Apbil 1, ISOG.] 



KNOWLEDGE 



83 



BOOKS RECEIVED. 



By 



Discoveries and Intentions of the Xineteenth Centura/. 

 B. Koutledge, B.Sc. 11th Edition. (Routledge.) Illustrated 



Outdoor Life in England. By Major A. T. Fisher. (Bentlev.) 



British Mo'thi. By J. W. Tutt, F.E.S. (Kentledge.) Illustrated. 5?. 



Moorland Idyls. By Grant Allen. (Chatto & Windus.) 6s. 



0» Seedlings. By Sir John Lubbock. International Scientific 

 Series. (Kegan Paul.) Illustrated. 5s. 



A Child's Historic of Scotland. By Hrs. Oliphant. (Fisher 

 TJnwin.) 2s. 6d. 



Segniiis Irritant ; or, Eight Primitive Folk-lore Stories. Bv 

 W. W. Strickland. (Forder.) Illustrated. 



The Xeiv Photography. V,y A. B. Chatwood. (Downey.) Illus- 

 trated. Is. 



Sctenw Notts. 



At a recent meeting of the Royal Geographical Society, 

 Mr. Clements R. Markham being in the chair, Dr. H. R. 

 Mill read a paper on " A proposed Geographical Description 

 of the British Islands, based on the Ordnance Survey.'' 

 In the course of an interesting and comprehensive address 

 the lecturer advocated the preparation of a complete geo- 

 graphical description of the British Islands, somewhat 

 upon the lines laid down by him recently in our columns. 

 (Knowledge for January, lb96.) In the discussion which 

 followed, Sir Charles Wilson and Colonel Farquharson 

 both commended the project, while Mr. Clements Markham 

 looked upon the matter as one of the greatest importance, 

 and undertook to recommend to his Council that the work 

 should be carried out under the Society's auspices. We 

 may mention that Dr. Mill has promised to continue the 

 discussion of the project in our columns a little later on. 



At the observatory of the Pic du Midi the zodiacal light is 

 always visible on clear moonless nights, and E. Marchand 

 has, during the last three years, made careful observations 

 upon it. It is not confined to a fusiform ret,'ion in the neigh- 

 bourhood of the sun, but continues that region right across 

 the sky as a faintly luminous track, always dimmer than 

 the Milky Way at its dimmest. The cosmic matter 

 surrounding the sun extends far beyond the earth's orbit 

 in a very much flattened ellipsoid, but is especially con- 

 densed in the neighbourhood of the sun, and forms there 

 the more brightly luminous fusiform zodiacal light a3 

 usually seen in the morning or evening. 



Hetttrs. 



[The Editors do not hold themselves responsible for the opinions or 

 statements of correspondents.] 



THE BED SPOT OX JUPITER. 

 To the Editors of Knowledge. 



Sirs, — I have jast been reading the interesting article 

 on the " Red Spot on Jupiter," by Mr. Maunder, in the 

 January number of Knowledge. There is necessarily a 

 great deal of mystery as to the nature of the spot ; never- 

 theless I cannot help thinking that it actually acts in the 

 same way as, and has some analogy to, an island in a river. 

 The following rough diagram may make this plainer. 



Here A is the S. equatorial belt, the material of the 

 southern portion of which rotates at approximately the same 

 rate as the red spot ; B is the S. temperate belt ; C is the 

 red spot or island. The whole of the surface material in 

 the zone E, between A and B (and also for some distance 

 south of B), drifts past the red spot in the direction of the 

 arrows with a velocity of sixteen miles per hour. (This 

 is Zone "VIII. of my paper on the drift of the surface 

 material of Jupiter in different latitudes, in the January 

 number of the ^lonthhj Xotkfs.) 



When the white material in the zone E encounters the 

 red spot or island C, it meets with an insurmountable 

 obstacle, and is obliged to force a passage round C, which 

 it does chiefly on the north side by forcing the south 

 equatorial belt A northwards. A portion of the white 

 material also usually passes in the narrow channel on the 

 south side of the spot. 



The reason why the main channel lies on the north 

 side of the spot would appear to be because the material is 

 in a more plastic state near the equator than it is nearer 

 the poles. (This is also indicated by the well-known fact 

 that the equatorial parts of the planet are the chief seat 

 of disturbance and change, and the region of greatest 

 spottedness.) So that there is less diflSculty in forcing A 

 northwards than B southwards. 



Here comes an important point. The channels north 

 and south of the red spot are together narrower than the 

 main channel E following the spot. The effect of this 

 to cause the white material to be heaped up in the region 



SiMSS^M^B 



The fifth annual report of the Society for the Protection 

 of Birds, which has been sent to us by the hon. secretary, 

 is a very satisfactory one. It shows that the Society is 

 increasing and that it is doing really good work, not only 

 in promoting bird protection, but in spreading a knowledge 

 of bird life by lectures illustrated with lantern slides. By 

 thus interesting and educating the public in bird:?, the 

 Society will be better able to put an end to the destruction 

 of our feathered friends than by mere legislation . 



Jmt following the spot, and also in the channels north and 

 south of the latter ; and these regions therefore appear 

 whiter than the average, owing to the greater depth of 

 white material, thus producing the bright annulus en- 

 circling the red spot. In the region just preceding the 

 latter, the meeting of the two currents causes eddying and 

 commotion of the white material before it finally flows off 

 along the now broad channel E preceding the spot. The 

 result of this eddying and commotion is to make appear 



