ig6 



NATURE 



[July 2, 1891 



nomenclature adopted. The proofs of Desargue's theorem 

 and its converse, given on p. 3, are unduly compressed, 

 considering the early stage at which they are introduced ; 

 and the student's preliminary difficulties will be increased 

 by the fact that the enunciations have been given in suc- 

 cession, while there is nothing to indicate which is to be 

 treated first. 



In the chapter on reciprocal figures, we would suggest 

 that the proof given of Theorem I., Art. 50, might with 

 advantage have been dispensed with. In Art. 52 it is 

 erroneously assumed that OB' is equal to force (i) ; this 

 assumption mars a proof which would be otherwise good. 



The work exhibits evidence of originality, and it is, per- 

 haps, to be regretted that the proof-sheets have apparently 

 been revised only by the author himself. Their revision 

 by one who had no part in compiling them would probably 

 have contributed to a better arrangement, and to the 

 exclusion of much that is vague. 



The carefully drawn diagrams of different problems 

 contained in the book form admirable illustrations to the 

 non-technical reader of the nature of the operations in- 

 volved in the application of the graphical calculus, and of 

 the character of the results obtained by it. They are the 

 more welcome as such information is not readily available 

 in English text-books, while in foreign treatises it is often 

 developed in such minute detail as to make the foundations 

 nearly inaccessible to the general reader. 



A word of praise is due to the interesting collections of 

 examples at the ends of the chapters, which are, it seems, 

 mostly original, but partly drawn from sources not often 

 laid under contribution in the ordinary text-books. 



Alex. Larmor. 



The Species of Epilobium occurring North of Mexico. 

 By Dr. Trelease, Director of the Missouri Botanic 

 Garden. From the Second Annual Report of the 

 Garden, issued April 1891. 48 pages, 48 plates. 

 Epilobium is not a very large genus, but is spread uni- 

 versally through the north temperate zone, both amongst 

 the plains and mountains, and reappears in plenty in 

 New Zealand. The species are very difficult of delimita- 

 tion and definition, and great diversity of opinion has 

 prevailed as to their number, and the validity of the charac- 

 ters which have been used to characterize species. It is 

 evident, moreover, that many of them hybridize freely in 

 nature. Passing over the earlier well-known writers, such 

 as Pursh, Muhlenberg, Hooker, and Gray, in 1876 Barbey 

 contributed a monograph of the Californian species to 

 Brewer, Watson, and Gray's " Flora of California," and later 

 published excellent figures of the new species whioh he 

 there described. In 1884, Haussknecht published a 

 monograph of the whole genus. Of the 38 species dealt 

 with in Dr. Trelease's paper, 13 have been proposed by 

 Haussknecht, 3 by Barbey, 4 by himself, and one by 

 Parish, so that more than half the 38 have been lately de- 

 scribed for the first time. Dr. Trelease describes fully 

 all the species known in Temperate North America, gives 

 an octavo plate of each of them, and a detailed account 

 of their geographical distribution, citing the numbers of 

 all the recent collectors. Of the 38 species only 9 extend 

 their range beyond the American continent. The paper 

 will be a very acceptable contribution to our knowledge 

 of a difficult genus, and will no doubt be incorporated in 

 the new " Flora of North America," of which the second 

 volume is already published, and the first and third of 

 which we anxiously wait for. J. G. B. 



A Guide Book to Books. Edited by E. B. Sargant and 



Bernhard Wishaw. (London : Henry Frowde, 1891.) 

 There are so many books of all kinds that ordinary 

 readers may be excused if they are sometimes at a loss 

 as to the works which they ought to select for study. 

 The editors of the present volume have come to the aid 

 of such readers, and may be congratulated on the 



NO. I 131, VOL. 44] 



manner in which they have accomplished a useful but 

 most troublesome task. They make no attempt, in a 

 philosophical sense, to classify the various subjects with 

 which authors have dealt ; they simply take these subjects 

 one after the other, in alphabetical order, and set down 

 what seem to them the best books relating to each. 

 Taking into account the amount of space at their disposal, 

 they probably could not have chosen a plan that would 

 have been more readily intelligible. Of course opinions 

 will differ about the value of the works included in the 

 several lists. Everyone who consults the volume will be 

 of opinion that the editors have omitted some things 

 which they ought to have noted, and that they have 

 noted some things which they ought to have omitted. 

 But there cannot but be a general agreement that, upon 

 the whole, the selection has been made on sound 

 principles, and that it is likely to be of real service to 

 very many of those who may have occasion to refer to it. 

 A large number of eminent writers have helped the 

 editors, not only by drawing up lists of books, but by 

 giving them much valuable advice. 



Tasmanian Official Record, 1891. By R. M. Johnston, 

 F.L.S. By Authority. Second Year of Issue. (Tas- 

 mania : William T. Strutt, Government Printer, Hobart, 

 1891.) 

 Anyone who may wish to obtain information about 

 Tasmania will be hard to please if he does not find what 

 he wants in this elaborate volume. It begins with an 

 account of the general physical outline of the island, and 

 then we come to Tasmanian history, and to the Tasmanian 

 constitution and government. After a chapter on Crown 

 lands we are invited to consider the geology and mineral 

 products of Tasmania, its flora and vegetable products, 

 fauna and animal products, population, vital statistics, 

 trade and interchange, accumulation, finance, production, 

 law, crime, and protection, and " intellectual and social 

 provision." The work is wound up with a view of the 

 progress of Australasia, and a summary of general 

 statistics. In the present issue some important additions 

 have been made to the book as originally published, and 

 by devoting attention to classification the editor has tried 

 to "obviate any difficulties that might arise from the 

 necessity of bringing together in one volume such a 

 variety of subjects." 



LETTERS TO THE EDITOR. 



{The Editor does not hold himself responsible for opinions ex- 

 pressed by his correspondents. Neither can he undertake 

 to return, or to correspond with the tvriters of, rejected 

 manuscripts intended for this or any other part of 'bi XTV^V.. 

 No notice is taken of anonymous communications. "^ 



The Albert University. 



Prof, Lankester, in the interesting letter published in 

 Nature for May 28 last (p. 76), expresses his} desire to have 

 " a genuine professorial University set on foot in London, not 

 because it is London, but because University and King's 

 Colleges are there, and respectfully petition Her Majesty to do 

 for them what the monarch has done in past days for other 

 Universities." 



I have not seen the petition of the Colleges. But I have 

 before me the draft charter adopted by their Councils, which I 

 presume is intended to give effect to the prayer of the petition. 

 I can hardly imagine that Prof. Lankester was acquainted with 

 its contents when he penned the sentence which I have quoted. 



If the Albert University is called into existence — and it seems 

 very probable that its charter will be granted — it will be an in- 

 stitution very similar to what the University of London was in 

 the early years of its existence, when it drew its candidates only 

 from the so-called affiliated Colleges. 



The charter commences by reciting " that it is expedient there 

 should be constituted in and for the London district (defined as 



