June 14, 1888] 



NATURE 



147 



the air may be taken as two thirds of the maximum possible. 

 This seems a very high value for a closed and artificially 

 heated room; certainly much in excess for air in a balance 

 case which contains any substance, such as chloride of 

 calcium, for absorbing the moisture. Perhaps it is the 

 uncertainty as to the condition of the air thus artificially 

 treated which causes the author to omit any reference to 

 any of the hygroscopic substances usually employed. 



The standard masses used at the Clarendon Laboratory 

 are stated to be marked with their apparent value in 

 air at io° C. and 76 cm. of mercury. It is the usual 

 custom, we believe, to mark the absolute value of the 

 masses. For work not requiring the most refined pre- 

 cautions, the convenience of weights marked with their 

 apparent value is obvious : no correction need be made 

 for the supporting force of the air on the weights ; but if 

 that accuracy is considered sufficient, it seems an un- 

 necessary refinement to complicate the formulae by 

 introducing a correction for the difference between the 

 temperature of the air and of the water in which the 

 substance is weighed. 



The work is very clearly written and admirably printed, 

 and will doubtless form, when completed (and we hope 

 this will not be at a distant date), a valuable addi- 

 tion to the text-books on this subject. We have only 

 noticed two mistakes in the text — the omission of the 

 small over-weight w at line 23, p. 12, and of the length of 

 the arm, a, at line 10, p. 16 ; but neither of these omissions 

 affects the final results. The average student would, 

 however, probably prefer that a larger portion of the 

 space should be devoted to the more practical side of 

 the subject, to hints and precautions to be taken in various 

 operations ; those given are very good, but they might 

 with advantage have been extended. It would also, we 

 think, be useful to indicate by numerical examples 

 the order of magnitude of the various corrections 

 to be applied, so that a student may judge what 

 corrections may be safely omitted in the particular 

 observation on which he is engaged. Some of the space 

 given to the description of the instrument might, we 

 think, have been more profitably devoted to a general 

 account of other types of construction. Only a passing 

 reference is made to the " short-beam " balance, and 

 other modifications of the physical balance are not 

 alluded to. 



OF WEST YORKSHIRE. 

 Yorkshire, with a Sketch of the 



THE FLORA 

 The Flora of West 



Climatology and Lithology in connection therewith. 



By Frederic Arnold Lees. 8vo, pp. 843, with a Map. 



(London : Lovell Reeve and Co., 1888.) 

 TT is just a quarter of a century since John Gilbert 

 J- Baker's excellent book on the botany, geology, 

 climate, and physical geography of North Yorkshire 

 appeared, 1 and the present volume, devoted to West 

 Yorkshire, is avowedly moulded on that model. Since 

 then, English county and other local "floras" have 

 become very numerous —many of them well executed, 

 others indifferently. We do not mean to say that Mr. 

 Baker was the originator of local "floras," for this branch 



1 We understand that a new edition is in preparation. 



of botanical literature early took root in this country, 

 and has perhaps attained a development unknown else- 

 where. Interesting among the earlier of such publications 

 is John Ray's " Catalogus Plantarum circa Cantabrigiam 

 nascentium," which dates (1660) nearly a hundred years 

 before the first edition of Linnasus's " Species Plantarum." 

 It is interesting alike for its botany and its botanical 

 history. But the importance of exactitude in recording 

 the localities of plants was not thoroughly realized by 

 amateur botanists until they were stimulated thereto by 

 the methodical and conscientious, though somewhat dis- 

 cursive, ph) togeographical writings of the late Hewett 

 Cottrell Watson. Now, thanks to the exertions of the 

 competent few, English amateur botanists are so tho- 

 roughly educated in geographical botany at the beginning 

 of their studies, that the careless, or, what is worse, the 

 unprincipled, recorder of assumed localities of the rarer 

 plants, is at once discovered and exposed. The lati- 

 tudinal and altitudinal range of each species is now 

 known with such accuracy that any new record outside 

 of the known limits is at once scrutinized and tested, 

 and only accepted on the best authority. It is a ques- 

 tion, however, whether this sort of thing is not being 

 overdone. 



Mr. Lees expresses a hope that the acknowledged 

 adoption of Baker's admirable method of inquiry and 

 statement will not be regarded as too servile. We think 

 it will not ; and had the imitation been carried a little 

 further, and the briefer and more condensed style of the 

 pattern followed, it would have been a distinct advantage, 

 because it would have reduced the size of the book with- 

 out in the least impairing its value. The area of West 

 Yorkshire is about 2750 square miles, and this is divided 

 into ten drainage districts, varying in size from 30 square 

 miles (Mersey tributaries) to 570 square miles — Don with 

 Dearne ; and the stations, or a selection of stations, in 

 which a given plant is known to occur in each of these 

 districts are given — in many instances, in what we should 

 regard as excessive detail. Whether it would not 

 have been better to amalgamate some of the districts, 

 instead of adhering so closely to a principle as to main- 

 tain a very small portion of a drainage area as a distinct 

 district, we will not pretend to decide ; but there is no 

 doubt it would have resulted in a considerable saving of 

 space, which might have been profitably devoted to a 

 brief exposition of the total geographical area of each 

 genus and species. 



With regard to the manner in which Mr. Lees has 

 executed the task he undertook, there is ample evi- 

 dence that he has spared no pains ; and we have 

 means of knowing that those most concerned are very 

 grateful for such a store of well-sifted records. Never- 

 theless, this work, which forms the second volume of 

 the botanical series of the Transactions of the York- 

 shire Naturalists' Union, has its peculiarities, chiefly 

 of a literary kind. On opening the book, we happened 

 to light on the " Foreword," first of all, and we naturally 

 expected that our author was a purist who wrote only 

 Saxon English ; but we soon discovered that uncommon 

 words, irrespective of their origin, are dragged into use, 

 and sometimes so piled up as to obscure not a little the 

 meaning of the somewhat inflated sentences. However, 

 this peculiarity is not carried so far as to constitute a 



