Feb. 9, 1888] 



NATURE 



341 



we may remark that it is more than double that which 

 the "Hand-book of British Fungi" included in 1871. One 

 of the many valuable features of the book is, that, 

 wherever possible, measurements are given of the sporidia 

 of the various species, in micromillimetres, in addition 

 to the dimensions of the fungus in its entirety. We 

 specially allude to this feature in order to have an 

 opportunity of adding that in our experience we have 

 never met with a more careful or expert hand at micro- 

 scopical measurement than the author of the present work, 

 an opinion based on hundreds of observations made in 

 concert during a series of years. Yet we must urge that, 

 however useful the micromillimetre undoubtedly is in 

 spore-measurement, it is not so well to use it for larger 

 bodies, such as the cup of a Peziza, when the millimetre 

 or its decimal part would appeal more directly to the eye 

 and experience. 500 fi may be equal to half a millimetre, 

 but the mind more quickly and readily conceives the half 

 millimetre than the 500 fi. We observe a lack of uniformity 

 in dimensions appreciable by the naked eye, which is 

 avoided in measurements under the microscope. For 

 instance "X to }i line broad" (p. 249), "cups 200 to 

 500 /*" (p. 257), "cups 500 to 800 /Lt" (p. 321). What 

 relation does the " line " bear to the micromillimetre ? 

 If half a line is about 500 /x, why use the two units 

 of measurement ? Would it not have been better to 

 follow Stevenson in his " British Fungi," and to reduce 

 all measurements to the centimetre, millimetre, and 

 micromillimetre, which would have been much more con- 

 sistent, and far better than the mysterious " line," and 

 had the merit of being more intelligible to the foreigner 

 than a unit of which he has no knowledge or experience. 



It would be useless to assume that the work is absolutely 

 free from errors, but these are mostly of a trivial 

 character, although more numerous than we could have 

 wished. We doubt whether "conidia" would not have 

 been a better term than " spermatia " in such a con- 

 nection as Calloria fusaiioides ; and we also doubt 

 whether our author accurately appreciates the value of 

 the terminations in such words as violascens, virescens, 

 fuscescens, nigrescens^ &c. 



As for the general scope of the work, we may 

 say that each species begins with the diagnosis, then 

 follows its synonymy, especially in British works, refer- 

 ences to figures, and published specimens. If these 

 are in the main accurate, as we have no reason to doubt, 

 they will be exceedingly valuable, but manifestly only 

 experience oan prove this, and figures are very liable to 

 become displaced or transposed. The habitat succeeds the 

 synonymy, which is followed by special notes or comments; 

 then the derivation of the specific name, now and then 

 hardly successfully interpreted, as for instance on pp. 

 29 ^> 325? a'^d 369, where ater would have been better 

 rendered "dark" instead of "black"; and finally a list 

 of localities. 



At page 358, Ephelis is inserted as a genus of Fries's. 

 The same genus is claimed by Saccardo (" Sylloge," iii. 

 p. 691) for a genus of Sphseropsideae, and we fear that 

 Phillips will have to give way to Saccardo, as both cannot 

 stand, and there is no evidence that Fries regarded his 

 genus as ascigerous. 



Forty pages at the end are most useful appendages 

 to the work, consisting of a glossary of terms, full titles 



of the various works quoted, and an exhaustive index. 

 To the last page Mr. PhilUps has spared no trouble to 

 make his work as complete and useful as practicable, and 

 we trust that he may be rewarded for his labour of love 

 (for such it undoubtedly has been) by being called upon 

 speedily to correct the verbal errors in preparation for a 

 new edition. M. C. C. 



OUR BOOK SHELF. 



Physiography : an Elementary Text-book. By W. Mawer, 

 F.G.S. (London : Marshall and Co., 1888.) 



This is another addition to the steadily increasing number 

 of text-books adapted to the elementary stage of physio- 

 graphy. The usual plan of dividing a book into chapters 

 is not adhered to, but probably the author is of opinion 

 that he is working according to the true spirit of physio- 

 graphy in drawing no hard and fast lines. 



In the majority of cases the author has succeeded in his 

 endeavours to explain everything in the simplest way, but 

 in a few cases his anxiety to do so has led him astray. 

 The following may be quoted as examples, and the 

 obvious shortcomings need no further comment : — 



" Work is the moving of matter " (p. 8) ; " Energy, 

 when active — when actually doing work — is in the condi- 

 tion called kinetic ; when it is passive and only ready to 

 do work, it x's, potentiaV (p. 9). 



With a few exceptions of this kind, the book is admir- 

 ably adapted to the syllabus which it is intended to cover. 

 That it is not a mere cram-book is evidenced by the mass 

 of useful information which is given. A good general 

 outline of the nebular hypothesis is presented, in so far as 

 it concerns the history of our globe, and there is also an 

 outline of the classification of animals and plants. The 

 astronomical portion of the syllabus also receives a fair 

 share of attention. One omission, however, has been 

 made, and that is the use and meaning of the term 

 " stress " : the word apparently does not occur even once 

 in the whole book ; this is rather unfortunate now that 

 modern physicists are beginning to regard gravitation, 

 magnetism, &c., as stresses. 



Apart from its use as a class-book, it can be recom- 

 mended to the general reader as an outline of science. 



A. F. 



Early Christian Art i?t Ireland. By Margaret Stokes. 

 (Published for the Committee of Council on Education, 

 by Chapman and Hall, 1887.) 



This is one of the South Kensington Museum Art Hand- 

 books, and it deserves to rank among the best of the 

 series. The Christian antiquities of Ireland are in their 

 own way as remarkable as any group of antiquities in the 

 world, and a satisfactory account of them, such as ordinary 

 readers might understand and appreciate, was greatly 

 needd. In undertaking to 'supply what was wanted. 

 Miss Stokes devoted herself to a task for which she was 

 well equipped by previous study, and she has produced a 

 little book which can hardly fail to excite interest in her 

 subject, and which will be welcomed even by antiquaries 

 to whom the facts of Irish archaeology are already well 

 known. A chapter on illumination is followed by one on 

 Irish scribes on the Continent ; and then come chapters 

 on metal-work, sculpture, building and architecture, 

 with a chronological table of examples of Irish art the 

 date of which can be approximately fixed. The work is 

 illustrated by upwards of a hundred good woodcuts. In 

 her treatment of all questions relating to early Christian 

 art in Ireland, Miss Stokes displays a thoroughly scien- 

 tific spirit, and her style has the merit of being always 

 clear, fresh, and unpretending. She rightly claims for 

 her subject that it has a practical as well as an intellectual 



