December 3, 1908J 



NA TURE 



127 



markedly boreal aspect, though probably immigrants, 

 at the close of the Ice age, by way of the North Sea, 

 over the sunk portion of Sweden. The var. arctica, 

 Harv., of Sphacelaria racemosa, Grev., is of peculiar 

 interest near Danzig, as it now occurs elsewhere only 

 in the Arctic seas and on the coast of Scotland, and 

 is not known from the south-western part of Norway 

 or from Sweden. A full enumeration of sources of 

 information adds to the value of an excellent piece 

 of work. 



OVR BOOK SHELF. 

 The Soil. An Introduction to the Scientific Study 



of the Growth of Crops. Second edition', revised 



and enlarged. By A. D. Hall. Pp. xv+311. 



(London : John Murray, 1908.) Price 5s. net. 

 The fact that a second edition of this book is neces- 

 sary is a welcome evidence of the increased attention 

 which is being paid to the study of the soil and also 

 of the undoubted value of the work. This edition has 

 evidentlv been most carefully revised in the light of 

 modern investigation, and is an accurate record of 

 existing knowledge on the soil considered from its 

 mechanical, chemical, and biological aspects. Ten 

 vears ago we were almost entirely indebted to 

 .-\merican or German workers for any scientific mono- 

 graph on the soil, then only considered from its 

 physical and chemical aspects, but in this work we 

 have in addition a most valuable chapter on the 

 functions of bacteria and fungi in the soil, in whicli 

 a well balanced judgment is pronounced on certain 

 recentlv much advertised work which has not yet 

 received the sanction of scientific opinion or even a 

 (rustworthy confirmation of its accuracy by practical 

 men. 



Mr. Hall's book is not only for the scientific student 

 of soil problems, who can, by the use of the biblio- 

 graphy in the appendix, become familiar with the 

 most important research on the subject, but the prac- 

 tical man will find a very considerable portion of 

 the book of interest and value to him, and the care- 

 fully reasoned conclusions will assure him of the 

 reliability of the recommendations. The chapter on 

 soil analysis shows the attempts which have been 

 made to evolve an official method, and it is to be 

 hoped, for the sake of those who often have to com- 

 pare and argue from analyses made by different 

 workers (in which the personal element must alwavs 

 be an important factor), that the methods which have 

 been selected after most careful consideration may be 

 generally adooted. Mr. Hall has a special facultv 

 for drawing from the almost inexhaustible store of 

 the Rothamsted treasure-house results which illus- 

 trate or emphasise his conclusions, and he has the 

 rare quality of clothing figures and tables with in- 

 terest. The mechanical effect of fertilisers on the 

 flocculation of clay .and the consequent alteration in 

 texture are well illustrated bv both Woburn and 

 Rothamsted results, and the theory that the " sad- 

 dening " effect of such fertilisers as nitrate of soda 

 is due to the presence of common salt and to the 

 hygroscopic character of the nitrate of soda is shown 

 to be only true to a limited extent, the main cause 

 being the deflocculation of the clav aggregates. 



We would also commend this book to the attention 

 of science masters in secondary schools, for much of 

 its contents could, with senior students, be utilised 

 both for direct instruction and alsp for exemplifying, 

 in a substance with which everyone must be more 

 or less acquainted, many of the laws of phvsical 

 and chemical science. M. J. R. D. 



NO. 2040, VOL. 79] 



Tlie Stars of the Year. By H. P. H. Pp. 23. 



(London : King, Sell and (jlding, Ltd., Knowledge 



Office.) Price i^. net. 

 Star Calendar for 1909. Edited by H. P. H. (London : 



Hirschfeld Brothers, Ltd.; Glasgow: A. Stenhouse.) 



Price IS. net. 

 Tlie Star Almanack , 1909. By H. P. H. (London : 



King, Sell and Olding, Ltd., Knowledge Office.) 



Price 3d. net. 

 The first of these three publications forms a useful 

 handbook for those people who, unacquainted with 

 the oldest of the sciences, take some kind of interest 

 in the stars and other celestial phenomena. A brief 

 introduction of five pages form a hors d'oeuvre cal- 

 culated to whet the appetite lor a more serious study 

 of astronomy, and gives a few facts relating to the 

 constellations, stars, meteors, comets, &c. Then 

 follow twelve circular charts showing the arrange- 

 ment of the constellations in the sky at 10 p.m. about 

 the middle of each month. These charts have a blue 

 background with white figuring, the zenith being 

 placed at the centre, and they are very clearly printed. 

 Beginners should find litt'le difficulty in locating 

 the various groupings after studying the current chart. 

 It should be noted that on p. 8, where the constellations 

 of the Zodiac are given, Aquarius is wrongly placed 

 before Capricornus. 



On the " Star Calendar," consisting of four cards 

 tied together, the charts are so combined as to give 

 the constellations for each quarter, whilst brief notes 

 describe the positions of the planets. The calendar is 

 of a convenient size (i5"xi2"), and, being printed in 

 colour with the conventional representations of the 

 zodiacal signs, forms quite a decorative wall-hanging. 



In addition to the four quarterly charts, the " Star 

 .■\lmanack " contains a deal of useful information con- 

 cerning the planets, standard times, comets, meteor 

 showers, &c., also portraits of Sir William and Lady 

 Huggins and a reproduction of Ritchey's Andromeda 

 nebula photograph, whilst a drawing by Mr. T. E. 

 Heath illustrates the conception of a limited universe, 

 ellipsoidal in form. The almanack would, no doubt, 

 prove interesting and instructive if prominently dis- 

 played in the class-rooms of elementarv schools. 



In the first few copies issued of both " The Stars 

 of the Year " (p. 7), and " The Star Almanack," there 

 occurred a slip which gave the earth's orbital velocity 

 as its velocity of rotation. In the later issues the 

 latter is given correctly, and the publishers offer to 

 exchange uncorrected copies returned to them. 



W. E. ROLSTON. 



Diptera Danica. Genera and Species of Flies hitherto 



found in Denmark. By William Lundbeck. Part 



ii., Asilidae, Bombyliidse, Therevidae, Scenopinid^e. 



With 48 figures. Published at the expense of the 



Carlsberg Fund. (Copenhagen : G. E. C. Gad ; 



London : W. Wesley and Son, igo8.) 



This useful and carefully written fauna commences 



with a lengthy account of the structure and habits 



of the interesting family Asilida;, or robber-flies, as 



the American entomologists call them. The author 



is inclined to believe that the powerful beak with 



which they attack their prey carries a poisonous 



secretion, but this remains to be proved by further 



observations. The systematic portion of the work is 



well done, the subfamilies, genera, and species being 



tabulated as well as described. The figures represent 



details, such as the head, antenna, or wing of various 



species, and full information is given as regards 



structure, habits, larva, distribution in Denmark and 



elsewhere, &c. One of the largest and handsomest 



of the .Asilidae, in Britain and Denmark, is Asilus 



crabroniformis, which is remarkable for its black and 



