Feb., 1904.] 



KNOwLi'iHii' .V scii':x rii-ic xi:\vs. 



5olar Activity and Terrestrial Magnetism. 



The principal subject of the papers at the Ivoyal Astrono- 

 mical Society, on January 8, 1904, related to the connection 

 between solar activity and terrestrial nia.sjnetisni. Mr. William 

 KUis pointed out an annual inequality in the frequency of 

 aurora; as observed in these latitudes, correspondini; to that 

 established in the frequency of magnetic disturbances. Mr. 

 Maunder drew attention to the two great periods of excep- 

 tional solar quiescence, and suggested a connection with the 

 secular change of magnetic declination. Mr. M.iundcr 

 examined the details of the nineteen greatest magnetic storms, 

 since 1S75, and the nineteen greatest sun spots, and suggested 

 that the action from disturbed regions on the Sun might have 

 a maximum eftect in a given direction, and that this would 

 explain quantitative discrepancies between certain sunspots 

 and the magnetic storms which appeared to synchronise with 

 them. 



Stellar Magnitude of the Sun. 



Mr. Charles Fabry, at the meeting of the Paris .'\cademic 

 des Sciences on December 2S, 1903, communicated the result 

 of his photometric determination of the stellar magnitude of 

 the Sun. On December 7 he had reported that he found the 

 Sun's light to be 100,000 times more intense than that produced 

 by a decimal candle at a distance of one metre. A similar in- 

 vestigation, with the star \'ega as the subject, gave the stars 

 light as equal to that of a decimal candle at "So metres. The 

 stellar magnitude of Vega being taken as 0-2, that of the Sun 

 was inferred to be — 26'7. 



Double Spiral Structure in Hercules. 



Professor J. M. Schaeberle, in the Astruiiumical Jaiiriui!. 

 No. 552, announces his discovery of a double spiral structure 

 in the great cluster in Hercules, the more pronounced spiral 

 being clockwise, the other being counter-clockwise ; the clock- 

 wise spiral being formed by the inner streams of ouli^oiti)^ 

 matter, the seeming counter-clockwise spiral by that part of 

 each stream which contains retiiniiug matter. The plane of 

 the spiral is not normal to the line of sight. A precisely 

 similar structure on a much larger scale appears to 

 exist in the stars and nebulosity surrounding Gamma 

 CassiopeitE. 



Botanical Notes. 



A New Rubber Plant. 



Another plant containing rubber is now arousing con- 

 siderable interest in Colorado, according to Mr. T. D. A. 

 Cockerell's paper in the Bulletin of the Colorado College 

 Museum, No. i, where a description of the plant is given 

 under the name of Picradenia Jloribunda utilis. It is a 

 native plant, belonging to a North American genus of 

 Composita^ and resembles in appearance the French 

 marigold genus (Tagetes), to which it is allied. Unlike 

 most of the previously known rubber plants, this is a 

 rather dwarf herb, and the rubber is obtained, not from 

 a woody stem, but from the roots, where it is found in 

 large quantities. 



A New (ienus. 



A curious new genus is described in the Japanese 

 Botanical Magazine for September, 1903, to wiiich the 

 name Miyoshia has been given. The only species at 

 present known is a small, saprophytic, leafless plant, 

 quite destitute of chlorophyll. It was found in a forest 

 in the province of Mino, Japan. The author considers 

 the genus to be closely related to Aletris in Liliaceae, but 

 as he cannot fit it into any already established order he 

 has putit into a new one, which hehas called Miyoshiacea'. 

 The tubeless perianth and semi-inferior ovary suggest 

 some Ha;modoracea;. 



Root Formation. 



In the Osterreichishe Botanische Zeitschrijt for December, 

 1903, Leopold Ritter von Portheim records his observa- 

 tions on root-formation on the cotyledons of Phaseolus 



vulgaris. Experiments with beans carried on for five 

 years before 1901 were unsuccessful, but in that year the 

 desired results were obtained in eleven cases. The plants 

 were grown in tliedark in distilled water or in a nutritive 

 solution free from lime. Roots developed, sometimes 

 one, sometimes two or three, on the cotyledons near the 

 attachment to the a.\is. It was also found that roots, 

 and less frequently shoots, would form on cotyledons 

 separated from the axis, but it was not quite clear whether 

 the shoots were auxiliary or not, in spite of the careful 

 separation of the cotyledons. 



British Orrvithological Notes. 



Tin: column in Knowledge hitherto devoted to British 

 (Ornithological Notes, and conducted by Mr. Harry F. 

 W'itherby, will, we regret to say, be now discontinued. 

 Mr. Witherby wishes us to convey his sincere regrets 

 to our readers that this course has been found necessary, 

 and that no longer notice could be given. 



REVIEWS OF BOOKS. 



"The Evolution of Barth Structure, with a theory of geomor- 

 phic changes." By T. Mellard Reade, F.G.S., F.R.I. B.A., 

 A.M.I.C.F. Pp. xvi. + 3.|2. (London: Longmans, Green, 

 and Co., ujoj; price 21s. net.) Mr. Mellard Keade, with his 

 long experience as an architect and engineer, has never lost an 

 opportunity of applying physical principles to the explanation 

 of the structure of the earth. His well known thermal theory 

 of the origin of mountain ranges is discussed in our geological 

 text-books; and he has been a consistent believer in the ade- 

 (juacy of subsidence and elevation in explaining the main 

 problems of our Pleistocene deposits. In the present work, 

 he has not attempted a continuous argument, but has brought 

 together a number of papers and experimental observations 

 which bear upon the development of the present surface of the 

 earth. Mr. Reade does not shrink from controversy, but his 

 methods of inquiry are always sympathetic. He relies (p. a) 

 on fluctuations of temperature in the earth's crust in account- 

 ing for surface-movements, diflerences of specific gravity, and 

 local increases or decreases of volume, being thereby set up in 

 the outer layers. A diagram (plate i) illustrates his views on 

 the formation of laccolites and batholites, by the expansion 

 and melting of portions of the igneous shell which underlies 

 the sedimentary series. We do not understand the •' 5956 

 miles" which are marked on this plate near the centre; of the 

 earth, and we are tempted to suspect the whole, on account of 

 its obvious simplification. The serious reader of this book 

 will come to it, however, well prepared, and will probably ac- 

 cept Mr. Osmond Fisher's permanently liquid layer, quite as 

 readily as Mr. Reade's " semi-plastic underlying shell." 

 Having shown how the vertical uplift of continental platforms, 

 and the vertical falling in of oceanic basins, may be brought 

 about, the author considers the local wrinklings in these areas, 

 such as have produced our mountain chains. He attributes 

 the tangential creep (p. 45) to the transference of material by 

 denudation from one place to another, promoting subsidence, 

 heating of the lower layers, and lateral expansion, with 

 consequent crumpling of the strata. But Mr. Keade urges, 

 and we think very wisely, that the alleged permanence of 

 continents and oceans does not rest on geological evi- 

 dence, when we extend our view over a sufficient lapse of 

 time. ' He emphasises the occurrence of considerable and 

 even mountainous irregularities in the floors of our present 

 oceans, and denies that the edge of the continental plateaux 

 represents any marked break between continental and oceanic 

 forms (p. 103). The scarp so often noticed is aptly compared 

 to the outer end of an artificial embankment formed by 

 tipping, the dcbns from the land l)eing largely responsible for 

 what are often styled "submerged platforms." 



