52 



NA TURE 



{Nov. 2 1, 1889 



monographed by De Candolle in the " Prodromus " be- 

 tween 1824 and 1830, and the scattered material relating 

 to many of the orders and genera has not since been 

 brought together and codified. As instances of genera 

 now involved in great confusion for want of a more recent 

 elaboration, w^e may cite Ranunculus, Viola, Papaver, 

 Alyssum, Draba, Dianthus, Geranium, Galium, and 

 many others. The present paper is, unfortunately, not 

 a monograph of Dianthus, but only a list of the known 

 species classified into groups, accompanied by general 

 remarks on the structure of the different organs in the 

 genus, and on their range of variation, so that, though 

 it is interesting and useful as far as it goes, it still leaves 

 very much to be desired. Although, on the one hand, 

 Caryophyllacese are dried for the herbarium very easily, 

 and suffer little in the process, yet Dianthus is a very 

 difficult genus for botanists to deal with and to under- 

 stand. There are 230 species for a monographer to 

 characterize. The range of variation between the ex- 

 treme types is not great, and some of the commoner 

 species {e.g. D. Seguieri, plu77iarius, and Carthusian- 

 orum) are very variable, the consequence being that, 

 one often sees them named in gardens very incorrectly, 

 forms of plumarius especially, which is hardy and 

 spreads readily, doing duty for many totally distinct 

 species. 



Dianthus is a genus quite characteristic of temperate 

 and sub-temperate climates. It has its head-quarters in 

 Europe and Western Asia. There are several species at 

 the Cape ; a few are Himalayan, Chinese, and Japanese ; 

 none reach Australia, New Zealand, or the Andes ; and 

 only one just touches the extreme north-western tip of the 

 American continent. There are two principal sub-genera : 

 Caryophyllastrum, of which the carnation may be taken 

 as the type, which is far the largest ; and Armeriastrum, 

 or Carthusianastrum, of which the flowers are numerous 

 and clustered, as in the sweet-william. There is a third 

 small sub-genus, intermediate between Tunica and the 

 true pinks, which is classified by Bentham and Hooker 

 with Tunica, and by Mr. Williams, following Linnaeus 

 and Koch, as a third sub-genus of Dianthus. Within the 

 bounds of the genus, Mr. Williams finds his primary 

 characters — those which mark groups— in the form of the 

 calyx, the nature of the margin of the lamina of the 

 petals, the presence or absence of a beard at the junction 

 of the blade and claw of the petals, filaments, and styles, 

 the shape of the leaf, and the disposition of the flowers ; 

 and his secondary characters — those which distinguish 

 species — in the number and shape of the bracts of the 

 epicalyx, the form of the lamina of the petals and their 

 apposition, the character of the calyx-teeth, the form and 

 structure of the capsule, the form and structure of the 

 seeds, and the disposition of the fascicles of veins in the 

 leaves of the barren shoots and flowering stems. His 

 groups and species do not differ materially from those 

 given in his paper in the Journal of Botany for 1885, 

 p. 340. The list would have been more useful if he had 

 stated the native country of each species, and added a 

 reference to where it was first described. We hope, how- 

 ever, that he will see his way to publish, before long, the 

 monograph of which this is a mere outline sketch. 



J. G. B. 



OUR BOOK SHELF. 



Mas;neiism and Electricity. By Arthur W. Peyser, M.A. 

 (London : Longmans, Green, and Co., 1889.) 



Since the amount of knowledge that is supposed to con- 

 stitute an elementary scientific education increases every 

 year, there is sufficient justification for the publication of 

 a series of science manuals designed to meet the growing 

 requirements of the Science and Art Department examina- 

 tions, and this work is an excellent representation of such 

 a series. Apart, however, from the value of this book 

 as an examination manual, it possesses considerable 

 merit. The matter contained in it is just about as much 

 as would cover the course usually taken in a year's 

 school work ; the explanatory text is couched in the 

 clearest language, and the experiments described are 

 capable of being easily brought to a successful termination. 

 Also the 235 illustrations will be of considerable assist- 

 ance to the student, whilst the many exercises and 

 examination questions interspersed throughout the book 

 may be useful tests of his knowledge. The text-books 

 that in their day have been eminently successful, if un- 

 revised, must be supplanted by others which take a more 

 extended view of the subject ; hence it is that this book 

 will compare most favourably with any written for the 

 purpose of imparting a rudimentary knowledge of mag- 

 netic and electrical phenomena and the laws by which 

 they are governed. 



The Engineer's Sketch-book. By Thomas Walter Barber. 

 (London : E. and F. N. Spon, 1889.) 



Engineers and draughtsmen generally keep note-books 

 in which are jotted down most things they wish to 

 particularly remember, accompanied by rough sketches 

 when necessary. The author of this book is no excep- 

 tion to the rule. He tells us he has made many notes 

 and sketches during his experience as an engineer, and 

 has often found the want of such a collection for refer- 

 ence. This volume consists of about 1936 sketches, 

 classified under different headings, of devices, appli- 

 ances, and contrivances of mechanical movements. The 

 book is certainly unique in its way, and will prove useful 

 to those who have machinery to design, who may require 

 suggestive sketches of mechanical combinations to ac- 

 complish some desired end. The author truly remarks 

 that a sketch properly executed is to a practical man 

 worth a folio of description. Hence the descriptions given 

 are generally mere names, with occasionally a concise 

 statement of purpose. Each sketch bears a number, and 

 on the opposite page this number is to be found with the 

 description, &c., — a very good arrangement. 



These sketches are clearly printed, and are probably 

 executed from scale drawings in most cases. Taken as a 

 whole, they fairly represent what they profess to do 

 Sketch 1636, however, is supposed to represent a Rams 

 bottom safety valve, but it gives a radically wrong im 

 pression of this valve. The lever is shown resting on the two 

 valves certainly, but the spring is attached to the lever a 

 a point considerably above the assumed straight lin< 

 joining the points resting on the valves — an impossible 

 position. Again, one of the two points of the leve: 

 resting on the valves is usually loose and connected wit! 

 the lever by a pin. The sketch shows the lever and th< 

 two projecting points made solid. This example is th( 

 most unpractical sketch discovered in the book, am 

 should be rectified in a future edition. A fairly goo(! 

 index adds to the usefulness of the volume. There i j 

 ample evidence of careful work on the part of the author 

 and he is to be congratulated on writing a book whici! 

 will probably be of use to many engineers and thos' 

 connected with the profession. N. J. L. 



