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NATURE 



\August I, 1889 



In this short notice we have been able to indicate only 

 a few of the more interesting topics dealt with in Prof. 

 Woeikof s treatise. The effects of the agent to which he 

 has directed attention are undeniable and far-reaching, 

 and the publication of his investigations should have the 

 result of making the registration of the depth and dura- 

 tion of snow a part of the regular work of meteorological 

 observatories. Other observations of a more detailed 

 character, which he specifies in the course of his work, 

 are also much needed. H. F. B. 



THE " CIRCOLO MA TEMA TICO" OE PALERMO. 

 Rendico7tti del Circolo Matematlco di Palermo. (Palermo : 

 Sede del Societa, 1887-89.) 



THE " Circolo Matematico " is one of the junior mem- 

 bers of the now large family of Mathematical 

 Societies. We have before us Tomo I., which gives an 

 account of the proceedings from March 1884 to July 1887. 

 Tomo II. contains like matter for 1888, and of the current 

 volume we have three parts, each of which contains an 

 account of the proceedings for a period of two months, 

 terminating with June last. The first general meeting of 

 which there is any record was held on March 10, 1884, 

 and in that year eleven meetings are recorded, and the 

 proceedings published within the narrow limits of thirteen 

 pages : it was then the day of small things, and we pre- 

 sume the gatherings were confined almost to conversa- 

 tional expositions of mathematical problems. With in- 

 crease of days came increase of strength, and the first 

 volume contains seventy communications from twenty-one 

 authors ; of these the only foreign contributors are Messrs. 

 E. Catalan, F. Cavallaro, Hirst, and Schoute. Dr. Hirst's 

 short note is " Sur la congruence Roccella, du troisi^me 

 ordre et de la troisieme classe," and in it he points out that 

 Dr. Roccella's congruence is a particular case of the Cre- 

 monian congruences discussed by him in his memoir " On 

 Congruences of the third order and class" (L. Math. Soc. 

 Proc, vol. xvi., 1885). These congruences are also the 

 subjects of papers read by Signor Guccia. Amongst the 

 longer papers in this volume are : " Intorno ad alcune 

 formole nella teorica delle funzione EUittiche," by Signor 

 Albeggiani ; " SuUe superficie dell' /2™° ordine immerse 

 nello spazio di ;; dimensioni," by P. del Pezzo ; " Sopra un 

 metodo per formare le equazioni a derivate parziali, delle 

 superficie che ammettono una generatrice di forma cos- 

 tante," by M. Gebbia ; " Sopra alcuni sistemi lineari di 

 curve plane algebriche di genere due" by V. Martinetti. 



In the second volume there are thirty-nine papers by 

 twenty-six authors. The only long papers are : " Intorno 

 alle curve razionali d'ordine n dello spazio q. n — \ 

 dimensioni," by G. Loria ; " Sul carattere aritmetico del 

 coefificienti delle serie che soddisfano ad equazioni 

 lineari differenziali o alle differenze," by S. Pincherle ; 

 " Sur la marche du cavalier," by C. Jordan. These papers 

 are of no great length ; the remaining communications 

 rarely exceed four or five pages. 



The May-June number of this year contains a " Solution 

 du probleme de Malfatti," by M. Lebon, and an " Etude 

 d'un deplacement particulier d'une figure de forme invari- 

 able par des proced^s clcmentaires et purement geome- 

 triques," by M. Mannheim. In selecting papers we have 

 had regard mainly to those which may be called memoirs ; ^ 



the smaller notes treat of similar matters, so that it is 

 readily seen that the field at present occupied by the 

 " Circle " is that of pure mathematics. 



The names of the majority of the contributors are 

 well known by their writings in other journals, and their 

 work here is in all cases interesting, and of a high class. 

 A peculiar feature of these volumes which strikes us is 

 the amount of space devoted to the " Biblioteca mate- 

 matica." In Vol. II., 236 pages are given up to the usual 

 matter of a Society's Proceedings, and 83 pages to the 

 titles of papers, &c., presented to the Society by in- 

 dividuals, or contained in the journals for which the 

 Circolo exchanges its Proceedings. This is a useful piece 

 of work, as the circle of exchanges is a large one. We 

 wish the junior member every success. 



OUR BOOK SHELF. 



Names and Synottyms of British Plants. By G. Egerton- 

 Warburton, B.A. Pp. 160. (London : G. Bell and 

 Son, 1889.) 



This little book is a synonymic catalogue of the British 

 flowering plants and vascular Cryptogamia, in which are 

 given the names under which the species stand in the 

 last edition of the four standard hand-books, Sowerby's 

 "English Botany,' Hooker's "Student's Flora," Bentham's 

 " Flora," Babington's " Manual," and in the London 

 Catalogue. In a considerable number of cases the five 

 differ more or less in the names which they adopt. This 

 arises partly from the five authors taking a different 

 view of specific limits. About two hundred of what Sir 

 J. D. Hooker and Dr. Boswell call sub-species are usually 

 regarded as species by Babington and as varieties by 

 Bentham. The whole series of genera has lately been 

 revised and redescribed by Mr. Bentham and Sir J. D. 

 Hooker, and many which have been proposed by other 

 authors are now placed as sub-genera or sunk altogether. 

 In the preparation of the great Darwin catalogue of 

 plants, under the editorship of Mr. B. Daydon Jackson, 

 the priority of names has been more systematically 

 investigated than has ever been previously attempted, 

 and this has led to a great many changes. These are 

 embodied in the last edition of the widely-used London 

 Catalogue ; but as the new or revised names stand there 

 without any explanation, those who wish to use the list 

 are often greatly puzzled, and it was a good idea of Mr. 

 Warburton to prepare the present synonymic catalogue. 

 It appears to have been drawn up very carefully, and 

 gives a reference to the page or number indicating 

 where in each of the five books every species will be 

 found, and in an appendix there is a list of synonyms used 

 by older British or Continental authorities. There is also 

 a full list of the original authorities for the specific names, 

 with the titles and dates of the books and papers in which 

 the plants were originally described. The author omits 

 to enumerate in his list two very useful books, the " Con- 

 spectus " of Nyman, and " Salictum Woburnense " of 

 Forbes. He has failed, and no wonder, to run down 

 some of the London Catalogue names of Rubi {e.g. 

 echinatus and longithyrsioer), that refer to long-known 

 plants, fully described in Babington's "Manual and 

 Synopsis." J. G. B. 



Geology in Systematic Notes and Tables for the Use of 

 Teachers and of Taught. By W. F. Gwinnell, F.G.S., 

 F.R.Met.Soc, &c. (London: AUman and Son, 1889.) 



While we cannot but regard the ch'ef educational value 

 of summary statements of the bare facts of a science, 

 like those contained in the work before us, as consisting 



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