NA TURE 



[December 17, 1908 



ago by the solid-stem type of thermometer had it 

 not been for the fact that it is nearly impossible to 

 make clear fine divisions on the kind of glass of 

 which these thermometers are usually made. The 

 sensitiveness, length of degree, size of bulb, &c., 

 of thermometers for calorimetric purposes are dealt 

 with in detail, the authors' conclusions being closely 

 in accord with the recommendations of the Bureau 

 International des Poids et M^sures. 



The chapter dealing with the " cooling correction " 

 is specially valuable, particularly the clearly described 

 way of graphically applying the Regnault-Pfaundler 

 method. 



In the chapter on specific-heat determination. Prof. 

 Louguinine's tramway calorimeter is described. De- 

 tails are given as to the curious fact, known to most 

 who have worked at the subject, that it is extremely 

 difficult in any form of vapour-heated vessel to ar- 

 range that the substance to be heated really reaches 

 the temperature of the heating vapour employed, even 

 if this be a vapour like steam, with a relatively 

 enormous latent heat. A list of suitable substances 

 for attaining various steady temperatures is also given. 



An interesting chapter by Prof. Schukarew deals 

 with some modifications of the Joly calorimeter, pre- 

 senting some obvious advantages and giving increased 

 precision. 



In conclusion, we may say that the book is well got 

 up, and the illustrations are numerous and excellent. 

 A fault, however, is the large number of misprints 

 and errata, many of which are not corrected in the 

 list given at the end. It is startling to find many 

 proper names, some those of leading authorities in 

 the domain of heat — such as Bunsen, Velten, Cal- 

 lendar, Plattner, Wiedemann, Walferdin, GritTiths, 

 and Dielerici — mis-spelt time after time. 



J. A. H.\RKF.R. 



TROPICAL AGRICILTURE. 

 Southern Agriculture. By F. S. Earle. Pp. vi-l-2g7. 

 (New York : The Macmillan Co. ; London : Mac- 

 millan and Co., Ltd., 1908.) Price 55. net. 

 TT'OR many years there was a noteworthy dearth 

 J- of books in English dealing generally with 

 agricultural methods in the tropics and subtropics, and 

 affording a concise summary of our knowledge of 

 the plants of those regions. The information, it is 

 true, was available in published form, but scattered 

 in handbooks and pamphlets on particular plants and 

 subjects, or buried in the files of numerous botanical 

 and agricultural journals, so that those not actually 

 engaged in the subject often found considerable and 

 at times insuperable difficulties in obtaining a good, 

 practical account of, for example, the principal fruits 

 or the fibre-producing plants of warm countries. 



To the still comparatively small series of books 

 which supply such information, " Southern Agricul- 

 ture," by F. S. Earle, is the latest addition. It does 

 not profess to cover the whole range of tropical agri- 

 culture—which, indeed, would not be practicable in 

 a volume of its size— but it so happens that the con- 

 ditions in the southern States and the American pos- 

 sessions in the West Indies are so diverse, ranging 

 NO. 2042, VOL. 79] 



from normal and arid subtropical regions to the 

 thoroughly tropical West Indian islands, that the book 

 will prove of utility to a much wider circle than 

 those immediately interested in the area with which 

 it specifically deals. This is particularly marked in 

 the first part of the book, entitled " General Con- 

 siderations." Here Mr. Earle has given us the benefit 

 of his experience in various lands, and in dealing, for 

 instance, with such subjects as irrigation he brings 

 out well the principles underlying practice in countries 

 possessing very different conditions, explains how irri- 

 gation may be of value in humid as well as in dry 

 countries, and gives useful descriptions of the methods 

 in vogue in various districts. Other sections in this 

 part which should be of wide interest are those re- 

 lating to the improvement of the soil, marketing 

 products, farm policy and management, and plant 

 diseases. The division of plant diseases into three 

 general groups — environmental, functional, and 

 diseases due to parasites — and the clear discussion of 

 the methods of dealing with each group will serve 

 to illustrate the successful attempt to make the work 

 more than a mere compilation of facts. 



The second part, " The Chief Southern Agricultural 

 Crops," is somewhat unequal in its treatment, but 

 this is apparently in the main intentional, and is 

 correlated with the relative local importance of the 

 plants. .Sugar-cane, the cereals, pasture and forage 

 crops, tobacco, cotton, and, in particular, the fruits, 

 are dealt with at considerable length, an account being 

 given, not onlv of their botanical identity and mode 

 of cultivation, but also of their principal pests, both 

 insect and fungoid. Coffee and cacao are less fully 

 treated, the large group of vegetables are disposed 

 of in a few pages under the name of " Truck Crops," 

 and a few notes on forestry and domestic animals 

 conclude the volume. 



The book contains the best account available, within 

 small compass, of the agriculture of the warmer 

 regions of North .America and the West Indies, and, 

 as already indicated, has in addition many features 

 which will ensure it being of use also in other parts 

 of the world. W. G. Freeman. 



ANALYTICAL CHEMISTRY. 



Qualitative .Analyse voni Standpunktc dcr loncnlchrc. 

 By Dr. Wilhelm Bottger. Second, revised and 

 greatly enlarged edition. Pp. xvi-l-524. (Leipzig : 

 Wilhelm Engelmann, 1908.) Price 10 marks. 



IN the second edition of this book, which made its 

 first appearance in 1902, the author has made very 

 considerable additions, resulting in an appro.ximate 

 doubling of the original size. As the title indicates, it 

 is written from the point of view of the theory of elec- 

 trolytic dissociation. This fact, in itself, may be suffi- 

 cient to condemn the book in the opinion of the 

 chemists of the anti-ionic school, but there can be no 

 doubt that the basis furnished by the ionic theory is 

 the one which at present must be recognised as 

 meeting with the approval of the great majority of 

 scientific chemists. 

 The arrangement of the subject-matter is such that 



