr. Sadler. 



The Botanical Magazine for February contains figures of the 

 following plants ; — Epidendrum syringot/iyrstis, a handsome 

 species from Bolivia, with large racemes of purple-red flowers, 

 tinged with lilac. Liliiim canadonse, var. parviini, a very hand- 

 some miniature lily, regarded by some as a distinct species. It 

 has small orange-red flowers spotted with purple-brown, ftv-tj. 

 nica pini;ui/olia, a shrubby species from New Zealand, with very 

 pale blue flowers. It is hardy at Kew. Fourcrova Solloa, an 

 agave-like plant from Guatemala, whose large flower-scapes 

 were allowed to protrude through the roof of the Succulent 

 House at Kew last summer, and must have been noticed by 

 many of our readers. Senccio macivglossiis, the plant with ivy- 

 like foliage alluded to in a recent number. Lastly, a new genus, 

 Erythrotis, of Commelynece : an exceedingly pretty trailing 

 plant from Malabar, having small leaves of a most brilliant 

 crimson on the under surface, and small bright blue and red 

 flowers. The species is called Beddomd, after CoL Beddome, its 

 discoverer. 



Zeitschrift der Ocstcrreichischcn GescUschaft fiir Meteorologis, 

 Jan. I. — On the cnrved tracks of cyclones issuing from the trade- 

 wind region, by Dr. W. C. Wittner. Water resembles air in 

 many of its movements, and is more easily observed ; its eddies 

 and currents especially may be studied with advantage in connec- 

 tion with cyclonic phenomena like the above-named. When a 

 stream of water is met by another at right angles, a depression is 

 formed at the point of interruption ; particles bordering this 

 depression sink into it in obedience to gravity, and particles at a 

 gicater distance move spirally inwards. Besides rotation there is 

 a progressive motion of the whole eddy, in the direction of the 

 resultant of the forces of the two streams. In turbulent streams 

 eddies last a very short time ; they are filled up almost as soon 

 as formed. In quiet rivers, on the contrary, the whirl continues 

 for a length of time sufficient for observation. In the develop- 

 ment of hurricanes, difference of air-density corresponds to dif- 

 * Philosophical Transactions for 1864, p. 305. 



ference of level in water. Hurricanes, like eddies, are destroyed 

 when the surrounding medium moves very irregularly, and we 

 should therefore look to the neighbourhood of the tropics, where 

 atmospheric conditions are remarkably regular, for a region 

 favourable to their growth and progress. Near the northern 

 boundary of the region of calms, the equatorial current begins at 

 about S., and the polar meets it from about E., nearly at right 

 angles, so that in this respect also the development of whirls, like 

 those in water at the junction of rivers, is favoured. The resultant 

 progression, towards N.W., becomes deflected as the storm 

 advances, until, at a latitude where the eastward component of 

 the equatorial may be supposed to vanish against the westward 

 component of the polar wind, an excess seems to remain of the 

 southerly over the northerly component, causing movement 

 towards N. In still higher latitudes the more westerly equa- 

 torial and northerly polar drive the cyclone in an easterly direc- 

 tion. Occasionally, when the northerly component of the polar 

 happens to be stronger than the southerly of the equatorial wind, 

 as in the storm of Oct. 10, 1S47, the system moves towards 

 S.W. In the southern hemisphere, as in the northern, the 

 direction of rotation indicates an irruption of the anti-trade into 

 the trade-wind. Tlie equatorial current, or anti-trade, appears 

 to be the strongest both by its invasion of the trade-wind region 

 and by the direction of advance of the consequent hurricane. — 

 A communication from Captain Hoffmeyer, in the Kleincre 

 Mitt/idlungen, contains Taluable remarks on the relation between 

 pressure and rainfall. In Denmark, most rain falls on the front 

 of a minimum, and when a considerable depression is near. Like 

 Mr. Ley, he believes that, at least in Europe, minima are formed 

 simultaneously -with heavy rains, but thinks that they are not 

 caused by them, only magnified. He has come to the conclusion 

 that minima must be looked upon not .as results of mechanical 

 rotation, but as functions of existing conditions and differences. 

 They seem to him to seek and require continual nourishment. 

 The principle of a descending current in maxima, and an ascend- 

 ing current in minima, broached by Mr. Buchan some years ago, 

 he considers the only one with which we can overcome the diffi^ 

 culties presented by these phenomena. Air is interchanged mainly 

 by vertical currents, resulting from thermal inequalities. Vapour 

 also plays a large part in ascending currents. Low pressure at the 

 earth's surface is not an indication but a cause of the courant ascen- 

 dant. With these views, and by the comparison of weather charts, 

 we can in general explain the main features of the atmospheric 

 condition, though not indeed its ever-varying relations. Dr. 

 Hann, in reply, maintains his opposition to the theory of Espy and 

 Reye, that the courant ascendant is the sole or chief cause of a 

 minimum in storms, and objects that the heaviest rains in the 

 tropics do not in the least disturb the regular daily movement of 

 the barometer, and to assume that the same cause in simijar 

 conditions could produce opposite effects would be illogic al. 

 Tropical rains have not been proved less extensive than those of 

 higher latitudes, as some have supposed them to be. We have 

 no clear evidence that condensation and rain diminish pressure. 

 On the other hand, mechanics teach us that pressure must 

 diminish towards the centre of a whirling mass of air. Fro m 

 these reasons, we should seek for an explanation in the laws of 

 dynamics. 



The Bullet m Mensuel de la Sociill d'Acclimatation de Fans 

 for October opens with a paper by M. S. Berthelot on "The 

 Domestication of Animals," in which the writer expresses the 

 opinion that the domestication of animals is due more to the art 

 and skill of man than to their natural qualities ; though the 

 aptitude for domestication is unalterable in those animals which 

 naturally possess it. — M. Bouillod contributes a paper on the 

 cultivation of wild turkeys, recounting his experience in the 

 matter, the object of which is not clear, seeing the domesticated 

 turkey cannot be excelled in any respect. — Silkworm culture 

 occupies its usual prominent position in the report. — The rapid 

 growth of the Eucalytpus globulus is exemplified by M. Laberenne, 

 who planted some seeds in Algeria on the 29th April, 1S73, 

 which twenty-six days later had already appeared above ground. 

 In September, 1874, some of the plants had attained a height of 

 65 centimetres (26 in.). — M. Drouyn de Lhuys, in a speech on 

 the I'hylloxera, suggests that new plantations of vine from seeds 

 should be formed, which he thinks would more easily repel the 

 attacks of the pest. — Germany is making advances in the culture 

 of the silkworm, which are detailed in a letter by M. A. Buvig- 

 nier. 



Aslronmnische Nachrichten, No. 2,020. — Mr. S. Bumham 

 contributes a note on certain double stars. 2 410 and H 334 



