3^4 



NA TURE 



[January 27, 1910 



of instruction begins with a series of introductory 

 exercises on such fundamental principles as the nature 

 of physical and chemical changes, the common 

 elements and some of their typical compounds, and the 

 processes of combustion, oxidation, reduction, &c. 

 Detailed explanations are to be supplied by the 

 demonstrator, who is also supposed to carry out the 

 more difficult experiments, and to devise the simple 

 apparatus required by the student. 



Simple volumetric analysis is introduced at an early 

 stage, but, unfortunately, the underlying principle of 

 equivalence is not adequately explained. Two 

 definitions of equivalent weight are given on p. 54, 

 one referring to acids, and the other to bases and 

 salts. In the latter, equivalent weight is stated to be 

 the molecular weight divided by the sum of the 

 valencies of the metallic radicle. This definition is not 

 applicable to potassium permanganate, an important 

 reagent generally introduced into an elementary 

 course of volumetric analysis. The working in- 

 structions for the volumetric analysis and for the 

 determination of equivalents and atomic weights are 

 excellent, and make for neatness and accuracy in 

 quantitative exercises. There are a few singular 

 omissions in the general practical course ; formic acid 

 is not indicated as a source of pure carbon monoxide, 

 and although the interaction of copper and hot con- 

 centrated sulphuric acid is mentioned thrice, on pp. 13, 

 92, and 98, no reference is made to the cuprous sulphide 

 which is produced as a bye-product together with 

 copper sulphate. 



The last chapter is devoted to qualitative 

 analysis, and contains the practical details of the dry 

 and wet tests for the commonly occurring metals and 

 acids, without equations or other theoretical explana- 

 tions. 



Although an experienced teacher could select, from 

 the large number of practical exercises contained in 

 this treatise, a typical set suitable for an elementary 

 course, yet it would certainly be necessary to add a 

 few simple gravimetric processes such as the estima- 

 tion of iron, copper, chlorine, or sulphate. Otherwise, 

 the student's practical experience would be sadly 

 lacking in balance, for while having had an op- 

 portunity of attempting the preparation of com- 

 paratively uncommon compounds, such as phosphine 

 and periodic and bromic acids, he might remain 

 ignorant of the methods of elementary gravimetric 

 analysis. 



(2) The author of the second volume under review 

 is of opinion that an elementary practical book should 

 contain more complete explanations than are generally 

 given. This course also begins with the practical 

 study of the non-metallic elements and their typical 

 compounds, but some of this introductory work may 

 be omitted by students who have an opportunity of 

 seeing these experiments demonstrated on the lecture 

 table. The work on the non-metals is followed by 

 the preparation of typical compounds of the metals. 

 These exercises are of special interest to medical and 

 dental students, as a knowledge of the preparations 

 given in detail is required by the syllabus of the 

 Conjoint Board. The list of preparations would be 

 considerably improved by the inclusion of a few double 

 NO. 2100, VOL. 82] 



salts (such as ferrous ammonium sulphate and the 

 alums), some of which are quite suitable for an 

 elementary course. The qualitative tests for the 

 metals and acids are described in considerable detail, 

 equations being given for the more important chemical 

 changes, together with a summary relating to each 

 metal and its notable compounds. Although this part 

 of the book is fairly comprehensive, the tests for nickel 

 and cobalt and for boric and hydrofluoric acids are 

 omitted. In other respects, the qualitative analysis is. 

 quite adequately treated in a systematic manner, and 

 the tables are remarkably free from errors. On p. 94 the 

 interaction of a silver salt and sodium hydroxide gives 

 the oxide Ag,0, whereas on p. 14S the product is said 

 to be the hydroxide AgOH. The first reaction on 

 p. 112 refers to stannous sulphide. 



The last chapter contains a brief introduction to 

 quantitative analysis, dealing chiefly with volumetric 

 processes. 



{3) The third of the foregoing books has been 

 re-written to meet the present requirements of the 

 Board of Education as regards the elementary stage 

 of practical inorganic chemistry. A description of the 

 properties of some common substances leads up to 

 elementary experiments consisting of observational 

 work and simple quantitative exercises. Full working 

 details are given as well as theoretical explanations. 

 The book is admirably suited to the work of the 

 elementary stage. G. T. M. 



OUR BOOK SHELF. 

 Balhy-oro graphical Wall Maps of the Pacific, Atlan- 

 tic and Indian Oceans. (Edinburgh and London : 

 \V. and A. K. Johnston, Ltd.) Price 12s. each. 

 These maps of the oceans are on MoUweide's equal- 

 area projection. The elevations and depressions 

 shown are at 6000, 1500, Ooo feet, and below sea-level 

 on the land, while 100, 1000, 2000, 3000, and 4000 

 fathoms are represented over the sea area. 



The elevations shown on the land are scarcely 

 sufficient for the purpose for which these maps arc 

 undoubtedly intended, the study of the build of con- 

 tinents, but the sea depths should render them useful 

 to teachers. 



Many points are admirably illustrated. The oceanic 

 islands are well shown as the culminating summits 

 of ridges, and the use of such maps should help to 

 correct the erroneous notions often prevalent as to the 

 position of island groups. 



The complicated series of islands in the Pacific 

 Ocean can only he understood by reference to a clear 

 ocean map. For example, the islands known as 

 Melanesia, which rest on the submarine plateau to 

 the east of .Australia, can be seen to have an intimate 

 connection with the mainland, with which they were 

 once connected. On the outer fringe of these islands 

 are the Solomon Islands and New Hebrides, and the 

 Mikronesian group from the Caroline Islands to the 

 Tonga Islands. 



Further to the east the South Pacific chain suggests 

 a possible land connection in former ages between 

 South America and Australia, which may account for 

 the migration of marsupial and land tortoises from 

 one coast to the other. 



The fringing chains of islands which extend on 

 the north-west of the Pacific from Formosa to .Alaska 

 are admirably shown on this map, in contrast to the 

 deep depressions known as the Tuscarora and Aleutian 

 trenches. 



