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NATURE 



\June 7, 1883 



description of various galvanic elements. These subjects 

 occupy the first volume, consisting of close on 800 pages. 

 The second volume begins with the electrical properties 

 of dielectrics. The section devoted to this subject is 

 erhaps the most interesting in the volume : it contains 

 the mathematical theory of the behaviour of dielectrics, 

 the experimental investigation of specific inductive capa- 

 city, the detailed study of electrical machines acting by 

 friction and by induction, together with various allied 

 matters. Next come thermoelectricity, pyroelectricity, 

 and the thermal effects of the discharge of accumulated 

 electricity and of continuous electric currents. After this 

 follows the section devoted to electrochemical action : 

 this occupies about five hundred pages, and concludes 

 with a chapter on the theory of electrification by contact, 

 which completes the volume. It is intended that the 

 whole work should be finished in four volumes, and the 

 manuscript of the two that still remain to be published is 

 for the most part ready. 



Prof. Wiedemann's great work has been so long known 

 to physicists that it is needless for us to dwell upon its 

 special qualities farther than to say that it fully retains in 

 its new form all its old characteristics. It is true that it 

 lacks the originality and unity of treatment of Clerk 

 Maxwell's " Electricity and Magnetism," probably the 

 most original systematic treatise on any great branch of 

 physics that was ever written. Nor does it equal in the 

 clearness and elegance of its mathematical discussions 

 the treatise of Mascart and Joubert, a work which, while 

 not laying claim to originality in respect of matter, ex- 

 hibits in a remarkable degree consecutiveness and lucidity 

 of exposition. Prof. Wiedemann's plan precludes his 

 attaining to these particular excellences in an equal 

 degree. Some sacrifice of unity and consecutiveness is 

 inevitable in a work which aims not only at giving a 

 complete account of what is known respecting a great 

 branch of science, but also at showing what each author 

 has contributed to the stock of knowledge and how he 

 has presented it. From this point of view Prof. Wiede- 

 mann's book is without a rival in any language, and is 

 indeed unapproached by any other work. G. C. F. 



FLORA OF HAMPSHIRE 



Flora of Hampshire, including the Isle of Wight, or a 

 List of the Flowering Plants and Ferns found in the 

 County of Southampton, with Localities of the Less 

 Common Species. By Frederick Townsend, M.A., 

 F.L.S., &e. Illustrated with Two Plates and a Map. 

 (London : L. Reeve and Co., 1883.) 



WE have here an important addition to the already 

 large class of English local floras. To the 

 general botanist, as to people who have made no study of 

 botany, it would seem that the plants of so comparatively 

 small a region as the British Islands must have been 

 catalogued long since, and that there is little to be done 

 in that direction which is worth doing. It certainly is 

 remarkable that, besides facts connected with geographical 

 distribution, which a more minute knowledge of the 

 plants of a country must bring to light, there are actually 

 new plants to be found— new, that is to say, not only to 

 Britain, but to science. A Pondweed (Potamogelon 



Griffithii), new to science, has recently been described 

 and figured by Mr. Arthur Bennett in the Journal of 

 Botany, from specimens brought from a mountain lake in 

 North Wales — the only place in the world where it is 

 known to occur. Not that this is the only species 

 peculiar to these islands. To take one example, there 

 is a species of Centaury (Erythnea latifolia), 1 which has 

 never been found anywhere in the world but on the 

 Lancastrian sandhills ; and there it is not known to have 

 been seen more recently than 1865, if then. In Mr. 

 Townsend's county, a Spearwort {Ranunculus ophioglossi- 

 folius), not hitherto found nearer these shores than 

 Jersey, has been detected so lately as to appear only on 

 the very last page of the book ; Spartina Townsendi is 

 another case in point ; and another example of a plant 

 having been long overlooked, and of which the distribu- 

 tion has quite recently been much extended, will be found 

 in Arum italicum, which was detected in the Isle of Wight 

 in 1854, and was afterwards found in West Cornwall and 

 Sussex ; this was recorded for Dorset last year, and its 

 range has been extended during the present year to Kent 

 (Folkestone). The volume now before us supplies a good 

 illustration of the way in which novelties may turn up in 

 the best known districts. Probably if there is one part 

 of England which has been more thoroughly botanised 

 than another it is the Isle of Wight ; yet it was here, and 

 in one of the best known parts — the Downs at Fresh- 

 water—that Mr. Townsend first distinguished in 1879 an 

 Erythrcea (E. capitata, var. sphcerocephald), which is, as 

 he says, "a peculiarly interesting addition to the British 

 flora. It is," he continues, "a well-marked species, and 

 is not known now to occur anywhere else in the world 

 but in the Isle of Wight and in Sussex. The other form 

 of it was found some fifty years ago somewhere in the 

 neighbourhood of Berlin (the exact locality .not being 

 known), and though sought for diligently, it has never 

 been found again." 



It will doubtless seem strange to some to learn that a 

 volume of more than 500 closely-printed pages can be 

 occupied by an enumeration of the plants of one English 

 county, especially when it is considered that the pages 

 devoted to descriptions of species are very few. An in- 

 teresting and instructive article might be written in which 

 the history and development of the local flora should be 

 traced. To undertake such is, however, not our present 

 purpose ; but we may note one or two of the more striking 

 features of these later contributions to local botany, of 

 which the " Flora of Hampshire " is the most recent. One 

 thing to be noticed is their historical nature. Messrs. 

 Trimen and Dyer, in their " Flora of Middlesex" (1869), 

 were the first to develop this aspect of the work : their 

 method of quoting the first authority for the occurrence 

 of the species as a Middlesex plant has been followed by 

 subsequent writers, and they also did good service by 

 quoting the synonymy of the older (and pre-Linnean) 

 authors — a work which has been very useful to their suc- 

 cessors. When it is considered that a book of this kind 

 is mainly undertaken by persons interested in the history 

 of some particular locality, it seems natural that what has 

 been called the antiquarian side of botany should be 

 represented, although there are those who consider that 



1 The plant so named in Continental fl ->ras is certainly not the same as 

 that of the Lancashire sandhills. 



